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([fe80::bfe:4ce1:556:4a9d]) by SJ2PR11MB7573.namprd11.prod.outlook.com ([fe80::bfe:4ce1:556:4a9d%5]) with mapi id 15.20.9891.015; Thu, 7 May 2026 18:30:55 +0000 Message-ID: Date: Thu, 7 May 2026 11:30:53 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] fs/resctrl: Fix deadlock for errors during mount To: "Luck, Tony" CC: Borislav Petkov , , Fenghua Yu , Maciej Wieczor-Retman , Peter Newman , James Morse , Babu Moger , "Drew Fustini" , Dave Martin , Chen Yu , , References: <20260504220149.157753-1-tony.luck@intel.com> <5d38c1fb-8f91-472b-8897-24b2f50c772b@intel.com> Content-Language: en-US From: Reinette Chatre In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4P223CA0013.NAMP223.PROD.OUTLOOK.COM (2603:10b6:303:80::18) To SJ2PR11MB7573.namprd11.prod.outlook.com (2603:10b6:a03:4d2::10) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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=?utf-8?B?RDhjbHFaNGxRUXk5TnVqRUkwR2RXLzlnQW5yZkdKU250SGFtSVBNbDZRV1pH?= =?utf-8?Q?Sjx51ZdVrlXafNhQ=3D?= X-Exchange-RoutingPolicyChecked: iRXP4sAPUL5i+U9GAk5YIbJoQt6DzqRiHzRa6pi3/qeLVhZBoJnmx63YJE1hJASkq80AeAJ95SomOB8JrPHppCC8QhX5ZH5sowHGYdATULkVMTnGF/YRo9vauH8v+OJXzncBbD31DlMyZ0rqBesoKhTet1t8GzPaL91rbS4ONeUF3ls/gqlrmOpLyPc4PbVnNnlU5+itywaCXvZPIq4qJ4YadvZQIAOFUG+/Zf7YXm4wHIic5M8/J9xJuf5OBjzddTIBjoeSKhVy1uiXMEmfn8iJgI9PeyX7AoxOG8ys//PLOt3bJ0RyZQAVhJCoAD02HmnfR/tHFRJWTCq9YAWw1A== X-MS-Exchange-CrossTenant-Network-Message-Id: 7c862bc4-f79a-43c0-e821-08deac66c6ae X-MS-Exchange-CrossTenant-AuthSource: SJ2PR11MB7573.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 May 2026 18:30:55.4398 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: +AhofWe4Na3QCbvVX0w+/Q/RV7B122GfvrvX3c1Cf3rRF5TN1WD2b0pdladKnEbK+VrjSh/nVNFIpCumvHXxQYskiguXZOAS+VeClKBOEXg= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA7PR11MB9596 X-OriginatorOrg: intel.com Hi Tony, On 5/7/26 10:47 AM, Luck, Tony wrote: > Reinette, > > This looks promising. > > I'll split out the missing call to mon_put_kn_priv(); into its own > patch before the deadlock fix. > > Going to re-run the tests I did before forcing kernfs_get_tree() > to fail early without setting new_sb_created, and also late. Thank you very much. > >> +/* >> + * Temporary forward declaration for testing only. Move functions instead. >> + */ >> +static void resctrl_unmount(void); >> +static void mon_put_kn_priv(void); > > Question: How much are forward declarations hated? And how to handle > this? I am not aware of forward declarations being hated and I am not aware of documented tip rules about this. Even so, I do find it cleaner if they can be avoided. To handle this a prep patch that just moves the code without any functional change should work? > Moving the functions around in the same patch really obscures the > actual change. Is it OK to have a patch to make the functional > change including the forward declarations. Then a separate commit > that does the re-order (where it is obvious that functions are > being picked up and moved without any code changes)? My preference would be a prep patch that does the move with new capability built on top. It seems unnecessary to me to add a forward declaration in one patch just to remove it in a following patch. I agree that moving code as part of functional change should be avoided. Reinette