Merge branch 'for-linus' of git://git.o-hand.com/linux-rpurdie-backlight

[linux-2.6-omap-h63xx.git] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index a1ddd2557af230fb70d784e81406e63596bbe984..ab8553658af3fb2fcfac7b0c80bc2ed8d1343721 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -116,12 +116,12 @@ void __remove_from_page_cache(struct page *page)
 {
        struct address_space *mapping = page->mapping;
 
-       mem_cgroup_uncharge_cache_page(page);
        radix_tree_delete(&mapping->page_tree, page->index);
        page->mapping = NULL;
        mapping->nrpages--;
        __dec_zone_page_state(page, NR_FILE_PAGES);
        BUG_ON(page_mapped(page));
+       mem_cgroup_uncharge_cache_page(page);
 
        /*
         * Some filesystems seem to re-dirty the page even after
@@ -573,17 +573,14 @@ EXPORT_SYMBOL(wait_on_page_bit);
  * mechananism between PageLocked pages and PageWriteback pages is shared.
  * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep.
  *
- * The first mb is necessary to safely close the critical section opened by the
- * test_and_set_bit() to lock the page; the second mb is necessary to enforce
- * ordering between the clear_bit and the read of the waitqueue (to avoid SMP
- * races with a parallel wait_on_page_locked()).
+ * The mb is necessary to enforce ordering between the clear_bit and the read
+ * of the waitqueue (to avoid SMP races with a parallel wait_on_page_locked()).
  */
 void unlock_page(struct page *page)
 {
-       smp_mb__before_clear_bit();
-       if (!test_and_clear_bit(PG_locked, &page->flags))
-               BUG();
-       smp_mb__after_clear_bit(); 
+       VM_BUG_ON(!PageLocked(page));
+       clear_bit_unlock(PG_locked, &page->flags);
+       smp_mb__after_clear_bit();
        wake_up_page(page, PG_locked);
 }
 EXPORT_SYMBOL(unlock_page);