From: linzhang <xiaolou4617@gmail.com>
Date: Mon, 17 Jul 2017 17:25:02 +0800
Subject: skbuff: optimize the pull_pages code in __pskb_pull_tail()
Patch-mainline: v4.14-rc1
Git-commit: 3ccc6c6faaa93da70989177b91c7c3ef0df10937
References: bsc#1109837
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/core/skbuff.c | 3 +++
1 file changed, 3 insertions(+)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1703,6 +1703,8 @@ pull_pages:
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++;
@@ -1710,6 +1712,7 @@ pull_pages:
}
skb_shinfo(skb)->nr_frags = k;
+end:
skb->tail += delta;
skb->data_len -= delta;