1 files changed, 15 insertions, 4 deletions

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index ef671d1a3bf0..902bbe788215 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -92,7 +92,7 @@ struct netfront_info {
 	 */
 	union skb_entry {
 		struct sk_buff *skb;
-		unsigned link;
+		unsigned long link;
 	} tx_skbs[NET_TX_RING_SIZE];
 	grant_ref_t gref_tx_head;
 	grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
@@ -125,6 +125,17 @@ struct netfront_rx_info {
 	struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 };
 
+static void skb_entry_set_link(union skb_entry *list, unsigned short id)
+{
+	list->link = id;
+}
+
+static int skb_entry_is_link(const union skb_entry *list)
+{
+	BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
+	return ((unsigned long)list->skb < PAGE_OFFSET);
+}
+
 /*
  * Access macros for acquiring freeing slots in tx_skbs[].
  */
@@ -132,7 +143,7 @@ struct netfront_rx_info {
 static void add_id_to_freelist(unsigned *head, union skb_entry *list,
 			       unsigned short id)
 {
-	list[id].link = *head;
+	skb_entry_set_link(&list[id], *head);
 	*head = id;
 }
 
@@ -993,7 +1004,7 @@ static void xennet_release_tx_bufs(struct netfront_info *np)
 
 	for (i = 0; i < NET_TX_RING_SIZE; i++) {
 		/* Skip over entries which are actually freelist references */
-		if ((unsigned long)np->tx_skbs[i].skb < PAGE_OFFSET)
+		if (skb_entry_is_link(&np->tx_skbs[i]))
 			continue;
 
 		skb = np->tx_skbs[i].skb;
@@ -1123,7 +1134,7 @@ static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev
 	/* Initialise tx_skbs as a free chain containing every entry. */
 	np->tx_skb_freelist = 0;
 	for (i = 0; i < NET_TX_RING_SIZE; i++) {
-		np->tx_skbs[i].link = i+1;
+		skb_entry_set_link(&np->tx_skbs[i], i+1);
 		np->grant_tx_ref[i] = GRANT_INVALID_REF;
 	}