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Commit 42da6994 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
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gro: Open-code frags copy in skb_gro_receive 



gcc does a poor job at generating code for the memcpy of the frags
array in skb_gro_receive, which is the primary purpose of that
function when merging frags.  In particular, it can't utilise the
alignment information of the source and destination.  This patch
open-codes the copy so we process words instead of bytes.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0fb2787b

net/core/skbuff.c

+6 −3
Original line number Original line Diff line number Diff line
@@ -2673,6 +2673,9 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) 
	if (skb_shinfo(p)->frag_list)

	if (skb_shinfo(p)->frag_list)

		goto merge;

		goto merge;

	else if (skb_headlen(skb) <= skb_gro_offset(skb)) {

	else if (skb_headlen(skb) <= skb_gro_offset(skb)) {

		skb_frag_t *frag;

		int i;



		if (skb_shinfo(p)->nr_frags + skb_shinfo(skb)->nr_frags >

		if (skb_shinfo(p)->nr_frags + skb_shinfo(skb)->nr_frags >

		    MAX_SKB_FRAGS)

		    MAX_SKB_FRAGS)

			return -E2BIG;

			return -E2BIG;
@@ -2682,9 +2685,9 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) 
		skb_shinfo(skb)->frags[0].size -=

		skb_shinfo(skb)->frags[0].size -=

			skb_gro_offset(skb) - skb_headlen(skb);

			skb_gro_offset(skb) - skb_headlen(skb);





		memcpy(skb_shinfo(p)->frags + skb_shinfo(p)->nr_frags,

		frag = skb_shinfo(p)->frags + skb_shinfo(p)->nr_frags;

		       skb_shinfo(skb)->frags,

		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)

		       skb_shinfo(skb)->nr_frags * sizeof(skb_frag_t));

			*frag++ = skb_shinfo(skb)->frags[i];





		skb_shinfo(p)->nr_frags += skb_shinfo(skb)->nr_frags;

		skb_shinfo(p)->nr_frags += skb_shinfo(skb)->nr_frags;

		skb_shinfo(skb)->nr_frags = 0;

		skb_shinfo(skb)->nr_frags = 0;