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 */
--
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