linux-kernel - Re: [PATCH 16/16] dm-zoned: ensure only power of 2 zone sizes are allowed

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Message-ID: <2586cd78-cd54-97ed-86b0-8f78a444387a@suse.de>
Date:   Wed, 4 May 2022 10:11:22 -0700
From:   Hannes Reinecke <hare@...e.de>
To:     undisclosed-recipients:;
Subject: Re: [PATCH 16/16] dm-zoned: ensure only power of 2 zone sizes are
 allowed

On 4/27/22 09:02, Pankaj Raghav wrote:
> From: Luis Chamberlain <mcgrof@...nel.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
> 
> Signed-off-by: Luis Chamberlain <mcgrof@...nel.org>
> Signed-off-by: Pankaj Raghav <p.raghav@...sung.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 57daa86c19cf..221e0aa0f1a7 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

Reviewed-by: Hannes Reinecke <hare@...e.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@...e.de                              +49 911 74053 688
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