Commit 43480aec authored Feb 08, 2012 by Eric Dumazet Committed by David S. Miller Feb 08, 2012

gro: more generic L2 header check



Shlomo Pongratz reported GRO L2 header check was suited for Ethernet
only, and failed on IB/ipoib traffic.

He provided a patch faking a zeroed header to let GRO aggregates frames.

Roland Dreier, Herbert Xu, and others suggested we change GRO L2 header
check to be more generic, ie not assuming L2 header is 14 bytes, but
taking into account hard_header_len.

__napi_gro_receive() has special handling for the common case (Ethernet)
to avoid a memcmp() call and use an inline optimized function instead.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Shlomo Pongratz <shlomop@mellanox.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 377cb4f9

net/core/dev.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -3491,14 +3491,20 @@ static inline gro_result_t
		__napi_gro_receive(struct napi_struct napi, struct sk_buff skb)
		{
		struct sk_buff *p;
		unsigned int maclen = skb->dev->hard_header_len;

		for (p = napi->gro_list; p; p = p->next) {
		unsigned long diffs;

		diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev;
		diffs \|= p->vlan_tci ^ skb->vlan_tci;
		if (maclen == ETH_HLEN)
		diffs \|= compare_ether_header(skb_mac_header(p),
		skb_gro_mac_header(skb));
		else if (!diffs)
		diffs = memcmp(skb_mac_header(p),
		skb_gro_mac_header(skb),
		maclen);
		NAPI_GRO_CB(p)->same_flow = !diffs;
		NAPI_GRO_CB(p)->flush = 0;
		}

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