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From:   Pankaj Raghav <p.raghav@samsung.com>
To:     axboe@kernel.dk, hch@lst.de, damien.lemoal@opensource.wdc.com,
        dsterba@suse.com, jaegeuk@kernel.org, bvanassche@acm.org,
        hare@suse.de
Cc:     jonathan.derrick@linux.dev, jiangbo.365@bytedance.com,
        matias.bjorling@wdc.com, gost.dev@samsung.com, pankydev8@gmail.com,
        Luis Chamberlain <mcgrof@kernel.org>,
        Pankaj Raghav <p.raghav@samsung.com>,
        Alasdair Kergon <agk@redhat.com>,
        Mike Snitzer <snitzer@kernel.org>, dm-devel@redhat.com,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 11/11] dm-zoned: ensure only power of 2 zone sizes are
 allowed
Date:   Thu,  5 May 2022 15:47:11 +0200
Message-Id: <20220505134710.132630-12-p.raghav@samsung.com>
In-Reply-To: <20220505134710.132630-1-p.raghav@samsung.com>
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References: <20220505134710.132630-1-p.raghav@samsung.com>
        <CGME20220505135111eucas1p218b79f4b1e54bb3a24d2ec189ec445d1@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-zone.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
index 3e7b1fe15..27dc4ddf2 100644
--- a/drivers/md/dm-zone.c
+++ b/drivers/md/dm-zone.c
@@ -231,6 +231,18 @@ 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;
+	char bname[BDEVNAME_SIZE];
+
+	zone_sectors = bdev_zone_sectors(bdev);
+
+	if (!is_power_of_2(zone_sectors)) {
+		DMWARN("%s: %s only power of two zone size supported\n",
+		       dm_device_name(md),
+		       bdevname(bdev, bname));
+		return 1;
+	}
 
 	/*
 	 * Check if something changed. If yes, cleanup the current resources
-- 
2.25.1