diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index 1ecf75ef276a..ccdd65148498 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -415,8 +415,7 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
 	/*
 	 * Work out how many "unsigned long"s we need to hold the bitset.
 	 */
-	bitset_size = dm_round_up(region_count,
-				  sizeof(*lc->clean_bits) << BYTE_SHIFT);
+	bitset_size = dm_round_up(region_count, BITS_PER_LONG);
 	bitset_size >>= BYTE_SHIFT;
 
 	lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);