mm: make rmap_walk() return void

There is no user of the return value from rmap_walk() and friends so
this patch makes them void-returning functions.

Link: http://lkml.kernel.org/r/1489555493-14659-9-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 23 insertions, 34 deletions

diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index e1cfda4bee58..78b44a024eaa 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -61,7 +61,7 @@ static inline void set_page_stable_node(struct page *page,
 struct page *ksm_might_need_to_copy(struct page *page,
                         struct vm_area_struct *vma, unsigned long address);
 
-int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc);
+void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc);
 void ksm_migrate_page(struct page *newpage, struct page *oldpage);
 
 #else  /* !CONFIG_KSM */
@@ -94,10 +94,9 @@ static inline int page_referenced_ksm(struct page *page,
         return 0;
 }
 
-static inline int rmap_walk_ksm(struct page *page,
+static inline void rmap_walk_ksm(struct page *page,
                         struct rmap_walk_control *rwc)
 {
-        return 0;
 }
 
 static inline void ksm_migrate_page(struct page *newpage, struct page *oldpage)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 6028c38d3cac..1d7d457ca0dc 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -264,8 +264,8 @@ struct rmap_walk_control {
         bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);
 };
 
-int rmap_walk(struct page *page, struct rmap_walk_control *rwc);
-int rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc);
+void rmap_walk(struct page *page, struct rmap_walk_control *rwc);
+void rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc);
 
 #else   /* !CONFIG_MMU */
 
diff --git a/mm/ksm.c b/mm/ksm.c
index 19b4f2dea7a5..6edffb9a795b 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1933,11 +1933,10 @@ struct page *ksm_might_need_to_copy(struct page *page,
         return new_page;
 }
 
-int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
+void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
 {
         struct stable_node *stable_node;
         struct rmap_item *rmap_item;
-        int ret = SWAP_AGAIN;
         int search_new_forks = 0;
 
         VM_BUG_ON_PAGE(!PageKsm(page), page);
@@ -1950,7 +1949,7 @@ int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
 
         stable_node = page_stable_node(page);
         if (!stable_node)
-                return ret;
+                return;
 again:
         hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {
                 struct anon_vma *anon_vma = rmap_item->anon_vma;
@@ -1978,23 +1977,20 @@ again:
                         if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
                                 continue;
 
-                        ret = rwc->rmap_one(page, vma,
-                                        rmap_item->address, rwc->arg);
-                        if (ret != SWAP_AGAIN) {
+                        if (SWAP_AGAIN != rwc->rmap_one(page, vma,
+                                        rmap_item->address, rwc->arg)) {
                                 anon_vma_unlock_read(anon_vma);
-                                goto out;
+                                return;
                         }
                         if (rwc->done && rwc->done(page)) {
                                 anon_vma_unlock_read(anon_vma);
-                                goto out;
+                                return;
                         }
                 }
                 anon_vma_unlock_read(anon_vma);
         }
         if (!search_new_forks++)
                 goto again;
-out:
-        return ret;
 }
 
 #ifdef CONFIG_MIGRATION
diff --git a/mm/rmap.c b/mm/rmap.c
index 928bdfe2be30..3b40d47e3300 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1607,13 +1607,12 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page,
  * vm_flags for that VMA.  That should be OK, because that vma shouldn't be
  * LOCKED.
  */
-static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
+static void rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
                 bool locked)
 {
         struct anon_vma *anon_vma;
         pgoff_t pgoff_start, pgoff_end;
         struct anon_vma_chain *avc;
-        int ret = SWAP_AGAIN;
 
         if (locked) {
                 anon_vma = page_anon_vma(page);
@@ -1623,7 +1622,7 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
                 anon_vma = rmap_walk_anon_lock(page, rwc);
         }
         if (!anon_vma)
-                return ret;
+                return;
 
         pgoff_start = page_to_pgoff(page);
         pgoff_end = pgoff_start + hpage_nr_pages(page) - 1;
@@ -1637,8 +1636,7 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
                 if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
                         continue;
 
-                ret = rwc->rmap_one(page, vma, address, rwc->arg);
-                if (ret != SWAP_AGAIN)
+                if (SWAP_AGAIN != rwc->rmap_one(page, vma, address, rwc->arg))
                         break;
                 if (rwc->done && rwc->done(page))
                         break;
@@ -1646,7 +1644,6 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
 
         if (!locked)
                 anon_vma_unlock_read(anon_vma);
-        return ret;
 }
 
 /*
@@ -1662,13 +1659,12 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
  * vm_flags for that VMA.  That should be OK, because that vma shouldn't be
  * LOCKED.
  */
-static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
+static void rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
                 bool locked)
 {
         struct address_space *mapping = page_mapping(page);
         pgoff_t pgoff_start, pgoff_end;
         struct vm_area_struct *vma;
-        int ret = SWAP_AGAIN;
 
         /*
          * The page lock not only makes sure that page->mapping cannot
@@ -1679,7 +1675,7 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
         VM_BUG_ON_PAGE(!PageLocked(page), page);
 
         if (!mapping)
-                return ret;
+                return;
 
         pgoff_start = page_to_pgoff(page);
         pgoff_end = pgoff_start + hpage_nr_pages(page) - 1;
@@ -1694,8 +1690,7 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
                 if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
                         continue;
 
-                ret = rwc->rmap_one(page, vma, address, rwc->arg);
-                if (ret != SWAP_AGAIN)
+                if (SWAP_AGAIN != rwc->rmap_one(page, vma, address, rwc->arg))
                         goto done;
                 if (rwc->done && rwc->done(page))
                         goto done;
@@ -1704,28 +1699,27 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
 done:
         if (!locked)
                 i_mmap_unlock_read(mapping);
-        return ret;
 }
 
-int rmap_walk(struct page *page, struct rmap_walk_control *rwc)
+void rmap_walk(struct page *page, struct rmap_walk_control *rwc)
 {
         if (unlikely(PageKsm(page)))
-                return rmap_walk_ksm(page, rwc);
+                rmap_walk_ksm(page, rwc);
         else if (PageAnon(page))
-                return rmap_walk_anon(page, rwc, false);
+                rmap_walk_anon(page, rwc, false);
         else
-                return rmap_walk_file(page, rwc, false);
+                rmap_walk_file(page, rwc, false);
 }
 
 /* Like rmap_walk, but caller holds relevant rmap lock */
-int rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc)
+void rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc)
 {
         /* no ksm support for now */
         VM_BUG_ON_PAGE(PageKsm(page), page);
         if (PageAnon(page))
-                return rmap_walk_anon(page, rwc, true);
+                rmap_walk_anon(page, rwc, true);
         else
-                return rmap_walk_file(page, rwc, true);
+                rmap_walk_file(page, rwc, true);
 }
 
 #ifdef CONFIG_HUGETLB_PAGE