[PATCH 3.13.y-ckt 26/96] dm raid: fix round up of default region size

From: Kamal Mostafa
Date: Fri Nov 13 2015 - 17:15:04 EST

3.13.11-ckt30 -stable review patch. If anyone has any objections, please let me know.


From: Mikulas Patocka <mpatocka@xxxxxxxxxx>

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@xxxxxxxxxx>
Fixes: 3a0f9aaee028 ("dm raid: round region_size to power of two")
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
drivers/md/dm-raid.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 5971538..19cfd7af 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -325,8 +325,7 @@ static int validate_region_size(struct raid_set *rs, unsigned long region_size)
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",
} else {

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/