UPSTREAM: 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.

Change-Id: I0fae3f75c7fbbf44f85da7d83f48c4cfed1fcae9
Signed-off-by: Dylan Yudaken <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Bug: 268174392
(cherry picked from commit aa4c9b3e45e234bc011bd26a045f6bdfd4783001)
Signed-off-by: Greg Kroah-Hartman <[email protected]>
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 91a177a..951a936 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -5122,9 +5122,6 @@ 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))
@@ -5137,6 +5134,8 @@ 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)