X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=mm%2Fmigrate.c;h=e9b161bde95b4c382092a1c94a8fcfbd4bcf58f0;hb=412ecd7751a2653ab17df39a1dc3565a548633fd;hp=b4979d423d2be5b7885f4cd7e24f45bdf7aa27ca;hpb=a0d2db26582a67b61f883d1469e561fbdef28419;p=powerpc.git

diff --git a/mm/migrate.c b/mm/migrate.c
index b4979d423d..e9b161bde9 100644
--- 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;