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)
commite33d0ba8047b049c9262fdb1fcafb93cb52ceceb
tree2b117a4733772f5ab63ab296c79ef1290cfc40f7
parent240a12d58e3935945c8c0f767134f3da1ac05371
net-gro: reset skb->truesize in napi_reuse_skb()

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