Re: [PATCH 04/16] block: allow blk-zoned devices to have non-power-of-2 zone size

Hannes Reinecke
2022-05-04T17:13:46Z

On 4/27/22 09:02, Pankaj Raghav wrote:
> Convert the calculations on zone size to be generic instead of relying on
> power_of_2 based logic in the block layer using the helpers wherever
> possible.
>
> The only hot path affected by this change for power_of_2 zoned devices
> is in blk_check_zone_append() but the effects should be negligible as the
> helper blk_queue_zone_aligned() optimizes the calculation for those
> devices. Note that the append path cannot be accessed by direct raw access
> to the block device but only through a filesystem abstraction.
>
> Finally, remove the check for power_of_2 zone size requirement in
> blk-zoned.c
>
> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
> ---
> block/blk-core.c | 3 +--
> block/blk-zoned.c | 12 ++++++------
> 2 files changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 937bb6b86331..850caf311064 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -634,8 +634,7 @@ static inline blk_status_t blk_check_zone_append(struct request_queue *q,
> return BLK_STS_NOTSUPP;
>
> /* The bio sector must point to the start of a sequential zone */
> - if (pos & (blk_queue_zone_sectors(q) - 1) ||
> - !blk_queue_zone_is_seq(q, pos))
> + if (!blk_queue_zone_aligned(q, pos) || !blk_queue_zone_is_seq(q, pos))
> return BLK_STS_IOERR;
>
> /*
> diff --git a/block/blk-zoned.c b/block/blk-zoned.c
> index 1dff4a8bd51d..f7c7c3bd148d 100644
> --- a/block/blk-zoned.c
> +++ b/block/blk-zoned.c
> @@ -288,10 +288,10 @@ int blkdev_zone_mgmt(struct block_device *bdev, enum req_opf op,
> return -EINVAL;
>
> /* Check alignment (handle eventual smaller last zone) */
> - if (sector & (zone_sectors - 1))
> + if (!blk_queue_zone_aligned(q, sector))
> return -EINVAL;
>
> - if ((nr_sectors & (zone_sectors - 1)) && end_sector != capacity)
> + if (!blk_queue_zone_aligned(q, nr_sectors) && end_sector != capacity)
> return -EINVAL;
>
> /*
> @@ -489,14 +489,14 @@ static int blk_revalidate_zone_cb(struct blk_zone *zone, unsigned int idx,
> * smaller last zone.
> */
> if (zone->start == 0) {
> - if (zone->len == 0 || !is_power_of_2(zone->len)) {
> - pr_warn("%s: Invalid zoned device with non power of two zone size (%llu)\n",
> - disk->disk_name, zone->len);
> + if (zone->len == 0) {
> + pr_warn("%s: Invalid zoned device size",
> + disk->disk_name);
> return -ENODEV;
> }
>
> args->zone_sectors = zone->len;
> - args->nr_zones = (capacity + zone->len - 1) >> ilog2(zone->len);
> + args->nr_zones = div64_u64(capacity + zone->len - 1, zone->len);

This is a different calculation than the one you're using in the first
patch. Can you please add a helper such that both are using the same
calculation?

Cheers,

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