From: Isaku Yamahata <yamahata@valinux.co.jp>
Date: Wed, 15 Oct 2008 00:50:42 +0000 (-0700)
Subject: xen-netfront: Avoid unaligned accesses to IP header
X-Git-Tag: firefly_0821_release~17212^2~15
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=617a20bbd099040b68f3578a0a1da5e8780d1831;p=firefly-linux-kernel-4.4.55.git

xen-netfront: Avoid unaligned accesses to IP header

Align ip header to a 16 byte boundary to avoid unaligned
access like other drivers.
Without this patch, xen-netfront doesn't work well on ia64.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
---

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index c749bdba214c..9ffe743f4eb1 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -239,11 +239,14 @@ static void xennet_alloc_rx_buffers(struct net_device *dev)
 	 */
 	batch_target = np->rx_target - (req_prod - np->rx.rsp_cons);
 	for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) {
-		skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD,
+		skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD + NET_IP_ALIGN,
 					 GFP_ATOMIC | __GFP_NOWARN);
 		if (unlikely(!skb))
 			goto no_skb;
 
+		/* Align ip header to a 16 bytes boundary */
+		skb_reserve(skb, NET_IP_ALIGN);
+
 		page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 		if (!page) {
 			kfree_skb(skb);