[v7,01/13] block: make blkdev_nr_zones and blk_queue_zone_no generic for npo2 zsze

Commit Message

Pankaj Raghav June 15, 2022, 10:19 a.m. UTC

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 <[e-mail]>
Reviewed by: Adam Manzanares <[e-mail]>
Reviewed-by: Hannes Reinecke <[e-mail]>
Signed-off-by: Pankaj Raghav <[e-mail]>
---
 block/blk-zoned.c      | 12 +++++++++---
 include/linux/blkdev.h |  8 +++++++-
 2 files changed, 16 insertions(+), 4 deletions(-)

Comments

Bart Van Assche June 15, 2022, 8:18 p.m. UTC | #1

On 6/15/22 03:19, Pankaj Raghav wrote:
> 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: Bart Van Assche <[e-mail]>

Patch

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 38cd840d8..8b0615287 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -111,16 +111,22 @@  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 DIV_ROUND_UP_SECTOR_T(capacity, zone_sectors);
 }
 EXPORT_SYMBOL_GPL(blkdev_nr_zones);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 914c613d8..39017ae9d 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -681,9 +681,15 @@  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,