9p/trans_virtio: discard zero-length reply

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: [email protected] Signed-off-by: Greg Kurz <[email protected]> Signed-off-by: Michael S. Tsirkin <[email protected]>
ambv · Feb 9, 2018 · 26d9983 · 26d9983
1 parent d25cc43
commit 26d9983
Showing 1 changed file with 2 additions and 1 deletion.
diff --git 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);
 	}
 }