[PATCH 3/3] io_uring: tweak io_req_task_work_add

[Pavel Begunkov <asml.silence@gmail.com>]

Whenever possible we don't want to fallback a request. task_work_add()
will be fine if the task is exiting, so don't check for PF_EXITING,
there is anyway only a relatively small gap between setting the flag
and doing the final task_work_run().

Also add likely for the hot path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 5fab427305e3..1893a4229dbb 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1990,9 +1990,6 @@ static int io_req_task_work_add(struct io_kiocb *req)
 	unsigned long flags;
 	int ret = 0;
 
-	if (unlikely(tsk->flags & PF_EXITING))
-		return -ESRCH;
-
 	WARN_ON_ONCE(!tctx);
 
 	spin_lock_irqsave(&tctx->task_lock, flags);
@@ -2000,7 +1997,7 @@ static int io_req_task_work_add(struct io_kiocb *req)
 	spin_unlock_irqrestore(&tctx->task_lock, flags);
 
 	/* task_work already pending, we're done */
-	if (test_bit(0, &tctx->task_state) ||
+	if (likely(test_bit(0, &tctx->task_state)) ||
 	    test_and_set_bit(0, &tctx->task_state))
 		return 0;
 
@@ -2011,8 +2008,7 @@ static int io_req_task_work_add(struct io_kiocb *req)
 	 * will do the job.
 	 */
 	notify = (req->ctx->flags & IORING_SETUP_SQPOLL) ? TWA_NONE : TWA_SIGNAL;
-
-	if (!task_work_add(tsk, &tctx->task_work, notify)) {
+	if (likely(!task_work_add(tsk, &tctx->task_work, notify))) {
 		wake_up_process(tsk);
 		return 0;
 	}
-- 
2.32.0