linux-kernel - [PATCH v2] net: eliminate meaningless memcpy to data in pskb_carve_inside

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Message-ID: <20200815084853.20216-1-linmiaohe@huawei.com>
Date:   Sat, 15 Aug 2020 04:48:53 -0400
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <davem@...emloft.net>, <kuba@...nel.org>, <pshelar@....org>,
        <martin.varghese@...ia.com>, <fw@...len.de>, <dcaratti@...hat.com>,
        <edumazet@...gle.com>, <steffen.klassert@...unet.com>,
        <pabeni@...hat.com>, <shmulik@...anetworks.com>,
        <kyk.segfault@...il.com>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linmiaohe@...wei.com>
Subject: [PATCH v2] net: eliminate meaningless memcpy to data in pskb_carve_inside_nonlinear()

The frags of skb_shared_info of the data is assigned in following loop. It
is meaningless to do a memcpy of frags here.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 net/core/skbuff.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index afbc1a79dc8a..44b7010e4813 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5953,8 +5953,7 @@ static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off,
 	size = SKB_WITH_OVERHEAD(ksize(data));
 
 	memcpy((struct skb_shared_info *)(data + size),
-	       skb_shinfo(skb), offsetof(struct skb_shared_info,
-					 frags[skb_shinfo(skb)->nr_frags]));
+	       skb_shinfo(skb), offsetof(struct skb_shared_info, frags[0]));
 	if (skb_orphan_frags(skb, gfp_mask)) {
 		kfree(data);
 		return -ENOMEM;
-- 
2.19.1