Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751781Ab2HaHBb (ORCPT ); Fri, 31 Aug 2012 03:01:31 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:48055 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751336Ab2HaHBa (ORCPT ); Fri, 31 Aug 2012 03:01:30 -0400 Subject: Re: [PATCH v2 1/2] 6lowpan: Make a copy of skb's delivered to 6lowpan From: Eric Dumazet To: Alan Ott Cc: Alexander Smirnov , Dmitry Eremin-Solenikov , "David S. Miller" , Tony Cheneau , linux-zigbee-devel@lists.sourceforge.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <1346294341-26808-2-git-send-email-alan@signal11.us> References: <1346294341-26808-1-git-send-email-alan@signal11.us> <1346294341-26808-2-git-send-email-alan@signal11.us> Content-Type: text/plain; charset="UTF-8" Date: Fri, 31 Aug 2012 00:01:25 -0700 Message-ID: <1346396485.2586.307.camel@edumazet-glaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1727 Lines: 49 On Wed, 2012-08-29 at 22:39 -0400, Alan Ott wrote: > Since lowpan_process_data() modifies the skb (by calling skb_pull()), we > need our own copy so that it doesn't affect the data received by other > protcols (in this case, af_ieee802154). > > Signed-off-by: Alan Ott > --- > net/ieee802154/6lowpan.c | 9 ++++++++- > 1 files changed, 8 insertions(+), 1 deletions(-) > > diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c > index 6a09522..ce33b02 100644 > --- a/net/ieee802154/6lowpan.c > +++ b/net/ieee802154/6lowpan.c > @@ -1133,6 +1133,8 @@ static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[]) > static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev, > struct packet_type *pt, struct net_device *orig_dev) > { > + struct sk_buff *local_skb; > + > if (!netif_running(dev)) > goto drop; > > @@ -1144,7 +1146,12 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev, > case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */ > case LOWPAN_DISPATCH_FRAG1: /* first fragment header */ > case LOWPAN_DISPATCH_FRAGN: /* next fragments headers */ > - lowpan_process_data(skb); > + local_skb = skb_copy(skb, GFP_ATOMIC); > + if (!local_skb) > + goto drop; > + lowpan_process_data(local_skb); > + > + kfree_skb(skb); > break; > default: > break; Its not clear to me why skb_copy() is needed here. >From patch description, I would say skb_clone() would be enough (and faster) ? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/