io_uring: check if opcode needs poll first on arming

->pollout or ->pollin are set only for opcodes that need a file, so if
io_arm_poll_handler() tests them first we can be sure that the request
has file set and the ->file check can be removed.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9adfe4f543d984875e516fce6da35348aab48668.1634987320.git.asml.silence@gmail.comReviewed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -5584,12 +5584,10 @@ static int io_arm_poll_handler(struct io_kiocb *req)
 	struct io_poll_table ipt;
 	__poll_t ret, mask = EPOLLONESHOT | POLLERR | POLLPRI;
 
-	if (!req->file || !file_can_poll(req->file))
-		return IO_APOLL_ABORTED;
-	if (req->flags & REQ_F_POLLED)
-		return IO_APOLL_ABORTED;
 	if (!def->pollin && !def->pollout)
 		return IO_APOLL_ABORTED;
+	if (!file_can_poll(req->file) || (req->flags & REQ_F_POLLED))
+		return IO_APOLL_ABORTED;
 
 	if (def->pollin) {
 		mask |= POLLIN | POLLRDNORM;