[PATCH v4 01/13] block: make blkdev_nr_zones and blk_queue_zone_no generic for npo2 zsze

Pankaj Raghav
2022-05-16T16:54:34Z

Adapt blkdev_nr_zones and blk_queue_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>
---
block/blk-zoned.c | 13 ++++++++++---
include/linux/blkdev.h | 8 +++++++-
2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 38cd840d8..140230134 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -111,16 +111,23 @@ EXPORT_SYMBOL_GPL(__blk_req_zone_write_unlock);
* blkdev_nr_zones - Get number of zones
* @disk: Target gendisk
*
- * 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 blkdev_nr_zones(struct gendisk *disk)
{
sector_t zone_sectors = blk_queue_zone_sectors(disk->queue);
+ sector_t capacity = get_capacity(disk);

if (!blk_queue_is_zoned(disk->queue))
return 0;
- return (get_capacity(disk) + zone_sectors - 1) >> ilog2(zone_sectors);
+
+ if (is_power_of_2(zone_sectors))
+ return (capacity + zone_sectors - 1) >>
+ ilog2(zone_sectors);
+
+ return div64_u64(capacity + zone_sectors - 1, zone_sectors);
}
EXPORT_SYMBOL_GPL(blkdev_nr_zones);

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1b24c1fb3..22fe512ee 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -675,9 +675,15 @@ static inline unsigned int blk_queue_nr_zones(struct request_queue *q)
static inline unsigned int blk_queue_zone_no(struct request_queue *q,
sector_t sector)
{
+ sector_t zone_sectors = blk_queue_zone_sectors(q);
+
if (!blk_queue_is_zoned(q))
return 0;
- return sector >> ilog2(q->limits.chunk_sectors);
+
+ if (is_power_of_2(zone_sectors))
+ return sector >> ilog2(zone_sectors);
+
+ return div64_u64(sector, zone_sectors);
}

static inline bool blk_queue_zone_is_seq(struct request_queue *q,
--
2.25.1