From: Jens Axboe <axboe@kernel.dk>
Date: Sat, 3 Oct 2020 17:53:38 +0000 (-0600)
Subject: io_uring: avoid syscall restart for signal_pending(), if possible
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=refs%2Fheads%2Ftif-task_work.3;p=linux-2.6-block.git

io_uring: avoid syscall restart for signal_pending(), if possible

Same kind of optimization we have for the JOBCTL_TASK_WORK. This is safe
to do, as we're running task_work manually for this case.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/fs/io_uring.c b/fs/io_uring.c
index aae0ef2ec34d..ee8c1b6aeead 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6755,6 +6755,11 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 		if (io_run_task_work())
 			continue;
 		if (signal_pending(current)) {
+			/* avoid restart, if we can */
+#ifdef TIF_NOTIFY_SIGNAL
+			if (test_and_clear_thread_flag(TIF_NOTIFY_SIGNAL))
+				continue;
+#endif
 			if (current->jobctl & JOBCTL_TASK_WORK) {
 				spin_lock_irq(&current->sighand->siglock);
 				current->jobctl &= ~JOBCTL_TASK_WORK;