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alloc
: add unstable cfg features no_rc
and no_sync
#89891
Conversation
r? @kennytm (rust-highfive has picked a reviewer for you, use r? to override) |
@nbdd0121 since he suggested it. |
@rustbot label +T-libs-api |
The rust/library/alloc/src/sync.rs Line 37 in 5e02151
rust/library/alloc/src/sync.rs Line 2134 in 5e02151
and the rust/library/alloc/src/task.rs Line 6 in 5e02151
I think the and |
Yeah, these were the minimum changes without worrying about inter-dependencies. Do we want to keep all possible combinations working and maintained if we keep adding this sort of flags (in the extreme, for every module)? If yes, could we leverage the compiler to do it for us? For instance, marking modules to create a partition on: #[modular_crate]
pub mod rc;
pub mod slice;
pub mod str;
pub mod string;
#[modular_crate]
pub mod sync; And then the |
The The
|
So my question was whether we want to promise that every single combination of If yes, one option is to have flags override others automatically, but that may be surprising, especially since these are negative (e.g. someone explicitly requested to remove Thus it may be reasonable to only allow a subset of combinations instead, with the constraints encoded somewhere. From what I see, the Cargo docs suggest using
That is definitely a good idea, will do. However, those PRs do not have a test for every combination, unless I am missing something. |
Unless there is something like |
Right now, I don't think we're prepared to promise that any of those flags work. :) If we want to stabilize these, we'll need to make the specific stability promise clear and any dependencies explicit. Until then, I think it's fine if these only work if used as tested. |
☔ The latest upstream changes (presumably #90542) made this pull request unmergeable. Please resolve the merge conflicts. |
@ojeda if you can resolve the conflicts we can get this merged |
@ojeda |
@Dylan-DPC @JohnCSimon Thanks for the ping and apologies for the delay. Rebased, added missing gates to allow for independent compilation of each flag, added a |
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You will need to add no_rc and no_sync to the array at Line 197 in 64137f0
|
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: #2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles warning-free under `no_global_oom_handling` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: #2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: Rust-for-Linux/linux#2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: rust-lang/rust#106142 [4] Link: rust-lang/rust#89891 [5] Link: rust-lang/rust#98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
In Rust for Linux we are using these to make
alloc
a bit more modular.See #86048 and #84266 for similar requests.
Of course, the particular names are not important.