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From:   Pankaj Raghav <p.raghav@samsung.com>
To:     jaegeuk@kernel.org, hare@suse.de, dsterba@suse.com,
        axboe@kernel.dk, hch@lst.de, damien.lemoal@opensource.wdc.com,
        snitzer@kernel.org
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        Sagi Grimberg <sagi@grimberg.me>,
        Alasdair Kergon <agk@redhat.com>, linux-block@vger.kernel.org,
        Chaitanya Kulkarni <kch@nvidia.com>,
        Keith Busch <kbusch@kernel.org>, linux-btrfs@vger.kernel.org,
        Pankaj Raghav <p.raghav@samsung.com>,
        Luis Chamberlain <mcgrof@kernel.org>
Subject: [PATCH v3 01/11] block: make blkdev_nr_zones and blk_queue_zone_no
 generic for npo2 zsze
Date:   Fri,  6 May 2022 10:10:55 +0200
Message-Id: <20220506081105.29134-2-p.raghav@samsung.com>
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References: <20220506081105.29134-1-p.raghav@samsung.com>
        <CGME20220506081107eucas1p1070e00b208e00090c235017435be1593@eucas1p1.samsung.com>
Precedence: bulk

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