[PATCH 6.0 014/862] io_uring/rw: dont lose short results on io_setup_async_rw()

[Greg Kroah-Hartman]

From: Pavel Begunkov <asml.silence@xxxxxxxxx>

commit c278d9f8ac0db5590909e6d9e85b5ca2b786704f upstream.

If a retry io_setup_async_rw() fails we lose result from the first
io_iter_do_read(), which is a problem mostly for streams/sockets.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Link: https://lore.kernel.org/r/0e8d20cebe5fc9c96ed268463c394237daabc384.1664235732.git.asml.silence@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 io_uring/rw.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -794,10 +794,12 @@ int io_read(struct io_kiocb *req, unsign
 	iov_iter_restore(&s->iter, &s->iter_state);
 
 	ret2 = io_setup_async_rw(req, iovec, s, true);
-	if (ret2)
-		return ret2;
-
 	iovec = NULL;
+	if (ret2) {
+		ret = ret > 0 ? ret : ret2;
+		goto done;
+	}
+
 	io = req->async_data;
 	s = &io->s;
 	/*