[PATCH] page migration cleanup: group functions

Reorder functions in migrate.c.  Group all migration functions for struct
address_space_operations together.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 72 insertions, 70 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 1c25040693d2..49e71ddb6792 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -120,15 +120,6 @@ int putback_lru_pages(struct list_head *l)
 }
 
 /*
- * Non migratable page
- */
-int fail_migrate_page(struct page *newpage, struct page *page)
-{
-        return -EIO;
-}
-EXPORT_SYMBOL(fail_migrate_page);
-
-/*
  * swapout a single page
  * page is locked upon entry, unlocked on exit
  */
@@ -297,6 +288,17 @@ void migrate_page_copy(struct page *newpage, struct page *page)
 }
 EXPORT_SYMBOL(migrate_page_copy);
 
+/************************************************************
+ *                    Migration functions
+ ***********************************************************/
+
+/* Always fail migration. Used for mappings that are not movable */
+int fail_migrate_page(struct page *newpage, struct page *page)
+{
+        return -EIO;
+}
+EXPORT_SYMBOL(fail_migrate_page);
+
 /*
  * Common logic to directly migrate a single page suitable for
  * pages that do not use PagePrivate.
@@ -330,6 +332,67 @@ int migrate_page(struct page *newpage, struct page *page)
 EXPORT_SYMBOL(migrate_page);
 
 /*
+ * Migration function for pages with buffers. This function can only be used
+ * if the underlying filesystem guarantees that no other references to "page"
+ * exist.
+ */
+int buffer_migrate_page(struct page *newpage, struct page *page)
+{
+        struct address_space *mapping = page->mapping;
+        struct buffer_head *bh, *head;
+        int rc;
+
+        if (!mapping)
+                return -EAGAIN;
+
+        if (!page_has_buffers(page))
+                return migrate_page(newpage, page);
+
+        head = page_buffers(page);
+
+        rc = migrate_page_remove_references(newpage, page, 3);
+
+        if (rc)
+                return rc;
+
+        bh = head;
+        do {
+                get_bh(bh);
+                lock_buffer(bh);
+                bh = bh->b_this_page;
+
+        } while (bh != head);
+
+        ClearPagePrivate(page);
+        set_page_private(newpage, page_private(page));
+        set_page_private(page, 0);
+        put_page(page);
+        get_page(newpage);
+
+        bh = head;
+        do {
+                set_bh_page(bh, newpage, bh_offset(bh));
+                bh = bh->b_this_page;
+
+        } while (bh != head);
+
+        SetPagePrivate(newpage);
+
+        migrate_page_copy(newpage, page);
+
+        bh = head;
+        do {
+                unlock_buffer(bh);
+                put_bh(bh);
+                bh = bh->b_this_page;
+
+        } while (bh != head);
+
+        return 0;
+}
+EXPORT_SYMBOL(buffer_migrate_page);
+
+/*
  * migrate_pages
  *
  * Two lists are passed to this function. The first list
@@ -529,67 +592,6 @@ next:
 }
 
 /*
- * Migration function for pages with buffers. This function can only be used
- * if the underlying filesystem guarantees that no other references to "page"
- * exist.
- */
-int buffer_migrate_page(struct page *newpage, struct page *page)
-{
-        struct address_space *mapping = page->mapping;
-        struct buffer_head *bh, *head;
-        int rc;
-
-        if (!mapping)
-                return -EAGAIN;
-
-        if (!page_has_buffers(page))
-                return migrate_page(newpage, page);
-
-        head = page_buffers(page);
-
-        rc = migrate_page_remove_references(newpage, page, 3);
-
-        if (rc)
-                return rc;
-
-        bh = head;
-        do {
-                get_bh(bh);
-                lock_buffer(bh);
-                bh = bh->b_this_page;
-
-        } while (bh != head);
-
-        ClearPagePrivate(page);
-        set_page_private(newpage, page_private(page));
-        set_page_private(page, 0);
-        put_page(page);
-        get_page(newpage);
-
-        bh = head;
-        do {
-                set_bh_page(bh, newpage, bh_offset(bh));
-                bh = bh->b_this_page;
-
-        } while (bh != head);
-
-        SetPagePrivate(newpage);
-
-        migrate_page_copy(newpage, page);
-
-        bh = head;
-        do {
-                unlock_buffer(bh);
-                put_bh(bh);
-                bh = bh->b_this_page;
-
-        } while (bh != head);
-
-        return 0;
-}
-EXPORT_SYMBOL(buffer_migrate_page);
-
-/*
  * Migrate the list 'pagelist' of pages to a certain destination.
  *
  * Specify destination with either non-NULL vma or dest_node >= 0