[PATCH v12 04/13] nvmet: Allow ZNS target to support non-power_of_2 zone sizes

[Pankaj Raghav]

A generic bdev_zone_no() helper is added to calculate zone number for a
given sector in a block device. This helper internally uses disk_zone_no()
to find the zone number.

Use the helper bdev_zone_no() to calculate nr of zones. This let's us
make modifications to the math if needed in one place and adds now
support for zoned devices with non po2 zone size.

Reviewed by: Adam Manzanares <a.manzanares at samsung.com>
Reviewed-by: Bart Van Assche <bvanassche at acm.org>
Reviewed-by: Hannes Reinecke <hare at suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn at wdc.com>
Signed-off-by: Luis Chamberlain <mcgrof at kernel.org>
Signed-off-by: Pankaj Raghav <p.raghav at samsung.com>
---
 drivers/nvme/target/zns.c | 3 +--
 include/linux/blkdev.h    | 5 +++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/zns.c b/drivers/nvme/target/zns.c
index c7ef69f29fe4..662f1a92f39b 100644
--- a/drivers/nvme/target/zns.c
+++ b/drivers/nvme/target/zns.c
@@ -241,8 +241,7 @@ static unsigned long nvmet_req_nr_zones_from_slba(struct nvmet_req *req)
 {
 	unsigned int sect = nvmet_lba_to_sect(req->ns, req->cmd->zmr.slba);
 
-	return bdev_nr_zones(req->ns->bdev) -
-		(sect >> ilog2(bdev_zone_sectors(req->ns->bdev)));
+	return bdev_nr_zones(req->ns->bdev) - bdev_zone_no(req->ns->bdev, sect);
 }
 
 static unsigned long get_nr_zones_from_buf(struct nvmet_req *req, u32 bufsize)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d0d66a0db224..b2636dcca105 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1340,6 +1340,11 @@ static inline enum blk_zoned_model bdev_zoned_model(struct block_device *bdev)
 	return BLK_ZONED_NONE;
 }
 
+static inline unsigned int bdev_zone_no(struct block_device *bdev, sector_t sec)
+{
+	return disk_zone_no(bdev->bd_disk, sec);
+}
+
 static inline int queue_dma_alignment(const struct request_queue *q)
 {
 	return q ? q->dma_alignment : 511;
-- 
2.25.1