Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756274AbYGCN00 (ORCPT ); Thu, 3 Jul 2008 09:26:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751880AbYGCN0Q (ORCPT ); Thu, 3 Jul 2008 09:26:16 -0400 Received: from mta23.gyao.ne.jp ([125.63.38.249]:43212 "EHLO mx.gate01.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751718AbYGCN0P (ORCPT ); Thu, 3 Jul 2008 09:26:15 -0400 Date: Thu, 3 Jul 2008 22:23:16 +0900 From: Paul Mundt To: "Hans J. Koch" Cc: Uwe Kleine-K??nig , Magnus Damm , "linux-kernel@vger.kernel.org" , "gregkh@suse.de" , "akpm@linux-foundation.org" , "tglx@linutronix.de" Subject: Re: [PATCH] uio: User IRQ Mode Message-ID: <20080703132316.GA1040@linux-sh.org> Mail-Followup-To: Paul Mundt , "Hans J. Koch" , Uwe Kleine-K??nig , Magnus Damm , "linux-kernel@vger.kernel.org" , "gregkh@suse.de" , "akpm@linux-foundation.org" , "tglx@linutronix.de" References: <20080702105951.22648.2197.sendpatchset@rx1.opensource.se> <20080702125400.GC3199@local> <20080703071019.GC12214@digi.com> <20080703124505.GB3197@local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080703124505.GB3197@local> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1097 Lines: 23 On Thu, Jul 03, 2008 at 02:45:05PM +0200, Hans J. Koch wrote: > On Thu, Jul 03, 2008 at 09:10:19AM +0200, Uwe Kleine-K??nig wrote: > > Moreover this might prevent some bugs. (And obviously this > > function has the potential to have a buggy implementation as > > the comment by Alan Cox shows.) > > For me, this shows two things: > > - I never ever had to use disable_irq_nosync() in any UIO driver yet, > otherwise I would have noticed. > > - Magnus turned in a patch that he never tested. > Note that the deadlock in question is in relation to SMP, it's true that the patch was never tested in an SMP environment and only on UP, but it certainly was tested. The vast majority of driver writers don't have a need to use disable_irq_nosync(), so whether you've had to use it or not is largely irrelevant to the conversation at hand ;-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/