From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from proxima.lasnet.de ([78.47.171.185]:50603 "EHLO proxima.lasnet.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753605AbeGFKHC (ORCPT ); Fri, 6 Jul 2018 06:07:02 -0400 Subject: Re: [PATCH wpan 1/2] net: 6lowpan: fix reserved space for single frames References: <20180702203203.21316-1-aring@mojatatu.com> From: Stefan Schmidt Message-ID: <51306609-93b9-0e80-34ef-f5692cf9e380@datenfreihafen.org> Date: Fri, 6 Jul 2018 12:06:59 +0200 MIME-Version: 1.0 In-Reply-To: <20180702203203.21316-1-aring@mojatatu.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-wpan-owner@vger.kernel.org List-ID: To: Alexander Aring , stefan@osg.samsung.com Cc: linux-wpan@vger.kernel.org, netdev@vger.kernel.org, kernel@mojatatu.com Hello. On 02.07.2018 22:32, Alexander Aring wrote: > This patch fixes patch add handling to take care tail and headroom for The "patch add" text here is form some patch managing? Please fix this when doing the re-spin for the problem below. > single 6lowpan frames. We need to be sure we have a skb with the right > head and tailroom for single frames. This patch do it by using > skb_copy_expand() if head and tailroom is not enough allocated by upper > layer. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=195059 > Reported-by: David Palma > Reported-by: Rabi Narayan Sahoo > Signed-off-by: Alexander Aring > --- > net/ieee802154/6lowpan/tx.c | 21 ++++++++++++++++++--- > 1 file changed, 18 insertions(+), 3 deletions(-) > > diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c > index e6ff5128e61a..d0c4d220de08 100644 > --- a/net/ieee802154/6lowpan/tx.c > +++ b/net/ieee802154/6lowpan/tx.c > @@ -265,9 +265,24 @@ netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev) > /* We must take a copy of the skb before we modify/replace the ipv6 > * header as the header could be used elsewhere > */ > - skb = skb_unshare(skb, GFP_ATOMIC); > - if (!skb) > - return NET_XMIT_DROP; > + if (unlikely(skb_headroom(skb) < ldev->needed_headroom || > + skb_tailroom(skb) < ldev->needed_tailroom)) { > + struct sk_buff *nskb; > + > + nskb = skb_copy_expand(skb, ldev->needed_headroom, > + ldev->needed_tailroom, GFP_ATOMIC); > + if (likely(skb)) { I think you wanted to check for nskb here. > + consume_skb(skb); > + skb = nskb; > + } else { > + kfree_skb(skb); > + return NET_XMIT_DROP; > + } > + } else { > + skb = skb_unshare(skb, GFP_ATOMIC); > + if (!skb) > + return NET_XMIT_DROP; > + } > > ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset); > if (ret < 0) { > The rest looks fine to me. regards Stefan Schmidt