mm: migrate: move migrate_page_lock_buffers()

buffer_migrate_page() is the only caller of migrate_page_lock_buffers()
move it close to it and also drop the now unused stub for !CONFIG_BLOCK.

Link: http://lkml.kernel.org/r/20181211172143.7358-4-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/migrate.c b/mm/migrate.c
index e0bc03e..8392140 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -374,56 +374,6 @@ unlock:
 }
 #endif
 
-#ifdef CONFIG_BLOCK
-/* Returns true if all buffers are successfully locked */
-static bool buffer_migrate_lock_buffers(struct buffer_head *head,
-                                                       enum migrate_mode mode)
-{
-       struct buffer_head *bh = head;
-
-       /* Simple case, sync compaction */
-       if (mode != MIGRATE_ASYNC) {
-               do {
-                       get_bh(bh);
-                       lock_buffer(bh);
-                       bh = bh->b_this_page;
-
-               } while (bh != head);
-
-               return true;
-       }
-
-       /* async case, we cannot block on lock_buffer so use trylock_buffer */
-       do {
-               get_bh(bh);
-               if (!trylock_buffer(bh)) {
-                       /*
-                        * We failed to lock the buffer and cannot stall in
-                        * async migration. Release the taken locks
-                        */
-                       struct buffer_head *failed_bh = bh;
-                       put_bh(failed_bh);
-                       bh = head;
-                       while (bh != failed_bh) {
-                               unlock_buffer(bh);
-                               put_bh(bh);
-                               bh = bh->b_this_page;
-                       }
-                       return false;
-               }
-
-               bh = bh->b_this_page;
-       } while (bh != head);
-       return true;
-}
-#else
-static inline bool buffer_migrate_lock_buffers(struct buffer_head *head,
-                                                       enum migrate_mode mode)
-{
-       return true;
-}
-#endif /* CONFIG_BLOCK */
-
 static int expected_page_refs(struct page *page)
 {
        int expected_count = 1;
@@ -751,6 +701,48 @@ int migrate_page(struct address_space *mapping,
 EXPORT_SYMBOL(migrate_page);
 
 #ifdef CONFIG_BLOCK
+/* Returns true if all buffers are successfully locked */
+static bool buffer_migrate_lock_buffers(struct buffer_head *head,
+                                                       enum migrate_mode mode)
+{
+       struct buffer_head *bh = head;
+
+       /* Simple case, sync compaction */
+       if (mode != MIGRATE_ASYNC) {
+               do {
+                       get_bh(bh);
+                       lock_buffer(bh);
+                       bh = bh->b_this_page;
+
+               } while (bh != head);
+
+               return true;
+       }
+
+       /* async case, we cannot block on lock_buffer so use trylock_buffer */
+       do {
+               get_bh(bh);
+               if (!trylock_buffer(bh)) {
+                       /*
+                        * We failed to lock the buffer and cannot stall in
+                        * async migration. Release the taken locks
+                        */
+                       struct buffer_head *failed_bh = bh;
+                       put_bh(failed_bh);
+                       bh = head;
+                       while (bh != failed_bh) {
+                               unlock_buffer(bh);
+                               put_bh(bh);
+                               bh = bh->b_this_page;
+                       }
+                       return false;
+               }
+
+               bh = bh->b_this_page;
+       } while (bh != head);
+       return true;
+}
+
 /*
  * Migration function for pages with buffers. This function can only be used
  * if the underlying filesystem guarantees that no other references to "page"