Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758893AbYGDCz3 (ORCPT ); Thu, 3 Jul 2008 22:55:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754338AbYGDCzV (ORCPT ); Thu, 3 Jul 2008 22:55:21 -0400 Received: from yw-out-2324.google.com ([74.125.46.28]:49470 "EHLO yw-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754104AbYGDCzU (ORCPT ); Thu, 3 Jul 2008 22:55:20 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=BithMtR1zQF6th/kvyAwt/ORnRF8/uRkcIaML6oVkjvfHSU3MIxqmOpCxrMuX4MlMe 5DyQaxejd9KrVhAYBSOElJ3fLTDHl5k+UWGcHy/pH2v4ekPUkCR2Csb7OPdAwLoqoGgn iIthR1AII/P8wpvfut1zWZbJtkIp4JnWSSiq8= Message-ID: Date: Fri, 4 Jul 2008 11:55:08 +0900 From: "Magnus Damm" To: "Hans J. Koch" Subject: Re: [PATCH] uio: User IRQ Mode Cc: "Paul Mundt" , "Uwe Kleine-K??nig" , "linux-kernel@vger.kernel.org" , "gregkh@suse.de" , "akpm@linux-foundation.org" , "tglx@linutronix.de" In-Reply-To: <20080703195538.GC3197@local> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080702105951.22648.2197.sendpatchset@rx1.opensource.se> <20080702125400.GC3199@local> <20080703071019.GC12214@digi.com> <20080703124505.GB3197@local> <20080703132316.GA1040@linux-sh.org> <20080703195538.GC3197@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2107 Lines: 51 On Fri, Jul 4, 2008 at 4:55 AM, Hans J. Koch wrote: > On Thu, Jul 03, 2008 at 10:23:16PM +0900, Paul Mundt wrote: >> 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. > > Ok, so I take back that accusation ;-) That's good, thank you. In the future it would be even better if you didn't accuse to begin with, since that will only heat up the discussion. > Nonetheless, the patch changes a UIO core file, and everything in there > should work in all situations on all architectures unless there is a > _very_ good reason to do something different. This not only applies to > SMP issues but also to the limitation to non-shared interrupts. I will resolve the SMP issue and repost, no problem. >> 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 ;-) > > Sure ;-) I merely wanted to point out that this is an unusual way to > handle an interrupt. Grep shows that there is nothing unusual about it. damm@rx1 ~/git/linux-2.6 $ find drivers/ | xargs grep -m 1 -e [[:blank:]]disable_irq\( -e [[:blank:]]disable_irq_nosync\( | wc -l 105 / magnus -- 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/