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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?p0VXA03RaiYjed81IHhkoMVIJRjn9ityjVoyZaQl5SRijz5zXMe8Fvvg5P0z?= =?us-ascii?Q?5bFMC1sZq887qQnS4wCh36cgbV/FzVGSjArDgUlVM6C9aKgZ8Q7vq8h0uNcM?= =?us-ascii?Q?cYV7iK8SE99PIn2A2M4CAOE8o9aDcfwtOgGcJFO2TnC3ZDgh34gm5uffK8eL?= =?us-ascii?Q?yKAvRkdMH0v5pRIKDfgEbLNQz9aZW1OqtcJXHjuNDTjM3/h/iiXxU9Juewep?= =?us-ascii?Q?LotVCPz8fuok6o7zDj43gyqJC4IvPvfvSW8niY/Qiowc8g97kkvn9PPPEdig?= =?us-ascii?Q?W33R8QAcVVJxAWLBromSRwSCmHUPaM6UrETfX+gRm8QesrwVuP2nuHTgnIM5?= =?us-ascii?Q?bn0Anw95It+MxqeMyU0ERWFuthpNDez8xLMfK0mE5+v88WPOAxaGhQEsBbeX?= =?us-ascii?Q?Xcg2rW7qIrjVNv6J94AIX/FrH4Gt8LRJj/ueLRdXSlRkMz73FyrzqqycdsB4?= =?us-ascii?Q?oL7TeeNwaAh8oQckvkPfSI1T64g8T9+e/ec9sUsB3Ifyvwy8u3nXsTVOez1w?= =?us-ascii?Q?6UuhbmnZxpYNj94pmkDNqxDG6b3HbLQkZJMik5w6ycq4J11wjk5rhnwmljDL?= =?us-ascii?Q?aFBkijyeWCAlLABpRtso2ifM4rISsG1akkcX9plCkPvC3bCjRwcGfl71ABk4?= =?us-ascii?Q?fPF7wnTpCf0q9tN8zsCte98r3S5rWYcmDcowdI0XC1G1MjYNw/skzWUIPWsm?= =?us-ascii?Q?3nCrly1jvriZT8YXfti0Cpyg/yAK4hlfJnJ+NCA6YLIBvmPsUeYiDbScDbv3?= =?us-ascii?Q?/UnJAASLIN0AeY+SBPEoKFO3NOYVcvThvfqyGXz6yTDNuBsP99R9pwWL3v8U?= =?us-ascii?Q?QCLfQogQzi3OlX+0F4e1U7v4tQGi6s/ueum8BoZQywwRIplYR/wAfYJgmhdQ?= =?us-ascii?Q?hfXf2Nu9zkcaGJ+Ch87DsH9jM+TCimplPX74p5T8b1pqxZzqZtnjXb2Wgjyl?= =?us-ascii?Q?DN4EBZCgytNCe6kd3gK7Pwkj5DdF6n5rJhRKBiG7hrSZCj3ABZ+ysrfvOfmi?= =?us-ascii?Q?pyULoZZuCw1t4bPcuj6EcTLl29tgogkjzEjkhGRoVPNNdeLaLXcZHQNo8ZPz?= =?us-ascii?Q?vHgSBEGAdDr/9lTipTGldChPPd6LKSj7PdoXl/PTrt0pUEZHXdl9h0qPnAzG?= =?us-ascii?Q?DdhgWjQTduS1YYdbauj6jTXsGNcSiEprzDgwuzTfJ1jy+pfQmZv+0t2n28s/?= =?us-ascii?Q?4lx7I1WVn7+kbWFdeFYXm8E2Nsjsa+HuZGyspM7x5ByUnvKfx+2Es3re6clJ?= =?us-ascii?Q?47gWTkP2hNQC5ZLn4Lyzm/2IGEN013xjB9/5NY/h+JCcog4y1aNRNmQ36Thg?= =?us-ascii?Q?T9aYUcS9Zjnwa4pUCQz48XgIypVlVoaC8txSydM2wGjnMc1/Ol4AJYJ6NYGG?= =?us-ascii?Q?kt1Rl8fzz0IT8/XCsGsX7jaaH+ycX4Y+PcfcuHWwKlvXySF5n2LX03qd96ov?= =?us-ascii?Q?I8V6Yx18nI0P2V/TUOECF9GNedFDRMdjdc/t1ai6kiLV/km2lAA7nx0MLAhs?= =?us-ascii?Q?0aVVnxZ2HPJTUVe3USv7LdnLjEDKaXLjzv/FCy+1HDKdz5fQdgm2ueVhLjRh?= =?us-ascii?Q?VBegvLn66ozHrku1hPwSHZplX3F3KRX1fxwWTQ0c?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: dfad804e-5784-4e08-c6ad-08de0dad2d41 X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB3613.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Oct 2025 18:44:17.8662 (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: PRmYuAxU8IbQL0CHOVXitO533pCDep+TALGoa46ezrEp/iJtRBjsKNIK+7zpj1p8 X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB8190 On Fri, Oct 17, 2025 at 08:19:06PM +0200, Danilo Krummrich wrote: > On 10/17/25 6:37 PM, Jason Gunthorpe wrote: > > On Fri, Oct 17, 2025 at 06:29:10PM +0200, Danilo Krummrich wrote: > > > >> I'm not sure about MISC device though. Unless there's a good reason, > >> I think MISC device should be "fenced" instead. > > > > misc is a very small wrapper around raw fops, and raw fops are > > optimized for performance. Adding locking that many important things > > like normal files don't need to all fops would not be agreed. > > > > The sketch in this series where we have a core helper to provide a > > shim fops that adds on the lock is smart and I think could be an > > agreeable way to make a synchronous misc and cdev unregister for > > everyone to trivially use. > > Sure, for MISC devices without a parent for instance there are no device > resources to access anyways. There are many situations with misc that can get people into trouble without parent: misc_deregister(x); timer_shutdown_sync(y); kfree(z); For example. It is is buggy if the fops touch y or z. This is why a _sync version is such a nice clean idea because with 5 letters the above can just be fixed. Wrapping everything in a revocable would be a huge PITA. Jason