From: Jens Axboe axboe@kernel.dk
[ Upstream commit 03941ccfda161c2680147fa5ab92aead2a79cac1 ]
All archs now support TIF_NOTIFY_SIGNAL.
Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/task_work.c | 30 +----------------------------- 1 file changed, 1 insertion(+), 29 deletions(-)
--- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -5,34 +5,6 @@
static struct callback_head work_exited; /* all we need is ->next == NULL */
-/* - * TWA_SIGNAL signaling - use TIF_NOTIFY_SIGNAL, if available, as it's faster - * than TIF_SIGPENDING as there's no dependency on ->sighand. The latter is - * shared for threads, and can cause contention on sighand->lock. Even for - * the non-threaded case TIF_NOTIFY_SIGNAL is more efficient, as no locking - * or IRQ disabling is involved for notification (or running) purposes. - */ -static void task_work_notify_signal(struct task_struct *task) -{ -#if defined(TIF_NOTIFY_SIGNAL) - set_notify_signal(task); -#else - unsigned long flags; - - /* - * 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); - } -#endif -} - /** * task_work_add - ask the @task to execute @work->func() * @task: the task which should run the callback @@ -76,7 +48,7 @@ int task_work_add(struct task_struct *ta set_notify_resume(task); break; case TWA_SIGNAL: - task_work_notify_signal(task); + set_notify_signal(task); break; default: WARN_ON_ONCE(1);