Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck...

[linux-2.6-microblaze.git] / kernel / task_work.c

diff --git a/kernel/task_work.c b/kernel/task_work.c
index 825f282..613b2d6 100644 (file)
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -25,9 +25,10 @@ static struct callback_head work_exited; /* all we need is ->next == NULL */
  * 0 if succeeds or -ESRCH.
  */
 int
-task_work_add(struct task_struct *task, struct callback_head *work, bool notify)
+task_work_add(struct task_struct *task, struct callback_head *work, int notify)
 {
        struct callback_head *head;
+       unsigned long flags;
 
        do {
                head = READ_ONCE(task->task_works);
@@ -36,8 +37,25 @@ task_work_add(struct task_struct *task, struct callback_head *work, bool notify)
                work->next = head;
        } while (cmpxchg(&task->task_works, head, work) != head);
 
-       if (notify)
+       switch (notify) {
+       case TWA_RESUME:
                set_notify_resume(task);
+               break;
+       case TWA_SIGNAL:
+               /*
+                * Only grab the sighand lock if we don't already have some
+                * task_work pending. This pairs with the smp_store_mb()
+                * in get_signal(), see comment there.
+                */
+               if (!(READ_ONCE(task->jobctl) & JOBCTL_TASK_WORK) &&
+                   lock_task_sighand(task, &flags)) {
+                       task->jobctl |= JOBCTL_TASK_WORK;
+                       signal_wake_up(task, 0);
+                       unlock_task_sighand(task, &flags);
+               }
+               break;
+       }
+
        return 0;
 }