[PATCH] ioremap balanced with iounmap for drivers/video/vesafb

[sfrench/cifs-2.6.git] / mm / migrate.c

diff --git a/mm/migrate.c b/mm/migrate.c
index b4979d423d2be5b7885f4cd7e24f45bdf7aa27ca..e9b161bde95b4c382092a1c94a8fcfbd4bcf58f0 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -294,7 +294,7 @@ out:
 static int migrate_page_move_mapping(struct address_space *mapping,
                struct page *newpage, struct page *page)
 {
-       struct page **radix_pointer;
+       void **pslot;
 
        if (!mapping) {
                /* Anonymous page */
@@ -305,12 +305,11 @@ static int migrate_page_move_mapping(struct address_space *mapping,
 
        write_lock_irq(&mapping->tree_lock);
 
-       radix_pointer = (struct page **)radix_tree_lookup_slot(
-                                               &mapping->page_tree,
-                                               page_index(page));
+       pslot = radix_tree_lookup_slot(&mapping->page_tree,
+                                       page_index(page));
 
        if (page_count(page) != 2 + !!PagePrivate(page) ||
-                       *radix_pointer != page) {
+                       (struct page *)radix_tree_deref_slot(pslot) != page) {
                write_unlock_irq(&mapping->tree_lock);
                return -EAGAIN;
        }
@@ -318,7 +317,7 @@ static int migrate_page_move_mapping(struct address_space *mapping,
        /*
         * Now we know that no one else is looking at the page.
         */
-       get_page(newpage);
+       get_page(newpage);      /* add cache reference */
 #ifdef CONFIG_SWAP
        if (PageSwapCache(page)) {
                SetPageSwapCache(newpage);
@@ -326,8 +325,14 @@ static int migrate_page_move_mapping(struct address_space *mapping,
        }
 #endif
 
-       *radix_pointer = newpage;
+       radix_tree_replace_slot(pslot, newpage);
+
+       /*
+        * Drop cache reference from old page.
+        * We know this isn't the last reference.
+        */
        __put_page(page);
+
        write_unlock_irq(&mapping->tree_lock);
 
        return 0;