virtio-net: make all RX paths handle errors consistently

receive mergeable now handles errors internally.
Do same for big and small packet paths, otherwise
the logic is too hard to follow.

Cc: Jason Wang <jasowang@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Acked-by: Michael Dalton <mwdalton@google.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit f121159d72091f25afb22007c833e60a6845e912)
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 36 insertions, 20 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ad9b385e1f3d..ec0e9f236ff0 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -294,6 +294,34 @@ static struct sk_buff *page_to_skb(struct receive_queue *rq,
         return skb;
 }
 
+static struct sk_buff *receive_small(void *buf, unsigned int len)
+{
+        struct sk_buff * skb = buf;
+
+        len -= sizeof(struct virtio_net_hdr);
+        skb_trim(skb, len);
+
+        return skb;
+}
+
+static struct sk_buff *receive_big(struct net_device *dev,
+                                   struct receive_queue *rq,
+                                   void *buf)
+{
+        struct page *page = buf;
+        struct sk_buff *skb = page_to_skb(rq, page, 0);
+
+        if (unlikely(!skb))
+                goto err;
+
+        return skb;
+
+err:
+        dev->stats.rx_dropped++;
+        give_pages(rq, page);
+        return NULL;
+}
+
 static struct sk_buff *receive_mergeable(struct net_device *dev,
                                          struct receive_queue *rq,
                                          void *buf,
@@ -357,7 +385,6 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
         struct net_device *dev = vi->dev;
         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
         struct sk_buff *skb;
-        struct page *page;
         struct skb_vnet_hdr *hdr;
 
         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
@@ -369,26 +396,15 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
                         dev_kfree_skb(buf);
                 return;
         }
+        if (vi->mergeable_rx_bufs)
+                skb = receive_mergeable(dev, rq, buf, len);
+        else if (vi->big_packets)
+                skb = receive_big(dev, rq, buf);
+        else
+                skb = receive_small(buf, len);
 
-        if (!vi->mergeable_rx_bufs && !vi->big_packets) {
-                skb = buf;
-                len -= sizeof(struct virtio_net_hdr);
-                skb_trim(skb, len);
-        } else {
-                page = buf;
-                if (vi->mergeable_rx_bufs) {
-                        skb = receive_mergeable(dev, rq, page, len);
-                        if (unlikely(!skb))
-                                return;
-                } else {
-                        skb = page_to_skb(rq, page, len);
-                        if (unlikely(!skb)) {
-                                dev->stats.rx_dropped++;
-                                give_pages(rq, page);
-                                return;
-                        }
-                }
-        }
+        if (unlikely(!skb))
+                return;
 
         hdr = skb_vnet_hdr(skb);