netfront: Check availability of grant references in start_xmit().

Signed-off-by: Tomonari Horikoshi <t.horikoshi@jp.fujitsu.com>

diff --git a/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c b/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c
index 448a972cc428336f26b666efb632d692a2f0b532..01ccb15b72cdaf0633d47ec0c90bb0b2bfe3f79f 100644 (file)
--- a/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c
+++ b/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c
@@ -613,6 +613,10 @@ static int network_open(struct net_device *dev)
 
 static inline int netfront_tx_slot_available(struct netfront_info *np)
 {
+       /* XXX Need to check we have enough grants for worst-case fragments. */
+       if (gnttab_empty_grant_references(&np->gref_tx_head))
+               return 0;
+
        return RING_FREE_REQUESTS(&np->tx) >= MAX_SKB_FRAGS + 2;
 }