From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamal Hadi Salim Subject: Re: [patch net-next 3/6] net_sched: cls_bpf: remove faulty use of list_for_each_entry_rcu Date: Wed, 03 Dec 2014 16:15:25 -0500 Message-ID: <547F7D6D.3000709@mojatatu.com> References: <1417539636-12710-1-git-send-email-jiri@resnulli.us> <1417539636-12710-4-git-send-email-jiri@resnulli.us> <547F0743.4040301@mojatatu.com> <20141203132635.GH1860@nanopsycho.orion> <547F203A.3080208@mojatatu.com> <20141203152051.GK1860@nanopsycho.orion> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, davem@davemloft.net To: Jiri Pirko Return-path: Received: from mail-ie0-f173.google.com ([209.85.223.173]:46990 "EHLO mail-ie0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751390AbaLCVP1 (ORCPT ); Wed, 3 Dec 2014 16:15:27 -0500 Received: by mail-ie0-f173.google.com with SMTP id y20so14466062ier.4 for ; Wed, 03 Dec 2014 13:15:26 -0800 (PST) In-Reply-To: <20141203152051.GK1860@nanopsycho.orion> Sender: netdev-owner@vger.kernel.org List-ID: On 12/03/14 10:20, Jiri Pirko wrote: > Wed, Dec 03, 2014 at 03:37:46PM CET, jhs@mojatatu.com wrote: > > Yep, but this is updater, protected by rtnl. _rcu list travelsal variant > should be used by reader only (classify callback in cls case). > > get op is only called from tc_ctl_tfilter which is always called with > rtnl held. > I am not an rcu officionado. So if the control path is doing a non-rcu get + rcu-del/change (update) then as long as the fastpath is (read) rcu locking we are fine and nothing will actually happen until the fastpath releases and rcu grace period ends, correct? In which case please accept my: ACKed-by: Jamal Hadi Salim cheers, jamal