DM RAID: Ensure the bitmap region_size is a power of 2 If the user does not supply a region_size, a reasonable size is computed automatically. However, region_size needs to be a power of 2 and the code was not properly ensuring that. Signed-off-by: Jonathan Brassow <jbrassow@xxxxxxxxxx> Index: linux-upstream/drivers/md/dm-raid.c =================================================================== --- linux-upstream.orig/drivers/md/dm-raid.c +++ linux-upstream/drivers/md/dm-raid.c @@ -288,6 +288,7 @@ static int dev_parms(struct raid_set *rs */ static int validate_region_size(struct raid_set *rs, unsigned long region_size) { + int i; unsigned long min_region_size = rs->ti->len / (1 << 21); if (!region_size) { @@ -295,9 +296,12 @@ static int validate_region_size(struct r * Choose a reasonable default. All figures in sectors. */ if (min_region_size > (1 << 13)) { + /* region_size must be a power of 2 */ + for (i = 13; min_region_size > (1 << i); i++); + + region_size = (1 << i); DMINFO("Choosing default region size of %lu sectors", region_size); - region_size = min_region_size; } else { DMINFO("Choosing default region size of 4MiB"); region_size = 1 << 13; /* sectors */ -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html