virtio-net: fix leaking page for gso packet during mergeable XDP
authorJason Wang <jasowang@redhat.com>
Tue, 22 May 2018 03:44:31 +0000 (11:44 +0800)
committerDavid S. Miller <davem@davemloft.net>
Wed, 23 May 2018 17:36:19 +0000 (13:36 -0400)
We need to drop refcnt to xdp_page if we see a gso packet. Otherwise
it will be leaked. Fixing this by moving the check of gso packet above
the linearizing logic. While at it, remove useless comment as well.

Cc: John Fastabend <john.fastabend@gmail.com>
Fixes: 72979a6c3590 ("virtio_net: xdp, add slowpath case for non contiguous buffers")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/virtio_net.c

index 326e247..032e1ac 100644 (file)
@@ -707,6 +707,13 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                void *data;
                u32 act;
 
+               /* Transient failure which in theory could occur if
+                * in-flight packets from before XDP was enabled reach
+                * the receive path after XDP is loaded.
+                */
+               if (unlikely(hdr->hdr.gso_type))
+                       goto err_xdp;
+
                /* This happens when rx buffer size is underestimated
                 * or headroom is not enough because of the buffer
                 * was refilled before XDP is set. This should only
@@ -727,14 +734,6 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                        xdp_page = page;
                }
 
-               /* Transient failure which in theory could occur if
-                * in-flight packets from before XDP was enabled reach
-                * the receive path after XDP is loaded. In practice I
-                * was not able to create this condition.
-                */
-               if (unlikely(hdr->hdr.gso_type))
-                       goto err_xdp;
-
                /* Allow consuming headroom but reserve enough space to push
                 * the descriptor on if we get an XDP_TX return code.
                 */