From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932764Ab3E1KlP (ORCPT ); Tue, 28 May 2013 06:41:15 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56078 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932547Ab3E1KlM (ORCPT ); Tue, 28 May 2013 06:41:12 -0400 From: Luis Henriques To: Jeff Layton Cc: Ben Hutchings , linux-kernel@vger.kernel.org, stable@vger.kernel.org, akpm@linux-foundation.org, "Trond Myklebust" Subject: Re: [54/94] sunrpc: clarify comments on rpc_make_runnable References: <20130528061435.0e1b1cc4@corrin.poochiereds.net> Date: Tue, 28 May 2013 11:41:08 +0100 In-Reply-To: <20130528061435.0e1b1cc4@corrin.poochiereds.net> (Jeff Layton's message of "Tue, 28 May 2013 06:14:35 -0400") Message-ID: <87ehcrqtdn.fsf@canonical.com> User-Agent: Gnus/5.130008 (Ma Gnus v0.8) Emacs/24.3.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jeff Layton writes: > On Tue, 28 May 2013 04:49:53 +0100 > Ben Hutchings wrote: > >> 3.2.46-rc1 review patch. If anyone has any objections, please let me know. >> >> ------------------ >> >> From: Jeff Layton >> >> commit 506026c3ec270e18402f0c9d33fee37482c23861 upstream. >> >> rpc_make_runnable is not generally called with the queue lock held, unless >> it's waking up a task that has been sitting on a waitqueue. This is safe >> when the task has not entered the FSM yet, but the comments don't really >> spell this out. >> >> Signed-off-by: Jeff Layton >> Signed-off-by: Trond Myklebust >> Signed-off-by: Ben Hutchings >> --- >> net/sunrpc/sched.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> --- a/net/sunrpc/sched.c >> +++ b/net/sunrpc/sched.c >> @@ -296,8 +296,9 @@ EXPORT_SYMBOL_GPL(__rpc_wait_for_complet >> /* >> * Make an RPC task runnable. >> * >> - * Note: If the task is ASYNC, this must be called with >> - * the spinlock held to protect the wait queue operation. >> + * Note: If the task is ASYNC, and is being made runnable after sitting on an >> + * rpc_wait_queue, this must be called with the queue spinlock held to protect >> + * the wait queue operation. >> */ >> static void rpc_make_runnable(struct rpc_task *task) >> { >> > > Just a comment patch, so this is harmless and I have no objection but > why pull it into stable? I had always thought stable-kernel-rules.txt > discouraged taking patches that don't fix real bugs... I believe the reason Ben took this patch is actually to provide the correct context for the next one: a3c3cac5d31879cd9ae2de7874dc6544ca704aec, "SUNRPC: Prevent an rpc_task wakeup race" So that this is a clean cherry-pick. (At least this was the reason I picked it for the 3.5 kernel.) Cheers, -- Luis