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authorHerbert Xu <herbert@gondor.apana.org.au>2009-05-26 18:50:32 +0000
committerDavid S. Miller <davem@davemloft.net>2009-05-27 03:26:04 -0700
commit66e92fcf1ded5dd0da30d016ed47882eb183ec71 (patch)
treebe7f0fc2415ada8eb5030af53f3063375c381d47 /net
parentcb18978cbf454c236db5e4191a12ef71eef9b3a0 (diff)
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gro: Nasty optimisations for page frags in skb_gro_receive
This patch reverses the direction of the frags array copy in skb_gro_receive in order simplify the loop conditional. It also avoids touching the first element of the original frags array. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/skbuff.c25
1 files changed, 15 insertions, 10 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 168e949df6a..19afb18abae 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2676,21 +2676,26 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
goto merge;
else if (headlen <= offset) {
skb_frag_t *frag;
- int i;
+ skb_frag_t *frag2;
+ int i = skb_shinfo(skb)->nr_frags;
+ int nr_frags = skb_shinfo(p)->nr_frags + i;
+
+ offset -= headlen;
- if (skb_shinfo(p)->nr_frags + skb_shinfo(skb)->nr_frags >
- MAX_SKB_FRAGS)
+ if (nr_frags > MAX_SKB_FRAGS)
return -E2BIG;
- skb_shinfo(skb)->frags[0].page_offset += offset - headlen;
- skb_shinfo(skb)->frags[0].size -= offset - headlen;
+ skb_shinfo(p)->nr_frags = nr_frags;
+ skb_shinfo(skb)->nr_frags = 0;
- 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];
+ frag = skb_shinfo(p)->frags + nr_frags;
+ frag2 = skb_shinfo(skb)->frags + i;
+ do {
+ *--frag = *--frag2;
+ } while (--i);
- skb_shinfo(p)->nr_frags += skb_shinfo(skb)->nr_frags;
- skb_shinfo(skb)->nr_frags = 0;
+ frag->page_offset += offset;
+ frag->size -= offset;
skb->truesize -= skb->data_len;
skb->len -= skb->data_len;