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Subject[PATCH v8 01/11] block: make bdev_nr_zones and disk_zone_no generic for npo2 zsze
Date
Adapt bdev_nr_zones and disk_zone_no function so that it can
also work for non-power-of-2 zone sizes.

As the existing deployments of zoned devices had power-of-2
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@kernel.org>
Reviewed-by: Adam Manzanares <a.manzanares@samsung.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
---
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)
--
2.25.1
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