This is a note to let you know that I've just added the patch titled
io_uring: treat -EAGAIN for REQ_F_NOWAIT as final for io-wq
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
io_uring-treat-eagain-for-req_f_nowait-as-final-for-io-wq.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a9be202269580ca611c6cebac90eaf1795497800 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@xxxxxxxxx>
Date: Thu, 20 Jul 2023 13:16:53 -0600
Subject: io_uring: treat -EAGAIN for REQ_F_NOWAIT as final for io-wq
From: Jens Axboe <axboe@xxxxxxxxx>
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@xxxxxxxxxxxxxxx # 5.10+
Link: https://github.com/axboe/liburing/issues/897
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
io_uring/io_uring.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2032,6 +2032,14 @@ fail:
ret = io_issue_sqe(req, issue_flags);
if (ret != -EAGAIN)
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;
+
/*
* We can get EAGAIN for iopolled IO even though we're
* forcing a sync submission from here, since we can't
Patches currently in stable-queue which might be from axboe@xxxxxxxxx are
queue-6.4/io_uring-fix-io_uring-mmap-by-using-architecture-provided-get_unmapped_area.patch
queue-6.4/io_uring-treat-eagain-for-req_f_nowait-as-final-for-io-wq.patch
