For improved const-correctness.
We select certain test functions which either invoke each other,
functions that are already const-ified, or no further functions.
It is therefore relatively trivial to const-ify them, which
provides a basis for further const-ification further up the call
stack.
(Even though seemingly unrelated, this also constifies the pointer
parameter of mmap_is_legacy() in arch/s390/mm/mmap.c because a copy of
the function exists in mm/util.c.)
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
---
arch/s390/mm/mmap.c | 2 +-
include/linux/mm.h | 6 +++---
include/linux/pagemap.h | 2 +-
mm/util.c | 10 +++++-----
4 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 547104ccc22a..e188cb6d4946 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -27,7 +27,7 @@ static unsigned long stack_maxrandom_size(void)
return STACK_RND_MASK << PAGE_SHIFT;
}
-static inline int mmap_is_legacy(struct rlimit *rlim_stack)
+static inline int mmap_is_legacy(const struct rlimit *rlim_stack)
{
if (current->personality & ADDR_COMPAT_LAYOUT)
return 1;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index f70c6b4d5f80..23864c3519d6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -986,7 +986,7 @@ static inline bool vma_is_shmem(const struct vm_area_struct *vma) { return false
static inline bool vma_is_anon_shmem(const struct vm_area_struct *vma) { return false; }
#endif
-int vma_is_stack_for_current(struct vm_area_struct *vma);
+int vma_is_stack_for_current(const struct vm_area_struct *vma);
/* flush_tlb_range() takes a vma, not a mm, and can care about flags */
#define TLB_FLUSH_VMA(mm,flags) { .vm_mm = (mm), .vm_flags = (flags) }
@@ -2585,7 +2585,7 @@ void folio_add_pin(struct folio *folio);
int account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc);
int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
- struct task_struct *task, bool bypass_rlim);
+ const struct task_struct *task, bool bypass_rlim);
struct kvec;
struct page *get_dump_page(unsigned long addr, int *locked);
@@ -3348,7 +3348,7 @@ void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
avc; avc = anon_vma_interval_tree_iter_next(avc, start, last))
/* mmap.c */
-extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
+extern int __vm_enough_memory(const struct mm_struct *mm, long pages, int cap_sys_admin);
extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
extern void exit_mmap(struct mm_struct *);
bool mmap_read_lock_maybe_expand(struct mm_struct *mm, struct vm_area_struct *vma,
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1d3803c397e9..185644e288ea 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -551,7 +551,7 @@ static inline void filemap_nr_thps_dec(struct address_space *mapping)
#endif
}
-struct address_space *folio_mapping(struct folio *);
+struct address_space *folio_mapping(const struct folio *folio);
/**
* folio_flush_mapping - Find the file mapping this folio belongs to.
diff --git a/mm/util.c b/mm/util.c
index d235b74f7aff..241d2eaf26ca 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -315,7 +315,7 @@ void *memdup_user_nul(const void __user *src, size_t len)
EXPORT_SYMBOL(memdup_user_nul);
/* Check if the vma is being used as a stack by this task */
-int vma_is_stack_for_current(struct vm_area_struct *vma)
+int vma_is_stack_for_current(const struct vm_area_struct *vma)
{
struct task_struct * __maybe_unused t = current;
@@ -410,7 +410,7 @@ unsigned long arch_mmap_rnd(void)
return rnd << PAGE_SHIFT;
}
-static int mmap_is_legacy(struct rlimit *rlim_stack)
+static int mmap_is_legacy(const struct rlimit *rlim_stack)
{
if (current->personality & ADDR_COMPAT_LAYOUT)
return 1;
@@ -504,7 +504,7 @@ EXPORT_SYMBOL_IF_KUNIT(arch_pick_mmap_layout);
* * -ENOMEM if RLIMIT_MEMLOCK would be exceeded.
*/
int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
- struct task_struct *task, bool bypass_rlim)
+ const struct task_struct *task, bool bypass_rlim)
{
unsigned long locked_vm, limit;
int ret = 0;
@@ -688,7 +688,7 @@ struct anon_vma *folio_anon_vma(const struct folio *folio)
* You can call this for folios which aren't in the swap cache or page
* cache and it will return NULL.
*/
-struct address_space *folio_mapping(struct folio *folio)
+struct address_space *folio_mapping(const struct folio *folio)
{
struct address_space *mapping;
@@ -926,7 +926,7 @@ EXPORT_SYMBOL_GPL(vm_memory_committed);
* Note this is a helper function intended to be used by LSMs which
* wish to use this logic.
*/
-int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
+int __vm_enough_memory(const struct mm_struct *mm, long pages, int cap_sys_admin)
{
long allowed;
unsigned long bytes_failed;
--
2.47.2On 01.09.25 22:50, Max Kellermann wrote: > For improved const-correctness. > > We select certain test functions which either invoke each other, > functions that are already const-ified, or no further functions. > > It is therefore relatively trivial to const-ify them, which > provides a basis for further const-ification further up the call > stack. > > (Even though seemingly unrelated, this also constifies the pointer > parameter of mmap_is_legacy() in arch/s390/mm/mmap.c because a copy of > the function exists in mm/util.c.) > > Signed-off-by: Max Kellermann <max.kellermann@ionos.com> > Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> > --- Acked-by: David Hildenbrand <david@redhat.com> -- Cheers David / dhildenb
On Mon, Sep 01, 2025 at 10:50:15PM +0200, Max Kellermann wrote:
> For improved const-correctness.
>
> We select certain test functions which either invoke each other,
> functions that are already const-ified, or no further functions.
>
> It is therefore relatively trivial to const-ify them, which
> provides a basis for further const-ification further up the call
> stack.
>
> (Even though seemingly unrelated, this also constifies the pointer
> parameter of mmap_is_legacy() in arch/s390/mm/mmap.c because a copy of
> the function exists in mm/util.c.)
>
> Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
LGTM, so:
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> ---
> arch/s390/mm/mmap.c | 2 +-
> include/linux/mm.h | 6 +++---
> include/linux/pagemap.h | 2 +-
> mm/util.c | 10 +++++-----
> 4 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
> index 547104ccc22a..e188cb6d4946 100644
> --- a/arch/s390/mm/mmap.c
> +++ b/arch/s390/mm/mmap.c
> @@ -27,7 +27,7 @@ static unsigned long stack_maxrandom_size(void)
> return STACK_RND_MASK << PAGE_SHIFT;
> }
>
> -static inline int mmap_is_legacy(struct rlimit *rlim_stack)
> +static inline int mmap_is_legacy(const struct rlimit *rlim_stack)
> {
> if (current->personality & ADDR_COMPAT_LAYOUT)
> return 1;
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index f70c6b4d5f80..23864c3519d6 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -986,7 +986,7 @@ static inline bool vma_is_shmem(const struct vm_area_struct *vma) { return false
> static inline bool vma_is_anon_shmem(const struct vm_area_struct *vma) { return false; }
> #endif
>
> -int vma_is_stack_for_current(struct vm_area_struct *vma);
> +int vma_is_stack_for_current(const struct vm_area_struct *vma);
>
> /* flush_tlb_range() takes a vma, not a mm, and can care about flags */
> #define TLB_FLUSH_VMA(mm,flags) { .vm_mm = (mm), .vm_flags = (flags) }
> @@ -2585,7 +2585,7 @@ void folio_add_pin(struct folio *folio);
>
> int account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc);
> int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
> - struct task_struct *task, bool bypass_rlim);
> + const struct task_struct *task, bool bypass_rlim);
>
> struct kvec;
> struct page *get_dump_page(unsigned long addr, int *locked);
> @@ -3348,7 +3348,7 @@ void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
> avc; avc = anon_vma_interval_tree_iter_next(avc, start, last))
>
> /* mmap.c */
> -extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
> +extern int __vm_enough_memory(const struct mm_struct *mm, long pages, int cap_sys_admin);
> extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
> extern void exit_mmap(struct mm_struct *);
> bool mmap_read_lock_maybe_expand(struct mm_struct *mm, struct vm_area_struct *vma,
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 1d3803c397e9..185644e288ea 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -551,7 +551,7 @@ static inline void filemap_nr_thps_dec(struct address_space *mapping)
> #endif
> }
>
> -struct address_space *folio_mapping(struct folio *);
> +struct address_space *folio_mapping(const struct folio *folio);
>
> /**
> * folio_flush_mapping - Find the file mapping this folio belongs to.
> diff --git a/mm/util.c b/mm/util.c
> index d235b74f7aff..241d2eaf26ca 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -315,7 +315,7 @@ void *memdup_user_nul(const void __user *src, size_t len)
> EXPORT_SYMBOL(memdup_user_nul);
>
> /* Check if the vma is being used as a stack by this task */
> -int vma_is_stack_for_current(struct vm_area_struct *vma)
> +int vma_is_stack_for_current(const struct vm_area_struct *vma)
> {
> struct task_struct * __maybe_unused t = current;
>
> @@ -410,7 +410,7 @@ unsigned long arch_mmap_rnd(void)
> return rnd << PAGE_SHIFT;
> }
>
> -static int mmap_is_legacy(struct rlimit *rlim_stack)
> +static int mmap_is_legacy(const struct rlimit *rlim_stack)
> {
> if (current->personality & ADDR_COMPAT_LAYOUT)
> return 1;
> @@ -504,7 +504,7 @@ EXPORT_SYMBOL_IF_KUNIT(arch_pick_mmap_layout);
> * * -ENOMEM if RLIMIT_MEMLOCK would be exceeded.
> */
> int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
> - struct task_struct *task, bool bypass_rlim)
> + const struct task_struct *task, bool bypass_rlim)
> {
> unsigned long locked_vm, limit;
> int ret = 0;
> @@ -688,7 +688,7 @@ struct anon_vma *folio_anon_vma(const struct folio *folio)
> * You can call this for folios which aren't in the swap cache or page
> * cache and it will return NULL.
> */
> -struct address_space *folio_mapping(struct folio *folio)
> +struct address_space *folio_mapping(const struct folio *folio)
> {
> struct address_space *mapping;
>
> @@ -926,7 +926,7 @@ EXPORT_SYMBOL_GPL(vm_memory_committed);
> * Note this is a helper function intended to be used by LSMs which
> * wish to use this logic.
> */
> -int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
> +int __vm_enough_memory(const struct mm_struct *mm, long pages, int cap_sys_admin)
> {
> long allowed;
> unsigned long bytes_failed;
> --
> 2.47.2
>
© 2016 - 2025 Red Hat, Inc.