On Wed, 2015-07-01 at 10:06 -0700, Joe Perches wrote:

On Wed, 2015-07-01 at 12:56 +0200, Eric Dumazet wrote:

quoted

On Tue, 2015-06-30 at 20:25 +0300, Nicolae Rosia wrote:

quoted

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c

[]

quoted

quoted

@@ -2554,9 +2554,9 @@ static void at91ether_rx(struct net_device *dev)
 	while (lp->rx_ring[lp->rx_tail].addr & MACB_BIT(RX_USED)) {
 		p_recv = lp->rx_buffers + lp->rx_tail * AT91ETHER_MAX_RBUFF_SZ;
 		pktlen = MACB_BF(RX_FRMLEN, lp->rx_ring[lp->rx_tail].ctrl);
-		skb = netdev_alloc_skb(dev, pktlen + 2);
+		skb = netdev_alloc_skb(dev, pktlen + NET_IP_ALIGN);
 		if (skb) {
-			skb_reserve(skb, 2);
+			skb_reserve(skb, NET_IP_ALIGN);
 			memcpy(skb_put(skb, pktlen), p_recv, pktlen);
 
 			skb->protocol = eth_type_trans(skb, dev);

Then please use netdev_alloc_skb_ip_align(), so that you get rid of
skb_reserve()

It seems there are ~50 of these in the kernel tree
that could be converted.

Make sure the 2 is really NET_IP_ALIGN

Some hardwares need 2, even if NET_IP_ALIGN is 0 (on x86 arches for
example)

I would rather not touch this without testing the change on real
hardware.