From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH] pktgen: Clone skb to avoid corruption of skbs in ndo_start_xmit methods Date: Wed, 20 Jul 2011 17:30:17 +0200 Message-ID: <1311175817.2338.44.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> References: <1311105179-26408-1-git-send-email-nhorman@tuxdriver.com> <1311105738.3113.11.camel@edumazet-laptop> <20110719202922.GA2352@minipsycho> <1311108107.3113.22.camel@edumazet-laptop> <20110720001904.GA1992@neilslaptop.think-freely.org> <1311122593.3113.46.camel@edumazet-laptop> <4E2626E1.6030005@candelatech.com> <20110720020737.GB2692@neilslaptop.think-freely.org> <1311135855.3113.66.camel@edumazet-laptop> <20110720151827.GD12349@hmsreliant.think-freely.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Ben Greear , Jiri Pirko , netdev@vger.kernel.org, Alexey Dobriyan , "David S. Miller" , robert.olsson@its.uu.se To: Neil Horman Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:60358 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751460Ab1GTPaZ (ORCPT ); Wed, 20 Jul 2011 11:30:25 -0400 Received: by wyg8 with SMTP id 8so252921wyg.19 for ; Wed, 20 Jul 2011 08:30:24 -0700 (PDT) In-Reply-To: <20110720151827.GD12349@hmsreliant.think-freely.org> Sender: netdev-owner@vger.kernel.org List-ID: Le mercredi 20 juillet 2011 =C3=A0 11:18 -0400, Neil Horman a =C3=A9cri= t : > On Wed, Jul 20, 2011 at 06:24:15AM +0200, Eric Dumazet wrote: > > Le mardi 19 juillet 2011 =C3=A0 22:07 -0400, Neil Horman a =C3=A9cr= it : > > > >=20 > > > I think this is a good idea. It lets pktgen dynamically make the= clone/share > > > decision dynamically and only impacts performance for those syste= ms. > > >=20 > >=20 > > Just let pktgen refuse to use clone_skb command for these devices. > >=20 > copy that, This is by no means final, but what do you think of this? = If its > agreeable to you, Ben, et al. I can add this to my local tree and sta= rt auditing > all the drivers that may need to have the flag set. >=20 > Regards > Neil >=20 >=20 > diff --git a/include/linux/if.h b/include/linux/if.h > index 3bc63e6..ae904fe 100644 > --- a/include/linux/if.h > +++ b/include/linux/if.h > @@ -76,6 +76,7 @@ > #define IFF_BRIDGE_PORT 0x4000 /* device used as bridge port */ > #define IFF_OVS_DATAPATH 0x8000 /* device used as Open vSwitch > * datapath port */ > +#define IFF_CANT_SHARE_SKB 0x10000 /* Device can't share skbs in tx = path */ > =20 > #define IF_GET_IFACE 0x0001 /* for querying only */ > #define IF_GET_PROTO 0x0002 > diff --git a/net/core/pktgen.c b/net/core/pktgen.c > index f76079c..bf6d88d 100644 > --- a/net/core/pktgen.c > +++ b/net/core/pktgen.c > @@ -1071,6 +1071,9 @@ static ssize_t pktgen_if_write(struct file *fil= e, > if (len < 0) > return len; > =20 > + if (pkt_dev->priv_flags & IFF_CANT_SHARE_SKB) > + return -EOPNOTSUPP; > + Well, the general idea was to intercept the "clone_skb XXX" command and cap XXX to 0 for said devices. So some admin can still use pktgen without clone_skb stuff.