FAILED: patch "[PATCH] io_uring: treat -EAGAIN for REQ_F_NOWAIT as final for io-wq" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x a9be202269580ca611c6cebac90eaf1795497800
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023072352-cage-carnage-b38a@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

a9be20226958 ("io_uring: treat -EAGAIN for REQ_F_NOWAIT as final for io-wq")
ed29b0b4fd83 ("io_uring: move to separate directory")
d01905db14eb ("io_uring: clean iowq submit work cancellation")
255657d23704 ("io_uring: clean io_wq_submit_work()'s main loop")
90fa02883f06 ("io_uring: implement async hybrid mode for pollable requests")
3b44b3712c5b ("io_uring: split logic of force_nonblock")
9882131cd9de ("io_uring: kill io_wq_current_is_worker() in iopoll")
9983028e7660 ("io_uring: optimise req->ctx reloads")
5e49c973fc39 ("io_uring: clean up io_import_iovec")
51aac424aef9 ("io_uring: optimise io_import_iovec nonblock passing")
c88598a92a58 ("io_uring: optimise read/write iov state storing")
538941e2681c ("io_uring: encapsulate rw state")
d886e185a128 ("io_uring: control ->async_data with a REQ_F flag")
30d51dd4ad20 ("io_uring: clean up buffer select")
ef05d9ebcc92 ("io_uring: kill off ->inflight_entry field")
6f33b0bc4ea4 ("io_uring: use slist for completion batching")
c450178d9be9 ("io_uring: dedup CQE flushing non-empty checks")
4c928904ff77 ("block: move CONFIG_BLOCK guard to top Makefile")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a9be202269580ca611c6cebac90eaf1795497800 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 20 Jul 2023 13:16:53 -0600
Subject: [PATCH] io_uring: treat -EAGAIN for REQ_F_NOWAIT as final for io-wq

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>

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index a9923676d16d..5e97235a82d6 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1948,6 +1948,14 @@ void io_wq_submit_work(struct io_wq_work *work)
 		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