From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756393Ab0CaPRM (ORCPT ); Wed, 31 Mar 2010 11:17:12 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.146]:55785 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752545Ab0CaPRK (ORCPT ); Wed, 31 Mar 2010 11:17:10 -0400 Date: Wed, 31 Mar 2010 08:16:04 -0700 From: "Paul E. McKenney" To: David Howells Cc: Eric Dumazet , Trond.Myklebust@netapp.com, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] NFS: Fix RCU warnings in nfs_inode_return_delegation_noreclaim() [ver #2] Message-ID: <20100331151604.GC2461@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20100319022527.GC2894@linux.vnet.ibm.com> <20100318133302.29754.1584.stgit@warthog.procyon.org.uk> <19192.1269889348@redhat.com> <23274.1269893706@redhat.com> <25276.1269901350@redhat.com> <26760.1269903543@redhat.com> <20100329232636.GT2569@linux.vnet.ibm.com> <2440.1269967151@redhat.com> <21972.1269993064@redhat.com> <10818.1270044273@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <10818.1270044273@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 31, 2010 at 03:04:33PM +0100, David Howells wrote: > Paul E. McKenney wrote: > > > How about Eric's suggestion of rcu_dereference_protected()? That name > > doesn't imply a lock, which as you say above, isn't always needed to > > keep the structure from changing. > > But 'protected' from what or by what? Protected by something that the caller did, be it holding the the correct lock, operating on it during initialization before other CPUs have access to it, operating on it during cleanup after other CPUs' access has been revoked, or whatever. Thanx, Paul