mm: migrate: drop unused argument of migrate_page_move_mapping()

All callers of migrate_page_move_mapping() now pass NULL for 'head'
argument.  Drop it.

Link: http://lkml.kernel.org/r/20181211172143.7358-7-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/fs/aio.c b/fs/aio.c
index aac9659..bc401d5 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -409,7 +409,7 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
 	BUG_ON(PageWriteback(old));
 	get_page(new);
 
-	rc = migrate_page_move_mapping(mapping, new, old, NULL, mode, 1);
+	rc = migrate_page_move_mapping(mapping, new, old, mode, 1);
 	if (rc != MIGRATEPAGE_SUCCESS) {
 		put_page(new);
 		goto out_unlock;
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b293cb3..008b74e 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2738,7 +2738,7 @@ int f2fs_migrate_page(struct address_space *mapping,
 	 */
 	extra_count = (atomic_written ? 1 : 0) - page_has_private(page);
 	rc = migrate_page_move_mapping(mapping, newpage,
-				page, NULL, mode, extra_count);
+				page, mode, extra_count);
 	if (rc != MIGRATEPAGE_SUCCESS) {
 		if (atomic_written)
 			mutex_unlock(&fi->inmem_lock);
diff --git a/fs/iomap.c b/fs/iomap.c
index ce837d9..2d9b93c 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -563,7 +563,7 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage,
 {
 	int ret;
 
-	ret = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0);
+	ret = migrate_page_move_mapping(mapping, newpage, page, mode, 0);
 	if (ret != MIGRATEPAGE_SUCCESS)
 		return ret;
 
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 1b78f2e..5d2ffb1 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1481,7 +1481,7 @@ static int ubifs_migrate_page(struct address_space *mapping,
 {
 	int rc;
 
-	rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0);
+	rc = migrate_page_move_mapping(mapping, newpage, page, mode, 0);
 	if (rc != MIGRATEPAGE_SUCCESS)
 		return rc;
 
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 617615f..e13d9bf2 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -77,8 +77,7 @@ extern void migrate_page_copy(struct page *newpage, struct page *page);
 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
 				  struct page *newpage, struct page *page);
 extern int migrate_page_move_mapping(struct address_space *mapping,
-		struct page *newpage, struct page *page,
-		struct buffer_head *head, enum migrate_mode mode,
+		struct page *newpage, struct page *page, enum migrate_mode mode,
 		int extra_count);
 #else
 
diff --git a/mm/migrate.c b/mm/migrate.c
index 8dd5760..4389696 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -399,8 +399,7 @@ static int expected_page_refs(struct page *page)
  * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
  */
 int migrate_page_move_mapping(struct address_space *mapping,
-		struct page *newpage, struct page *page,
-		struct buffer_head *head, enum migrate_mode mode,
+		struct page *newpage, struct page *page, enum migrate_mode mode,
 		int extra_count)
 {
 	XA_STATE(xas, &mapping->i_pages, page_index(page));
@@ -687,7 +686,7 @@ int migrate_page(struct address_space *mapping,
 
 	BUG_ON(PageWriteback(page));	/* Writeback must be complete */
 
-	rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0);
+	rc = migrate_page_move_mapping(mapping, newpage, page, mode, 0);
 
 	if (rc != MIGRATEPAGE_SUCCESS)
 		return rc;
@@ -790,7 +789,7 @@ static int __buffer_migrate_page(struct address_space *mapping,
 		}
 	}
 
-	rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0);
+	rc = migrate_page_move_mapping(mapping, newpage, page, mode, 0);
 	if (rc != MIGRATEPAGE_SUCCESS)
 		goto unlock_buffers;