Merge branch 'virtio_net-mergeable-XDP'

Jason Wang says:

====================
Fix several issues of virtio-net mergeable XDP

Please review the patches that tries to fix several issues of
virtio-net mergeable XDP.

Changes from V1:
- check against 1 before decreasing instead of resetting to 1
- typoe fixes
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 11 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 770422e953f7..032e1ac10a30 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -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.
                  */
@@ -775,7 +774,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                         }
                         *xdp_xmit = true;
                         if (unlikely(xdp_page != page))
-                                goto err_xdp;
+                                put_page(page);
                         rcu_read_unlock();
                         goto xdp_xmit;
                 case XDP_REDIRECT:
@@ -787,7 +786,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                         }
                         *xdp_xmit = true;
                         if (unlikely(xdp_page != page))
-                                goto err_xdp;
+                                put_page(page);
                         rcu_read_unlock();
                         goto xdp_xmit;
                 default:
@@ -875,7 +874,7 @@ err_xdp:
         rcu_read_unlock();
 err_skb:
         put_page(page);
-        while (--num_buf) {
+        while (num_buf-- > 1) {
                 buf = virtqueue_get_buf(rq->vq, &len);
                 if (unlikely(!buf)) {
                         pr_debug("%s: rx error: %d buffers missing\n",