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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: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2009-05-26 18:50:19 +00:00 committed by David S. Miller
parent 0fb2787bf2
commit 42da6994ca
1 changed files with 6 additions and 3 deletions
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9
net/core/skbuff.c
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@ -2673,6 +2673,9 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
if (skb_shinfo(p)->frag_list)
goto merge;
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 >
MAX_SKB_FRAGS)
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_gro_offset(skb) - skb_headlen(skb);
memcpy(skb_shinfo(p)->frags + skb_shinfo(p)->nr_frags,
skb_shinfo(skb)->frags,
skb_shinfo(skb)->nr_frags * sizeof(skb_frag_t));
frag = skb_shinfo(p)->frags + skb_shinfo(p)->nr_frags;
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
*frag++ = skb_shinfo(skb)->frags[i];
skb_shinfo(p)->nr_frags += skb_shinfo(skb)->nr_frags;
skb_shinfo(skb)->nr_frags = 0;