drivers/block/null_blk/zoned.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/vmalloc.h>
 #include <linux/bitmap.h>
 #include "null_blk.h"

 #define CREATE_TRACE_POINTS
 #include "trace.h"

 #undef pr_fmt
 #define pr_fmt(fmt)	"null_blk: " fmt

 static inline sector_t mb_to_sects(unsigned long mb)
 {
 	return ((sector_t)mb * SZ_1M) >> SECTOR_SHIFT;
 }

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

 static inline void null_lock_zone_res(struct nullb_device *dev)
 {
 	if (dev->need_zone_res_mgmt)
 		spin_lock_irq(&dev->zone_res_lock);
 }

 static inline void null_unlock_zone_res(struct nullb_device *dev)
 {
 	if (dev->need_zone_res_mgmt)
 		spin_unlock_irq(&dev->zone_res_lock);
 }

 static inline void null_init_zone_lock(struct nullb_device *dev,
 				       struct nullb_zone *zone)
 {
 	if (!dev->memory_backed)
 		spin_lock_init(&zone->spinlock);
 	else
 		mutex_init(&zone->mutex);
 }

 static inline void null_lock_zone(struct nullb_device *dev,
 				  struct nullb_zone *zone)
 {
 	if (!dev->memory_backed)
 		spin_lock_irq(&zone->spinlock);
 	else
 		mutex_lock(&zone->mutex);
 }

 static inline void null_unlock_zone(struct nullb_device *dev,
 				    struct nullb_zone *zone)
 {
 	if (!dev->memory_backed)
 		spin_unlock_irq(&zone->spinlock);
 	else
 		mutex_unlock(&zone->mutex);
 }

 int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
 {
 	sector_t dev_capacity_sects, zone_capacity_sects;
 	struct nullb_zone *zone;
 	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;
 	}

 	if (!dev->zone_capacity)
 		dev->zone_capacity = dev->zone_size;

 	if (dev->zone_capacity > dev->zone_size) {
 		pr_err("zone capacity (%lu MB) larger than zone size (%lu MB)\n",
 		       dev->zone_capacity, dev->zone_size);
 		return -EINVAL;
 	}

 	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);

 	dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct nullb_zone),
 				    GFP_KERNEL | __GFP_ZERO);
 	if (!dev->zones)
 		return -ENOMEM;

 	spin_lock_init(&dev->zone_res_lock);

 	if (dev->zone_nr_conv >= dev->nr_zones) {
 		dev->zone_nr_conv = dev->nr_zones - 1;
 		pr_info("changed the number of conventional zones to %u",
 			dev->zone_nr_conv);
 	}

 	/* Max active zones has to be < nbr of seq zones in order to be enforceable */
 	if (dev->zone_max_active >= dev->nr_zones - dev->zone_nr_conv) {
 		dev->zone_max_active = 0;
 		pr_info("zone_max_active limit disabled, limit >= zone count\n");
 	}

 	/* Max open zones has to be <= max active zones */
 	if (dev->zone_max_active && dev->zone_max_open > dev->zone_max_active) {
 		dev->zone_max_open = dev->zone_max_active;
 		pr_info("changed the maximum number of open zones to %u\n",
 			dev->nr_zones);
 	} else if (dev->zone_max_open >= dev->nr_zones - dev->zone_nr_conv) {
 		dev->zone_max_open = 0;
 		pr_info("zone_max_open limit disabled, limit >= zone count\n");
 	}
 	dev->need_zone_res_mgmt = dev->zone_max_active || dev->zone_max_open;
 	dev->imp_close_zone_no = dev->zone_nr_conv;

 	for (i = 0; i <  dev->zone_nr_conv; i++) {
 		zone = &dev->zones[i];

 		null_init_zone_lock(dev, zone);
 		zone->start = sector;
 		zone->len = dev->zone_size_sects;
 		zone->capacity = zone->len;
 		zone->wp = zone->start + zone->len;
 		zone->type = BLK_ZONE_TYPE_CONVENTIONAL;
 		zone->cond = BLK_ZONE_COND_NOT_WP;

 		sector += dev->zone_size_sects;
 	}

 	for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
 		zone = &dev->zones[i];

 		null_init_zone_lock(dev, zone);
 		zone->start = zone->wp = sector;
 		if (zone->start + dev->zone_size_sects > dev_capacity_sects)
 			zone->len = dev_capacity_sects - zone->start;
 		else
 			zone->len = dev->zone_size_sects;
 		zone->capacity =
 			min_t(sector_t, zone->len, zone_capacity_sects);
 		zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ;
 		zone->cond = BLK_ZONE_COND_EMPTY;

 		sector += dev->zone_size_sects;
 	}

 	return 0;
 }

 int null_register_zoned_dev(struct nullb *nullb)
 {
 	struct nullb_device *dev = nullb->dev;
 	struct request_queue *q = nullb->q;

 	disk_set_zoned(nullb->disk, BLK_ZONED_HM);
 	blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
 	blk_queue_required_elevator_features(q, ELEVATOR_F_ZBD_SEQ_WRITE);

 	if (queue_is_mq(q)) {
 		int ret = blk_revalidate_disk_zones(nullb->disk, NULL);

 		if (ret)
 			return ret;
 	} else {
 		blk_queue_chunk_sectors(q, dev->zone_size_sects);
 		nullb->disk->nr_zones = bdev_nr_zones(nullb->disk->part0);
 	}

 	blk_queue_max_zone_append_sectors(q, dev->zone_size_sects);
 	disk_set_max_open_zones(nullb->disk, dev->zone_max_open);
 	disk_set_max_active_zones(nullb->disk, dev->zone_max_active);

 	return 0;
 }

 void null_free_zoned_dev(struct nullb_device *dev)
 {
 	kvfree(dev->zones);
 	dev->zones = NULL;
 }

 int null_report_zones(struct gendisk *disk, sector_t sector,
 		unsigned int nr_zones, report_zones_cb cb, void *data)
 {
 	struct nullb *nullb = disk->private_data;
 	struct nullb_device *dev = nullb->dev;
 	unsigned int first_zone, i;
 	struct nullb_zone *zone;
 	struct blk_zone blkz;
 	int error;

 	first_zone = null_zone_no(dev, sector);
 	if (first_zone >= dev->nr_zones)
 		return 0;

 	nr_zones = min(nr_zones, dev->nr_zones - first_zone);
 	trace_nullb_report_zones(nullb, nr_zones);

 	memset(&blkz, 0, sizeof(struct blk_zone));
 	zone = &dev->zones[first_zone];
 	for (i = 0; i < nr_zones; i++, zone++) {
 		/*
 		 * Stacked DM target drivers will remap the zone information by
 		 * modifying the zone information passed to the report callback.
 		 * So use a local copy to avoid corruption of the device zone
 		 * array.
 		 */
 		null_lock_zone(dev, zone);
 		blkz.start = zone->start;
 		blkz.len = zone->len;
 		blkz.wp = zone->wp;
 		blkz.type = zone->type;
 		blkz.cond = zone->cond;
 		blkz.capacity = zone->capacity;
 		null_unlock_zone(dev, zone);

 		error = cb(&blkz, i, data);
 		if (error)
 			return error;
 	}

 	return nr_zones;
 }

 /*
  * This is called in the case of memory backing from null_process_cmd()
  * with the target zone already locked.
  */
 size_t null_zone_valid_read_len(struct nullb *nullb,
 				sector_t sector, unsigned int len)
 {
 	struct nullb_device *dev = nullb->dev;
 	struct nullb_zone *zone = &dev->zones[null_zone_no(dev, sector)];
 	unsigned int nr_sectors = len >> SECTOR_SHIFT;

 	/* Read must be below the write pointer position */
 	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL ||
 	    sector + nr_sectors <= zone->wp)
 		return len;

 	if (sector > zone->wp)
 		return 0;

 	return (zone->wp - sector) << SECTOR_SHIFT;
 }

 static blk_status_t __null_close_zone(struct nullb_device *dev,
 				      struct nullb_zone *zone)
 {
 	switch (zone->cond) {
 	case BLK_ZONE_COND_CLOSED:
 		/* close operation on closed is not an error */
 		return BLK_STS_OK;
 	case BLK_ZONE_COND_IMP_OPEN:
 		dev->nr_zones_imp_open--;
 		break;
 	case BLK_ZONE_COND_EXP_OPEN:
 		dev->nr_zones_exp_open--;
 		break;
 	case BLK_ZONE_COND_EMPTY:
 	case BLK_ZONE_COND_FULL:
 	default:
 		return BLK_STS_IOERR;
 	}

 	if (zone->wp == zone->start) {
 		zone->cond = BLK_ZONE_COND_EMPTY;
 	} else {
 		zone->cond = BLK_ZONE_COND_CLOSED;
 		dev->nr_zones_closed++;
 	}

 	return BLK_STS_OK;
 }

 static void null_close_imp_open_zone(struct nullb_device *dev)
 {
 	struct nullb_zone *zone;
 	unsigned int zno, i;

 	zno = dev->imp_close_zone_no;
 	if (zno >= dev->nr_zones)
 		zno = dev->zone_nr_conv;

 	for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
 		zone = &dev->zones[zno];
 		zno++;
 		if (zno >= dev->nr_zones)
 			zno = dev->zone_nr_conv;

 		if (zone->cond == BLK_ZONE_COND_IMP_OPEN) {
 			__null_close_zone(dev, zone);
 			dev->imp_close_zone_no = zno;
 			return;
 		}
 	}
 }

 static blk_status_t null_check_active(struct nullb_device *dev)
 {
 	if (!dev->zone_max_active)
 		return BLK_STS_OK;

 	if (dev->nr_zones_exp_open + dev->nr_zones_imp_open +
 			dev->nr_zones_closed < dev->zone_max_active)
 		return BLK_STS_OK;

 	return BLK_STS_ZONE_ACTIVE_RESOURCE;
 }

 static blk_status_t null_check_open(struct nullb_device *dev)
 {
 	if (!dev->zone_max_open)
 		return BLK_STS_OK;

 	if (dev->nr_zones_exp_open + dev->nr_zones_imp_open < dev->zone_max_open)
 		return BLK_STS_OK;

 	if (dev->nr_zones_imp_open) {
 		if (null_check_active(dev) == BLK_STS_OK) {
 			null_close_imp_open_zone(dev);
 			return BLK_STS_OK;
 		}
 	}

 	return BLK_STS_ZONE_OPEN_RESOURCE;
 }

 /*
  * This function matches the manage open zone resources function in the ZBC standard,
  * with the addition of max active zones support (added in the ZNS standard).
  *
  * The function determines if a zone can transition to implicit open or explicit open,
  * while maintaining the max open zone (and max active zone) limit(s). It may close an
  * implicit open zone in order to make additional zone resources available.
  *
  * ZBC states that an implicit open zone shall be closed only if there is not
  * room within the open limit. However, with the addition of an active limit,
  * it is not certain that closing an implicit open zone will allow a new zone
  * to be opened, since we might already be at the active limit capacity.
  */
 static blk_status_t null_check_zone_resources(struct nullb_device *dev,
 					      struct nullb_zone *zone)
 {
 	blk_status_t ret;

 	switch (zone->cond) {
 	case BLK_ZONE_COND_EMPTY:
 		ret = null_check_active(dev);
 		if (ret != BLK_STS_OK)
 			return ret;
 		fallthrough;
 	case BLK_ZONE_COND_CLOSED:
 		return null_check_open(dev);
 	default:
 		/* Should never be called for other states */
 		WARN_ON(1);
 		return BLK_STS_IOERR;
 	}
 }

 static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
 				    unsigned int nr_sectors, bool append)
 {
 	struct nullb_device *dev = cmd->nq->dev;
 	unsigned int zno = null_zone_no(dev, sector);
 	struct nullb_zone *zone = &dev->zones[zno];
 	blk_status_t ret;

 	trace_nullb_zone_op(cmd, zno, zone->cond);

 	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL) {
 		if (append)
 			return BLK_STS_IOERR;
 		return null_process_cmd(cmd, REQ_OP_WRITE, sector, nr_sectors);
 	}

 	null_lock_zone(dev, zone);

 	if (zone->cond == BLK_ZONE_COND_FULL ||
 	    zone->cond == BLK_ZONE_COND_READONLY ||
 	    zone->cond == BLK_ZONE_COND_OFFLINE) {
 		/* Cannot write to the zone */
 		ret = BLK_STS_IOERR;
 		goto unlock;
 	}

 	/*
 	 * Regular writes must be at the write pointer position.
 	 * Zone append writes are automatically issued at the write
 	 * pointer and the position returned using the request or BIO
 	 * sector.
 	 */
 	if (append) {
 		sector = zone->wp;
 		if (dev->queue_mode == NULL_Q_MQ)
 			cmd->rq->__sector = sector;
 		else
 			cmd->bio->bi_iter.bi_sector = sector;
 	} else if (sector != zone->wp) {
 		ret = BLK_STS_IOERR;
 		goto unlock;
 	}

 	if (zone->wp + nr_sectors > zone->start + zone->capacity) {
 		ret = BLK_STS_IOERR;
 		goto unlock;
 	}

 	if (zone->cond == BLK_ZONE_COND_CLOSED ||
 	    zone->cond == BLK_ZONE_COND_EMPTY) {
 		null_lock_zone_res(dev);

 		ret = null_check_zone_resources(dev, zone);
 		if (ret != BLK_STS_OK) {
 			null_unlock_zone_res(dev);
 			goto unlock;
 		}
 		if (zone->cond == BLK_ZONE_COND_CLOSED) {
 			dev->nr_zones_closed--;
 			dev->nr_zones_imp_open++;
 		} else if (zone->cond == BLK_ZONE_COND_EMPTY) {
 			dev->nr_zones_imp_open++;
 		}

 		if (zone->cond != BLK_ZONE_COND_EXP_OPEN)
 			zone->cond = BLK_ZONE_COND_IMP_OPEN;

 		null_unlock_zone_res(dev);
 	}

 	ret = null_process_cmd(cmd, REQ_OP_WRITE, sector, nr_sectors);
 	if (ret != BLK_STS_OK)
 		goto unlock;

 	zone->wp += nr_sectors;
 	if (zone->wp == zone->start + zone->capacity) {
 		null_lock_zone_res(dev);
 		if (zone->cond == BLK_ZONE_COND_EXP_OPEN)
 			dev->nr_zones_exp_open--;
 		else if (zone->cond == BLK_ZONE_COND_IMP_OPEN)
 			dev->nr_zones_imp_open--;
 		zone->cond = BLK_ZONE_COND_FULL;
 		null_unlock_zone_res(dev);
 	}

 	ret = BLK_STS_OK;

 unlock:
 	null_unlock_zone(dev, zone);

 	return ret;
 }

 static blk_status_t null_open_zone(struct nullb_device *dev,
 				   struct nullb_zone *zone)
 {
 	blk_status_t ret = BLK_STS_OK;

 	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
 		return BLK_STS_IOERR;

 	null_lock_zone_res(dev);

 	switch (zone->cond) {
 	case BLK_ZONE_COND_EXP_OPEN:
 		/* open operation on exp open is not an error */
 		goto unlock;
 	case BLK_ZONE_COND_EMPTY:
 		ret = null_check_zone_resources(dev, zone);
 		if (ret != BLK_STS_OK)
 			goto unlock;
 		break;
 	case BLK_ZONE_COND_IMP_OPEN:
 		dev->nr_zones_imp_open--;
 		break;
 	case BLK_ZONE_COND_CLOSED:
 		ret = null_check_zone_resources(dev, zone);
 		if (ret != BLK_STS_OK)
 			goto unlock;
 		dev->nr_zones_closed--;
 		break;
 	case BLK_ZONE_COND_FULL:
 	default:
 		ret = BLK_STS_IOERR;
 		goto unlock;
 	}

 	zone->cond = BLK_ZONE_COND_EXP_OPEN;
 	dev->nr_zones_exp_open++;

 unlock:
 	null_unlock_zone_res(dev);

 	return ret;
 }

 static blk_status_t null_close_zone(struct nullb_device *dev,
 				    struct nullb_zone *zone)
 {
 	blk_status_t ret;

 	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
 		return BLK_STS_IOERR;

 	null_lock_zone_res(dev);
 	ret = __null_close_zone(dev, zone);
 	null_unlock_zone_res(dev);

 	return ret;
 }

 static blk_status_t null_finish_zone(struct nullb_device *dev,
 				     struct nullb_zone *zone)
 {
 	blk_status_t ret = BLK_STS_OK;

 	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
 		return BLK_STS_IOERR;

 	null_lock_zone_res(dev);

 	switch (zone->cond) {
 	case BLK_ZONE_COND_FULL:
 		/* finish operation on full is not an error */
 		goto unlock;
 	case BLK_ZONE_COND_EMPTY:
 		ret = null_check_zone_resources(dev, zone);
 		if (ret != BLK_STS_OK)
 			goto unlock;
 		break;
 	case BLK_ZONE_COND_IMP_OPEN:
 		dev->nr_zones_imp_open--;
 		break;
 	case BLK_ZONE_COND_EXP_OPEN:
 		dev->nr_zones_exp_open--;
 		break;
 	case BLK_ZONE_COND_CLOSED:
 		ret = null_check_zone_resources(dev, zone);
 		if (ret != BLK_STS_OK)
 			goto unlock;
 		dev->nr_zones_closed--;
 		break;
 	default:
 		ret = BLK_STS_IOERR;
 		goto unlock;
 	}

 	zone->cond = BLK_ZONE_COND_FULL;
 	zone->wp = zone->start + zone->len;

 unlock:
 	null_unlock_zone_res(dev);

 	return ret;
 }

 static blk_status_t null_reset_zone(struct nullb_device *dev,
 				    struct nullb_zone *zone)
 {
 	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
 		return BLK_STS_IOERR;

 	null_lock_zone_res(dev);

 	switch (zone->cond) {
 	case BLK_ZONE_COND_EMPTY:
 		/* reset operation on empty is not an error */
 		null_unlock_zone_res(dev);
 		return BLK_STS_OK;
 	case BLK_ZONE_COND_IMP_OPEN:
 		dev->nr_zones_imp_open--;
 		break;
 	case BLK_ZONE_COND_EXP_OPEN:
 		dev->nr_zones_exp_open--;
 		break;
 	case BLK_ZONE_COND_CLOSED:
 		dev->nr_zones_closed--;
 		break;
 	case BLK_ZONE_COND_FULL:
 		break;
 	default:
 		null_unlock_zone_res(dev);
 		return BLK_STS_IOERR;
 	}

 	zone->cond = BLK_ZONE_COND_EMPTY;
 	zone->wp = zone->start;

 	null_unlock_zone_res(dev);

 	if (dev->memory_backed)
 		return null_handle_discard(dev, zone->start, zone->len);

 	return BLK_STS_OK;
 }

 static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_op op,
 				   sector_t sector)
 {
 	struct nullb_device *dev = cmd->nq->dev;
 	unsigned int zone_no;
 	struct nullb_zone *zone;
 	blk_status_t ret;
 	size_t i;

 	if (op == REQ_OP_ZONE_RESET_ALL) {
 		for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
 			zone = &dev->zones[i];
 			null_lock_zone(dev, zone);
 			if (zone->cond != BLK_ZONE_COND_EMPTY &&
 			    zone->cond != BLK_ZONE_COND_READONLY &&
 			    zone->cond != BLK_ZONE_COND_OFFLINE) {
 				null_reset_zone(dev, zone);
 				trace_nullb_zone_op(cmd, i, zone->cond);
 			}
 			null_unlock_zone(dev, zone);
 		}
 		return BLK_STS_OK;
 	}

 	zone_no = null_zone_no(dev, sector);
 	zone = &dev->zones[zone_no];

 	null_lock_zone(dev, zone);

 	if (zone->cond == BLK_ZONE_COND_READONLY ||
 	    zone->cond == BLK_ZONE_COND_OFFLINE) {
 		ret = BLK_STS_IOERR;
 		goto unlock;
 	}

 	switch (op) {
 	case REQ_OP_ZONE_RESET:
 		ret = null_reset_zone(dev, zone);
 		break;
 	case REQ_OP_ZONE_OPEN:
 		ret = null_open_zone(dev, zone);
 		break;
 	case REQ_OP_ZONE_CLOSE:
 		ret = null_close_zone(dev, zone);
 		break;
 	case REQ_OP_ZONE_FINISH:
 		ret = null_finish_zone(dev, zone);
 		break;
 	default:
 		ret = BLK_STS_NOTSUPP;
 		break;
 	}

 	if (ret == BLK_STS_OK)
 		trace_nullb_zone_op(cmd, zone_no, zone->cond);

 unlock:
 	null_unlock_zone(dev, zone);

 	return ret;
 }

 blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd, enum req_op op,
 				    sector_t sector, sector_t nr_sectors)
 {
 	struct nullb_device *dev;
 	struct nullb_zone *zone;
 	blk_status_t sts;

 	switch (op) {
 	case REQ_OP_WRITE:
 		return null_zone_write(cmd, sector, nr_sectors, false);
 	case REQ_OP_ZONE_APPEND:
 		return null_zone_write(cmd, sector, nr_sectors, true);
 	case REQ_OP_ZONE_RESET:
 	case REQ_OP_ZONE_RESET_ALL:
 	case REQ_OP_ZONE_OPEN:
 	case REQ_OP_ZONE_CLOSE:
 	case REQ_OP_ZONE_FINISH:
 		return null_zone_mgmt(cmd, op, sector);
 	default:
 		dev = cmd->nq->dev;
 		zone = &dev->zones[null_zone_no(dev, sector)];
 		if (zone->cond == BLK_ZONE_COND_OFFLINE)
 			return BLK_STS_IOERR;

 		null_lock_zone(dev, zone);
 		sts = null_process_cmd(cmd, op, sector, nr_sectors);
 		null_unlock_zone(dev, zone);
 		return sts;
 	}
 }

 /*
  * Set a zone in the read-only or offline condition.
  */
 static void null_set_zone_cond(struct nullb_device *dev,
 			       struct nullb_zone *zone, enum blk_zone_cond cond)
 {
 	if (WARN_ON_ONCE(cond != BLK_ZONE_COND_READONLY &&
 			 cond != BLK_ZONE_COND_OFFLINE))
 		return;

 	null_lock_zone(dev, zone);

 	/*
 	 * If the read-only condition is requested again to zones already in
 	 * read-only condition, restore back normal empty condition. Do the same
 	 * if the offline condition is requested for offline zones. Otherwise,
 	 * set the specified zone condition to the zones. Finish the zones
 	 * beforehand to free up zone resources.
 	 */
 	if (zone->cond == cond) {
 		zone->cond = BLK_ZONE_COND_EMPTY;
 		zone->wp = zone->start;
 		if (dev->memory_backed)
 			null_handle_discard(dev, zone->start, zone->len);
 	} else {
 		if (zone->cond != BLK_ZONE_COND_READONLY &&
 		    zone->cond != BLK_ZONE_COND_OFFLINE)
 			null_finish_zone(dev, zone);
 		zone->cond = cond;
 		zone->wp = (sector_t)-1;
 	}

 	null_unlock_zone(dev, zone);
 }

 /*
  * Identify a zone from the sector written to configfs file. Then set zone
  * condition to the zone.
  */
 ssize_t zone_cond_store(struct nullb_device *dev, const char *page,
 			size_t count, enum blk_zone_cond cond)
 {
 	unsigned long long sector;
 	unsigned int zone_no;
 	int ret;

 	if (!dev->zoned) {
 		pr_err("null_blk device is not zoned\n");
 		return -EINVAL;
 	}

 	if (!dev->zones) {
 		pr_err("null_blk device is not yet powered\n");
 		return -EINVAL;
 	}

 	ret = kstrtoull(page, 0, &sector);
 	if (ret < 0)
 		return ret;

 	zone_no = null_zone_no(dev, sector);
 	if (zone_no >= dev->nr_zones) {
 		pr_err("Sector out of range\n");
 		return -EINVAL;
 	}

 	if (dev->zones[zone_no].type == BLK_ZONE_TYPE_CONVENTIONAL) {
 		pr_err("Can not change condition of conventional zones\n");
 		return -EINVAL;
 	}

 	null_set_zone_cond(dev, &dev->zones[zone_no], cond);

 	return count;
 }
	// SPDX-License-Identifier: GPL-2.0
	#include <linux/vmalloc.h>
	#include <linux/bitmap.h>
	#include "null_blk.h"

	#define CREATE_TRACE_POINTS
	#include "trace.h"

	#undef pr_fmt
	#define pr_fmt(fmt) "null_blk: " fmt

	static inline sector_t mb_to_sects(unsigned long mb)
	{
	return ((sector_t)mb * SZ_1M) >> SECTOR_SHIFT;
	}

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

	static inline void null_lock_zone_res(struct nullb_device *dev)
	{
	if (dev->need_zone_res_mgmt)
	spin_lock_irq(&dev->zone_res_lock);
	}

	static inline void null_unlock_zone_res(struct nullb_device *dev)
	{
	if (dev->need_zone_res_mgmt)
	spin_unlock_irq(&dev->zone_res_lock);
	}

	static inline void null_init_zone_lock(struct nullb_device *dev,
	struct nullb_zone *zone)
	{
	if (!dev->memory_backed)
	spin_lock_init(&zone->spinlock);
	else
	mutex_init(&zone->mutex);
	}

	static inline void null_lock_zone(struct nullb_device *dev,
	struct nullb_zone *zone)
	{
	if (!dev->memory_backed)
	spin_lock_irq(&zone->spinlock);
	else
	mutex_lock(&zone->mutex);
	}

	static inline void null_unlock_zone(struct nullb_device *dev,
	struct nullb_zone *zone)
	{
	if (!dev->memory_backed)
	spin_unlock_irq(&zone->spinlock);
	else
	mutex_unlock(&zone->mutex);
	}

	int null_init_zoned_dev(struct nullb_device dev, struct request_queue q)
	{
	sector_t dev_capacity_sects, zone_capacity_sects;
	struct nullb_zone *zone;
	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;
	}

	if (!dev->zone_capacity)
	dev->zone_capacity = dev->zone_size;

	if (dev->zone_capacity > dev->zone_size) {
	pr_err("zone capacity (%lu MB) larger than zone size (%lu MB)\n",
	dev->zone_capacity, dev->zone_size);
	return -EINVAL;
	}

	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);

	dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct nullb_zone),
	GFP_KERNEL \| __GFP_ZERO);
	if (!dev->zones)
	return -ENOMEM;

	spin_lock_init(&dev->zone_res_lock);

	if (dev->zone_nr_conv >= dev->nr_zones) {
	dev->zone_nr_conv = dev->nr_zones - 1;
	pr_info("changed the number of conventional zones to %u",
	dev->zone_nr_conv);
	}

	/* Max active zones has to be < nbr of seq zones in order to be enforceable */
	if (dev->zone_max_active >= dev->nr_zones - dev->zone_nr_conv) {
	dev->zone_max_active = 0;
	pr_info("zone_max_active limit disabled, limit >= zone count\n");
	}

	/* Max open zones has to be <= max active zones */
	if (dev->zone_max_active && dev->zone_max_open > dev->zone_max_active) {
	dev->zone_max_open = dev->zone_max_active;
	pr_info("changed the maximum number of open zones to %u\n",
	dev->nr_zones);
	} else if (dev->zone_max_open >= dev->nr_zones - dev->zone_nr_conv) {
	dev->zone_max_open = 0;
	pr_info("zone_max_open limit disabled, limit >= zone count\n");
	}
	dev->need_zone_res_mgmt = dev->zone_max_active \|\| dev->zone_max_open;
	dev->imp_close_zone_no = dev->zone_nr_conv;

	for (i = 0; i < dev->zone_nr_conv; i++) {
	zone = &dev->zones[i];

	null_init_zone_lock(dev, zone);
	zone->start = sector;
	zone->len = dev->zone_size_sects;
	zone->capacity = zone->len;
	zone->wp = zone->start + zone->len;
	zone->type = BLK_ZONE_TYPE_CONVENTIONAL;
	zone->cond = BLK_ZONE_COND_NOT_WP;

	sector += dev->zone_size_sects;
	}

	for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
	zone = &dev->zones[i];

	null_init_zone_lock(dev, zone);
	zone->start = zone->wp = sector;
	if (zone->start + dev->zone_size_sects > dev_capacity_sects)
	zone->len = dev_capacity_sects - zone->start;
	else
	zone->len = dev->zone_size_sects;
	zone->capacity =
	min_t(sector_t, zone->len, zone_capacity_sects);
	zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ;
	zone->cond = BLK_ZONE_COND_EMPTY;

	sector += dev->zone_size_sects;
	}

	return 0;
	}

	int null_register_zoned_dev(struct nullb *nullb)
	{
	struct nullb_device *dev = nullb->dev;
	struct request_queue *q = nullb->q;

	disk_set_zoned(nullb->disk, BLK_ZONED_HM);
	blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
	blk_queue_required_elevator_features(q, ELEVATOR_F_ZBD_SEQ_WRITE);

	if (queue_is_mq(q)) {
	int ret = blk_revalidate_disk_zones(nullb->disk, NULL);

	if (ret)
	return ret;
	} else {
	blk_queue_chunk_sectors(q, dev->zone_size_sects);
	nullb->disk->nr_zones = bdev_nr_zones(nullb->disk->part0);
	}

	blk_queue_max_zone_append_sectors(q, dev->zone_size_sects);
	disk_set_max_open_zones(nullb->disk, dev->zone_max_open);
	disk_set_max_active_zones(nullb->disk, dev->zone_max_active);

	return 0;
	}

	void null_free_zoned_dev(struct nullb_device *dev)
	{
	kvfree(dev->zones);
	dev->zones = NULL;
	}

	int null_report_zones(struct gendisk *disk, sector_t sector,
	unsigned int nr_zones, report_zones_cb cb, void *data)
	{
	struct nullb *nullb = disk->private_data;
	struct nullb_device *dev = nullb->dev;
	unsigned int first_zone, i;
	struct nullb_zone *zone;
	struct blk_zone blkz;
	int error;

	first_zone = null_zone_no(dev, sector);
	if (first_zone >= dev->nr_zones)
	return 0;

	nr_zones = min(nr_zones, dev->nr_zones - first_zone);
	trace_nullb_report_zones(nullb, nr_zones);

	memset(&blkz, 0, sizeof(struct blk_zone));
	zone = &dev->zones[first_zone];
	for (i = 0; i < nr_zones; i++, zone++) {
	/*
	* Stacked DM target drivers will remap the zone information by
	* modifying the zone information passed to the report callback.
	* So use a local copy to avoid corruption of the device zone
	* array.
	*/
	null_lock_zone(dev, zone);
	blkz.start = zone->start;
	blkz.len = zone->len;
	blkz.wp = zone->wp;
	blkz.type = zone->type;
	blkz.cond = zone->cond;
	blkz.capacity = zone->capacity;
	null_unlock_zone(dev, zone);

	error = cb(&blkz, i, data);
	if (error)
	return error;
	}

	return nr_zones;
	}

	/*
	* This is called in the case of memory backing from null_process_cmd()
	* with the target zone already locked.
	*/
	size_t null_zone_valid_read_len(struct nullb *nullb,
	sector_t sector, unsigned int len)
	{
	struct nullb_device *dev = nullb->dev;
	struct nullb_zone *zone = &dev->zones[null_zone_no(dev, sector)];
	unsigned int nr_sectors = len >> SECTOR_SHIFT;

	/* Read must be below the write pointer position */
	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL \|\|
	sector + nr_sectors <= zone->wp)
	return len;

	if (sector > zone->wp)
	return 0;

	return (zone->wp - sector) << SECTOR_SHIFT;
	}

	static blk_status_t __null_close_zone(struct nullb_device *dev,
	struct nullb_zone *zone)
	{
	switch (zone->cond) {
	case BLK_ZONE_COND_CLOSED:
	/* close operation on closed is not an error */
	return BLK_STS_OK;
	case BLK_ZONE_COND_IMP_OPEN:
	dev->nr_zones_imp_open--;
	break;
	case BLK_ZONE_COND_EXP_OPEN:
	dev->nr_zones_exp_open--;
	break;
	case BLK_ZONE_COND_EMPTY:
	case BLK_ZONE_COND_FULL:
	default:
	return BLK_STS_IOERR;
	}

	if (zone->wp == zone->start) {
	zone->cond = BLK_ZONE_COND_EMPTY;
	} else {
	zone->cond = BLK_ZONE_COND_CLOSED;
	dev->nr_zones_closed++;
	}

	return BLK_STS_OK;
	}

	static void null_close_imp_open_zone(struct nullb_device *dev)
	{
	struct nullb_zone *zone;
	unsigned int zno, i;

	zno = dev->imp_close_zone_no;
	if (zno >= dev->nr_zones)
	zno = dev->zone_nr_conv;

	for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
	zone = &dev->zones[zno];
	zno++;
	if (zno >= dev->nr_zones)
	zno = dev->zone_nr_conv;

	if (zone->cond == BLK_ZONE_COND_IMP_OPEN) {
	__null_close_zone(dev, zone);
	dev->imp_close_zone_no = zno;
	return;
	}
	}
	}

	static blk_status_t null_check_active(struct nullb_device *dev)
	{
	if (!dev->zone_max_active)
	return BLK_STS_OK;

	if (dev->nr_zones_exp_open + dev->nr_zones_imp_open +
	dev->nr_zones_closed < dev->zone_max_active)
	return BLK_STS_OK;

	return BLK_STS_ZONE_ACTIVE_RESOURCE;
	}

	static blk_status_t null_check_open(struct nullb_device *dev)
	{
	if (!dev->zone_max_open)
	return BLK_STS_OK;

	if (dev->nr_zones_exp_open + dev->nr_zones_imp_open < dev->zone_max_open)
	return BLK_STS_OK;

	if (dev->nr_zones_imp_open) {
	if (null_check_active(dev) == BLK_STS_OK) {
	null_close_imp_open_zone(dev);
	return BLK_STS_OK;
	}
	}

	return BLK_STS_ZONE_OPEN_RESOURCE;
	}

	/*
	* This function matches the manage open zone resources function in the ZBC standard,
	* with the addition of max active zones support (added in the ZNS standard).
	*
	* The function determines if a zone can transition to implicit open or explicit open,
	* while maintaining the max open zone (and max active zone) limit(s). It may close an
	* implicit open zone in order to make additional zone resources available.
	*
	* ZBC states that an implicit open zone shall be closed only if there is not
	* room within the open limit. However, with the addition of an active limit,
	* it is not certain that closing an implicit open zone will allow a new zone
	* to be opened, since we might already be at the active limit capacity.
	*/
	static blk_status_t null_check_zone_resources(struct nullb_device *dev,
	struct nullb_zone *zone)
	{
	blk_status_t ret;

	switch (zone->cond) {
	case BLK_ZONE_COND_EMPTY:
	ret = null_check_active(dev);
	if (ret != BLK_STS_OK)
	return ret;
	fallthrough;
	case BLK_ZONE_COND_CLOSED:
	return null_check_open(dev);
	default:
	/* Should never be called for other states */
	WARN_ON(1);
	return BLK_STS_IOERR;
	}
	}

	static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
	unsigned int nr_sectors, bool append)
	{
	struct nullb_device *dev = cmd->nq->dev;
	unsigned int zno = null_zone_no(dev, sector);
	struct nullb_zone *zone = &dev->zones[zno];
	blk_status_t ret;

	trace_nullb_zone_op(cmd, zno, zone->cond);

	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL) {
	if (append)
	return BLK_STS_IOERR;
	return null_process_cmd(cmd, REQ_OP_WRITE, sector, nr_sectors);
	}

	null_lock_zone(dev, zone);

	if (zone->cond == BLK_ZONE_COND_FULL \|\|
	zone->cond == BLK_ZONE_COND_READONLY \|\|
	zone->cond == BLK_ZONE_COND_OFFLINE) {
	/* Cannot write to the zone */
	ret = BLK_STS_IOERR;
	goto unlock;
	}

	/*
	* Regular writes must be at the write pointer position.
	* Zone append writes are automatically issued at the write
	* pointer and the position returned using the request or BIO
	* sector.
	*/
	if (append) {
	sector = zone->wp;
	if (dev->queue_mode == NULL_Q_MQ)
	cmd->rq->__sector = sector;
	else
	cmd->bio->bi_iter.bi_sector = sector;
	} else if (sector != zone->wp) {
	ret = BLK_STS_IOERR;
	goto unlock;
	}

	if (zone->wp + nr_sectors > zone->start + zone->capacity) {
	ret = BLK_STS_IOERR;
	goto unlock;
	}

	if (zone->cond == BLK_ZONE_COND_CLOSED \|\|
	zone->cond == BLK_ZONE_COND_EMPTY) {
	null_lock_zone_res(dev);

	ret = null_check_zone_resources(dev, zone);
	if (ret != BLK_STS_OK) {
	null_unlock_zone_res(dev);
	goto unlock;
	}
	if (zone->cond == BLK_ZONE_COND_CLOSED) {
	dev->nr_zones_closed--;
	dev->nr_zones_imp_open++;
	} else if (zone->cond == BLK_ZONE_COND_EMPTY) {
	dev->nr_zones_imp_open++;
	}

	if (zone->cond != BLK_ZONE_COND_EXP_OPEN)
	zone->cond = BLK_ZONE_COND_IMP_OPEN;

	null_unlock_zone_res(dev);
	}

	ret = null_process_cmd(cmd, REQ_OP_WRITE, sector, nr_sectors);
	if (ret != BLK_STS_OK)
	goto unlock;

	zone->wp += nr_sectors;
	if (zone->wp == zone->start + zone->capacity) {
	null_lock_zone_res(dev);
	if (zone->cond == BLK_ZONE_COND_EXP_OPEN)
	dev->nr_zones_exp_open--;
	else if (zone->cond == BLK_ZONE_COND_IMP_OPEN)
	dev->nr_zones_imp_open--;
	zone->cond = BLK_ZONE_COND_FULL;
	null_unlock_zone_res(dev);
	}

	ret = BLK_STS_OK;

	unlock:
	null_unlock_zone(dev, zone);

	return ret;
	}

	static blk_status_t null_open_zone(struct nullb_device *dev,
	struct nullb_zone *zone)
	{
	blk_status_t ret = BLK_STS_OK;

	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
	return BLK_STS_IOERR;

	null_lock_zone_res(dev);

	switch (zone->cond) {
	case BLK_ZONE_COND_EXP_OPEN:
	/* open operation on exp open is not an error */
	goto unlock;
	case BLK_ZONE_COND_EMPTY:
	ret = null_check_zone_resources(dev, zone);
	if (ret != BLK_STS_OK)
	goto unlock;
	break;
	case BLK_ZONE_COND_IMP_OPEN:
	dev->nr_zones_imp_open--;
	break;
	case BLK_ZONE_COND_CLOSED:
	ret = null_check_zone_resources(dev, zone);
	if (ret != BLK_STS_OK)
	goto unlock;
	dev->nr_zones_closed--;
	break;
	case BLK_ZONE_COND_FULL:
	default:
	ret = BLK_STS_IOERR;
	goto unlock;
	}

	zone->cond = BLK_ZONE_COND_EXP_OPEN;
	dev->nr_zones_exp_open++;

	unlock:
	null_unlock_zone_res(dev);

	return ret;
	}

	static blk_status_t null_close_zone(struct nullb_device *dev,
	struct nullb_zone *zone)
	{
	blk_status_t ret;

	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
	return BLK_STS_IOERR;

	null_lock_zone_res(dev);
	ret = __null_close_zone(dev, zone);
	null_unlock_zone_res(dev);

	return ret;
	}

	static blk_status_t null_finish_zone(struct nullb_device *dev,
	struct nullb_zone *zone)
	{
	blk_status_t ret = BLK_STS_OK;

	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
	return BLK_STS_IOERR;

	null_lock_zone_res(dev);

	switch (zone->cond) {
	case BLK_ZONE_COND_FULL:
	/* finish operation on full is not an error */
	goto unlock;
	case BLK_ZONE_COND_EMPTY:
	ret = null_check_zone_resources(dev, zone);
	if (ret != BLK_STS_OK)
	goto unlock;
	break;
	case BLK_ZONE_COND_IMP_OPEN:
	dev->nr_zones_imp_open--;
	break;
	case BLK_ZONE_COND_EXP_OPEN:
	dev->nr_zones_exp_open--;
	break;
	case BLK_ZONE_COND_CLOSED:
	ret = null_check_zone_resources(dev, zone);
	if (ret != BLK_STS_OK)
	goto unlock;
	dev->nr_zones_closed--;
	break;
	default:
	ret = BLK_STS_IOERR;
	goto unlock;
	}

	zone->cond = BLK_ZONE_COND_FULL;
	zone->wp = zone->start + zone->len;

	unlock:
	null_unlock_zone_res(dev);

	return ret;
	}

	static blk_status_t null_reset_zone(struct nullb_device *dev,
	struct nullb_zone *zone)
	{
	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
	return BLK_STS_IOERR;

	null_lock_zone_res(dev);

	switch (zone->cond) {
	case BLK_ZONE_COND_EMPTY:
	/* reset operation on empty is not an error */
	null_unlock_zone_res(dev);
	return BLK_STS_OK;
	case BLK_ZONE_COND_IMP_OPEN:
	dev->nr_zones_imp_open--;
	break;
	case BLK_ZONE_COND_EXP_OPEN:
	dev->nr_zones_exp_open--;
	break;
	case BLK_ZONE_COND_CLOSED:
	dev->nr_zones_closed--;
	break;
	case BLK_ZONE_COND_FULL:
	break;
	default:
	null_unlock_zone_res(dev);
	return BLK_STS_IOERR;
	}

	zone->cond = BLK_ZONE_COND_EMPTY;
	zone->wp = zone->start;

	null_unlock_zone_res(dev);

	if (dev->memory_backed)
	return null_handle_discard(dev, zone->start, zone->len);

	return BLK_STS_OK;
	}

	static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_op op,
	sector_t sector)
	{
	struct nullb_device *dev = cmd->nq->dev;
	unsigned int zone_no;
	struct nullb_zone *zone;
	blk_status_t ret;
	size_t i;

	if (op == REQ_OP_ZONE_RESET_ALL) {
	for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
	zone = &dev->zones[i];
	null_lock_zone(dev, zone);
	if (zone->cond != BLK_ZONE_COND_EMPTY &&
	zone->cond != BLK_ZONE_COND_READONLY &&
	zone->cond != BLK_ZONE_COND_OFFLINE) {
	null_reset_zone(dev, zone);
	trace_nullb_zone_op(cmd, i, zone->cond);
	}
	null_unlock_zone(dev, zone);
	}
	return BLK_STS_OK;
	}

	zone_no = null_zone_no(dev, sector);
	zone = &dev->zones[zone_no];

	null_lock_zone(dev, zone);

	if (zone->cond == BLK_ZONE_COND_READONLY \|\|
	zone->cond == BLK_ZONE_COND_OFFLINE) {
	ret = BLK_STS_IOERR;
	goto unlock;
	}

	switch (op) {
	case REQ_OP_ZONE_RESET:
	ret = null_reset_zone(dev, zone);
	break;
	case REQ_OP_ZONE_OPEN:
	ret = null_open_zone(dev, zone);
	break;
	case REQ_OP_ZONE_CLOSE:
	ret = null_close_zone(dev, zone);
	break;
	case REQ_OP_ZONE_FINISH:
	ret = null_finish_zone(dev, zone);
	break;
	default:
	ret = BLK_STS_NOTSUPP;
	break;
	}

	if (ret == BLK_STS_OK)
	trace_nullb_zone_op(cmd, zone_no, zone->cond);

	unlock:
	null_unlock_zone(dev, zone);

	return ret;
	}

	blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd, enum req_op op,
	sector_t sector, sector_t nr_sectors)
	{
	struct nullb_device *dev;
	struct nullb_zone *zone;
	blk_status_t sts;

	switch (op) {
	case REQ_OP_WRITE:
	return null_zone_write(cmd, sector, nr_sectors, false);
	case REQ_OP_ZONE_APPEND:
	return null_zone_write(cmd, sector, nr_sectors, true);
	case REQ_OP_ZONE_RESET:
	case REQ_OP_ZONE_RESET_ALL:
	case REQ_OP_ZONE_OPEN:
	case REQ_OP_ZONE_CLOSE:
	case REQ_OP_ZONE_FINISH:
	return null_zone_mgmt(cmd, op, sector);
	default:
	dev = cmd->nq->dev;
	zone = &dev->zones[null_zone_no(dev, sector)];
	if (zone->cond == BLK_ZONE_COND_OFFLINE)
	return BLK_STS_IOERR;

	null_lock_zone(dev, zone);
	sts = null_process_cmd(cmd, op, sector, nr_sectors);
	null_unlock_zone(dev, zone);
	return sts;
	}
	}

	/*
	* Set a zone in the read-only or offline condition.
	*/
	static void null_set_zone_cond(struct nullb_device *dev,
	struct nullb_zone *zone, enum blk_zone_cond cond)
	{
	if (WARN_ON_ONCE(cond != BLK_ZONE_COND_READONLY &&
	cond != BLK_ZONE_COND_OFFLINE))
	return;

	null_lock_zone(dev, zone);

	/*
	* If the read-only condition is requested again to zones already in
	* read-only condition, restore back normal empty condition. Do the same
	* if the offline condition is requested for offline zones. Otherwise,
	* set the specified zone condition to the zones. Finish the zones
	* beforehand to free up zone resources.
	*/
	if (zone->cond == cond) {
	zone->cond = BLK_ZONE_COND_EMPTY;
	zone->wp = zone->start;
	if (dev->memory_backed)
	null_handle_discard(dev, zone->start, zone->len);
	} else {
	if (zone->cond != BLK_ZONE_COND_READONLY &&
	zone->cond != BLK_ZONE_COND_OFFLINE)
	null_finish_zone(dev, zone);
	zone->cond = cond;
	zone->wp = (sector_t)-1;
	}

	null_unlock_zone(dev, zone);
	}

	/*
	* Identify a zone from the sector written to configfs file. Then set zone
	* condition to the zone.
	*/
	ssize_t zone_cond_store(struct nullb_device dev, const char page,
	size_t count, enum blk_zone_cond cond)
	{
	unsigned long long sector;
	unsigned int zone_no;
	int ret;

	if (!dev->zoned) {
	pr_err("null_blk device is not zoned\n");
	return -EINVAL;
	}

	if (!dev->zones) {
	pr_err("null_blk device is not yet powered\n");
	return -EINVAL;
	}

	ret = kstrtoull(page, 0, &sector);
	if (ret < 0)
	return ret;

	zone_no = null_zone_no(dev, sector);
	if (zone_no >= dev->nr_zones) {
	pr_err("Sector out of range\n");
	return -EINVAL;
	}

	if (dev->zones[zone_no].type == BLK_ZONE_TYPE_CONVENTIONAL) {
	pr_err("Can not change condition of conventional zones\n");
	return -EINVAL;
	}

	null_set_zone_cond(dev, &dev->zones[zone_no], cond);

	return count;
	}