Linux 6.12: support 3arg dequeue_signal() without task param

See torvalds/linux@a2b80ce87a87. It claims the task arg is always `current`, and so it is with us, so this is a safe change to make. The only spanner is that we also support the older pre-5.17 3-arg dequeue_signal() which had different meaning, so we have to check the types to get the right one. Sponsored-by: https://despairlabs.com/sponsor/ Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Rob Norris <robn@despairlabs.com> Closes openzfs#16582
darkbasic · Nov 16, 2024 · 2999a90 · 2999a90
1 parent 25ca775
commit 2999a90
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Showing 2 changed files with 40 additions and 15 deletions.
diff --git a/config/kernel-kthread.m4 b/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
 ])
diff --git a/module/os/linux/spl/spl-thread.c b/module/os/linux/spl/spl-thread.c
@@ -172,21 +172,23 @@ issig(int why)
 	if (why != FORREAL)
 		return (1);
 
-	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
 #ifdef HAVE_SIGNAL_STOP
-		spin_unlock_irq(&task->sighand->siglock);
+		spin_unlock_irq(&current->sighand->siglock);
 		kernel_signal_stop();
 #else
 		if (current->jobctl & JOBCTL_STOP_DEQUEUED)
@@ -199,7 +201,7 @@ issig(int why)
 		return (0);
 	}
 
-	spin_unlock_irq(&task->sighand->siglock);
+	spin_unlock_irq(&current->sighand->siglock);
 
 	return (1);
 }