From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752569AbaBRUVt (ORCPT ); Tue, 18 Feb 2014 15:21:49 -0500 Received: from mail-qa0-f45.google.com ([209.85.216.45]:42695 "EHLO mail-qa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752539AbaBRUVq (ORCPT ); Tue, 18 Feb 2014 15:21:46 -0500 Date: Tue, 18 Feb 2014 12:21:42 -0800 From: Jens Axboe To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, 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, oleg@redhat.com, sbw@mit.edu Subject: Re: [PATCH tip/core/rcu 10/12] block: Substitute rcu_access_pointer() for rcu_dereference_raw() Message-ID: <20140218202142.GE25515@kernel.dk> References: <20140217213533.GA5387@linux.vnet.ibm.com> <1392672959-6386-1-git-send-email-paulmck@linux.vnet.ibm.com> <1392672959-6386-10-git-send-email-paulmck@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1392672959-6386-10-git-send-email-paulmck@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 17 2014, Paul E. McKenney wrote: > From: "Paul E. McKenney" > > (Trivial patch.) > > If the code is looking at the RCU-protected pointer itself, but not > dereferencing it, the rcu_dereference() functions can be downgraded to > rcu_access_pointer(). This commit makes this downgrade in blkg_destroy() > and ioc_destroy_icq(), both of which simply compare the RCU-protected > pointer against another pointer with no dereferencing. Thanks Paul, applied. -- Jens Axboe