Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 766 insertions, 0 deletions

diff --git a/drivers/block/null_blk/zoned.c b/drivers/block/null_blk/zoned.c
new file mode 100644
index 0000000000..55c5b48bc2
--- /dev/null
+++ b/drivers/block/null_blk/zoned.c
@@ -0,0 +1,766 @@
+// 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);
+	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);
+
+	if (queue_is_mq(q))
+		return blk_revalidate_disk_zones(nullb->disk, NULL);
+
+	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;
+}