1 files changed, 5 insertions, 6 deletions

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index fb70e3ecc3e4..bb15d0e03d4f 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -318,9 +318,7 @@ igmp_scount(struct ip_mc_list *pmc, int type, int gdeleted, int sdeleted)
         return scount;
 }
 
-#define igmp_skb_size(skb) (*(unsigned int *)((skb)->cb))
-
-static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
+static struct sk_buff *igmpv3_newpack(struct net_device *dev, unsigned int mtu)
 {
         struct sk_buff *skb;
         struct rtable *rt;
@@ -330,6 +328,7 @@ static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
         struct flowi4 fl4;
         int hlen = LL_RESERVED_SPACE(dev);
         int tlen = dev->needed_tailroom;
+        unsigned int size = mtu;
 
         while (1) {
                 skb = alloc_skb(size + hlen + tlen,
@@ -341,7 +340,6 @@ static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
                         return NULL;
         }
         skb->priority = TC_PRIO_CONTROL;
-        igmp_skb_size(skb) = size;
 
         rt = ip_route_output_ports(net, &fl4, NULL, IGMPV3_ALL_MCR, 0,
                                    0, 0,
@@ -354,6 +352,8 @@ static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
         skb_dst_set(skb, &rt->dst);
         skb->dev = dev;
 
+        skb->reserved_tailroom = skb_end_offset(skb) -
+                                 min(mtu, skb_end_offset(skb));
         skb_reserve(skb, hlen);
 
         skb_reset_network_header(skb);
@@ -423,8 +423,7 @@ static struct sk_buff *add_grhead(struct sk_buff *skb, struct ip_mc_list *pmc,
         return skb;
 }
 
-#define AVAILABLE(skb) ((skb) ? ((skb)->dev ? igmp_skb_size(skb) - (skb)->len : \
-        skb_tailroom(skb)) : 0)
+#define AVAILABLE(skb)  ((skb) ? skb_availroom(skb) : 0)
 
 static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
         int type, int gdeleted, int sdeleted)