[PATCH 01/16] block: make blkdev_nr_zones and blk_queue_zone_no generic for npo2 zsze

Pankaj Raghav
2022-04-27T16:03:47Z

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>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
block/blk-zoned.c | 8 +++++++-
include/linux/blkdev.h | 8 +++++++-
2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 38cd840d8838..1dff4a8bd51d 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -117,10 +117,16 @@ EXPORT_SYMBOL_GPL(__blk_req_zone_write_unlock);
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 60d016138997..c4e4c7071b7b 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -665,9 +665,15 @@ 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