io_uring: don't do extra EXITING cancellations

io_match_task() matches all requests with PF_EXITING task, even though
those may be valid requests. It was necessary for SQPOLL cancellation,
but now it kills all requests before exiting via
io_uring_cancel_sqpoll(), so it's not needed.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -1079,12 +1079,8 @@ static bool io_match_task(struct io_kiocb *head,
 {
 	struct io_kiocb *req;
 
-	if (task && head->task != task) {
-		/* in terms of cancelation, always match if req task is dead */
-		if (head->task->flags & PF_EXITING)
-			return true;
+	if (task && head->task != task)
 		return false;
-	}
 	if (!files)
 		return true;