55//!
66//! How to build only modules:
77//! make LLVM=1 M=samples/rust
8- use core:: marker:: PhantomPinned ;
8+ //!
9+ //! How to use:
10+ //! / # insmod rust_ldd06.ko
11+ //! / # mknod /dev/rust_ldd06 c 10 124
12+ //! / # echo "hello" > /dev/rust_ldd06
13+ //! / # cat /dev/rust_ldd06
914use kernel:: prelude:: * ;
1015use kernel:: {
1116 bindings,
1217 file:: { self , File } ,
1318 fmt,
1419 io_buffer:: { IoBufferReader , IoBufferWriter } ,
15- miscdev, pin_init,
16- sync:: { Arc , ArcBorrow } ,
17- types:: Opaque ,
20+ miscdev, new_mutex, pin_init,
21+ sync:: { Arc , ArcBorrow , Mutex } ,
1822} ;
1923
2024module ! {
@@ -25,24 +29,40 @@ module! {
2529 license: "GPL" ,
2630}
2731
32+ // Fist I made CompletionDev { completion: bindings::completion }.
33+ // But it didn't work because we cannot get mutable reference to CompletionDev in read/write functions.
34+ // The argument of read/write functions is ArcBorrow<'_, CompletionDev>.
35+ // So it's not allowed to get the mutable reference to CompletionDev.
36+ // The only way to mutate through ArcBorrow is to use Mutex/RwLock/Atomic types.
37+ // (see doc.rust-lang.org/std/sync/struct.Mutex.html)
38+ // Finally I makde CompletionInner struct and put it into Mutex.
39+ struct CompletionInner {
40+ completion : bindings:: completion ,
41+ dummy : usize , // nothing but to check how to use Mutex
42+ }
43+
2844// internal info between file operations
2945#[ pin_data]
3046struct CompletionDev {
3147 pub completion : bindings:: completion ,
3248
3349 #[ pin]
34- _pin : PhantomPinned ,
50+ inner : Mutex < CompletionInner > ,
3551}
3652
3753// TODO: impl CompletionDev::try_new
3854impl CompletionDev {
3955 fn try_new ( ) -> Result < Arc < Self > > {
4056 pr_info ! ( "completion_dev created\n " ) ;
41-
42- Ok ( Arc :: try_new ( Self {
43- _pin : PhantomPinned ,
44- completion : bindings:: completion:: default ( ) ,
45- } ) ?)
57+ let dev = Arc :: pin_init ( pin_init ! ( Self {
58+ completion: bindings:: completion:: default ( ) , // Default trait is implmented by bindget. See rust/bindings/bindings_generates.rs
59+ inner <- new_mutex!( CompletionInner {
60+ completion: bindings:: completion:: default ( ) ,
61+ dummy: 0 ,
62+ } ) ,
63+ } ) ) ?;
64+
65+ Ok ( dev)
4666 }
4767}
4868
@@ -66,29 +86,51 @@ impl file::Operations for RustFile {
6686 fn read (
6787 shared : ArcBorrow < ' _ , CompletionDev > ,
6888 _: & File ,
69- data : & mut impl IoBufferWriter ,
70- offset : u64 ,
89+ _data : & mut impl IoBufferWriter ,
90+ _offset : u64 ,
7191 ) -> Result < usize > {
7292 pr_info ! ( "read is invoked\n " ) ;
7393
94+ let mut inner_guard = shared. inner . lock ( ) ;
95+ inner_guard. dummy += 1 ;
96+ pr_info ! ( "read:dummy={}\n " , inner_guard. dummy) ;
97+
98+ unsafe {
99+ bindings:: wait_for_completion ( & mut inner_guard. completion ) ;
100+ }
101+
74102 Ok ( 0 )
75103 }
76104
77105 fn write (
78106 shared : ArcBorrow < ' _ , CompletionDev > ,
79107 _: & File ,
80108 data : & mut impl IoBufferReader ,
81- offset : u64 ,
109+ _offset : u64 ,
82110 ) -> Result < usize > {
83111 pr_debug ! ( "write is invoked\n " ) ;
84112
85- let len: usize = data. len ( ) ;
86- pr_info ! ( "write: {} bytes\n " , len) ;
87- Ok ( len)
113+ let mut inner_guard = shared. inner . lock ( ) ;
114+ pr_info ! ( "write:dummy={}\n " , inner_guard. dummy) ;
115+ if inner_guard. dummy == 1 {
116+ pr_info ! ( "read() is waiting for completion\n " ) ;
117+
118+ unsafe {
119+ bindings:: complete ( & mut inner_guard. completion ) ;
120+ }
121+ } else if inner_guard. dummy == 0 {
122+ pr_info ! ( "read() is not waiting for completion\n " ) ;
123+ } else {
124+ pr_info ! ( "Something went wrong\n " ) ;
125+ }
126+
127+ // return non-zero value to avoid infinite re-try
128+ Ok ( data. len ( ) )
88129 }
89130
90- fn release ( _data : Self :: Data , _file : & File ) {
131+ fn release ( data : Self :: Data , _file : & File ) {
91132 pr_info ! ( "release is invoked\n " ) ;
133+ pr_info ! ( "release:dummy={}\n " , data. inner. lock( ) . dummy) ;
92134 }
93135}
94136
@@ -101,6 +143,7 @@ impl kernel::Module for RustCompletion {
101143 pr_info ! ( "rust_ldd06 is loaded\n " ) ;
102144
103145 let dev: Arc < CompletionDev > = CompletionDev :: try_new ( ) ?;
146+
104147 let reg = miscdev:: Registration :: new_pinned ( fmt ! ( "rust_ldd06" ) , dev) ?;
105148
106149 Ok ( RustCompletion { _dev : reg } )
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