Merge branch 'for-ingo' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-sfi-2.6 into x86/apic

Merge reason: the SFI (Simple Firmware Interface) feature in the ACPI
              tree needs this cleanup, pull it into the APIC branch as
	      well so that there's no interactions.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index a3ef091a45bd..28f320fac4d4 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1165,8 +1165,11 @@ void mark_buffer_dirty(struct buffer_head *bh)
 
         if (!test_set_buffer_dirty(bh)) {
                 struct page *page = bh->b_page;
-                if (!TestSetPageDirty(page))
-                        __set_page_dirty(page, page_mapping(page), 0);
+                if (!TestSetPageDirty(page)) {
+                        struct address_space *mapping = page_mapping(page);
+                        if (mapping)
+                                __set_page_dirty(page, mapping, 0);
+                }
         }
 }