Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 1160 insertions, 0 deletions

diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c
new file mode 100644
index 0000000000..b487f7acc8
--- /dev/null
+++ b/drivers/md/dm-zoned-target.c
@@ -0,0 +1,1160 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017 Western Digital Corporation or its affiliates.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-zoned.h"
+
+#include <linux/module.h>
+
+#define	DM_MSG_PREFIX		"zoned"
+
+#define DMZ_MIN_BIOS		8192
+
+/*
+ * Zone BIO context.
+ */
+struct dmz_bioctx {
+	struct dmz_dev		*dev;
+	struct dm_zone		*zone;
+	struct bio		*bio;
+	refcount_t		ref;
+};
+
+/*
+ * Chunk work descriptor.
+ */
+struct dm_chunk_work {
+	struct work_struct	work;
+	refcount_t		refcount;
+	struct dmz_target	*target;
+	unsigned int		chunk;
+	struct bio_list		bio_list;
+};
+
+/*
+ * Target descriptor.
+ */
+struct dmz_target {
+	struct dm_dev		**ddev;
+	unsigned int		nr_ddevs;
+
+	unsigned int		flags;
+
+	/* Zoned block device information */
+	struct dmz_dev		*dev;
+
+	/* For metadata handling */
+	struct dmz_metadata     *metadata;
+
+	/* For chunk work */
+	struct radix_tree_root	chunk_rxtree;
+	struct workqueue_struct *chunk_wq;
+	struct mutex		chunk_lock;
+
+	/* For cloned BIOs to zones */
+	struct bio_set		bio_set;
+
+	/* For flush */
+	spinlock_t		flush_lock;
+	struct bio_list		flush_list;
+	struct delayed_work	flush_work;
+	struct workqueue_struct *flush_wq;
+};
+
+/*
+ * Flush intervals (seconds).
+ */
+#define DMZ_FLUSH_PERIOD	(10 * HZ)
+
+/*
+ * Target BIO completion.
+ */
+static inline void dmz_bio_endio(struct bio *bio, blk_status_t status)
+{
+	struct dmz_bioctx *bioctx =
+		dm_per_bio_data(bio, sizeof(struct dmz_bioctx));
+
+	if (status != BLK_STS_OK && bio->bi_status == BLK_STS_OK)
+		bio->bi_status = status;
+	if (bioctx->dev && bio->bi_status != BLK_STS_OK)
+		bioctx->dev->flags |= DMZ_CHECK_BDEV;
+
+	if (refcount_dec_and_test(&bioctx->ref)) {
+		struct dm_zone *zone = bioctx->zone;
+
+		if (zone) {
+			if (bio->bi_status != BLK_STS_OK &&
+			    bio_op(bio) == REQ_OP_WRITE &&
+			    dmz_is_seq(zone))
+				set_bit(DMZ_SEQ_WRITE_ERR, &zone->flags);
+			dmz_deactivate_zone(zone);
+		}
+		bio_endio(bio);
+	}
+}
+
+/*
+ * Completion callback for an internally cloned target BIO. This terminates the
+ * target BIO when there are no more references to its context.
+ */
+static void dmz_clone_endio(struct bio *clone)
+{
+	struct dmz_bioctx *bioctx = clone->bi_private;
+	blk_status_t status = clone->bi_status;
+
+	bio_put(clone);
+	dmz_bio_endio(bioctx->bio, status);
+}
+
+/*
+ * Issue a clone of a target BIO. The clone may only partially process the
+ * original target BIO.
+ */
+static int dmz_submit_bio(struct dmz_target *dmz, struct dm_zone *zone,
+			  struct bio *bio, sector_t chunk_block,
+			  unsigned int nr_blocks)
+{
+	struct dmz_bioctx *bioctx =
+		dm_per_bio_data(bio, sizeof(struct dmz_bioctx));
+	struct dmz_dev *dev = zone->dev;
+	struct bio *clone;
+
+	if (dev->flags & DMZ_BDEV_DYING)
+		return -EIO;
+
+	clone = bio_alloc_clone(dev->bdev, bio, GFP_NOIO, &dmz->bio_set);
+	if (!clone)
+		return -ENOMEM;
+
+	bioctx->dev = dev;
+	clone->bi_iter.bi_sector =
+		dmz_start_sect(dmz->metadata, zone) + dmz_blk2sect(chunk_block);
+	clone->bi_iter.bi_size = dmz_blk2sect(nr_blocks) << SECTOR_SHIFT;
+	clone->bi_end_io = dmz_clone_endio;
+	clone->bi_private = bioctx;
+
+	bio_advance(bio, clone->bi_iter.bi_size);
+
+	refcount_inc(&bioctx->ref);
+	submit_bio_noacct(clone);
+
+	if (bio_op(bio) == REQ_OP_WRITE && dmz_is_seq(zone))
+		zone->wp_block += nr_blocks;
+
+	return 0;
+}
+
+/*
+ * Zero out pages of discarded blocks accessed by a read BIO.
+ */
+static void dmz_handle_read_zero(struct dmz_target *dmz, struct bio *bio,
+				 sector_t chunk_block, unsigned int nr_blocks)
+{
+	unsigned int size = nr_blocks << DMZ_BLOCK_SHIFT;
+
+	/* Clear nr_blocks */
+	swap(bio->bi_iter.bi_size, size);
+	zero_fill_bio(bio);
+	swap(bio->bi_iter.bi_size, size);
+
+	bio_advance(bio, size);
+}
+
+/*
+ * Process a read BIO.
+ */
+static int dmz_handle_read(struct dmz_target *dmz, struct dm_zone *zone,
+			   struct bio *bio)
+{
+	struct dmz_metadata *zmd = dmz->metadata;
+	sector_t chunk_block = dmz_chunk_block(zmd, dmz_bio_block(bio));
+	unsigned int nr_blocks = dmz_bio_blocks(bio);
+	sector_t end_block = chunk_block + nr_blocks;
+	struct dm_zone *rzone, *bzone;
+	int ret;
+
+	/* Read into unmapped chunks need only zeroing the BIO buffer */
+	if (!zone) {
+		zero_fill_bio(bio);
+		return 0;
+	}
+
+	DMDEBUG("(%s): READ chunk %llu -> %s zone %u, block %llu, %u blocks",
+		dmz_metadata_label(zmd),
+		(unsigned long long)dmz_bio_chunk(zmd, bio),
+		(dmz_is_rnd(zone) ? "RND" :
+		 (dmz_is_cache(zone) ? "CACHE" : "SEQ")),
+		zone->id,
+		(unsigned long long)chunk_block, nr_blocks);
+
+	/* Check block validity to determine the read location */
+	bzone = zone->bzone;
+	while (chunk_block < end_block) {
+		nr_blocks = 0;
+		if (dmz_is_rnd(zone) || dmz_is_cache(zone) ||
+		    chunk_block < zone->wp_block) {
+			/* Test block validity in the data zone */
+			ret = dmz_block_valid(zmd, zone, chunk_block);
+			if (ret < 0)
+				return ret;
+			if (ret > 0) {
+				/* Read data zone blocks */
+				nr_blocks = ret;
+				rzone = zone;
+			}
+		}
+
+		/*
+		 * No valid blocks found in the data zone.
+		 * Check the buffer zone, if there is one.
+		 */
+		if (!nr_blocks && bzone) {
+			ret = dmz_block_valid(zmd, bzone, chunk_block);
+			if (ret < 0)
+				return ret;
+			if (ret > 0) {
+				/* Read buffer zone blocks */
+				nr_blocks = ret;
+				rzone = bzone;
+			}
+		}
+
+		if (nr_blocks) {
+			/* Valid blocks found: read them */
+			nr_blocks = min_t(unsigned int, nr_blocks,
+					  end_block - chunk_block);
+			ret = dmz_submit_bio(dmz, rzone, bio,
+					     chunk_block, nr_blocks);
+			if (ret)
+				return ret;
+			chunk_block += nr_blocks;
+		} else {
+			/* No valid block: zeroout the current BIO block */
+			dmz_handle_read_zero(dmz, bio, chunk_block, 1);
+			chunk_block++;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Write blocks directly in a data zone, at the write pointer.
+ * If a buffer zone is assigned, invalidate the blocks written
+ * in place.
+ */
+static int dmz_handle_direct_write(struct dmz_target *dmz,
+				   struct dm_zone *zone, struct bio *bio,
+				   sector_t chunk_block,
+				   unsigned int nr_blocks)
+{
+	struct dmz_metadata *zmd = dmz->metadata;
+	struct dm_zone *bzone = zone->bzone;
+	int ret;
+
+	if (dmz_is_readonly(zone))
+		return -EROFS;
+
+	/* Submit write */
+	ret = dmz_submit_bio(dmz, zone, bio, chunk_block, nr_blocks);
+	if (ret)
+		return ret;
+
+	/*
+	 * Validate the blocks in the data zone and invalidate
+	 * in the buffer zone, if there is one.
+	 */
+	ret = dmz_validate_blocks(zmd, zone, chunk_block, nr_blocks);
+	if (ret == 0 && bzone)
+		ret = dmz_invalidate_blocks(zmd, bzone, chunk_block, nr_blocks);
+
+	return ret;
+}
+
+/*
+ * Write blocks in the buffer zone of @zone.
+ * If no buffer zone is assigned yet, get one.
+ * Called with @zone write locked.
+ */
+static int dmz_handle_buffered_write(struct dmz_target *dmz,
+				     struct dm_zone *zone, struct bio *bio,
+				     sector_t chunk_block,
+				     unsigned int nr_blocks)
+{
+	struct dmz_metadata *zmd = dmz->metadata;
+	struct dm_zone *bzone;
+	int ret;
+
+	/* Get the buffer zone. One will be allocated if needed */
+	bzone = dmz_get_chunk_buffer(zmd, zone);
+	if (IS_ERR(bzone))
+		return PTR_ERR(bzone);
+
+	if (dmz_is_readonly(bzone))
+		return -EROFS;
+
+	/* Submit write */
+	ret = dmz_submit_bio(dmz, bzone, bio, chunk_block, nr_blocks);
+	if (ret)
+		return ret;
+
+	/*
+	 * Validate the blocks in the buffer zone
+	 * and invalidate in the data zone.
+	 */
+	ret = dmz_validate_blocks(zmd, bzone, chunk_block, nr_blocks);
+	if (ret == 0 && chunk_block < zone->wp_block)
+		ret = dmz_invalidate_blocks(zmd, zone, chunk_block, nr_blocks);
+
+	return ret;
+}
+
+/*
+ * Process a write BIO.
+ */
+static int dmz_handle_write(struct dmz_target *dmz, struct dm_zone *zone,
+			    struct bio *bio)
+{
+	struct dmz_metadata *zmd = dmz->metadata;
+	sector_t chunk_block = dmz_chunk_block(zmd, dmz_bio_block(bio));
+	unsigned int nr_blocks = dmz_bio_blocks(bio);
+
+	if (!zone)
+		return -ENOSPC;
+
+	DMDEBUG("(%s): WRITE chunk %llu -> %s zone %u, block %llu, %u blocks",
+		dmz_metadata_label(zmd),
+		(unsigned long long)dmz_bio_chunk(zmd, bio),
+		(dmz_is_rnd(zone) ? "RND" :
+		 (dmz_is_cache(zone) ? "CACHE" : "SEQ")),
+		zone->id,
+		(unsigned long long)chunk_block, nr_blocks);
+
+	if (dmz_is_rnd(zone) || dmz_is_cache(zone) ||
+	    chunk_block == zone->wp_block) {
+		/*
+		 * zone is a random zone or it is a sequential zone
+		 * and the BIO is aligned to the zone write pointer:
+		 * direct write the zone.
+		 */
+		return dmz_handle_direct_write(dmz, zone, bio,
+					       chunk_block, nr_blocks);
+	}
+
+	/*
+	 * This is an unaligned write in a sequential zone:
+	 * use buffered write.
+	 */
+	return dmz_handle_buffered_write(dmz, zone, bio, chunk_block, nr_blocks);
+}
+
+/*
+ * Process a discard BIO.
+ */
+static int dmz_handle_discard(struct dmz_target *dmz, struct dm_zone *zone,
+			      struct bio *bio)
+{
+	struct dmz_metadata *zmd = dmz->metadata;
+	sector_t block = dmz_bio_block(bio);
+	unsigned int nr_blocks = dmz_bio_blocks(bio);
+	sector_t chunk_block = dmz_chunk_block(zmd, block);
+	int ret = 0;
+
+	/* For unmapped chunks, there is nothing to do */
+	if (!zone)
+		return 0;
+
+	if (dmz_is_readonly(zone))
+		return -EROFS;
+
+	DMDEBUG("(%s): DISCARD chunk %llu -> zone %u, block %llu, %u blocks",
+		dmz_metadata_label(dmz->metadata),
+		(unsigned long long)dmz_bio_chunk(zmd, bio),
+		zone->id,
+		(unsigned long long)chunk_block, nr_blocks);
+
+	/*
+	 * Invalidate blocks in the data zone and its
+	 * buffer zone if one is mapped.
+	 */
+	if (dmz_is_rnd(zone) || dmz_is_cache(zone) ||
+	    chunk_block < zone->wp_block)
+		ret = dmz_invalidate_blocks(zmd, zone, chunk_block, nr_blocks);
+	if (ret == 0 && zone->bzone)
+		ret = dmz_invalidate_blocks(zmd, zone->bzone,
+					    chunk_block, nr_blocks);
+	return ret;
+}
+
+/*
+ * Process a BIO.
+ */
+static void dmz_handle_bio(struct dmz_target *dmz, struct dm_chunk_work *cw,
+			   struct bio *bio)
+{
+	struct dmz_bioctx *bioctx =
+		dm_per_bio_data(bio, sizeof(struct dmz_bioctx));
+	struct dmz_metadata *zmd = dmz->metadata;
+	struct dm_zone *zone;
+	int ret;
+
+	dmz_lock_metadata(zmd);
+
+	/*
+	 * Get the data zone mapping the chunk. There may be no
+	 * mapping for read and discard. If a mapping is obtained,
+	 + the zone returned will be set to active state.
+	 */
+	zone = dmz_get_chunk_mapping(zmd, dmz_bio_chunk(zmd, bio),
+				     bio_op(bio));
+	if (IS_ERR(zone)) {
+		ret = PTR_ERR(zone);
+		goto out;
+	}
+
+	/* Process the BIO */
+	if (zone) {
+		dmz_activate_zone(zone);
+		bioctx->zone = zone;
+		dmz_reclaim_bio_acc(zone->dev->reclaim);
+	}
+
+	switch (bio_op(bio)) {
+	case REQ_OP_READ:
+		ret = dmz_handle_read(dmz, zone, bio);
+		break;
+	case REQ_OP_WRITE:
+		ret = dmz_handle_write(dmz, zone, bio);
+		break;
+	case REQ_OP_DISCARD:
+	case REQ_OP_WRITE_ZEROES:
+		ret = dmz_handle_discard(dmz, zone, bio);
+		break;
+	default:
+		DMERR("(%s): Unsupported BIO operation 0x%x",
+		      dmz_metadata_label(dmz->metadata), bio_op(bio));
+		ret = -EIO;
+	}
+
+	/*
+	 * Release the chunk mapping. This will check that the mapping
+	 * is still valid, that is, that the zone used still has valid blocks.
+	 */
+	if (zone)
+		dmz_put_chunk_mapping(zmd, zone);
+out:
+	dmz_bio_endio(bio, errno_to_blk_status(ret));
+
+	dmz_unlock_metadata(zmd);
+}
+
+/*
+ * Increment a chunk reference counter.
+ */
+static inline void dmz_get_chunk_work(struct dm_chunk_work *cw)
+{
+	refcount_inc(&cw->refcount);
+}
+
+/*
+ * Decrement a chunk work reference count and
+ * free it if it becomes 0.
+ */
+static void dmz_put_chunk_work(struct dm_chunk_work *cw)
+{
+	if (refcount_dec_and_test(&cw->refcount)) {
+		WARN_ON(!bio_list_empty(&cw->bio_list));
+		radix_tree_delete(&cw->target->chunk_rxtree, cw->chunk);
+		kfree(cw);
+	}
+}
+
+/*
+ * Chunk BIO work function.
+ */
+static void dmz_chunk_work(struct work_struct *work)
+{
+	struct dm_chunk_work *cw = container_of(work, struct dm_chunk_work, work);
+	struct dmz_target *dmz = cw->target;
+	struct bio *bio;
+
+	mutex_lock(&dmz->chunk_lock);
+
+	/* Process the chunk BIOs */
+	while ((bio = bio_list_pop(&cw->bio_list))) {
+		mutex_unlock(&dmz->chunk_lock);
+		dmz_handle_bio(dmz, cw, bio);
+		mutex_lock(&dmz->chunk_lock);
+		dmz_put_chunk_work(cw);
+	}
+
+	/* Queueing the work incremented the work refcount */
+	dmz_put_chunk_work(cw);
+
+	mutex_unlock(&dmz->chunk_lock);
+}
+
+/*
+ * Flush work.
+ */
+static void dmz_flush_work(struct work_struct *work)
+{
+	struct dmz_target *dmz = container_of(work, struct dmz_target, flush_work.work);
+	struct bio *bio;
+	int ret;
+
+	/* Flush dirty metadata blocks */
+	ret = dmz_flush_metadata(dmz->metadata);
+	if (ret)
+		DMDEBUG("(%s): Metadata flush failed, rc=%d",
+			dmz_metadata_label(dmz->metadata), ret);
+
+	/* Process queued flush requests */
+	while (1) {
+		spin_lock(&dmz->flush_lock);
+		bio = bio_list_pop(&dmz->flush_list);
+		spin_unlock(&dmz->flush_lock);
+
+		if (!bio)
+			break;
+
+		dmz_bio_endio(bio, errno_to_blk_status(ret));
+	}
+
+	queue_delayed_work(dmz->flush_wq, &dmz->flush_work, DMZ_FLUSH_PERIOD);
+}
+
+/*
+ * Get a chunk work and start it to process a new BIO.
+ * If the BIO chunk has no work yet, create one.
+ */
+static int dmz_queue_chunk_work(struct dmz_target *dmz, struct bio *bio)
+{
+	unsigned int chunk = dmz_bio_chunk(dmz->metadata, bio);
+	struct dm_chunk_work *cw;
+	int ret = 0;
+
+	mutex_lock(&dmz->chunk_lock);
+
+	/* Get the BIO chunk work. If one is not active yet, create one */
+	cw = radix_tree_lookup(&dmz->chunk_rxtree, chunk);
+	if (cw) {
+		dmz_get_chunk_work(cw);
+	} else {
+		/* Create a new chunk work */
+		cw = kmalloc(sizeof(struct dm_chunk_work), GFP_NOIO);
+		if (unlikely(!cw)) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		INIT_WORK(&cw->work, dmz_chunk_work);
+		refcount_set(&cw->refcount, 1);
+		cw->target = dmz;
+		cw->chunk = chunk;
+		bio_list_init(&cw->bio_list);
+
+		ret = radix_tree_insert(&dmz->chunk_rxtree, chunk, cw);
+		if (unlikely(ret)) {
+			kfree(cw);
+			goto out;
+		}
+	}
+
+	bio_list_add(&cw->bio_list, bio);
+
+	if (queue_work(dmz->chunk_wq, &cw->work))
+		dmz_get_chunk_work(cw);
+out:
+	mutex_unlock(&dmz->chunk_lock);
+	return ret;
+}
+
+/*
+ * Check if the backing device is being removed. If it's on the way out,
+ * start failing I/O. Reclaim and metadata components also call this
+ * function to cleanly abort operation in the event of such failure.
+ */
+bool dmz_bdev_is_dying(struct dmz_dev *dmz_dev)
+{
+	if (dmz_dev->flags & DMZ_BDEV_DYING)
+		return true;
+
+	if (dmz_dev->flags & DMZ_CHECK_BDEV)
+		return !dmz_check_bdev(dmz_dev);
+
+	if (blk_queue_dying(bdev_get_queue(dmz_dev->bdev))) {
+		dmz_dev_warn(dmz_dev, "Backing device queue dying");
+		dmz_dev->flags |= DMZ_BDEV_DYING;
+	}
+
+	return dmz_dev->flags & DMZ_BDEV_DYING;
+}
+
+/*
+ * Check the backing device availability. This detects such events as
+ * backing device going offline due to errors, media removals, etc.
+ * This check is less efficient than dmz_bdev_is_dying() and should
+ * only be performed as a part of error handling.
+ */
+bool dmz_check_bdev(struct dmz_dev *dmz_dev)
+{
+	struct gendisk *disk;
+
+	dmz_dev->flags &= ~DMZ_CHECK_BDEV;
+
+	if (dmz_bdev_is_dying(dmz_dev))
+		return false;
+
+	disk = dmz_dev->bdev->bd_disk;
+	if (disk->fops->check_events &&
+	    disk->fops->check_events(disk, 0) & DISK_EVENT_MEDIA_CHANGE) {
+		dmz_dev_warn(dmz_dev, "Backing device offline");
+		dmz_dev->flags |= DMZ_BDEV_DYING;
+	}
+
+	return !(dmz_dev->flags & DMZ_BDEV_DYING);
+}
+
+/*
+ * Process a new BIO.
+ */
+static int dmz_map(struct dm_target *ti, struct bio *bio)
+{
+	struct dmz_target *dmz = ti->private;
+	struct dmz_metadata *zmd = dmz->metadata;
+	struct dmz_bioctx *bioctx = dm_per_bio_data(bio, sizeof(struct dmz_bioctx));
+	sector_t sector = bio->bi_iter.bi_sector;
+	unsigned int nr_sectors = bio_sectors(bio);
+	sector_t chunk_sector;
+	int ret;
+
+	if (dmz_dev_is_dying(zmd))
+		return DM_MAPIO_KILL;
+
+	DMDEBUG("(%s): BIO op %d sector %llu + %u => chunk %llu, block %llu, %u blocks",
+		dmz_metadata_label(zmd),
+		bio_op(bio), (unsigned long long)sector, nr_sectors,
+		(unsigned long long)dmz_bio_chunk(zmd, bio),
+		(unsigned long long)dmz_chunk_block(zmd, dmz_bio_block(bio)),
+		(unsigned int)dmz_bio_blocks(bio));
+
+	if (!nr_sectors && bio_op(bio) != REQ_OP_WRITE)
+		return DM_MAPIO_REMAPPED;
+
+	/* The BIO should be block aligned */
+	if ((nr_sectors & DMZ_BLOCK_SECTORS_MASK) || (sector & DMZ_BLOCK_SECTORS_MASK))
+		return DM_MAPIO_KILL;
+
+	/* Initialize the BIO context */
+	bioctx->dev = NULL;
+	bioctx->zone = NULL;
+	bioctx->bio = bio;
+	refcount_set(&bioctx->ref, 1);
+
+	/* Set the BIO pending in the flush list */
+	if (!nr_sectors && bio_op(bio) == REQ_OP_WRITE) {
+		spin_lock(&dmz->flush_lock);
+		bio_list_add(&dmz->flush_list, bio);
+		spin_unlock(&dmz->flush_lock);
+		mod_delayed_work(dmz->flush_wq, &dmz->flush_work, 0);
+		return DM_MAPIO_SUBMITTED;
+	}
+
+	/* Split zone BIOs to fit entirely into a zone */
+	chunk_sector = sector & (dmz_zone_nr_sectors(zmd) - 1);
+	if (chunk_sector + nr_sectors > dmz_zone_nr_sectors(zmd))
+		dm_accept_partial_bio(bio, dmz_zone_nr_sectors(zmd) - chunk_sector);
+
+	/* Now ready to handle this BIO */
+	ret = dmz_queue_chunk_work(dmz, bio);
+	if (ret) {
+		DMDEBUG("(%s): BIO op %d, can't process chunk %llu, err %i",
+			dmz_metadata_label(zmd),
+			bio_op(bio), (u64)dmz_bio_chunk(zmd, bio),
+			ret);
+		return DM_MAPIO_REQUEUE;
+	}
+
+	return DM_MAPIO_SUBMITTED;
+}
+
+/*
+ * Get zoned device information.
+ */
+static int dmz_get_zoned_device(struct dm_target *ti, char *path,
+				int idx, int nr_devs)
+{
+	struct dmz_target *dmz = ti->private;
+	struct dm_dev *ddev;
+	struct dmz_dev *dev;
+	int ret;
+	struct block_device *bdev;
+
+	/* Get the target device */
+	ret = dm_get_device(ti, path, dm_table_get_mode(ti->table), &ddev);
+	if (ret) {
+		ti->error = "Get target device failed";
+		return ret;
+	}
+
+	bdev = ddev->bdev;
+	if (bdev_zoned_model(bdev) == BLK_ZONED_NONE) {
+		if (nr_devs == 1) {
+			ti->error = "Invalid regular device";
+			goto err;
+		}
+		if (idx != 0) {
+			ti->error = "First device must be a regular device";
+			goto err;
+		}
+		if (dmz->ddev[0]) {
+			ti->error = "Too many regular devices";
+			goto err;
+		}
+		dev = &dmz->dev[idx];
+		dev->flags = DMZ_BDEV_REGULAR;
+	} else {
+		if (dmz->ddev[idx]) {
+			ti->error = "Too many zoned devices";
+			goto err;
+		}
+		if (nr_devs > 1 && idx == 0) {
+			ti->error = "First device must be a regular device";
+			goto err;
+		}
+		dev = &dmz->dev[idx];
+	}
+	dev->bdev = bdev;
+	dev->dev_idx = idx;
+
+	dev->capacity = bdev_nr_sectors(bdev);
+	if (ti->begin) {
+		ti->error = "Partial mapping is not supported";
+		goto err;
+	}
+
+	dmz->ddev[idx] = ddev;
+
+	return 0;
+err:
+	dm_put_device(ti, ddev);
+	return -EINVAL;
+}
+
+/*
+ * Cleanup zoned device information.
+ */
+static void dmz_put_zoned_devices(struct dm_target *ti)
+{
+	struct dmz_target *dmz = ti->private;
+	int i;
+
+	for (i = 0; i < dmz->nr_ddevs; i++)
+		if (dmz->ddev[i])
+			dm_put_device(ti, dmz->ddev[i]);
+
+	kfree(dmz->ddev);
+}
+
+static int dmz_fixup_devices(struct dm_target *ti)
+{
+	struct dmz_target *dmz = ti->private;
+	struct dmz_dev *reg_dev = NULL;
+	sector_t zone_nr_sectors = 0;
+	int i;
+
+	/*
+	 * When we have more than on devices, the first one must be a
+	 * regular block device and the others zoned block devices.
+	 */
+	if (dmz->nr_ddevs > 1) {
+		reg_dev = &dmz->dev[0];
+		if (!(reg_dev->flags & DMZ_BDEV_REGULAR)) {
+			ti->error = "Primary disk is not a regular device";
+			return -EINVAL;
+		}
+		for (i = 1; i < dmz->nr_ddevs; i++) {
+			struct dmz_dev *zoned_dev = &dmz->dev[i];
+			struct block_device *bdev = zoned_dev->bdev;
+
+			if (zoned_dev->flags & DMZ_BDEV_REGULAR) {
+				ti->error = "Secondary disk is not a zoned device";
+				return -EINVAL;
+			}
+			if (zone_nr_sectors &&
+			    zone_nr_sectors != bdev_zone_sectors(bdev)) {
+				ti->error = "Zone nr sectors mismatch";
+				return -EINVAL;
+			}
+			zone_nr_sectors = bdev_zone_sectors(bdev);
+			zoned_dev->zone_nr_sectors = zone_nr_sectors;
+			zoned_dev->nr_zones = bdev_nr_zones(bdev);
+		}
+	} else {
+		struct dmz_dev *zoned_dev = &dmz->dev[0];
+		struct block_device *bdev = zoned_dev->bdev;
+
+		if (zoned_dev->flags & DMZ_BDEV_REGULAR) {
+			ti->error = "Disk is not a zoned device";
+			return -EINVAL;
+		}
+		zoned_dev->zone_nr_sectors = bdev_zone_sectors(bdev);
+		zoned_dev->nr_zones = bdev_nr_zones(bdev);
+	}
+
+	if (reg_dev) {
+		sector_t zone_offset;
+
+		reg_dev->zone_nr_sectors = zone_nr_sectors;
+		reg_dev->nr_zones =
+			DIV_ROUND_UP_SECTOR_T(reg_dev->capacity,
+					      reg_dev->zone_nr_sectors);
+		reg_dev->zone_offset = 0;
+		zone_offset = reg_dev->nr_zones;
+		for (i = 1; i < dmz->nr_ddevs; i++) {
+			dmz->dev[i].zone_offset = zone_offset;
+			zone_offset += dmz->dev[i].nr_zones;
+		}
+	}
+	return 0;
+}
+
+/*
+ * Setup target.
+ */
+static int dmz_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+	struct dmz_target *dmz;
+	int ret, i;
+
+	/* Check arguments */
+	if (argc < 1) {
+		ti->error = "Invalid argument count";
+		return -EINVAL;
+	}
+
+	/* Allocate and initialize the target descriptor */
+	dmz = kzalloc(sizeof(struct dmz_target), GFP_KERNEL);
+	if (!dmz) {
+		ti->error = "Unable to allocate the zoned target descriptor";
+		return -ENOMEM;
+	}
+	dmz->dev = kcalloc(argc, sizeof(struct dmz_dev), GFP_KERNEL);
+	if (!dmz->dev) {
+		ti->error = "Unable to allocate the zoned device descriptors";
+		kfree(dmz);
+		return -ENOMEM;
+	}
+	dmz->ddev = kcalloc(argc, sizeof(struct dm_dev *), GFP_KERNEL);
+	if (!dmz->ddev) {
+		ti->error = "Unable to allocate the dm device descriptors";
+		ret = -ENOMEM;
+		goto err;
+	}
+	dmz->nr_ddevs = argc;
+
+	ti->private = dmz;
+
+	/* Get the target zoned block device */
+	for (i = 0; i < argc; i++) {
+		ret = dmz_get_zoned_device(ti, argv[i], i, argc);
+		if (ret)
+			goto err_dev;
+	}
+	ret = dmz_fixup_devices(ti);
+	if (ret)
+		goto err_dev;
+
+	/* Initialize metadata */
+	ret = dmz_ctr_metadata(dmz->dev, argc, &dmz->metadata,
+			       dm_table_device_name(ti->table));
+	if (ret) {
+		ti->error = "Metadata initialization failed";
+		goto err_dev;
+	}
+
+	/* Set target (no write same support) */
+	ti->max_io_len = dmz_zone_nr_sectors(dmz->metadata);
+	ti->num_flush_bios = 1;
+	ti->num_discard_bios = 1;
+	ti->num_write_zeroes_bios = 1;
+	ti->per_io_data_size = sizeof(struct dmz_bioctx);
+	ti->flush_supported = true;
+	ti->discards_supported = true;
+
+	/* The exposed capacity is the number of chunks that can be mapped */
+	ti->len = (sector_t)dmz_nr_chunks(dmz->metadata) <<
+		dmz_zone_nr_sectors_shift(dmz->metadata);
+
+	/* Zone BIO */
+	ret = bioset_init(&dmz->bio_set, DMZ_MIN_BIOS, 0, 0);
+	if (ret) {
+		ti->error = "Create BIO set failed";
+		goto err_meta;
+	}
+
+	/* Chunk BIO work */
+	mutex_init(&dmz->chunk_lock);
+	INIT_RADIX_TREE(&dmz->chunk_rxtree, GFP_NOIO);
+	dmz->chunk_wq = alloc_workqueue("dmz_cwq_%s",
+					WQ_MEM_RECLAIM | WQ_UNBOUND, 0,
+					dmz_metadata_label(dmz->metadata));
+	if (!dmz->chunk_wq) {
+		ti->error = "Create chunk workqueue failed";
+		ret = -ENOMEM;
+		goto err_bio;
+	}
+
+	/* Flush work */
+	spin_lock_init(&dmz->flush_lock);
+	bio_list_init(&dmz->flush_list);
+	INIT_DELAYED_WORK(&dmz->flush_work, dmz_flush_work);
+	dmz->flush_wq = alloc_ordered_workqueue("dmz_fwq_%s", WQ_MEM_RECLAIM,
+						dmz_metadata_label(dmz->metadata));
+	if (!dmz->flush_wq) {
+		ti->error = "Create flush workqueue failed";
+		ret = -ENOMEM;
+		goto err_cwq;
+	}
+	mod_delayed_work(dmz->flush_wq, &dmz->flush_work, DMZ_FLUSH_PERIOD);
+
+	/* Initialize reclaim */
+	for (i = 0; i < dmz->nr_ddevs; i++) {
+		ret = dmz_ctr_reclaim(dmz->metadata, &dmz->dev[i].reclaim, i);
+		if (ret) {
+			ti->error = "Zone reclaim initialization failed";
+			goto err_fwq;
+		}
+	}
+
+	DMINFO("(%s): Target device: %llu 512-byte logical sectors (%llu blocks)",
+	       dmz_metadata_label(dmz->metadata),
+	       (unsigned long long)ti->len,
+	       (unsigned long long)dmz_sect2blk(ti->len));
+
+	return 0;
+err_fwq:
+	destroy_workqueue(dmz->flush_wq);
+err_cwq:
+	destroy_workqueue(dmz->chunk_wq);
+err_bio:
+	mutex_destroy(&dmz->chunk_lock);
+	bioset_exit(&dmz->bio_set);
+err_meta:
+	dmz_dtr_metadata(dmz->metadata);
+err_dev:
+	dmz_put_zoned_devices(ti);
+err:
+	kfree(dmz->dev);
+	kfree(dmz);
+
+	return ret;
+}
+
+/*
+ * Cleanup target.
+ */
+static void dmz_dtr(struct dm_target *ti)
+{
+	struct dmz_target *dmz = ti->private;
+	int i;
+
+	destroy_workqueue(dmz->chunk_wq);
+
+	for (i = 0; i < dmz->nr_ddevs; i++)
+		dmz_dtr_reclaim(dmz->dev[i].reclaim);
+
+	cancel_delayed_work_sync(&dmz->flush_work);
+	destroy_workqueue(dmz->flush_wq);
+
+	(void) dmz_flush_metadata(dmz->metadata);
+
+	dmz_dtr_metadata(dmz->metadata);
+
+	bioset_exit(&dmz->bio_set);
+
+	dmz_put_zoned_devices(ti);
+
+	mutex_destroy(&dmz->chunk_lock);
+
+	kfree(dmz->dev);
+	kfree(dmz);
+}
+
+/*
+ * Setup target request queue limits.
+ */
+static void dmz_io_hints(struct dm_target *ti, struct queue_limits *limits)
+{
+	struct dmz_target *dmz = ti->private;
+	unsigned int chunk_sectors = dmz_zone_nr_sectors(dmz->metadata);
+
+	limits->logical_block_size = DMZ_BLOCK_SIZE;
+	limits->physical_block_size = DMZ_BLOCK_SIZE;
+
+	blk_limits_io_min(limits, DMZ_BLOCK_SIZE);
+	blk_limits_io_opt(limits, DMZ_BLOCK_SIZE);
+
+	limits->discard_alignment = 0;
+	limits->discard_granularity = DMZ_BLOCK_SIZE;
+	limits->max_discard_sectors = chunk_sectors;
+	limits->max_hw_discard_sectors = chunk_sectors;
+	limits->max_write_zeroes_sectors = chunk_sectors;
+
+	/* FS hint to try to align to the device zone size */
+	limits->chunk_sectors = chunk_sectors;
+	limits->max_sectors = chunk_sectors;
+
+	/* We are exposing a drive-managed zoned block device */
+	limits->zoned = BLK_ZONED_NONE;
+}
+
+/*
+ * Pass on ioctl to the backend device.
+ */
+static int dmz_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
+{
+	struct dmz_target *dmz = ti->private;
+	struct dmz_dev *dev = &dmz->dev[0];
+
+	if (!dmz_check_bdev(dev))
+		return -EIO;
+
+	*bdev = dev->bdev;
+
+	return 0;
+}
+
+/*
+ * Stop works on suspend.
+ */
+static void dmz_suspend(struct dm_target *ti)
+{
+	struct dmz_target *dmz = ti->private;
+	int i;
+
+	flush_workqueue(dmz->chunk_wq);
+	for (i = 0; i < dmz->nr_ddevs; i++)
+		dmz_suspend_reclaim(dmz->dev[i].reclaim);
+	cancel_delayed_work_sync(&dmz->flush_work);
+}
+
+/*
+ * Restart works on resume or if suspend failed.
+ */
+static void dmz_resume(struct dm_target *ti)
+{
+	struct dmz_target *dmz = ti->private;
+	int i;
+
+	queue_delayed_work(dmz->flush_wq, &dmz->flush_work, DMZ_FLUSH_PERIOD);
+	for (i = 0; i < dmz->nr_ddevs; i++)
+		dmz_resume_reclaim(dmz->dev[i].reclaim);
+}
+
+static int dmz_iterate_devices(struct dm_target *ti,
+			       iterate_devices_callout_fn fn, void *data)
+{
+	struct dmz_target *dmz = ti->private;
+	unsigned int zone_nr_sectors = dmz_zone_nr_sectors(dmz->metadata);
+	sector_t capacity;
+	int i, r;
+
+	for (i = 0; i < dmz->nr_ddevs; i++) {
+		capacity = dmz->dev[i].capacity & ~(zone_nr_sectors - 1);
+		r = fn(ti, dmz->ddev[i], 0, capacity, data);
+		if (r)
+			break;
+	}
+	return r;
+}
+
+static void dmz_status(struct dm_target *ti, status_type_t type,
+		       unsigned int status_flags, char *result,
+		       unsigned int maxlen)
+{
+	struct dmz_target *dmz = ti->private;
+	ssize_t sz = 0;
+	char buf[BDEVNAME_SIZE];
+	struct dmz_dev *dev;
+	int i;
+
+	switch (type) {
+	case STATUSTYPE_INFO:
+		DMEMIT("%u zones %u/%u cache",
+		       dmz_nr_zones(dmz->metadata),
+		       dmz_nr_unmap_cache_zones(dmz->metadata),
+		       dmz_nr_cache_zones(dmz->metadata));
+		for (i = 0; i < dmz->nr_ddevs; i++) {
+			/*
+			 * For a multi-device setup the first device
+			 * contains only cache zones.
+			 */
+			if ((i == 0) &&
+			    (dmz_nr_cache_zones(dmz->metadata) > 0))
+				continue;
+			DMEMIT(" %u/%u random %u/%u sequential",
+			       dmz_nr_unmap_rnd_zones(dmz->metadata, i),
+			       dmz_nr_rnd_zones(dmz->metadata, i),
+			       dmz_nr_unmap_seq_zones(dmz->metadata, i),
+			       dmz_nr_seq_zones(dmz->metadata, i));
+		}
+		break;
+	case STATUSTYPE_TABLE:
+		dev = &dmz->dev[0];
+		format_dev_t(buf, dev->bdev->bd_dev);
+		DMEMIT("%s", buf);
+		for (i = 1; i < dmz->nr_ddevs; i++) {
+			dev = &dmz->dev[i];
+			format_dev_t(buf, dev->bdev->bd_dev);
+			DMEMIT(" %s", buf);
+		}
+		break;
+	case STATUSTYPE_IMA:
+		*result = '\0';
+		break;
+	}
+}
+
+static int dmz_message(struct dm_target *ti, unsigned int argc, char **argv,
+		       char *result, unsigned int maxlen)
+{
+	struct dmz_target *dmz = ti->private;
+	int r = -EINVAL;
+
+	if (!strcasecmp(argv[0], "reclaim")) {
+		int i;
+
+		for (i = 0; i < dmz->nr_ddevs; i++)
+			dmz_schedule_reclaim(dmz->dev[i].reclaim);
+		r = 0;
+	} else
+		DMERR("unrecognized message %s", argv[0]);
+	return r;
+}
+
+static struct target_type zoned_target = {
+	.name		 = "zoned",
+	.version	 = {2, 0, 0},
+	.features	 = DM_TARGET_SINGLETON | DM_TARGET_MIXED_ZONED_MODEL,
+	.module		 = THIS_MODULE,
+	.ctr		 = dmz_ctr,
+	.dtr		 = dmz_dtr,
+	.map		 = dmz_map,
+	.io_hints	 = dmz_io_hints,
+	.prepare_ioctl	 = dmz_prepare_ioctl,
+	.postsuspend	 = dmz_suspend,
+	.resume		 = dmz_resume,
+	.iterate_devices = dmz_iterate_devices,
+	.status		 = dmz_status,
+	.message	 = dmz_message,
+};
+module_dm(zoned);
+
+MODULE_DESCRIPTION(DM_NAME " target for zoned block devices");
+MODULE_AUTHOR("Damien Le Moal <damien.lemoal@wdc.com>");
+MODULE_LICENSE("GPL");