5 files changed, 27 insertions, 21 deletions

diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 45c9b6a17bcb..0eef8cb0baf7 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -76,8 +76,7 @@ struct page *ksm_might_need_to_copy(struct page *page,
 int page_referenced_ksm(struct page *page,
                         struct mem_cgroup *memcg, unsigned long *vm_flags);
 int try_to_unmap_ksm(struct page *page, enum ttu_flags flags);
-int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *,
-                  struct vm_area_struct *, unsigned long, void *), void *arg);
+int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc);
 void ksm_migrate_page(struct page *newpage, struct page *oldpage);
 
 #else  /* !CONFIG_KSM */
@@ -120,8 +119,8 @@ static inline int try_to_unmap_ksm(struct page *page, enum ttu_flags flags)
         return 0;
 }
 
-static inline int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page*,
-                struct vm_area_struct *, unsigned long, void *), void *arg)
+static inline int rmap_walk_ksm(struct page *page,
+                        struct rmap_walk_control *rwc)
 {
         return 0;
 }
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 6dacb93a6d94..6a456ce6de20 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -235,11 +235,16 @@ struct anon_vma *page_lock_anon_vma_read(struct page *page);
 void page_unlock_anon_vma_read(struct anon_vma *anon_vma);
 int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
 
+struct rmap_walk_control {
+        void *arg;
+        int (*rmap_one)(struct page *page, struct vm_area_struct *vma,
+                                        unsigned long addr, void *arg);
+};
+
 /*
  * Called by migrate.c to remove migration ptes, but might be used more later.
  */
-int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
-                struct vm_area_struct *, unsigned long, void *), void *arg);
+int rmap_walk(struct page *page, struct rmap_walk_control *rwc);
 
 #else   /* !CONFIG_MMU */
 
diff --git a/mm/ksm.c b/mm/ksm.c
index 175fff79dc95..c3035fee8080 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1997,8 +1997,7 @@ out:
 }
 
 #ifdef CONFIG_MIGRATION
-int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *,
-                  struct vm_area_struct *, unsigned long, void *), void *arg)
+int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
 {
         struct stable_node *stable_node;
         struct rmap_item *rmap_item;
@@ -2033,7 +2032,8 @@ again:
                         if ((rmap_item->mm == vma->vm_mm) == search_new_forks)
                                 continue;
 
-                        ret = rmap_one(page, vma, rmap_item->address, arg);
+                        ret = rwc->rmap_one(page, vma,
+                                        rmap_item->address, rwc->arg);
                         if (ret != SWAP_AGAIN) {
                                 anon_vma_unlock_read(anon_vma);
                                 goto out;
diff --git a/mm/migrate.c b/mm/migrate.c
index 9194375b2307..11d89dc0574c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -199,7 +199,12 @@ out:
  */
 static void remove_migration_ptes(struct page *old, struct page *new)
 {
-        rmap_walk(new, remove_migration_pte, old);
+        struct rmap_walk_control rwc = {
+                .rmap_one = remove_migration_pte,
+                .arg = old,
+        };
+
+        rmap_walk(new, &rwc);
 }
 
 /*
diff --git a/mm/rmap.c b/mm/rmap.c
index 5a79bf585e27..f8f10ad5d359 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1706,8 +1706,7 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page)
  * rmap_walk() and its helpers rmap_walk_anon() and rmap_walk_file():
  * Called by migrate.c to remove migration ptes, but might be used more later.
  */
-static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
-                struct vm_area_struct *, unsigned long, void *), void *arg)
+static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
 {
         struct anon_vma *anon_vma;
         pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
@@ -1721,7 +1720,7 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
         anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
                 struct vm_area_struct *vma = avc->vma;
                 unsigned long address = vma_address(page, vma);
-                ret = rmap_one(page, vma, address, arg);
+                ret = rwc->rmap_one(page, vma, address, rwc->arg);
                 if (ret != SWAP_AGAIN)
                         break;
         }
@@ -1729,8 +1728,7 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
         return ret;
 }
 
-static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
-                struct vm_area_struct *, unsigned long, void *), void *arg)
+static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc)
 {
         struct address_space *mapping = page->mapping;
         pgoff_t pgoff = page->index << compound_order(page);
@@ -1742,7 +1740,7 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
         mutex_lock(&mapping->i_mmap_mutex);
         vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
                 unsigned long address = vma_address(page, vma);
-                ret = rmap_one(page, vma, address, arg);
+                ret = rwc->rmap_one(page, vma, address, rwc->arg);
                 if (ret != SWAP_AGAIN)
                         break;
         }
@@ -1755,17 +1753,16 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
         return ret;
 }
 
-int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
-                struct vm_area_struct *, unsigned long, void *), void *arg)
+int rmap_walk(struct page *page, struct rmap_walk_control *rwc)
 {
         VM_BUG_ON(!PageLocked(page));
 
         if (unlikely(PageKsm(page)))
-                return rmap_walk_ksm(page, rmap_one, arg);
+                return rmap_walk_ksm(page, rwc);
         else if (PageAnon(page))
-                return rmap_walk_anon(page, rmap_one, arg);
+                return rmap_walk_anon(page, rwc);
         else
-                return rmap_walk_file(page, rmap_one, arg);
+                return rmap_walk_file(page, rwc);
 }
 #endif /* CONFIG_MIGRATION */