From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 20 Jul 2023 19:16:53 +0000 (-0600)
Subject: io_uring: treat -EAGAIN for REQ_F_NOWAIT as final for io-wq
X-Git-Tag: v5.15.124~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3359fdf49de48aa7ef898d0e52132d9ec561b741;p=thirdparty%2Fkernel%2Fstable.git

io_uring: treat -EAGAIN for REQ_F_NOWAIT as final for io-wq

commit a9be202269580ca611c6cebac90eaf1795497800 upstream.

io-wq assumes that an issue is blocking, but it may not be if the
request type has asked for a non-blocking attempt. If we get
-EAGAIN for that case, then we need to treat it as a final result
and not retry or arm poll for it.

Cc: stable@vger.kernel.org # 5.10+
Link: https://github.com/axboe/liburing/issues/897
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index f65c6811ede81..774b1ae8adf7c 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -7066,6 +7066,14 @@ static void io_wq_submit_work(struct io_wq_work *work)
 			 */
 			if (ret != -EAGAIN || !(req->ctx->flags & IORING_SETUP_IOPOLL))
 				break;
+
+			/*
+			 * If REQ_F_NOWAIT is set, then don't wait or retry with
+			 * poll. -EAGAIN is final for that case.
+			 */
+			if (req->flags & REQ_F_NOWAIT)
+				break;
+
 			cond_resched();
 		} while (1);
 	}