net-gro: reset skb->truesize in napi_reuse_skb()
authorEric Dumazet <edumazet@google.com>
Thu, 3 Apr 2014 16:28:10 +0000 (09:28 -0700)
committerDavid S. Miller <davem@davemloft.net>
Thu, 3 Apr 2014 20:17:52 +0000 (16:17 -0400)
Recycling skb always had been very tough...

This time it appears GRO layer can accumulate skb->truesize
adjustments made by drivers when they attach a fragment to skb.

skb_gro_receive() can only subtract from skb->truesize the used part
of a fragment.

I spotted this problem seeing TcpExtPruneCalled and
TcpExtTCPRcvCollapsed that were unexpected with a recent kernel, where
TCP receive window should be sized properly to accept traffic coming
from a driver not overshooting skb->truesize.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/core/dev.c

index 75e88e0372cbc727232d029702b2f43e8f499d4f..577701839f5205227219089706529b72ed095860 100644 (file)
@@ -4043,6 +4043,7 @@ static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
        skb->vlan_tci = 0;
        skb->dev = napi->dev;
        skb->skb_iif = 0;
+       skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
 
        napi->skb = skb;
 }