btrfs: use DIV_ROUND_UP instead of open-coded variants

The form

  (value + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT

is equivalent to

  (value + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE

The rest is a simple subsitution, no difference in the generated
assembly code.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index f181c9afe5f4..2f0fe1028e51 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -279,8 +279,7 @@ static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
         int num_pages;
         int check_crcs = 0;
 
-        num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
-                    PAGE_CACHE_SHIFT;
+        num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE);
 
         if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
                 check_crcs = 1;