From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936476Ab2C3WG4 (ORCPT ); Fri, 30 Mar 2012 18:06:56 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:40131 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965342Ab2C3VQF (ORCPT ); Fri, 30 Mar 2012 17:16:05 -0400 Message-Id: <20120330194903.023849109@linuxfoundation.org> User-Agent: quilt/0.60-19.1 Date: Fri, 30 Mar 2012 12:50:52 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Eric Dumazet , Herbert Xu , "David S. Miller" Subject: [ 139/149] net: fix napi_reuse_skb() skb reserve In-Reply-To: <20120330195823.GA31857@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 2a2a459eeeff48640dc557548ce576d666ab06ed ] napi->skb is allocated in napi_get_frags() using netdev_alloc_skb_ip_align(), with a reserve of NET_SKB_PAD + NET_IP_ALIGN bytes. However, when such skb is recycled in napi_reuse_skb(), it ends with a reserve of NET_IP_ALIGN which is suboptimal. Signed-off-by: Eric Dumazet Cc: Herbert Xu Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3634,7 +3634,8 @@ EXPORT_SYMBOL(napi_gro_receive); static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) { __skb_pull(skb, skb_headlen(skb)); - skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb)); + /* restore the reserve we had after netdev_alloc_skb_ip_align() */ + skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb)); skb->vlan_tci = 0; skb->dev = napi->dev; skb->skb_iif = 0;