From 30b90689344b9f357dcbf9532973c1e749438c1c Mon Sep 17 00:00:00 2001
From: Dylan Yudaken <dylany@meta.com>
Date: Sat, 21 Jan 2023 09:13:12 -0700
Subject: [PATCH] io_uring: fix async accept on O_NONBLOCK sockets
commit a73825ba70c93e1eb39a845bb3d9885a787f8ffe upstream.
Do not set REQ_F_NOWAIT if the socket is non blocking. When enabled this
causes the accept to immediately post a CQE with EAGAIN, which means you
cannot perform an accept SQE on a NONBLOCK socket asynchronously.
By removing the flag if there is no pending accept then poll is armed as
usual and when a connection comes in the CQE is posted.
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220324143435.2875844-1-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
io_uring/io_uring.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 997a7264e1d4..e1e15d40d758 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -5272,9 +5272,6 @@ static int io_accept(struct io_kiocb *req, unsigned int issue_flags)
struct file *file;
int ret, fd;
- if (req->file->f_flags & O_NONBLOCK)
- req->flags |= REQ_F_NOWAIT;
-
if (!fixed) {
fd = __get_unused_fd_flags(accept->flags, accept->nofile);
if (unlikely(fd < 0))
@@ -5286,6 +5283,8 @@ static int io_accept(struct io_kiocb *req, unsigned int issue_flags)
if (!fixed)
put_unused_fd(fd);
ret = PTR_ERR(file);
+ /* safe to retry */
+ req->flags |= REQ_F_PARTIAL_IO;
if (ret == -EAGAIN && force_nonblock)
return -EAGAIN;
if (ret == -ERESTARTSYS)