From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F5B4C433FE for ; Fri, 10 Dec 2021 18:00:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245043AbhLJSEa (ORCPT ); Fri, 10 Dec 2021 13:04:30 -0500 Received: from mga04.intel.com ([192.55.52.120]:32303 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245006AbhLJSE3 (ORCPT ); Fri, 10 Dec 2021 13:04:29 -0500 X-IronPort-AV: E=McAfee;i="6200,9189,10194"; a="237138446" X-IronPort-AV: E=Sophos;i="5.88,196,1635231600"; d="scan'208";a="237138446" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Dec 2021 10:00:54 -0800 X-IronPort-AV: E=Sophos;i="5.88,196,1635231600"; d="scan'208";a="607538587" Received: from smile.fi.intel.com ([10.237.72.184]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Dec 2021 10:00:51 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.95) (envelope-from ) id 1mvkBV-004bDa-4s; Fri, 10 Dec 2021 19:59:53 +0200 Date: Fri, 10 Dec 2021 19:59:52 +0200 From: Andy Shevchenko To: Sergei Shtylyov Cc: Sergey Shtylyov , Damien Le Moal , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, Hans de Goede , Jens Axboe Subject: Re: [PATCH v1 1/2] ata: libahci_platform: Get rid of dup message when IRQ can't be retrieved Message-ID: References: <20211209145937.77719-1-andriy.shevchenko@linux.intel.com> <9e6b2e9a-e958-0c14-6570-135607041978@omp.ru> <6c03ffef-b2e0-16ba-35f3-206af2a611d2@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6c03ffef-b2e0-16ba-35f3-206af2a611d2@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 10, 2021 at 08:15:43PM +0300, Sergei Shtylyov wrote: > On 12/10/21 2:36 PM, Andy Shevchenko wrote: > > >>>>>> platform_get_irq() will print a message when it fails. > >>>>>> No need to repeat this. > >>>>>> > >>>>>> While at it, drop redundant check for 0 as platform_get_irq() spills > >>>>>> out a big WARN() in such case. > >>>>> > >>>>> The reason you should be able to remove the "if (!irq)" test is that > >>>>> platform_get_irq() never returns 0. At least, that is what the function kdoc > >>>>> says. But looking at platform_get_irq_optional(), which is called by > >>>>> platform_get_irq(), the out label is: > >>>>> > >>>>> WARN(ret == 0, "0 is an invalid IRQ number\n"); > >>>>> return ret; > >>>>> > >>>>> So 0 will be returned as-is. That is rather weird. That should be fixed to > >>>>> return -ENXIO: > >>>>> > >>>>> if (WARN(ret == 0, "0 is an invalid IRQ number\n")) > >>>>> return -ENXIO; > >>>>> return ret; > >>>> > >>>> My unmerged patch (https://marc.info/?l=linux-kernel&m=163623041902285) does this > >>>> but returns -EINVAL instead. > >>>> > >>>>> Otherwise, I do not think that removing the "if (!irq)" hunk is safe. no ? > >>>> > >>>> Of course it isn't... > >>> > >>> It's unsubstantiated statement. The vIRQ 0 shouldn't be returned by any of > >>> those API calls. > >> > >> We do _not_ know what needs to be fixed, that's the problem, and that's why the WARN() > >> is there... > > > > So, have you seen this warning (being reported) related to libahci_platform? > > No (as if you need to really see this while it's obvious from the code review). > > > If no, what we are discussing about then? The workaround is redundant and > > I don't know. :-) Your arguments so far seem bogus (sorry! :-))... It seems you haven't got them at all. The problems of platform_get_irq() et al shouldn't be worked around in the callers. > > no need to have a dead code in the driver, really. > > "Jazz isn't dead, it just smells funny". :-) > > >>> If it is the case, go and fix them, no need to workaround > >>> in each of the callers. > >> > >> There's a need to work around as long as IRQ0 ican be returned, otherwise > >> we get partly functioning or non-functioning drivers... > > > > You get them unfunctioning anyways > > The drivers would be broken in not quite obvious ways. With IRQ0 check, they just > don't probe anymore. See the explanation of the IRQ0 check (in the drivers) in my > previous mail... > > > and you get the big WARN() even before this patch. > > As if that was enough... > The IRQ0 problem exists for at least 15 (if not 20) years... -- With Best Regards, Andy Shevchenko