From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: [PATCH] PKT_SCHED: dsmark must take care of shared/cloned skbs Date: Mon, 20 Dec 2004 09:06:06 +0100 Message-ID: <41C687EE.1090205@trash.net> References: <20041218170017.GH17998@postel.suug.ch> <1103487827.1048.188.camel@jzny.localdomain> <20041219203641.GL17998@postel.suug.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: jamal , "David S. Miller" , netdev@oss.sgi.com Return-path: To: Thomas Graf In-Reply-To: <20041219203641.GL17998@postel.suug.ch> Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Thomas Graf wrote: > * jamal <1103487827.1048.188.camel@jzny.localdomain> 2004-12-19 15:23 > >>If the qdisc at that level muddies the packet thats fair game - thats >>what goes out on the wire. So we should leave the code as is. > > > Agreed for egress but I think it is needed for stuff like IMQ. It's > debatable whether we should take care of IMQ and alike though. > You shouldn't care about IMQ, but we still need to copy the packet before modifying it if the data is shared. Otherwise we have a race on SMP with AF_PACKET sockets, depending on when the packet is read it can be either modified or not. Converting dsmark to an action sounds like the best long-term solution. Regards Patrick