skbuff: optimize the pull_pages code in __pskb_pull_tail()
In the pull_pages code block, if the first frag size > eat,
we can end the loop in advance to avoid extra copy.
Signed-off-by: Lin Zhang <xiaolou4617@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 8b11341..b352c6b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1719,6 +1719,8 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta)
if (eat) {
skb_shinfo(skb)->frags[k].page_offset += eat;
skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat);
+ if (!i)
+ goto end;
eat = 0;
}
k++;
@@ -1726,6 +1728,7 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta)
}
skb_shinfo(skb)->nr_frags = k;
+end:
skb->tail += delta;
skb->data_len -= delta;