[PATCH 4/5] mm: migrate: clean up migrate_prep{_local}

[Yang Shi]

The migrate_prep{_local} never fails, so it is pointless to have return
value and check the return value.

Signed-off-by: Yang Shi <shy828...@gmail.com>
---
 include/linux/migrate.h | 4 ++--
 mm/mempolicy.c          | 8 ++------
 mm/migrate.c            | 8 ++------
 3 files changed, 6 insertions(+), 14 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 0f8d1583fa8e..4594838a0f7c 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -45,8 +45,8 @@ extern struct page *alloc_migration_target(struct page *page, 
unsigned long priv
 extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
 extern void putback_movable_page(struct page *page);
 
-extern int migrate_prep(void);
-extern int migrate_prep_local(void);
+extern void migrate_prep(void);
+extern void migrate_prep_local(void);
 extern void migrate_page_states(struct page *newpage, struct page *page);
 extern void migrate_page_copy(struct page *newpage, struct page *page);
 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 3fde772ef5ef..780861312008 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1114,9 +1114,7 @@ int do_migrate_pages(struct mm_struct *mm, const 
nodemask_t *from,
        int err;
        nodemask_t tmp;
 
-       err = migrate_prep();
-       if (err)
-               return err;
+       migrate_prep();
 
        mmap_read_lock(mm);
 
@@ -1315,9 +1313,7 @@ static long do_mbind(unsigned long start, unsigned long 
len,
 
        if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
 
-               err = migrate_prep();
-               if (err)
-                       goto mpol_out;
+               migrate_prep();
        }
        {
                NODEMASK_SCRATCH(scratch);
diff --git a/mm/migrate.c b/mm/migrate.c
index 9a32bb128f31..8f6a61c9274b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -62,7 +62,7 @@
  * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is
  * undesirable, use migrate_prep_local()
  */
-int migrate_prep(void)
+void migrate_prep(void)
 {
        /*
         * Clear the LRU lists so pages can be isolated.
@@ -71,16 +71,12 @@ int migrate_prep(void)
         * pages that may be busy.
         */
        lru_add_drain_all();
-
-       return 0;
 }
 
 /* Do the necessary work of migrate_prep but not if it involves other CPUs */
-int migrate_prep_local(void)
+void migrate_prep_local(void)
 {
        lru_add_drain();
-
-       return 0;
 }
 
 int isolate_movable_page(struct page *page, isolate_mode_t mode)
-- 
2.26.2