Linux 6.12 compatibility

config/kernel-file.m4

@@ -0,0 +1,31 @@
+dnl #
+dnl # 6.12 removed f_version from struct file
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_SRC_FILE_F_VERSION], [
+	ZFS_LINUX_TEST_SRC([file_f_version], [
+		#include <linux/fs.h>
+
+		static const struct f __attribute__((unused)) = {
+			.f_version = 0;
+		};
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_FILE_F_VERSION], [
+	AC_MSG_CHECKING([whether file->f_version exists])
+	ZFS_LINUX_TEST_RESULT([file_f_version], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_FILE_F_VERSION, 1,
+		    [file->f_version exists])
+	], [
+		AC_MSG_RESULT(no)
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_FILE], [
+	ZFS_AC_KERNEL_FILE_F_VERSION
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_SRC_FILE], [
+	ZFS_AC_KERNEL_SRC_FILE_F_VERSION
+])

config/kernel-kthread.m4

@@ -15,20 +15,32 @@ AC_DEFUN([ZFS_AC_KERNEL_KTHREAD_COMPLETE_AND_EXIT], [
 	])
 ])
 
-AC_DEFUN([ZFS_AC_KERNEL_KTHREAD_DEQUEUE_SIGNAL_4ARG], [
+AC_DEFUN([ZFS_AC_KERNEL_KTHREAD_DEQUEUE_SIGNAL], [
 	dnl #
 	dnl # 5.17 API: enum pid_type * as new 4th dequeue_signal() argument,
 	dnl # 5768d8906bc23d512b1a736c1e198aa833a6daa4 ("signal: Requeue signals in the appropriate queue")
 	dnl #
 	dnl # int dequeue_signal(struct task_struct *task, sigset_t *mask, kernel_siginfo_t *info);
 	dnl # int dequeue_signal(struct task_struct *task, sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type);
 	dnl #
+	dnl # 6.12 API: first arg struct_task* removed
+	dnl # int dequeue_signal(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type);
+	dnl #
 	AC_MSG_CHECKING([whether dequeue_signal() takes 4 arguments])
-	ZFS_LINUX_TEST_RESULT([kthread_dequeue_signal], [
+	ZFS_LINUX_TEST_RESULT([kthread_dequeue_signal_4arg], [
 		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_DEQUEUE_SIGNAL_4ARG, 1, [dequeue_signal() takes 4 arguments])
+		AC_DEFINE(HAVE_DEQUEUE_SIGNAL_4ARG, 1,
+		    [dequeue_signal() takes 4 arguments])
 	], [
 		AC_MSG_RESULT(no)
+		AC_MSG_CHECKING([whether dequeue_signal() a task argument])
+		ZFS_LINUX_TEST_RESULT([kthread_dequeue_signal_3arg_task], [
+			AC_MSG_RESULT(yes)
+			AC_DEFINE(HAVE_DEQUEUE_SIGNAL_3ARG_TASK, 1,
+			    [dequeue_signal() takes a task argument])
+		], [
+			AC_MSG_RESULT(no)
+		])
 	])
 ])
 
@@ -43,8 +55,19 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_KTHREAD_COMPLETE_AND_EXIT], [
 	])
 ])
 
-AC_DEFUN([ZFS_AC_KERNEL_SRC_KTHREAD_DEQUEUE_SIGNAL_4ARG], [
-	ZFS_LINUX_TEST_SRC([kthread_dequeue_signal], [
+AC_DEFUN([ZFS_AC_KERNEL_SRC_KTHREAD_DEQUEUE_SIGNAL], [
+	ZFS_LINUX_TEST_SRC([kthread_dequeue_signal_3arg_task], [
+		#include <linux/sched/signal.h>
+	], [
+		struct task_struct *task = NULL;
+		sigset_t *mask = NULL;
+		kernel_siginfo_t *info = NULL;
+		int error __attribute__ ((unused));
+
+		error = dequeue_signal(task, mask, info);
+	])
+
+	ZFS_LINUX_TEST_SRC([kthread_dequeue_signal_4arg], [
 		#include <linux/sched/signal.h>
 	], [
 		struct task_struct *task = NULL;
@@ -59,10 +82,10 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_KTHREAD_DEQUEUE_SIGNAL_4ARG], [
 
 AC_DEFUN([ZFS_AC_KERNEL_KTHREAD], [
 	ZFS_AC_KERNEL_KTHREAD_COMPLETE_AND_EXIT
-	ZFS_AC_KERNEL_KTHREAD_DEQUEUE_SIGNAL_4ARG
+	ZFS_AC_KERNEL_KTHREAD_DEQUEUE_SIGNAL
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_SRC_KTHREAD], [
 	ZFS_AC_KERNEL_SRC_KTHREAD_COMPLETE_AND_EXIT
-	ZFS_AC_KERNEL_SRC_KTHREAD_DEQUEUE_SIGNAL_4ARG
+	ZFS_AC_KERNEL_SRC_KTHREAD_DEQUEUE_SIGNAL
 ])

config/kernel-mm-page-flags.m4

@@ -0,0 +1,24 @@
+AC_DEFUN([ZFS_AC_KERNEL_SRC_MM_PAGE_FLAG_ERROR], [
+	ZFS_LINUX_TEST_SRC([mm_page_flag_error], [
+		#include <linux/page-flags.h>
+
+		static enum pageflags
+		    test_flag __attribute__((unused)) = PG_error;
+	])
+])
+AC_DEFUN([ZFS_AC_KERNEL_MM_PAGE_FLAG_ERROR], [
+	AC_MSG_CHECKING([whether PG_error flag is available])
+	ZFS_LINUX_TEST_RESULT([mm_page_flag_error], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_MM_PAGE_FLAG_ERROR, 1, [PG_error flag is available])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_SRC_MM_PAGE_FLAGS], [
+	ZFS_AC_KERNEL_SRC_MM_PAGE_FLAG_ERROR
+])
+AC_DEFUN([ZFS_AC_KERNEL_MM_PAGE_FLAGS], [
+	ZFS_AC_KERNEL_MM_PAGE_FLAG_ERROR
+])

config/kernel.m4

@@ -125,8 +125,10 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
 	ZFS_AC_KERNEL_SRC_PROC_HANDLER_CTL_TABLE_CONST
 	ZFS_AC_KERNEL_SRC_COPY_SPLICE_READ
 	ZFS_AC_KERNEL_SRC_SYNC_BDEV
+	ZFS_AC_KERNEL_SRC_MM_PAGE_FLAGS
 	ZFS_AC_KERNEL_SRC_MM_PAGE_SIZE
 	ZFS_AC_KERNEL_SRC_MM_PAGE_MAPPING
+	ZFS_AC_KERNEL_SRC_FILE
 	case "$host_cpu" in
 		powerpc*)
 			ZFS_AC_KERNEL_SRC_CPU_HAS_FEATURE
@@ -235,9 +237,11 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
 	ZFS_AC_KERNEL_PROC_HANDLER_CTL_TABLE_CONST
 	ZFS_AC_KERNEL_COPY_SPLICE_READ
 	ZFS_AC_KERNEL_SYNC_BDEV
+	ZFS_AC_KERNEL_MM_PAGE_FLAGS
 	ZFS_AC_KERNEL_MM_PAGE_SIZE
 	ZFS_AC_KERNEL_MM_PAGE_MAPPING
 	ZFS_AC_KERNEL_1ARG_ASSIGN_STR
+	ZFS_AC_KERNEL_FILE
 	case "$host_cpu" in
 		powerpc*)
 			ZFS_AC_KERNEL_CPU_HAS_FEATURE

include/os/linux/kernel/linux/mm_compat.h

@@ -40,4 +40,18 @@
 #define	page_mapping(p) folio_mapping(page_folio(p))
 #endif
 
+/*
+ * 6.12 removed PG_error, SetPageError and ClearPageError, with no direct
+ * replacement, because page writeback errors are recorded elsewhere. Since we
+ * only use the page cache to assist with mmap(), never directly backing it
+ * with IO, it shouldn't be possible for this condition to occur on our pages
+ * anyway, even if this is the right way to report it. So it should be safe
+ * to remove, but for avoidance of doubt, we make it a no-op on 6.12 and leave
+ * it for everything else.
+ */
+#ifndef HAVE_MM_PAGE_FLAG_ERROR
+#define	SetPageError(p)		do {} while (0)
+#define	ClearPageError(p)	do {} while (0)
+#endif
+
 #endif /* _ZFS_MM_COMPAT_H */

include/os/linux/kernel/linux/vfs_compat.h

@@ -68,7 +68,11 @@ lseek_execute(
 	loff_t offset,
 	loff_t maxsize)
 {
+#ifdef FMODE_UNSIGNED_OFFSET
 	if (offset < 0 && !(filp->f_mode & FMODE_UNSIGNED_OFFSET))
+#else
+	if (offset < 0 && !(filp->f_op->fop_flags & FOP_UNSIGNED_OFFSET))
+#endif
 		return (-EINVAL);
 
 	if (offset > maxsize)
@@ -77,7 +81,9 @@ lseek_execute(
 	if (offset != filp->f_pos) {
 		spin_lock(&filp->f_lock);
 		filp->f_pos = offset;
+#ifdef HAVE_FILE_F_VERSION
 		filp->f_version = 0;
+#endif
 		spin_unlock(&filp->f_lock);
 	}
 

include/os/linux/spl/sys/kmem_cache.h

@@ -200,6 +200,7 @@ extern uint64_t spl_kmem_cache_entry_size(kmem_cache_t *cache);
 
 /* Avoid conflicts with kernel names that might be implemented as macros. */
 #undef	kmem_cache_alloc
+#undef	kmem_cache_create
 
 #define	kmem_cache_create(name, size, align, ctor, dtor, rclm, priv, vmp, fl) \
     spl_kmem_cache_create(name, size, align, ctor, dtor, rclm, priv, vmp, fl)

module/os/linux/spl/spl-thread.c

@@ -162,20 +162,22 @@ issig(void)
 	if (!signal_pending(current))
 		return (0);
 
-	struct task_struct *task = current;
 	spl_kernel_siginfo_t __info;
 	sigset_t set;
 	siginitsetinv(&set, 1ULL << (SIGSTOP - 1) | 1ULL << (SIGTSTP - 1));
-	sigorsets(&set, &task->blocked, &set);
+	sigorsets(&set, &current->blocked, &set);
 
-	spin_lock_irq(&task->sighand->siglock);
-#ifdef HAVE_DEQUEUE_SIGNAL_4ARG
+	spin_lock_irq(&current->sighand->siglock);
+#if defined(HAVE_DEQUEUE_SIGNAL_4ARG)
 	enum pid_type __type;
-	if (dequeue_signal(task, &set, &__info, &__type) != 0) {
+	if (dequeue_signal(current, &set, &__info, &__type) != 0) {
+#elif defined(HAVE_DEQUEUE_SIGNAL_3ARG_TASK)
+	if (dequeue_signal(current, &set, &__info) != 0) {
 #else
-	if (dequeue_signal(task, &set, &__info) != 0) {
+	enum pid_type __type;
+	if (dequeue_signal(&set, &__info, &__type) != 0) {
 #endif
-		spin_unlock_irq(&task->sighand->siglock);
+		spin_unlock_irq(&current->sighand->siglock);
 		kernel_signal_stop();
 
 		/*
@@ -188,7 +190,7 @@ issig(void)
 		return (0);
 	}
 
-	spin_unlock_irq(&task->sighand->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	return (1);
 }

module/os/linux/zfs/zfs_znode_os.c

@@ -58,6 +58,7 @@
 #include <sys/sa.h>
 #include <sys/zfs_sa.h>
 #include <sys/zfs_stat.h>
+#include <linux/mm_compat.h>
 
 #include "zfs_prop.h"
 #include "zfs_comutil.h"