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Howlett" , "Vlastimil Babka" , "Jann Horn" , "Pedro Falcato" , "David Hildenbrand" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Jonathan Corbet" , "Greg Kroah-Hartman" , "Dennis Dalessandro" , "Jason Gunthorpe" , "Leon Romanovsky" , "Paul Moore" , "Stephen Smalley" , "Jaroslav Kysela" , "Takashi Iwai" , "Alexei Starovoitov" , "Daniel Borkmann" , "Andrii Nakryiko" , "Eduard Zingerman" , "Kumar Kartikeya Dwivedi" , "Baolin Wang" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Barry Song" , "Lance Yang" , "Usama Arif" , "Kiryl Shutsemau" , "Doug Gilbert" , "James E.J. Bottomley" , "Martin K. Petersen" , "Jaya Kumar" , "Simona Vetter" , "Helge Deller" , "Sebastian Reichel" , "John Hubbard" , "Peter Xu" , "Masami Hiramatsu" , "Oleg Nesterov" , "Peter Zijlstra" , "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "Dave Hansen" , , "Arnaldo Carvalho de Melo" , "Namhyung Kim" , "Mark Rutland" , "Rik van Riel" , "Harry Yoo" , "Juri Lelli" , "Vincent Guittot" , "Maarten Lankhorst" , "Maxime Ripard" , "Thomas Zimmermann" , "David Airlie" , "Will Deacon" , "Aneesh Kumar K.V" , "Nick Piggin" , "Arnd Bergmann" , "Muchun Song" , "Oscar Salvador" , "Matthew Wilcox (Oracle)" , "Jan Kara" , "Marc Zyngier" , "Oliver Upton" , "Catalin Marinas" , "Madhavan Srinivasan" , "Anup Patel" , "Paul Walmsley" , "Palmer Dabbelt" , "Albert Ou" , "Christian Borntraeger" , "Janosch Frank" , "Claudio Imbrenda" , "Alexander Gordeev" , "Gerald Schaefer" , "Heiko Carstens" , "Vasily Gorbik" , "David S. Miller" , "Andreas Larsson" , "Alexander Viro" , "Christian Brauner" , "Matthew Brost" , "Joshua Hahn" , "Rakie Kim" , "Byungchul Park" , "Gregory Price" , "Ying Huang" , "Alistair Popple" , "Chris Li" , "Kairui Song" , "Kemeng Shi" , "Nhat Pham" , "Baoquan He" , "Youngjun Park" , "Johannes Weiner" , "Qi Zheng" , "Shakeel Butt" , "Axel Rasmussen" , "Yuanchu Xie" , "Wei Xu" , "Chengming Zhou" , "Michal Hocko" , "Miklos Szeredi" , "Xu Xin" From: "Zi Yan" X-Mailer: aerc 0.22.0 References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> <20260917-b4-mmap-prepare-vma-flag-sanify-v3-33-4583d8a23bca@kernel.org> In-Reply-To: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-33-4583d8a23bca@kernel.org> X-ClientProxiedBy: YQBPR0101CA0140.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c01:e::13) To IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) 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: IA0PR12MB8374:EE_|CH1PPF2EB7CF87B:EE_ X-MS-Office365-Filtering-Correlation-Id: bd9379ec-ac7f-4064-b53f-08df1e9a7a1b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|1800799024|7416014|376014|366016|11063799006|10067099003|921020|56012099006|18002099003|22082099003|4143699003; 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Previously we simply > disallowed VM_SPECIAL i.e. kernel-owned mappings, fixed mappings and > VMA_IO_BIT. > > Now the invariant is established that only kernel-owned mappings can set > VMA_IO_BIT, the VMA_IO_BIT check is redundant. > > The rest is equivalent to testing for a kernel-owned or fixed mapping, > i.e. exactly the same check as whether the VMA is permitted to be merged. > > This was established by commit 0b2758f48f22 ("Require (reasonably) normal > mappings for MADV_DOFORK") containing my hands-down favourite call out of > all time. > > Express the same thing differently - if we wouldn't be allowed to merge i= t, > then we aren't allowed to manipulate CoW behaviour on fork. > > No functional change intended. > > Signed-off-by: Lorenzo Stoakes (ARM) > --- > mm/madvise.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > Makes sense. Acked-by: Zi Yan --=20 Best Regards, Yan, Zi