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 AF313C433F5 for ; Fri, 11 Mar 2022 19:35:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351141AbiCKTgm (ORCPT ); Fri, 11 Mar 2022 14:36:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234259AbiCKTgl (ORCPT ); Fri, 11 Mar 2022 14:36:41 -0500 Received: from mxout01.lancloud.ru (mxout01.lancloud.ru [45.84.86.81]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68E21F68C0 for ; Fri, 11 Mar 2022 11:35:33 -0800 (PST) Received: from LanCloud DKIM-Filter: OpenDKIM Filter v2.11.0 mxout01.lancloud.ru 2A131206FFD9 Received: from LanCloud Received: from LanCloud Received: from LanCloud From: Sergey Shtylyov Subject: [PATCH v2] platform: finally disallow IRQ0 in platform_get_irq() and its ilk To: Greg Kroah-Hartman , "Rafael J. Wysocki" CC: , Marc Zyngier Organization: Open Mobile Platform Message-ID: <025679e1-1f0a-ae4b-4369-01164f691511@omp.ru> Date: Fri, 11 Mar 2022 22:35:29 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.11.198] X-ClientProxiedBy: LFEXT01.lancloud.ru (fd00:f066::141) To LFEX1907.lancloud.ru (fd00:f066::207) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Acked-by: Marc Zyngier --- The patch is against the 'driver-core-next' branch of Greg Kroah-Hartman's 'driver-core.git' repo. Changes in version 2: - added Marc's ACK. 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); @@ -446,7 +447,8 @@ 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; }