[PATCH v14 06/13] null_blk: allow zoned devices with non power-of-2 zone sizes

Pankaj Raghav
2022-09-20T09:17:34Z

Convert the power-of-2(po2) based calculation with zone size to be generic
in null_zone_no with optimization for po2 zone sizes.

The nr_zones calculation in null_init_zoned_dev has been replaced with a
division without special handling for po2 zone sizes as this function is
called only during the initialization and will not be invoked in the hot
path.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed by: Adam Manzanares <a.manzanares@samsung.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
drivers/block/null_blk/main.c | 5 ++---
drivers/block/null_blk/null_blk.h | 1 +
drivers/block/null_blk/zoned.c | 18 +++++++++++-------
3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 1f154f92f4c2..3b24125d8594 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1976,9 +1976,8 @@ static int null_validate_conf(struct nullb_device *dev)
if (dev->queue_mode == NULL_Q_BIO)
dev->mbps = 0;

- if (dev->zoned &&
- (!dev->zone_size || !is_power_of_2(dev->zone_size))) {
- pr_err("zone_size must be power-of-two\n");
+ if (dev->zoned && !dev->zone_size) {
+ pr_err("Invalid zero zone size\n");
return -EINVAL;
}

diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h
index 94ff68052b1e..f63b6bed1bb3 100644
--- a/drivers/block/null_blk/null_blk.h
+++ b/drivers/block/null_blk/null_blk.h
@@ -83,6 +83,7 @@ struct nullb_device {
unsigned int imp_close_zone_no;
struct nullb_zone *zones;
sector_t zone_size_sects;
+ unsigned int zone_size_sects_shift;
bool need_zone_res_mgmt;
spinlock_t zone_res_lock;

diff --git a/drivers/block/null_blk/zoned.c b/drivers/block/null_blk/zoned.c
index 55a69e48ef8b..015f6823706c 100644
--- a/drivers/block/null_blk/zoned.c
+++ b/drivers/block/null_blk/zoned.c
@@ -16,7 +16,10 @@ static inline sector_t mb_to_sects(unsigned long mb)

static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect)
{
- return sect >> ilog2(dev->zone_size_sects);
+ if (dev->zone_size_sects_shift)
+ return sect >> dev->zone_size_sects_shift;
+
+ return div64_u64(sect, dev->zone_size_sects);
}

static inline void null_lock_zone_res(struct nullb_device *dev)
@@ -65,10 +68,6 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
sector_t sector = 0;
unsigned int i;

- if (!is_power_of_2(dev->zone_size)) {
- pr_err("zone_size must be power-of-two\n");
- return -EINVAL;
- }
if (dev->zone_size > dev->size) {
pr_err("Zone size larger than device capacity\n");
return -EINVAL;
@@ -86,9 +85,14 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
zone_capacity_sects = mb_to_sects(dev->zone_capacity);
dev_capacity_sects = mb_to_sects(dev->size);
dev->zone_size_sects = mb_to_sects(dev->zone_size);
- dev->nr_zones = round_up(dev_capacity_sects, dev->zone_size_sects)
- >> ilog2(dev->zone_size_sects);

+ if (is_power_of_2(dev->zone_size_sects))
+ dev->zone_size_sects_shift = ilog2(dev->zone_size_sects);
+ else
+ dev->zone_size_sects_shift = 0;
+
+ dev->nr_zones = DIV_ROUND_UP_SECTOR_T(dev_capacity_sects,
+ dev->zone_size_sects);
dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct nullb_zone),
GFP_KERNEL | __GFP_ZERO);
if (!dev->zones)
--
2.25.1