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From:   Pankaj Raghav <p.raghav@samsung.com>
To:     hch@lst.de, snitzer@redhat.com, damien.lemoal@opensource.wdc.com,
        axboe@kernel.dk
Cc:     bvanassche@acm.org, linux-kernel@vger.kernel.org,
        jiangbo.365@bytedance.com, hare@suse.de, pankydev8@gmail.com,
        dm-devel@redhat.com, jonathan.derrick@linux.dev,
        gost.dev@samsung.com, dsterba@suse.com, jaegeuk@kernel.org,
        linux-nvme@lists.infradead.org, Johannes.Thumshirn@wdc.com,
        linux-block@vger.kernel.org, Luis Chamberlain <mcgrof@kernel.org>,
        Pankaj Raghav <p.raghav@samsung.com>
Subject: [PATCH v7 08/13] dm-zoned: ensure only power of 2 zone sizes are
 allowed
Date:   Wed, 15 Jun 2022 12:19:15 +0200
Message-Id: <20220615101920.329421-9-p.raghav@samsung.com>
In-Reply-To: <20220615101920.329421-1-p.raghav@samsung.com>
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References: <20220615101920.329421-1-p.raghav@samsung.com>
        <CGME20220615101951eucas1p238eb45e563bd9645af81bf16c56d98ec@eucas1p2.samsung.com>
Precedence: bulk

From: Luis Chamberlain <mcgrof@kernel.org>

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@suse.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
 drivers/md/dm-zoned-target.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c
index 0ec5d8b9b..ad4228db5 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(zoned_dev->zone_nr_sectors)) {
+			ti->error = "Zone size not power of 2";
+			return -EINVAL;
+		}
 	}
 
 	if (reg_dev) {
-- 
2.25.1