io_uring/net: fix notif cqe reordering

[ upstream commit 108893ddcc4d3aa0a4a02aeb02d478e997001227 ]

send zc is not restricted to !IO_URING_F_UNLOCKED anymore and so
we can't use task-tw ordering trick to order notification cqes
with requests completions. In this case leave it alone and let
io_send_zc_cleanup() flush it.

Cc: stable@vger.kernel.org
Fixes: 53bdc88aac9a2 ("io_uring/notif: order notif vs send CQEs")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0031f3a00d492e814a4a0935a2029a46d9c9ba06.1664486545.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/io_uring/net.c b/io_uring/net.c
index c7926a4ac7520d2a4efa47add638d6f35ad7eb9e..4878bf40f8b1c6bf34526afc7f546c545447c61c 100644 (file)
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1073,8 +1073,14 @@ int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
        else if (zc->done_io)
                ret = zc->done_io;
 
-       io_notif_flush(zc->notif);
-       req->flags &= ~REQ_F_NEED_CLEANUP;
+       /*
+        * If we're in io-wq we can't rely on tw ordering guarantees, defer
+        * flushing notif to io_send_zc_cleanup()
+        */
+       if (!(issue_flags & IO_URING_F_UNLOCKED)) {
+               io_notif_flush(zc->notif);
+               req->flags &= ~REQ_F_NEED_CLEANUP;
+       }
        io_req_set_res(req, ret, IORING_CQE_F_MORE);
        return IOU_OK;
 }