From: Greg Kurz Date: Mon, 22 Jan 2018 21:02:05 +0000 (+0100) Subject: 9p/trans_virtio: discard zero-length reply X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=8a8c9588c289bcd2dbaf7a198144293978833a7c;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git 9p/trans_virtio: discard zero-length reply commit 26d99834f89e76514076d9cd06f61e56e6a509b8 upstream. When a 9p request is successfully flushed, the server is expected to just mark it as used without sending a 9p reply (ie, without writing data into the buffer). In this case, virtqueue_get_buf() will return len == 0 and we must not report a REQ_STATUS_RCVD status to the client, otherwise the client will erroneously assume the request has not been flushed. Cc: stable@vger.kernel.org Signed-off-by: Greg Kurz Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index f3a4efcf1456..3aa5a93ad107 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -160,7 +160,8 @@ static void req_done(struct virtqueue *vq) spin_unlock_irqrestore(&chan->lock, flags); /* Wakeup if anyone waiting for VirtIO ring space. */ wake_up(chan->vc_wq); - p9_client_cb(chan->client, req, REQ_STATUS_RCVD); + if (len) + p9_client_cb(chan->client, req, REQ_STATUS_RCVD); } }