1 files changed, 1 insertions, 2 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 97e73e555d11..17e2b472e16d 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1727,8 +1727,7 @@ int bitmap_create(struct mddev *mddev)
         bitmap->chunkshift = (ffz(~mddev->bitmap_info.chunksize)
                               - BITMAP_BLOCK_SHIFT);
 
-        /* now that chunksize and chunkshift are set, we can use these macros */
-        chunks = (blocks + bitmap->chunkshift - 1) >>
+        chunks = (blocks + (1 << bitmap->chunkshift) - 1) >>
                         bitmap->chunkshift;
         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;