[PATCH v6 7/8] dm-zoned: ensure only power of 2 zone sizes are allowed

[Pankaj Raghav]

From: Luis Chamberlain <mcgrof@xxxxxxxxxx>

Today dm-zoned relies on the assumption that you have a zone size
with a power of 2. Even though the block layer today enforces this
requirement, these devices do exist and so provide a stop-gap measure
to ensure these devices cannot be used by mistake

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
---
 drivers/md/dm-zone.c         | 10 ++++++++++
 drivers/md/dm-zoned-target.c |  8 ++++++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
index 57daa86c19cf..41188091fe6b 100644
--- a/drivers/md/dm-zone.c
+++ b/drivers/md/dm-zone.c
@@ -231,6 +231,16 @@ static int dm_revalidate_zones(struct mapped_device *md, struct dm_table *t)
 	struct request_queue *q = md->queue;
 	unsigned int noio_flag;
 	int ret;
+	struct block_device *bdev = md->disk->part0;
+	sector_t zone_sectors;
+
+	zone_sectors = bdev_zone_sectors(bdev);
+
+	if (!is_power_of_2(zone_sectors)) {
+		DMWARN("%s: %pg only power of two zone size supported",
+		       dm_device_name(md), bdev);
+		return -EINVAL;
+	}
 
 	/*
 	 * Check if something changed. If yes, cleanup the current resources
diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c
index cac295cc8840..e4cef1b1b46c 100644
--- a/drivers/md/dm-zoned-target.c
+++ b/drivers/md/dm-zoned-target.c
@@ -792,6 +792,10 @@ static int dmz_fixup_devices(struct dm_target *ti)
 				return -EINVAL;
 			}
 			zone_nr_sectors = blk_queue_zone_sectors(q);
+			if (!is_power_of_2(zone_nr_sectors)) {
+				ti->error = "Zone size not power of 2";
+				return -EINVAL;
+			}
 			zoned_dev->zone_nr_sectors = zone_nr_sectors;
 			zoned_dev->nr_zones =
 				blkdev_nr_zones(zoned_dev->bdev->bd_disk);
@@ -806,6 +810,10 @@ static int dmz_fixup_devices(struct dm_target *ti)
 		q = bdev_get_queue(zoned_dev->bdev);
 		zoned_dev->zone_nr_sectors = blk_queue_zone_sectors(q);
 		zoned_dev->nr_zones = blkdev_nr_zones(zoned_dev->bdev->bd_disk);
+		if (!is_power_of_2(zone_nr_sectors)) {
+			ti->error = "Zone size not power of 2";
+			return -EINVAL;
+		}
 	}
 
 	if (reg_dev) {
-- 
2.25.1