mm, s390: constify mapping related test/getter functions

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.)

Link: https://lkml.kernel.org/r/20250901205021.3573313-7-max.kellermann@ionos.com
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Zankel <chris@zankel.net>
Cc: David Rientjes <rientjes@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Bottomley <james.bottomley@HansenPartnership.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jocelyn Falempe <jfalempe@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Nysal Jan K.A" <nysal@linux.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russel King <linux@armlinux.org.uk>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Huth <thuth@redhat.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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 b3b63058e1a3..221e98bb7689 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1002,7 +1002,7 @@ 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) }
@@ -2617,7 +2617,7 @@ 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);
@@ -3380,7 +3380,7 @@ 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 0d66a252b06f..aec4a11565bc 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -545,7 +545,7 @@ 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 e29d3310e26b..391f6e7daf83 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;