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[2003:dc:6f1d:f00:230:64ff:fe74:809]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-afefcbd8656sm597512566b.56.2025.08.31.02.39.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Aug 2025 02:39:35 -0700 (PDT) From: Max Kellermann To: akpm@linux-foundation.org, david@redhat.com, axelrasmussen@google.com, yuanchu@google.com, willy@infradead.org, hughd@google.com, mhocko@suse.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, vishal.moola@gmail.com Cc: Max Kellermann Subject: [PATCH v2 00/12] mm: add `const` to lots of pointer parameters Date: Sun, 31 Aug 2025 11:39:06 +0200 Message-ID: <20250831093918.2815332-1-max.kellermann@ionos.com> X-Mailer: git-send-email 2.47.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 4FB7540005 X-Rspamd-Server: rspam04 X-Rspam-User: X-Stat-Signature: 76cc9aemwu75b8a8m78yqnjr68taaqst X-HE-Tag: 1756633177-570407 X-HE-Meta: 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 ngNXzw1/ 31o0AjT1qC/LAf5vz7BJbPtdd3kKzoT8JZxU6vIz/1fpugCgClEQCmpDu4seinbsyJMPPkd1Qi06RwtxuGUYSHz8Sly50/R7Z4cYh1k+lqNnE33usgQ6CRvBKyjh24YYSxTt1btnY6FRP35EIWzvBEdtgAJ2UKXWnT+adUuiMYI1gANGlubUyOdtDiuC2YBjaqWHsB9s45kTnsraCXdcpTbLAHJdq8z66fTgT9LshvGR6v33GpgC+7CL1XWym0Oil8vfEkTMWZFMCk4bz3ThWUYgdghXp+nvxU6ZjRvRIENL+nL/svINMU9ZQW2wuAEv5o3/nGCeguGA4PHVpN6CNIiDqaxKbZJnd2Vx2dRAz/Pwk5QaYLWeQ0XxivWhXk/w+kNBqUnkcZ7Qa5ElzdwESYSmAexUDt57JYWGRSezVdVSNk6k= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: For improved const-correctness. This work was initially posted here: https://lore.kernel.org/lkml/20250827192233.447920-1-max.kellermann@ionos.com/ .. but got rejected by Lorenzo Stoakes: https://lore.kernel.org/lkml/d6bf808d-7d74-4e22-ac4b-a6d1f4892262@lucifer.local/ David Hildenbrand and Lorenzo Stoakes suggested splitting the patch into smaller chunks. My second attempt with one smaller patch was met with agreement: https://lore.kernel.org/lkml/20250828130311.772993-1-max.kellermann@ionos.com/ Now this is the rest of the initial patch in small pieces, plus some more. Establishing const-correctness in this low-level part of the kernel enables doing the same in higher-level parts, e.g. filesystems. Signed-off-by: Max Kellermann --- v1-> v2: - made several parameter values const (i.e. the pointer address, not just the pointed-to memory), as suggested by Andrew Morton and Yuanchu Xie - drop existing+obsolete "extern" keywords on lines modified by these patches (suggested by Vishal Moola) - add missing parameter names on lines modified by these patches (suggested by Vishal Moola) - more "const" pointers (e.g. the task_struct passed to process_shares_mm()) - add missing "const" to s390, fixing s390 build failure - moved the mmap_is_legacy() change in arch/s390/mm/mmap.c from 08/12 to 06/12 (suggested by Vishal Moola) Max Kellermann (12): mm/shmem: add `const` to lots of pointer parameters include/pagemap.h: add `const` to lots of pointer parameters include/mmzone.h: add `const` to lots of pointer parameters include/fs.h: add `const` to several pointer parameters mm/oom_kill: add `const` to pointer parameter mm/util: add `const` to several pointer parameters parisc/sys_parisc.c: add `const` to mmap_upper_limit() parameter arch, mm/util: add const to arch_pick_mmap_layout() parameter include/mm_types.h: add `const` to several pointer parameters include/mm_inline.h: add `const` to lots of pointer parameters include/mm.h: add `const` to lots of pointer parameters mm/highmem: add `const` to lots of pointer parameters arch/arm/include/asm/highmem.h | 6 +-- arch/parisc/include/asm/processor.h | 2 +- arch/parisc/kernel/sys_parisc.c | 2 +- arch/s390/mm/mmap.c | 7 ++-- arch/sparc/kernel/sys_sparc_64.c | 5 ++- arch/x86/mm/mmap.c | 7 ++-- arch/xtensa/include/asm/highmem.h | 2 +- include/linux/fs.h | 7 ++-- include/linux/highmem-internal.h | 38 ++++++++++--------- include/linux/highmem.h | 8 ++-- include/linux/mm.h | 48 +++++++++++------------ include/linux/mm_inline.h | 26 +++++++------ include/linux/mm_types.h | 4 +- include/linux/mmzone.h | 42 ++++++++++---------- include/linux/pagemap.h | 59 +++++++++++++++-------------- include/linux/sched/mm.h | 4 +- include/linux/shmem_fs.h | 4 +- mm/highmem.c | 10 ++--- mm/oom_kill.c | 3 +- mm/shmem.c | 6 +-- mm/util.c | 20 ++++++---- 21 files changed, 163 insertions(+), 147 deletions(-) -- 2.47.2