[PATCH] virtio_net: Fix IP alignment on non-mergeable RX path

[Rusty Russell <rusty@rustcorp.com.au>]

From: Herbert Xu <herbert@gondor.apana.org.au>

We need to enforce the IP alignment on the non-mergeable RX path just
like the other RX path.  Not doing so results in misaligned IP
headers.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 4d1d479..52fba8e 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -283,10 +283,11 @@ static void try_fill_recv_maxbufs(struct virtnet_info *vi)
 	for (;;) {
 		struct virtio_net_hdr *hdr;
 
-		skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
+		skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN + NET_IP_ALIGN);
 		if (unlikely(!skb))
 			break;
 
+		skb_reserve(skb, NET_IP_ALIGN);
 		skb_put(skb, MAX_PACKET_LEN);
 
 		hdr = skb_vnet_hdr(skb);