[PATCH 3.10 20/54] dm raid: fix round up of default region size

Greg Kroah-Hartman
2015-10-18T02:53:35Z

From: Mikulas Patocka <mpatocka@redhat.com>

commit 042745ee53a0a7c1f5aff191a4a24213c6dcfb52 upstream.

Commit 3a0f9aaee028 ("dm raid: round region_size to power of two")
intended to make sure that the default region size is a power of two.
However, the logic in that commit is incorrect and sets the variable
region_size to 0 or 1, depending on whether min_region_size is a power
of two.

Fix this logic, using roundup_pow_of_two(), so that region_size is
properly rounded up to the next power of two.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 3a0f9aaee028 ("dm raid: round region_size to power of two")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/dm-raid.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -325,8 +325,7 @@ static int validate_region_size(struct r
*/
if (min_region_size > (1 << 13)) {
/* If not a power of 2, make it the next power of 2 */
- if (min_region_size & (min_region_size - 1))
- region_size = 1 << fls(region_size);
+ region_size = roundup_pow_of_two(min_region_size);
DMINFO("Choosing default region size of %lu sectors",
region_size);
} else {