diff options
| author | Ingo Molnar <mingo@kernel.org> | 2016-08-10 14:36:23 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-08-10 14:36:23 +0200 |
| commit | fdbdfefbabefcdf3f57560163b43fdc4cf95eb2f (patch) | |
| tree | 1d0c420d4eaff48cf2486f10dded8d551241ee94 /kernel/task_work.c | |
| parent | 6731b0d611a1274f9e785fa0189ac2aeeabd0591 (diff) | |
| parent | a0cba2179ea4c1820fce2ee046b6ed90ecc56196 (diff) | |
Merge branch 'linus' into timers/urgent, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/task_work.c')
| -rw-r--r-- | kernel/task_work.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/task_work.c b/kernel/task_work.c index 6ab4842b00e8..d513051fcca2 100644 --- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -29,7 +29,7 @@ task_work_add(struct task_struct *task, struct callback_head *work, bool notify) struct callback_head *head; do { - head = ACCESS_ONCE(task->task_works); + head = READ_ONCE(task->task_works); if (unlikely(head == &work_exited)) return -ESRCH; work->next = head; @@ -57,6 +57,9 @@ task_work_cancel(struct task_struct *task, task_work_func_t func) struct callback_head **pprev = &task->task_works; struct callback_head *work; unsigned long flags; + + if (likely(!task->task_works)) + return NULL; /* * If cmpxchg() fails we continue without updating pprev. * Either we raced with task_work_add() which added the @@ -64,8 +67,7 @@ task_work_cancel(struct task_struct *task, task_work_func_t func) * we raced with task_work_run(), *pprev == NULL/exited. */ raw_spin_lock_irqsave(&task->pi_lock, flags); - while ((work = ACCESS_ONCE(*pprev))) { - smp_read_barrier_depends(); + while ((work = lockless_dereference(*pprev))) { if (work->func != func) pprev = &work->next; else if (cmpxchg(pprev, work, work->next) == work) @@ -95,7 +97,7 @@ void task_work_run(void) * work_exited unless the list is empty. */ do { - work = ACCESS_ONCE(task->task_works); + work = READ_ONCE(task->task_works); head = !work && (task->flags & PF_EXITING) ? &work_exited : NULL; } while (cmpxchg(&task->task_works, work, head) != work); |