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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: LktygSK8bcLJrIJ5DyC4B3rCTrgRcWWFlhT4HPCmXnzGZr8ko9eNgKMThv9dHemQXA5vUaym86QYWgm1YBIyfqe2w3+Ag9nrq1mCh9BWtxX7KDCAjkGl85VPPSsfo5rUDhDZxHRfQjUr9XSBQUHof3by8uGI/pcGAfGupOPdrUHZQLkd8STJhDO1qjka6VBnNzBt9WQY0sy8ioInX5nVuj7+l5PUL+PiEFKuM+ZFU4O/irODdmD3q+6M+Fku1xFEhDi4wpgHQ5fjaBfrdobte3cvdhMzA2yIZsr7jtck39c5NBO7tLExw8OBq+/83lAUwfe/UdEPJKqsfg85nvBzxqwIdYjiXL+caJ7lIRsfgZlapnNT0whFJKzPatW5AelBGe3k4DjgrycsNwrAMInIRokCoILn2nAHlT3w8dEZ6QNr5uD6V8br1MyA+9/UTZUH X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Sep 2026 08:21:51.9494 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 03425880-20b9-4bb3-aac0-08df194bb8a5 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[4.158.2.129];Helo=[outbound-uk1.az.dlp.m.darktrace.com] X-MS-Exchange-CrossTenant-AuthSource: ZR1PEPF0000E6B1.eurprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB4PR08MB9358 Hi, On 2026. 09. 23. 4:18, Andrew Morton wrote: > On Tue, 22 Sep 2026 09:29:31 +0200 Bence Csokas wrote: > >> Currently, if there are no registered handlers, >> cpu_cache_invalidate_memregion() returns 0. Callers are expected to check >> cpu_cache_has_invalidate_memregion() and return -ENXIO themselves, instead >> of calling this function. If a caller forgets to do this, they may >> erroneously think the operation succeeded. This is in contrast to x86, >> where cpu_cache_invalidate_memregion() itself checks if the operation is >> supported, and returns -ENXIO if it is not. > > Do you expect any callers to be altered as a result of this change? > > If so, full details would be helpful. Current callers, not necessarily. Future callers, maybe. Presently, as far as I see, there are 2 consumers: CXL and NVDIMM, with 3 call sites in total. 2 of these call sites [1] [2] are in the form of: if (!has_invalidate()) { if (TEST) return 0; return -ENXIO; } invalidate(); These types of call sites can stay as-is. The remaining one [3] is in a void function, and in the form: if (has_invalidate()) invalidate(); Lastly, while not a consumer, here's what x86 [4] does. It's possible a future caller will want to replicate this: if (!has_invalidate()) return -ENXIO; invalidate(); These types of call sites can do away with calling has_invalidate() going forward. [1] https://elixir.bootlin.com/linux/v7.3-rc3/source/drivers/cxl/core/region.c#L242 [2] https://elixir.bootlin.com/linux/v7.3-rc3/source/drivers/nvdimm/region_devs.c#L93 [3] https://elixir.bootlin.com/linux/v7.3-rc3/source/drivers/nvdimm/region.c#L113 [4] https://elixir.bootlin.com/linux/v7.3-rc3/source/arch/x86/mm/pat/set_memory.c#L372 Bence