io_uring: remove ctx variable in io_poll_check_events

ctx is only used by io_poll_check_events() for multishot poll CQE
posting, don't save it on stack in advance.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/552c1771f8a0e7688afdb4f538ead245f53e80e7.1669821213.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/poll.c

@@ -237,7 +237,6 @@ enum {
  */
 static int io_poll_check_events(struct io_kiocb *req, bool *locked)
 {
-	struct io_ring_ctx *ctx = req->ctx;
 	int v, ret;
 
 	/* req->task == current here, checking PF_EXITING is safe */
@@ -289,7 +288,7 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked)
 			__poll_t mask = mangle_poll(req->cqe.res &
 						    req->apoll_events);
 
-			if (!io_aux_cqe(ctx, *locked, req->cqe.user_data,
+			if (!io_aux_cqe(req->ctx, *locked, req->cqe.user_data,
 					mask, IORING_CQE_F_MORE, false)) {
 				io_req_set_res(req, mask, 0);
 				return IOU_POLL_REMOVE_POLL_USE_RES;