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 CB652C433F5 for ; Wed, 12 Jan 2022 17:54:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355810AbiALRyB (ORCPT ); Wed, 12 Jan 2022 12:54:01 -0500 Received: from mxout03.lancloud.ru ([45.84.86.113]:49460 "EHLO mxout03.lancloud.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355808AbiALRx4 (ORCPT ); Wed, 12 Jan 2022 12:53:56 -0500 Received: from LanCloud DKIM-Filter: OpenDKIM Filter v2.11.0 mxout03.lancloud.ru 5784E205F304 Received: from LanCloud Received: from LanCloud Received: from LanCloud Subject: Re: [PATCH] platform: finally disallow IRQ0 in platform_get_irq() and its ilk To: Marc Zyngier CC: Greg Kroah-Hartman , "Rafael J. Wysocki" , , Thomas Gleixner , Geert Uytterhoeven References: <5e001ec1-d3f1-bcb8-7f30-a6301fd9930c@omp.ru> <87pmp7volh.wl-maz@kernel.org> From: Sergey Shtylyov Organization: Open Mobile Platform Message-ID: <9c3f9a6e-89b6-b73b-032f-e4b4ee6f72ac@omp.ru> Date: Wed, 12 Jan 2022 20:53:51 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <87pmp7volh.wl-maz@kernel.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.11.198] X-ClientProxiedBy: LFEXT02.lancloud.ru (fd00:f066::142) To LFEX1907.lancloud.ru (fd00:f066::207) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/4/22 12:26 PM, Marc Zyngier wrote: > [Adding Geert] > > On Sat, 06 Nov 2021 20:26:47 +0000, > Sergey Shtylyov wrote: >> >> The commit a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is >> invalid") only calls WARN() when IRQ0 is about to be returned, however >> using IRQ0 is considered invalid (according to Linus) outside the arch/ >> code where it's used by the i8253 drivers. Many driver subsystems treat >> 0 specially (e.g. as an indication of the polling mode by libata), so >> the users of platform_get_irq[_byname]() in them would have to filter >> out IRQ0 explicitly and this (quite obviously) doesn't scale... >> Let's finally get this straight and return -EINVAL instead of IRQ0! >> >> Fixes: a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is invalid") >> Signed-off-by: Sergey Shtylyov >> >> --- >> The patch is against the 'driver-core-linus' branch of Greg Kroah-Hartman's >> 'driver-core.git' repo. >> >> drivers/base/platform.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> Index: driver-core/drivers/base/platform.c >> =================================================================== >> --- driver-core.orig/drivers/base/platform.c >> +++ driver-core/drivers/base/platform.c >> @@ -231,7 +231,8 @@ int platform_get_irq_optional(struct pla >> out_not_found: >> ret = -ENXIO; >> out: >> - WARN(ret == 0, "0 is an invalid IRQ number\n"); >> + if (WARN(!ret, "0 is an invalid IRQ number\n")) >> + return -EINVAL; >> return ret; >> } >> EXPORT_SYMBOL_GPL(platform_get_irq_optional); >> @@ -445,7 +446,8 @@ static int __platform_get_irq_byname(str >> >> r = platform_get_resource_byname(dev, IORESOURCE_IRQ, name); >> if (r) { >> - WARN(r->start == 0, "0 is an invalid IRQ number\n"); >> + if (WARN(!r->start, "0 is an invalid IRQ number\n")) >> + return -EINVAL; >> return r->start; >> } > > Geert recently mentioned that a few architectures (such as sh?) still > use IRQ0 as something valid in limited cases. > > From my PoV, this patch is fine, but please be prepared to fix things > in a couple of years when someone decides to boot a recent kernel on > their pet dinosaur. With that in mind: > > Acked-by: Marc Zyngier Greg, so would that ACK be enough? Is there a chance this patch gets finally included into 5.17-rc1? Or should I look into fixing the recently found arch/sh/ issue 1st (as you can see, just WARN()'ing about IRQ0 wasn't enough to get this fixed)? > M. MBR, Sergey