igmp: refine skb allocations
IGMP allocates MTU sized skbs. This may fail for large MTU (order-2
allocations), so add a fallback to try lower sizes.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 50f6bc1..e0e77e2 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -300,6 +300,8 @@
return scount;
}
+#define igmp_skb_size(skb) (*(unsigned int *)((skb)->cb))
+
static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
{
struct sk_buff *skb;
@@ -308,9 +310,16 @@
struct igmpv3_report *pig;
struct net *net = dev_net(dev);
- skb = alloc_skb(size + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
- if (skb == NULL)
- return NULL;
+ while (1) {
+ skb = alloc_skb(size + LL_ALLOCATED_SPACE(dev),
+ GFP_ATOMIC | __GFP_NOWARN);
+ if (skb)
+ break;
+ size >>= 1;
+ if (size < 256)
+ return NULL;
+ }
+ igmp_skb_size(skb) = size;
{
struct flowi fl = { .oif = dev->ifindex,
@@ -399,7 +408,7 @@
return skb;
}
-#define AVAILABLE(skb) ((skb) ? ((skb)->dev ? (skb)->dev->mtu - (skb)->len : \
+#define AVAILABLE(skb) ((skb) ? ((skb)->dev ? igmp_skb_size(skb) - (skb)->len : \
skb_tailroom(skb)) : 0)
static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,