From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751196Ab0JSNn4 (ORCPT ); Tue, 19 Oct 2010 09:43:56 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:58718 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750787Ab0JSNnz (ORCPT ); Tue, 19 Oct 2010 09:43:55 -0400 X-Authority-Analysis: v=1.1 cv=NFUeGz0loTdi/T6hXKngYYtckjed7x3pKvNOqmBBK18= c=1 sm=0 a=uClON0xspYwA:10 a=Q9fys5e9bTEA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=VY8Fu2yrwOplFC62wbIA:9 a=_Aeb6o9nrB9pm4_2sAIwhUaL-AwA:4 a=PUjeQqilurYA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Subject: Re: [Ksummit-2010-discuss] [v2] Remaining BKL users, what to do From: Steven Rostedt To: Arnd Bergmann Cc: Greg KH , linux-kernel@vger.kernel.org, Christoph Hellwig , Ingo Molnar , Dave Airlie , dri-devel@lists.freedesktop.org, ksummit-2010-discuss@lists.linux-foundation.org In-Reply-To: <201010191536.33373.arnd@arndb.de> References: <201009161632.59210.arnd@arndb.de> <201010190926.54635.arnd@arndb.de> <1287491998.16971.360.camel@gandalf.stny.rr.com> <201010191536.33373.arnd@arndb.de> Content-Type: text/plain; charset="ISO-8859-15" Date: Tue, 19 Oct 2010 09:43:52 -0400 Message-ID: <1287495832.16971.368.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2010-10-19 at 15:36 +0200, Arnd Bergmann wrote: > [trimming Cc list] > > On Tuesday 19 October 2010, Steven Rostedt wrote: > > I think we also need to cover the PREEMPT case too. But that could be a > > compile time check, since you can't boot a preempt kernel and make it > > non preempt. > > Right. Can we turn the lock_kernel() into preempt_disable() in these > drivers when we know we never run on SMP? I'm not sure that will work. A holder of the BKL can call schedule or even a mutex. The schedule code will drop the BKL and re-enable preemption. Unless the code is known not to schedule while holding BKL, we would need to open code the preempt_enable() around the locations that the code may schedule. -- Steve