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[2003:dc:6f1d:f00:230:64ff:fe74:809]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b01902d0e99sm541005766b.12.2025.09.01.02.19.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Sep 2025 02:19:29 -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, linux@armlinux.org.uk, James.Bottomley@HansenPartnership.com, deller@gmx.de, agordeev@linux.ibm.com, gerald.schaefer@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, davem@davemloft.net, andreas@gaisler.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, chris@zankel.net, jcmvbkbc@gmail.com, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, weixugc@google.com, baolin.wang@linux.alibaba.com, rientjes@google.com, shakeel.butt@linux.dev, max.kellermann@ionos.com, thuth@redhat.com, broonie@kernel.org, osalvador@suse.de, jfalempe@redhat.com, mpe@ellerman.id.au, nysal@linux.ibm.com, linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v4 03/12] mm/mmzone: add const to pointer parameters for improved const-correctness Date: Mon, 1 Sep 2025 11:19:06 +0200 Message-ID: <20250901091916.3002082-4-max.kellermann@ionos.com> X-Mailer: git-send-email 2.47.2 In-Reply-To: <20250901091916.3002082-1-max.kellermann@ionos.com> References: <20250901091916.3002082-1-max.kellermann@ionos.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The memory management (mm) subsystem is a fundamental low-level component of the Linux kernel. Establishing const-correctness at this foundational level enables higher-level subsystems, such as filesystems and drivers, to also adopt const-correctness in their interfaces. This patch lays the groundwork for broader const-correctness throughout the kernel by starting with the core mm subsystem. This patch adds const qualifiers to zone, zoneref, and mem_section pointer parameters in mmzone.h functions that do not modify the referenced memory, improving type safety and enabling compiler optimizations. Functions improved: - zone_managed_pages() - zone_is_initialized() - zone_is_empty() - zone_intersects() - zone_is_zone_device() - managed_zone() - populated_zone() - zone_to_nid() - is_highmem() - zonelist_zone_idx() - zonelist_node_idx() - present_section() - valid_section() - early_section() - online_section() - online_device_section() - preinited_vmemmap_section() Signed-off-by: Max Kellermann Reviewed-by: Vishal Moola (Oracle) --- include/linux/mmzone.h | 42 +++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 21 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index f3272ef5131b..9a25fb1ade82 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1104,7 +1104,7 @@ static inline unsigned long promo_wmark_pages(const s= truct zone *z) return wmark_pages(z, WMARK_PROMO); } =20 -static inline unsigned long zone_managed_pages(struct zone *zone) +static inline unsigned long zone_managed_pages(const struct zone *const zo= ne) { return (unsigned long)atomic_long_read(&zone->managed_pages); } @@ -1128,12 +1128,12 @@ static inline bool zone_spans_pfn(const struct zone= *zone, unsigned long pfn) return zone->zone_start_pfn <=3D pfn && pfn < zone_end_pfn(zone); } =20 -static inline bool zone_is_initialized(struct zone *zone) +static inline bool zone_is_initialized(const struct zone *const zone) { return zone->initialized; } =20 -static inline bool zone_is_empty(struct zone *zone) +static inline bool zone_is_empty(const struct zone *const zone) { return zone->spanned_pages =3D=3D 0; } @@ -1273,7 +1273,7 @@ static inline bool folio_is_zone_movable(const struct= folio *folio) * Return true if [start_pfn, start_pfn + nr_pages) range has a non-empty * intersection with the given zone */ -static inline bool zone_intersects(struct zone *zone, +static inline bool zone_intersects(const struct zone *const zone, unsigned long start_pfn, unsigned long nr_pages) { if (zone_is_empty(zone)) @@ -1581,12 +1581,12 @@ static inline int local_memory_node(int node_id) { = return node_id; }; #define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones) =20 #ifdef CONFIG_ZONE_DEVICE -static inline bool zone_is_zone_device(struct zone *zone) +static inline bool zone_is_zone_device(const struct zone *const zone) { return zone_idx(zone) =3D=3D ZONE_DEVICE; } #else -static inline bool zone_is_zone_device(struct zone *zone) +static inline bool zone_is_zone_device(const struct zone *const zone) { return false; } @@ -1598,19 +1598,19 @@ static inline bool zone_is_zone_device(struct zone = *zone) * populated_zone(). If the whole zone is reserved then we can easily * end up with populated_zone() && !managed_zone(). */ -static inline bool managed_zone(struct zone *zone) +static inline bool managed_zone(const struct zone *const zone) { return zone_managed_pages(zone); } =20 /* Returns true if a zone has memory */ -static inline bool populated_zone(struct zone *zone) +static inline bool populated_zone(const struct zone *const zone) { return zone->present_pages; } =20 #ifdef CONFIG_NUMA -static inline int zone_to_nid(struct zone *zone) +static inline int zone_to_nid(const struct zone *const zone) { return zone->node; } @@ -1620,7 +1620,7 @@ static inline void zone_set_nid(struct zone *zone, in= t nid) zone->node =3D nid; } #else -static inline int zone_to_nid(struct zone *zone) +static inline int zone_to_nid(const struct zone *zone) { return 0; } @@ -1647,7 +1647,7 @@ static inline int is_highmem_idx(enum zone_type idx) * @zone: pointer to struct zone variable * Return: 1 for a highmem zone, 0 otherwise */ -static inline int is_highmem(struct zone *zone) +static inline int is_highmem(const struct zone *const zone) { return is_highmem_idx(zone_idx(zone)); } @@ -1713,12 +1713,12 @@ static inline struct zone *zonelist_zone(struct zon= eref *zoneref) return zoneref->zone; } =20 -static inline int zonelist_zone_idx(struct zoneref *zoneref) +static inline int zonelist_zone_idx(const struct zoneref *const zoneref) { return zoneref->zone_idx; } =20 -static inline int zonelist_node_idx(struct zoneref *zoneref) +static inline int zonelist_node_idx(const struct zoneref *const zoneref) { return zone_to_nid(zoneref->zone); } @@ -2021,7 +2021,7 @@ static inline struct page *__section_mem_map_addr(str= uct mem_section *section) return (struct page *)map; } =20 -static inline int present_section(struct mem_section *section) +static inline int present_section(const struct mem_section *const section) { return (section && (section->section_mem_map & SECTION_MARKED_PRESENT)); } @@ -2031,12 +2031,12 @@ static inline int present_section_nr(unsigned long = nr) return present_section(__nr_to_section(nr)); } =20 -static inline int valid_section(struct mem_section *section) +static inline int valid_section(const struct mem_section *const section) { return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP)); } =20 -static inline int early_section(struct mem_section *section) +static inline int early_section(const struct mem_section *const section) { return (section && (section->section_mem_map & SECTION_IS_EARLY)); } @@ -2046,27 +2046,27 @@ static inline int valid_section_nr(unsigned long nr) return valid_section(__nr_to_section(nr)); } =20 -static inline int online_section(struct mem_section *section) +static inline int online_section(const struct mem_section *const section) { return (section && (section->section_mem_map & SECTION_IS_ONLINE)); } =20 #ifdef CONFIG_ZONE_DEVICE -static inline int online_device_section(struct mem_section *section) +static inline int online_device_section(const struct mem_section *const se= ction) { unsigned long flags =3D SECTION_IS_ONLINE | SECTION_TAINT_ZONE_DEVICE; =20 return section && ((section->section_mem_map & flags) =3D=3D flags); } #else -static inline int online_device_section(struct mem_section *section) +static inline int online_device_section(const struct mem_section *const se= ction) { return 0; } #endif =20 #ifdef CONFIG_SPARSEMEM_VMEMMAP_PREINIT -static inline int preinited_vmemmap_section(struct mem_section *section) +static inline int preinited_vmemmap_section(const struct mem_section *cons= t section) { return (section && (section->section_mem_map & SECTION_IS_VMEMMAP_PREINIT)); @@ -2076,7 +2076,7 @@ void sparse_vmemmap_init_nid_early(int nid); void sparse_vmemmap_init_nid_late(int nid); =20 #else -static inline int preinited_vmemmap_section(struct mem_section *section) +static inline int preinited_vmemmap_section(const struct mem_section *cons= t section) { return 0; } --=20 2.47.2