On 7/28/22 01:22, Pankaj Raghav wrote:
> Adapt bdev_nr_zones and disk_zone_no function so that it can
s/function/functions
s/it/they
> also work for non-power-of-2 zone sizes.
>
> As the existing deployments of zoned devices had power-of-2
had power-of-2 assumption -> assume that a device zone size is a power of
2 number of sectors
Existing deployments still exist, so do not use the past tense please.
> assumption, power-of-2 optimized calculation is kept for those devices.
>
> There are no direct hot paths modified and the changes just
> introduce one new branch per call.
>
> Reviewed-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
> Reviewed-by: Adam Manzanares <a.manzanares@xxxxxxxxxxx>
> Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
> Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
> Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> block/blk-zoned.c | 13 +++++++++----
> include/linux/blkdev.h | 8 +++++++-
> 2 files changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/block/blk-zoned.c b/block/blk-zoned.c
> index a264621d4905..dce9c95b4bcd 100644
> --- a/block/blk-zoned.c
> +++ b/block/blk-zoned.c
> @@ -111,17 +111,22 @@ EXPORT_SYMBOL_GPL(__blk_req_zone_write_unlock);
> * bdev_nr_zones - Get number of zones
> * @bdev: Target device
> *
> - * Return the total number of zones of a zoned block device. For a block
> - * device without zone capabilities, the number of zones is always 0.
> + * Return the total number of zones of a zoned block device, including the
> + * eventual small last zone if present. For a block device without zone
> + * capabilities, the number of zones is always 0.
> */
> unsigned int bdev_nr_zones(struct block_device *bdev)
> {
> sector_t zone_sectors = bdev_zone_sectors(bdev);
> + sector_t capacity = bdev_nr_sectors(bdev);
>
> if (!bdev_is_zoned(bdev))
> return 0;
> - return (bdev_nr_sectors(bdev) + zone_sectors - 1) >>
> - ilog2(zone_sectors);
> +
> + if (is_power_of_2(zone_sectors))
> + return (capacity + zone_sectors - 1) >> ilog2(zone_sectors);
> +
> + return DIV_ROUND_UP_SECTOR_T(capacity, zone_sectors);
> }
> EXPORT_SYMBOL_GPL(bdev_nr_zones);
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index dccdf1551c62..85b832908f28 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -673,9 +673,15 @@ static inline unsigned int disk_nr_zones(struct gendisk *disk)
>
> static inline unsigned int disk_zone_no(struct gendisk *disk, sector_t sector)
> {
> + sector_t zone_sectors = disk->queue->limits.chunk_sectors;
> +
> if (!blk_queue_is_zoned(disk->queue))
> return 0;
> - return sector >> ilog2(disk->queue->limits.chunk_sectors);
> +
> + if (is_power_of_2(zone_sectors))
> + return sector >> ilog2(zone_sectors);
> +
> + return div64_u64(sector, zone_sectors);
> }
>
> static inline bool disk_zone_is_seq(struct gendisk *disk, sector_t sector)
--
Damien Le Moal
Western Digital Research
