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McKenney" , Herve Codina , Jia Jia , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 4/6] gpiolib: cdev: don't sleep in the SRCU read section in read() Date: Fri, 16 Oct 2026 10:46:52 +0300 Message-ID: <20261016074704.1860749-5-aambrozewicz@nvidia.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: <20261012-gpiolib-chip-removal-v1-0-aambrozewicz@nvidia.com> <20261012-gpiolib-chip-removal-v1-4-aambrozewicz@nvidia.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: TL0P290CA0001.ISRP290.PROD.OUTLOOK.COM (2603:1096:950:5::15) To PH7PR12MB5974.namprd12.prod.outlook.com (2603:10b6:510:1d9::19) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5974:EE_|MN2PR12MB4320:EE_ X-MS-Office365-Filtering-Correlation-Id: 2809b608-27fb-4280-e620-08df2b59bc8d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|23010399003|376014|1800799024|366016|10067099003|22082099003|18002099003|11063799006|4143699003|56012099006; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?k/UQkD4aBAgRvBlgSnHNg89CfQlzqZ8wKSRhcwf5O8zlDFIHqzzVbuBpcwf1?= =?us-ascii?Q?L1svV13kGTRzYsv5CIYcNg+Z5LyIt1W+Ngc71whV1TEtvKx04JBcG+Twh6t2?= =?us-ascii?Q?BWxYOA2Lil7cu6Ysk0qRza+Hd6UhJUg9fjxvTg4rgOHWVgSP8XK/cmRGSJ1E?= =?us-ascii?Q?gedWSj/5aUc5sWH+iXGDjcwFDt2uif9E45mK4vj2i/q2YCZ9TGEVeRlKH0wg?= =?us-ascii?Q?KP7KmXdCzEdoqLLsbiJ0FZ8/bPFJx+g5ibrFZD5THj4DQDgqQlcF8FFJWuEk?= =?us-ascii?Q?l7kyumYBdyelfiK2UK4AnGGDJgRbCkLVRfthYaly2p68jsEF5j6LUPjEbgK3?= =?us-ascii?Q?fw/wqquqTZi+HcEZbtAE17zOOcpiW3yNgdbbHkcOG+tmZD0PctdNwFGBTm4Y?= =?us-ascii?Q?N8jblXZtqby3o9qG06QyplUaVjSsOlsfZdenncBeK5E/yZaB+qUweW1LTqhe?= =?us-ascii?Q?5qbtb48OjEHSd9G0eYLqTGStfNjNBpHV4s3lzee16hFrNX9vH1bolpf4qEjk?= =?us-ascii?Q?TjRkxwR53kjclqJ1uUyixoPzA993iBWQCggSOFKJuJRwislxEpgowdPt2/7g?= =?us-ascii?Q?6c+b1Phb1p5LAzddvM2ILMU0sK/Fka75Mv5Wy+PplwVOHLJMA1lSHpP7T1Iu?= =?us-ascii?Q?rQSdb+uoWeXMgQ25+n/85ag08q1HUnBgEgzBfrXDVR8f/Aoaz1JTYEY+gk4k?= =?us-ascii?Q?5zuG5HJ0+jFepQXVJeWr5+ihHtpyjiXHCjfR7FvASwxzfUgwLbqdx3qrxvF6?= =?us-ascii?Q?KS0eAiKXvyCLF0OWWu+iOBdwrPN0SeFUNHDHMfhAFKpUsIGOXvz/Bkk+j2iY?= =?us-ascii?Q?lTqcPLZQR3LrNIuTgB1M/dIrL4jS7a1LUTQyYabUOrOUn261CkwNGyrinJW4?= =?us-ascii?Q?mLKhM5YiwQ+nPAylWGQV0s7m/OS44uPZz9dVS4f2qjXIpKqMjUjTpmIB8NFD?= =?us-ascii?Q?bT9w4Rn9D+0rjNs4J/RzahuvMj1bPAlaOENl7PjLd6iZJVwLjWQgPECtyGDj?= =?us-ascii?Q?lFaDi7IP2hSGgSMoqlFUW031BCjlckPdJyyyL4Xlk7TtP8HXiyuj/8DdSx6/?= =?us-ascii?Q?8kLswtOYRmi+jxBkrxRA4r/7nepWmiVnugsYOp5pyrLZNGaId/pn3nc4Gs2/?= =?us-ascii?Q?cvwU+/u0DYPV3MAa9iFBIgKuQbZkZmBnrFRn79lQ/rYQZqX0gOd7qSqfwc9O?= =?us-ascii?Q?21ThaJcnfUaJsbw4f/kuyHN0TcFO6UFXJPjXe+w6eH3NqN73F1wCyPYNn91H?= =?us-ascii?Q?2pZdMFElBNehRwtl3am+bbiotoDiV1/W6d3F92kJuv1WLRJNrNsmm3Z14mwQ?= =?us-ascii?Q?ProNU1/62tFmarlV9Dk6QERk0Trt9I0IKWX998hynonMaSua92txtP95Iy3D?= =?us-ascii?Q?plZLIIaZ4WKKsO2Vwykz8ughoTNoQQDV9dEJo8IFHwFdI9gRqcBwhhy2XZx/?= =?us-ascii?Q?o4G+9mPk4RvAZ/srSLbreRleikDLQ3Jes494LhHh5M9lQ/yq6qt6mKtMS5Ur?= =?us-ascii?Q?NTHQZmJT9g9L5Jvnu1vqvjn7hesU/xiFeghhmjBxLudzxqDjd/WQWYzslHPk?= =?us-ascii?Q?53izALLajG4TdIRE7eUk1OVQW4bd2k+IDQNDaIkWaLLtxGky2avSHkyzwVA0?= =?us-ascii?Q?xECKKD/tOucNrACvUOFgeTiBr7IsdTO60IkiynEozzDeGygPP6up+QmGUekH?= =?us-ascii?Q?xEcmBigJHMwy1mg6X0Mhy4aivzf8fVKqkRC1PXlzTeXhaGuQZcbsqomovr0p?= =?us-ascii?Q?mYZ1/49tEA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2809b608-27fb-4280-e620-08df2b59bc8d X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5974.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Oct 2026 07:47:32.6178 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: WNfa/KLDpYtoyU4To54qBn8S+lefmYiUp+jsEiBoxpK2ZOTpIWlsVaYhnP/viszKWS1ed8ctjmNB0sisjLJZAQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB4320 On Tue, Oct 13, 2026 at 06:48:24PM +0300, Andy Shevchenko wrote: > It's duplicated a few times, perhaps you can make a static helper? Yes, v2 adds one for the three read() paths. > Caveat: not an SRCU expert, so it might be actually wrong from run-time > behaviour perspective. It is fine: the read section of the guard() in the helper ends when the helper returns, and that is what the patch needs, as read() must not stay in it while it sleeps. The callers do not use the chip after the check. Adrian