mm/rmap: Constify the rmap_walk_control argument

The rmap walking functions do not modify the rmap_walk_control, and
page_idle_clear_pte_refs() takes advantage of that to move construction
of the rmap_walk_control to compile time.  This lets us remove an
unclean cast.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 0b4f17418f64c11ab7a840b398d8585733715194..0630e545f4cb1f8b351a0405877add0af15fc024 100644 (file)
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -51,7 +51,7 @@ static inline void ksm_exit(struct mm_struct *mm)
 struct page *ksm_might_need_to_copy(struct page *page,
                        struct vm_area_struct *vma, unsigned long address);
 
-void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc);
+void rmap_walk_ksm(struct folio *folio, const struct rmap_walk_control *rwc);
 void folio_migrate_ksm(struct folio *newfolio, struct folio *folio);
 
 #else  /* !CONFIG_KSM */
@@ -79,7 +79,7 @@ static inline struct page *ksm_might_need_to_copy(struct page *page,
 }
 
 static inline void rmap_walk_ksm(struct folio *folio,
-                       struct rmap_walk_control *rwc)
+                       const struct rmap_walk_control *rwc)
 {
 }
 

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index a74d811c5b3f3c27e84dd077d0b57a0171752432..17230c458341ee5f975d41ca9c7691b249a09f94 100644 (file)
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -292,8 +292,8 @@ struct rmap_walk_control {
        bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);
 };
 
-void rmap_walk(struct folio *folio, struct rmap_walk_control *rwc);
-void rmap_walk_locked(struct folio *folio, struct rmap_walk_control *rwc);
+void rmap_walk(struct folio *folio, const struct rmap_walk_control *rwc);
+void rmap_walk_locked(struct folio *folio, const struct rmap_walk_control *rwc);
 
 #else  /* !CONFIG_MMU */
 

diff --git a/mm/ksm.c b/mm/ksm.c
index dd737f925c04fff3063ede672903bde3655275f8..eed2ff25a2fb64cd8c303abc96d5e2d225ea83fc 100644 (file)
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2588,7 +2588,7 @@ struct page *ksm_might_need_to_copy(struct page *page,
        return new_page;
 }
 
-void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc)
+void rmap_walk_ksm(struct folio *folio, const struct rmap_walk_control *rwc)
 {
        struct stable_node *stable_node;
        struct rmap_item *rmap_item;

diff --git a/mm/page_idle.c b/mm/page_idle.c
index e34ba04e22e2acdb0574e7815170e8a9f0adb8b9..fc0435abf909506c043aaf9adb8ace7bb598f622 100644 (file)
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -103,7 +103,7 @@ static void page_idle_clear_pte_refs(struct page *page)
        if (need_lock && !folio_trylock(folio))
                return;
 
-       rmap_walk(folio, (struct rmap_walk_control *)&rwc);
+       rmap_walk(folio, &rwc);
 
        if (need_lock)
                folio_unlock(folio);

diff --git a/mm/rmap.c b/mm/rmap.c
index 2cc97c64901e82edec5ea4aed2f67bac06d9eb43..8192cb5809bcccf072fd7327c431b4f0d633a751 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -2173,7 +2173,7 @@ void __put_anon_vma(struct anon_vma *anon_vma)
 }
 
 static struct anon_vma *rmap_walk_anon_lock(struct folio *folio,
-                                       struct rmap_walk_control *rwc)
+                                       const struct rmap_walk_control *rwc)
 {
        struct anon_vma *anon_vma;
 
@@ -2203,8 +2203,8 @@ static struct anon_vma *rmap_walk_anon_lock(struct folio *folio,
  * Find all the mappings of a page using the mapping pointer and the vma chains
  * contained in the anon_vma struct it points to.
  */
-static void rmap_walk_anon(struct folio *folio, struct rmap_walk_control *rwc,
-               bool locked)
+static void rmap_walk_anon(struct folio *folio,
+               const struct rmap_walk_control *rwc, bool locked)
 {
        struct anon_vma *anon_vma;
        pgoff_t pgoff_start, pgoff_end;
@@ -2251,8 +2251,8 @@ static void rmap_walk_anon(struct folio *folio, struct rmap_walk_control *rwc,
  * Find all the mappings of a page using the mapping pointer and the vma chains
  * contained in the address_space struct it points to.
  */
-static void rmap_walk_file(struct folio *folio, struct rmap_walk_control *rwc,
-               bool locked)
+static void rmap_walk_file(struct folio *folio,
+               const struct rmap_walk_control *rwc, bool locked)
 {
        struct address_space *mapping = folio_mapping(folio);
        pgoff_t pgoff_start, pgoff_end;
@@ -2294,7 +2294,7 @@ done:
                i_mmap_unlock_read(mapping);
 }
 
-void rmap_walk(struct folio *folio, struct rmap_walk_control *rwc)
+void rmap_walk(struct folio *folio, const struct rmap_walk_control *rwc)
 {
        if (unlikely(folio_test_ksm(folio)))
                rmap_walk_ksm(folio, rwc);
@@ -2305,7 +2305,7 @@ void rmap_walk(struct folio *folio, struct rmap_walk_control *rwc)
 }
 
 /* Like rmap_walk, but caller holds relevant rmap lock */
-void rmap_walk_locked(struct folio *folio, struct rmap_walk_control *rwc)
+void rmap_walk_locked(struct folio *folio, const struct rmap_walk_control *rwc)
 {
        /* no ksm support for now */
        VM_BUG_ON_FOLIO(folio_test_ksm(folio), folio);