2 files changed, 188 insertions, 120 deletions

diff --git a/drivers/block/null_blk.h b/drivers/block/null_blk.h
index c24d9b5ad81a..14546ead1d66 100644
--- a/drivers/block/null_blk.h
+++ b/drivers/block/null_blk.h
@@ -12,6 +12,8 @@
 #include <linux/configfs.h>
 #include <linux/badblocks.h>
 #include <linux/fault-inject.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
 
 struct nullb_cmd {
 	struct request *rq;
@@ -32,6 +34,26 @@ struct nullb_queue {
 	struct nullb_cmd *cmds;
 };
 
+struct nullb_zone {
+	/*
+	 * Zone lock to prevent concurrent modification of a zone write
+	 * pointer position and condition: with memory backing, a write
+	 * command execution may sleep on memory allocation. For this case,
+	 * use mutex as the zone lock. Otherwise, use the spinlock for
+	 * locking the zone.
+	 */
+	union {
+		spinlock_t spinlock;
+		struct mutex mutex;
+	};
+	enum blk_zone_type type;
+	enum blk_zone_cond cond;
+	sector_t start;
+	sector_t wp;
+	unsigned int len;
+	unsigned int capacity;
+};
+
 struct nullb_device {
 	struct nullb *nullb;
 	struct config_item item;
@@ -45,10 +67,10 @@ struct nullb_device {
 	unsigned int nr_zones_imp_open;
 	unsigned int nr_zones_exp_open;
 	unsigned int nr_zones_closed;
-	struct blk_zone *zones;
+	struct nullb_zone *zones;
 	sector_t zone_size_sects;
-	spinlock_t zone_lock;
-	unsigned long *zone_locks;
+	bool need_zone_res_mgmt;
+	spinlock_t zone_res_lock;
 
 	unsigned long size; /* device size in MB */
 	unsigned long completion_nsec; /* time in ns to complete a request */
diff --git a/drivers/block/null_blk_zoned.c b/drivers/block/null_blk_zoned.c
index 172f720b8d63..4d5c0b938618 100644
--- a/drivers/block/null_blk_zoned.c
+++ b/drivers/block/null_blk_zoned.c
@@ -13,9 +13,49 @@ 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;
 
@@ -44,26 +84,12 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
 	if (dev_capacity_sects & (dev->zone_size_sects - 1))
 		dev->nr_zones++;
 
-	dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct blk_zone),
-			GFP_KERNEL | __GFP_ZERO);
+	dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct nullb_zone),
+				    GFP_KERNEL | __GFP_ZERO);
 	if (!dev->zones)
 		return -ENOMEM;
 
-	/*
-	 * With memory backing, the zone_lock spinlock needs to be temporarily
-	 * released to avoid scheduling in atomic context. To guarantee zone
-	 * information protection, use a bitmap to lock zones with
-	 * wait_on_bit_lock_io(). Sleeping on the lock is OK as memory backing
-	 * implies that the queue is marked with BLK_MQ_F_BLOCKING.
-	 */
-	spin_lock_init(&dev->zone_lock);
-	if (dev->memory_backed) {
-		dev->zone_locks = bitmap_zalloc(dev->nr_zones, GFP_KERNEL);
-		if (!dev->zone_locks) {
-			kvfree(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;
@@ -86,10 +112,12 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
 		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;
 
 	for (i = 0; i <  dev->zone_nr_conv; i++) {
-		struct blk_zone *zone = &dev->zones[i];
+		zone = &dev->zones[i];
 
+		null_init_zone_lock(dev, zone);
 		zone->start = sector;
 		zone->len = dev->zone_size_sects;
 		zone->capacity = zone->len;
@@ -101,8 +129,9 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
 	}
 
 	for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
-		struct blk_zone *zone = &dev->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;
@@ -147,32 +176,17 @@ int null_register_zoned_dev(struct nullb *nullb)
 
 void null_free_zoned_dev(struct nullb_device *dev)
 {
-	bitmap_free(dev->zone_locks);
 	kvfree(dev->zones);
 }
 
-static inline void null_lock_zone(struct nullb_device *dev, unsigned int zno)
-{
-	if (dev->memory_backed)
-		wait_on_bit_lock_io(dev->zone_locks, zno, TASK_UNINTERRUPTIBLE);
-	spin_lock_irq(&dev->zone_lock);
-}
-
-static inline void null_unlock_zone(struct nullb_device *dev, unsigned int zno)
-{
-	spin_unlock_irq(&dev->zone_lock);
-
-	if (dev->memory_backed)
-		clear_and_wake_up_bit(zno, dev->zone_locks);
-}
-
 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, zno;
-	struct blk_zone zone;
+	unsigned int first_zone, i;
+	struct nullb_zone *zone;
+	struct blk_zone blkz;
 	int error;
 
 	first_zone = null_zone_no(dev, sector);
@@ -182,19 +196,25 @@ int null_report_zones(struct gendisk *disk, sector_t sector,
 	nr_zones = min(nr_zones, dev->nr_zones - first_zone);
 	trace_nullb_report_zones(nullb, nr_zones);
 
-	zno = first_zone;
-	for (i = 0; i < nr_zones; i++, zno++) {
+	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, zno);
-		memcpy(&zone, &dev->zones[zno], sizeof(struct blk_zone));
-		null_unlock_zone(dev, zno);
-
-		error = cb(&zone, i, data);
+		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;
 	}
@@ -210,7 +230,7 @@ size_t null_zone_valid_read_len(struct nullb *nullb,
 				sector_t sector, unsigned int len)
 {
 	struct nullb_device *dev = nullb->dev;
-	struct blk_zone *zone = &dev->zones[null_zone_no(dev, sector)];
+	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 */
@@ -224,11 +244,9 @@ size_t null_zone_valid_read_len(struct nullb *nullb,
 	return (zone->wp - sector) << SECTOR_SHIFT;
 }
 
-static blk_status_t null_close_zone(struct nullb_device *dev, struct blk_zone *zone)
+static blk_status_t __null_close_zone(struct nullb_device *dev,
+				      struct nullb_zone *zone)
 {
-	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
-		return BLK_STS_IOERR;
-
 	switch (zone->cond) {
 	case BLK_ZONE_COND_CLOSED:
 		/* close operation on closed is not an error */
@@ -261,7 +279,7 @@ static void null_close_first_imp_zone(struct nullb_device *dev)
 
 	for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
 		if (dev->zones[i].cond == BLK_ZONE_COND_IMP_OPEN) {
-			null_close_zone(dev, &dev->zones[i]);
+			__null_close_zone(dev, &dev->zones[i]);
 			return;
 		}
 	}
@@ -310,7 +328,8 @@ static blk_status_t null_check_open(struct nullb_device *dev)
  * 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 blk_zone *zone)
+static blk_status_t null_check_zone_resources(struct nullb_device *dev,
+					      struct nullb_zone *zone)
 {
 	blk_status_t ret;
 
@@ -334,7 +353,7 @@ static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
 {
 	struct nullb_device *dev = cmd->nq->dev;
 	unsigned int zno = null_zone_no(dev, sector);
-	struct blk_zone *zone = &dev->zones[zno];
+	struct nullb_zone *zone = &dev->zones[zno];
 	blk_status_t ret;
 
 	trace_nullb_zone_op(cmd, zno, zone->cond);
@@ -345,26 +364,12 @@ static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
 		return null_process_cmd(cmd, REQ_OP_WRITE, sector, nr_sectors);
 	}
 
-	null_lock_zone(dev, zno);
+	null_lock_zone(dev, zone);
 
-	switch (zone->cond) {
-	case BLK_ZONE_COND_FULL:
+	if (zone->cond == BLK_ZONE_COND_FULL) {
 		/* Cannot write to a full zone */
 		ret = BLK_STS_IOERR;
 		goto unlock;
-	case BLK_ZONE_COND_EMPTY:
-	case BLK_ZONE_COND_CLOSED:
-		ret = null_check_zone_resources(dev, zone);
-		if (ret != BLK_STS_OK)
-			goto unlock;
-		break;
-	case BLK_ZONE_COND_IMP_OPEN:
-	case BLK_ZONE_COND_EXP_OPEN:
-		break;
-	default:
-		/* Invalid zone condition */
-		ret = BLK_STS_IOERR;
-		goto unlock;
 	}
 
 	/*
@@ -389,60 +394,69 @@ static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
 		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_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);
 	}
-	if (zone->cond != BLK_ZONE_COND_EXP_OPEN)
-		zone->cond = BLK_ZONE_COND_IMP_OPEN;
 
-	/*
-	 * Memory backing allocation may sleep: release the zone_lock spinlock
-	 * to avoid scheduling in atomic context. Zone operation atomicity is
-	 * still guaranteed through the zone_locks bitmap.
-	 */
-	if (dev->memory_backed)
-		spin_unlock_irq(&dev->zone_lock);
 	ret = null_process_cmd(cmd, REQ_OP_WRITE, sector, nr_sectors);
-	if (dev->memory_backed)
-		spin_lock_irq(&dev->zone_lock);
-
 	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, zno);
+	null_unlock_zone(dev, zone);
 
 	return ret;
 }
 
-static blk_status_t null_open_zone(struct nullb_device *dev, struct blk_zone *zone)
+static blk_status_t null_open_zone(struct nullb_device *dev,
+				   struct nullb_zone *zone)
 {
-	blk_status_t ret;
+	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 */
-		return BLK_STS_OK;
+		goto unlock;
 	case BLK_ZONE_COND_EMPTY:
 		ret = null_check_zone_resources(dev, zone);
 		if (ret != BLK_STS_OK)
-			return ret;
+			goto unlock;
 		break;
 	case BLK_ZONE_COND_IMP_OPEN:
 		dev->nr_zones_imp_open--;
@@ -450,35 +464,57 @@ static blk_status_t null_open_zone(struct nullb_device *dev, struct blk_zone *zo
 	case BLK_ZONE_COND_CLOSED:
 		ret = null_check_zone_resources(dev, zone);
 		if (ret != BLK_STS_OK)
-			return ret;
+			goto unlock;
 		dev->nr_zones_closed--;
 		break;
 	case BLK_ZONE_COND_FULL:
 	default:
-		return BLK_STS_IOERR;
+		ret = BLK_STS_IOERR;
+		goto unlock;
 	}
 
 	zone->cond = BLK_ZONE_COND_EXP_OPEN;
 	dev->nr_zones_exp_open++;
 
-	return BLK_STS_OK;
+unlock:
+	null_unlock_zone_res(dev);
+
+	return ret;
 }
 
-static blk_status_t null_finish_zone(struct nullb_device *dev, struct blk_zone *zone)
+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 */
-		return BLK_STS_OK;
+		goto unlock;
 	case BLK_ZONE_COND_EMPTY:
 		ret = null_check_zone_resources(dev, zone);
 		if (ret != BLK_STS_OK)
-			return ret;
+			goto unlock;
 		break;
 	case BLK_ZONE_COND_IMP_OPEN:
 		dev->nr_zones_imp_open--;
@@ -489,27 +525,35 @@ static blk_status_t null_finish_zone(struct nullb_device *dev, struct blk_zone *
 	case BLK_ZONE_COND_CLOSED:
 		ret = null_check_zone_resources(dev, zone);
 		if (ret != BLK_STS_OK)
-			return ret;
+			goto unlock;
 		dev->nr_zones_closed--;
 		break;
 	default:
-		return BLK_STS_IOERR;
+		ret = BLK_STS_IOERR;
+		goto unlock;
 	}
 
 	zone->cond = BLK_ZONE_COND_FULL;
 	zone->wp = zone->start + zone->len;
 
-	return BLK_STS_OK;
+unlock:
+	null_unlock_zone_res(dev);
+
+	return ret;
 }
 
-static blk_status_t null_reset_zone(struct nullb_device *dev, struct blk_zone *zone)
+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--;
@@ -523,12 +567,15 @@ static blk_status_t null_reset_zone(struct nullb_device *dev, struct blk_zone *z
 	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);
+
 	return BLK_STS_OK;
 }
 
@@ -537,19 +584,19 @@ static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_opf op,
 {
 	struct nullb_device *dev = cmd->nq->dev;
 	unsigned int zone_no;
-	struct blk_zone *zone;
+	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++) {
-			null_lock_zone(dev, i);
 			zone = &dev->zones[i];
+			null_lock_zone(dev, zone);
 			if (zone->cond != BLK_ZONE_COND_EMPTY) {
 				null_reset_zone(dev, zone);
 				trace_nullb_zone_op(cmd, i, zone->cond);
 			}
-			null_unlock_zone(dev, i);
+			null_unlock_zone(dev, zone);
 		}
 		return BLK_STS_OK;
 	}
@@ -557,7 +604,7 @@ static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_opf op,
 	zone_no = null_zone_no(dev, sector);
 	zone = &dev->zones[zone_no];
 
-	null_lock_zone(dev, zone_no);
+	null_lock_zone(dev, zone);
 
 	switch (op) {
 	case REQ_OP_ZONE_RESET:
@@ -580,7 +627,7 @@ static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_opf op,
 	if (ret == BLK_STS_OK)
 		trace_nullb_zone_op(cmd, zone_no, zone->cond);
 
-	null_unlock_zone(dev, zone_no);
+	null_unlock_zone(dev, zone);
 
 	return ret;
 }
@@ -588,29 +635,28 @@ static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_opf op,
 blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd, enum req_opf op,
 				    sector_t sector, sector_t nr_sectors)
 {
-	struct nullb_device *dev = cmd->nq->dev;
-	unsigned int zno = null_zone_no(dev, sector);
+	struct nullb_device *dev;
+	struct nullb_zone *zone;
 	blk_status_t sts;
 
 	switch (op) {
 	case REQ_OP_WRITE:
-		sts = null_zone_write(cmd, sector, nr_sectors, false);
-		break;
+		return null_zone_write(cmd, sector, nr_sectors, false);
 	case REQ_OP_ZONE_APPEND:
-		sts = null_zone_write(cmd, sector, nr_sectors, true);
-		break;
+		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:
-		sts = null_zone_mgmt(cmd, op, sector);
-		break;
+		return null_zone_mgmt(cmd, op, sector);
 	default:
-		null_lock_zone(dev, zno);
+		dev = cmd->nq->dev;
+		zone = &dev->zones[null_zone_no(dev, sector)];
+
+		null_lock_zone(dev, zone);
 		sts = null_process_cmd(cmd, op, sector, nr_sectors);
-		null_unlock_zone(dev, zno);
+		null_unlock_zone(dev, zone);
+		return sts;
 	}
-
-	return sts;
 }