From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] pkt_sched: Destroy gen estimators under rtnl_lock(). Date: Tue, 19 Aug 2008 01:32:05 -0700 (PDT) Message-ID: <20080819.013205.72459707.davem@davemloft.net> References: <20080819080557.GA17977@gondor.apana.org.au> <20080819081713.GF4376@ff.dom.local> <20080819082355.GA28869@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: jarkao2@gmail.com, netdev@vger.kernel.org, denys@visp.net.lb To: herbert@gondor.apana.org.au Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:48977 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1750992AbYHSIcG (ORCPT ); Tue, 19 Aug 2008 04:32:06 -0400 In-Reply-To: <20080819082355.GA28869@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: From: Herbert Xu Date: Tue, 19 Aug 2008 18:23:55 +1000 > On Tue, Aug 19, 2008 at 08:17:13AM +0000, Jarek Poplawski wrote: > > > > As I've written before I'm mainly concerned with things like > > tcf_destroy_chain(), especially wrt. cls_u32, but I can be wrong with > > this. So, if you don't have such concerns, let's forget it for now, > > and after I look at this more maybe we'll get back to this discussion. > > Well I can't vouch for every single qdisc in the tree. However, > what I can say is that as long as they respect the rules I outlined > earlier with regards to holding the root qdisc lock when deleting > or using children, then they'll work as expected. > > You're definitely welcome to audit the qdiscs to make sure that > they are obeying the rules. Jarek may have a point about the u32 classifier. So we should think about it. The hash tables and tp_u_common objects are shared, and it does non-atomic refcounting during destruction, see u32_destroy(). However, this all might be OK because all of this management is performed only under the RTNL semaphore.