Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756484Ab3JJA2n (ORCPT ); Wed, 9 Oct 2013 20:28:43 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:49418 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755030Ab3JJA2l (ORCPT ); Wed, 9 Oct 2013 20:28:41 -0400 Date: Wed, 9 Oct 2013 17:28:33 -0700 From: "Paul E. McKenney" To: Eric Dumazet Cc: Josh Triplett , linux-kernel@vger.kernel.org, mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , netdev@vger.kernel.org Subject: Re: [PATCH v2 tip/core/rcu 07/13] ipv6/ip6_tunnel: Apply rcu_access_pointer() to avoid sparse false positive Message-ID: <20131010002833.GJ5790@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1381354186-16285-7-git-send-email-paulmck@linux.vnet.ibm.com> <1381354949.4971.20.camel@edumazet-glaptop.roam.corp.google.com> <20131009215747.GA5790@linux.vnet.ibm.com> <1381356624.4971.26.camel@edumazet-glaptop.roam.corp.google.com> <20131009223652.GC5790@linux.vnet.ibm.com> <1381359077.4971.37.camel@edumazet-glaptop.roam.corp.google.com> <20131009225617.GH11709@jtriplet-mobl1> <1381360675.4971.45.camel@edumazet-glaptop.roam.corp.google.com> <20131009234040.GB14055@jtriplet-mobl1> <1381363960.4971.55.camel@edumazet-glaptop.roam.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1381363960.4971.55.camel@edumazet-glaptop.roam.corp.google.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13101000-1344-0000-0000-0000024F2668 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 863 Lines: 24 On Wed, Oct 09, 2013 at 05:12:40PM -0700, Eric Dumazet wrote: > On Wed, 2013-10-09 at 16:40 -0700, Josh Triplett wrote: > > > that. Constructs like list_del_rcu are much clearer, and not > > open-coded. Open-coding synchronization code is almost always a Bad > > Idea. > > OK, so you think there is synchronization code. > > I will shut up then, no need to waste time. As you said earlier, we should at least get rid of the memory barrier as long as we are changing the code. Josh, what would you suggest as the best way to avoid the memory barrier, keep sparse happy, and not be too ugly? Thanx, Paul -- 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/