[PATCH 2/3] btrfs: use offset_in_page for start_offset in map_private_extent_buffer()

[Johannes Thumshirn]

In map_private_extent_buffer() use offset_in_page() to initialize
'start_offset' instead of open-coding it.

Signed-off-by: Johannes Thumshirn <jthumsh...@suse.de>
---
 fs/btrfs/extent_io.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 7aafdec49dc3..85cd3975c680 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -5383,7 +5383,7 @@ int map_private_extent_buffer(const struct extent_buffer 
*eb,
        size_t offset;
        char *kaddr;
        struct page *p;
-       size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
+       size_t start_offset = offset_in_page(eb->start);
        unsigned long i = (start_offset + start) >> PAGE_SHIFT;
        unsigned long end_i = (start_offset + start + min_len - 1) >>
                PAGE_SHIFT;
-- 
2.16.4