1 files changed, 648 insertions, 0 deletions

diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
new file mode 100644
index 000000000..3dafc0e8b
--- /dev/null
+++ b/drivers/md/dm-zone.c
@@ -0,0 +1,648 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#include <linux/blkdev.h>
+#include <linux/mm.h>
+#include <linux/sched/mm.h>
+#include <linux/slab.h>
+
+#include "dm-core.h"
+
+#define DM_MSG_PREFIX "zone"
+
+#define DM_ZONE_INVALID_WP_OFST		UINT_MAX
+
+/*
+ * For internal zone reports bypassing the top BIO submission path.
+ */
+static int dm_blk_do_report_zones(struct mapped_device *md, struct dm_table *t,
+				  sector_t sector, unsigned int nr_zones,
+				  report_zones_cb cb, void *data)
+{
+	struct gendisk *disk = md->disk;
+	int ret;
+	struct dm_report_zones_args args = {
+		.next_sector = sector,
+		.orig_data = data,
+		.orig_cb = cb,
+	};
+
+	do {
+		struct dm_target *tgt;
+
+		tgt = dm_table_find_target(t, args.next_sector);
+		if (WARN_ON_ONCE(!tgt->type->report_zones))
+			return -EIO;
+
+		args.tgt = tgt;
+		ret = tgt->type->report_zones(tgt, &args,
+					      nr_zones - args.zone_idx);
+		if (ret < 0)
+			return ret;
+	} while (args.zone_idx < nr_zones &&
+		 args.next_sector < get_capacity(disk));
+
+	return args.zone_idx;
+}
+
+/*
+ * User facing dm device block device report zone operation. This calls the
+ * report_zones operation for each target of a device table. This operation is
+ * generally implemented by targets using dm_report_zones().
+ */
+int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
+			unsigned int nr_zones, report_zones_cb cb, void *data)
+{
+	struct mapped_device *md = disk->private_data;
+	struct dm_table *map;
+	int srcu_idx, ret;
+
+	if (dm_suspended_md(md))
+		return -EAGAIN;
+
+	map = dm_get_live_table(md, &srcu_idx);
+	if (!map)
+		return -EIO;
+
+	ret = dm_blk_do_report_zones(md, map, sector, nr_zones, cb, data);
+
+	dm_put_live_table(md, srcu_idx);
+
+	return ret;
+}
+
+static int dm_report_zones_cb(struct blk_zone *zone, unsigned int idx,
+			      void *data)
+{
+	struct dm_report_zones_args *args = data;
+	sector_t sector_diff = args->tgt->begin - args->start;
+
+	/*
+	 * Ignore zones beyond the target range.
+	 */
+	if (zone->start >= args->start + args->tgt->len)
+		return 0;
+
+	/*
+	 * Remap the start sector and write pointer position of the zone
+	 * to match its position in the target range.
+	 */
+	zone->start += sector_diff;
+	if (zone->type != BLK_ZONE_TYPE_CONVENTIONAL) {
+		if (zone->cond == BLK_ZONE_COND_FULL)
+			zone->wp = zone->start + zone->len;
+		else if (zone->cond == BLK_ZONE_COND_EMPTY)
+			zone->wp = zone->start;
+		else
+			zone->wp += sector_diff;
+	}
+
+	args->next_sector = zone->start + zone->len;
+	return args->orig_cb(zone, args->zone_idx++, args->orig_data);
+}
+
+/*
+ * Helper for drivers of zoned targets to implement struct target_type
+ * report_zones operation.
+ */
+int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector,
+		    struct dm_report_zones_args *args, unsigned int nr_zones)
+{
+	/*
+	 * Set the target mapping start sector first so that
+	 * dm_report_zones_cb() can correctly remap zone information.
+	 */
+	args->start = start;
+
+	return blkdev_report_zones(bdev, sector, nr_zones,
+				   dm_report_zones_cb, args);
+}
+EXPORT_SYMBOL_GPL(dm_report_zones);
+
+bool dm_is_zone_write(struct mapped_device *md, struct bio *bio)
+{
+	struct request_queue *q = md->queue;
+
+	if (!blk_queue_is_zoned(q))
+		return false;
+
+	switch (bio_op(bio)) {
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE:
+		return !op_is_flush(bio->bi_opf) && bio_sectors(bio);
+	default:
+		return false;
+	}
+}
+
+void dm_cleanup_zoned_dev(struct mapped_device *md)
+{
+	if (md->disk) {
+		kfree(md->disk->conv_zones_bitmap);
+		md->disk->conv_zones_bitmap = NULL;
+		kfree(md->disk->seq_zones_wlock);
+		md->disk->seq_zones_wlock = NULL;
+	}
+
+	kvfree(md->zwp_offset);
+	md->zwp_offset = NULL;
+	md->nr_zones = 0;
+}
+
+static unsigned int dm_get_zone_wp_offset(struct blk_zone *zone)
+{
+	switch (zone->cond) {
+	case BLK_ZONE_COND_IMP_OPEN:
+	case BLK_ZONE_COND_EXP_OPEN:
+	case BLK_ZONE_COND_CLOSED:
+		return zone->wp - zone->start;
+	case BLK_ZONE_COND_FULL:
+		return zone->len;
+	case BLK_ZONE_COND_EMPTY:
+	case BLK_ZONE_COND_NOT_WP:
+	case BLK_ZONE_COND_OFFLINE:
+	case BLK_ZONE_COND_READONLY:
+	default:
+		/*
+		 * Conventional, offline and read-only zones do not have a valid
+		 * write pointer. Use 0 as for an empty zone.
+		 */
+		return 0;
+	}
+}
+
+static int dm_zone_revalidate_cb(struct blk_zone *zone, unsigned int idx,
+				 void *data)
+{
+	struct mapped_device *md = data;
+	struct gendisk *disk = md->disk;
+
+	switch (zone->type) {
+	case BLK_ZONE_TYPE_CONVENTIONAL:
+		if (!disk->conv_zones_bitmap) {
+			disk->conv_zones_bitmap =
+				kcalloc(BITS_TO_LONGS(disk->nr_zones),
+					sizeof(unsigned long), GFP_NOIO);
+			if (!disk->conv_zones_bitmap)
+				return -ENOMEM;
+		}
+		set_bit(idx, disk->conv_zones_bitmap);
+		break;
+	case BLK_ZONE_TYPE_SEQWRITE_REQ:
+	case BLK_ZONE_TYPE_SEQWRITE_PREF:
+		if (!disk->seq_zones_wlock) {
+			disk->seq_zones_wlock =
+				kcalloc(BITS_TO_LONGS(disk->nr_zones),
+					sizeof(unsigned long), GFP_NOIO);
+			if (!disk->seq_zones_wlock)
+				return -ENOMEM;
+		}
+		if (!md->zwp_offset) {
+			md->zwp_offset =
+				kvcalloc(disk->nr_zones, sizeof(unsigned int),
+					 GFP_KERNEL);
+			if (!md->zwp_offset)
+				return -ENOMEM;
+		}
+		md->zwp_offset[idx] = dm_get_zone_wp_offset(zone);
+
+		break;
+	default:
+		DMERR("Invalid zone type 0x%x at sectors %llu",
+		      (int)zone->type, zone->start);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+/*
+ * Revalidate the zones of a mapped device to initialize resource necessary
+ * for zone append emulation. Note that we cannot simply use the block layer
+ * blk_revalidate_disk_zones() function here as the mapped device is suspended
+ * (this is called from __bind() context).
+ */
+static int dm_revalidate_zones(struct mapped_device *md, struct dm_table *t)
+{
+	struct gendisk *disk = md->disk;
+	unsigned int noio_flag;
+	int ret;
+
+	/*
+	 * Check if something changed. If yes, cleanup the current resources
+	 * and reallocate everything.
+	 */
+	if (!disk->nr_zones || disk->nr_zones != md->nr_zones)
+		dm_cleanup_zoned_dev(md);
+	if (md->nr_zones)
+		return 0;
+
+	/*
+	 * Scan all zones to initialize everything. Ensure that all vmalloc
+	 * operations in this context are done as if GFP_NOIO was specified.
+	 */
+	noio_flag = memalloc_noio_save();
+	ret = dm_blk_do_report_zones(md, t, 0, disk->nr_zones,
+				     dm_zone_revalidate_cb, md);
+	memalloc_noio_restore(noio_flag);
+	if (ret < 0)
+		goto err;
+	if (ret != disk->nr_zones) {
+		ret = -EIO;
+		goto err;
+	}
+
+	md->nr_zones = disk->nr_zones;
+
+	return 0;
+
+err:
+	DMERR("Revalidate zones failed %d", ret);
+	dm_cleanup_zoned_dev(md);
+	return ret;
+}
+
+static int device_not_zone_append_capable(struct dm_target *ti,
+					  struct dm_dev *dev, sector_t start,
+					  sector_t len, void *data)
+{
+	return !bdev_is_zoned(dev->bdev);
+}
+
+static bool dm_table_supports_zone_append(struct dm_table *t)
+{
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+
+		if (ti->emulate_zone_append)
+			return false;
+
+		if (!ti->type->iterate_devices ||
+		    ti->type->iterate_devices(ti, device_not_zone_append_capable, NULL))
+			return false;
+	}
+
+	return true;
+}
+
+int dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q)
+{
+	struct mapped_device *md = t->md;
+
+	/*
+	 * For a zoned target, the number of zones should be updated for the
+	 * correct value to be exposed in sysfs queue/nr_zones.
+	 */
+	WARN_ON_ONCE(queue_is_mq(q));
+	md->disk->nr_zones = bdev_nr_zones(md->disk->part0);
+
+	/* Check if zone append is natively supported */
+	if (dm_table_supports_zone_append(t)) {
+		clear_bit(DMF_EMULATE_ZONE_APPEND, &md->flags);
+		dm_cleanup_zoned_dev(md);
+		return 0;
+	}
+
+	/*
+	 * Mark the mapped device as needing zone append emulation and
+	 * initialize the emulation resources once the capacity is set.
+	 */
+	set_bit(DMF_EMULATE_ZONE_APPEND, &md->flags);
+	if (!get_capacity(md->disk))
+		return 0;
+
+	return dm_revalidate_zones(md, t);
+}
+
+static int dm_update_zone_wp_offset_cb(struct blk_zone *zone, unsigned int idx,
+				       void *data)
+{
+	unsigned int *wp_offset = data;
+
+	*wp_offset = dm_get_zone_wp_offset(zone);
+
+	return 0;
+}
+
+static int dm_update_zone_wp_offset(struct mapped_device *md, unsigned int zno,
+				    unsigned int *wp_ofst)
+{
+	sector_t sector = zno * bdev_zone_sectors(md->disk->part0);
+	unsigned int noio_flag;
+	struct dm_table *t;
+	int srcu_idx, ret;
+
+	t = dm_get_live_table(md, &srcu_idx);
+	if (!t)
+		return -EIO;
+
+	/*
+	 * Ensure that all memory allocations in this context are done as if
+	 * GFP_NOIO was specified.
+	 */
+	noio_flag = memalloc_noio_save();
+	ret = dm_blk_do_report_zones(md, t, sector, 1,
+				     dm_update_zone_wp_offset_cb, wp_ofst);
+	memalloc_noio_restore(noio_flag);
+
+	dm_put_live_table(md, srcu_idx);
+
+	if (ret != 1)
+		return -EIO;
+
+	return 0;
+}
+
+struct orig_bio_details {
+	enum req_op op;
+	unsigned int nr_sectors;
+};
+
+/*
+ * First phase of BIO mapping for targets with zone append emulation:
+ * check all BIO that change a zone writer pointer and change zone
+ * append operations into regular write operations.
+ */
+static bool dm_zone_map_bio_begin(struct mapped_device *md,
+				  unsigned int zno, struct bio *clone)
+{
+	sector_t zsectors = bdev_zone_sectors(md->disk->part0);
+	unsigned int zwp_offset = READ_ONCE(md->zwp_offset[zno]);
+
+	/*
+	 * If the target zone is in an error state, recover by inspecting the
+	 * zone to get its current write pointer position. Note that since the
+	 * target zone is already locked, a BIO issuing context should never
+	 * see the zone write in the DM_ZONE_UPDATING_WP_OFST state.
+	 */
+	if (zwp_offset == DM_ZONE_INVALID_WP_OFST) {
+		if (dm_update_zone_wp_offset(md, zno, &zwp_offset))
+			return false;
+		WRITE_ONCE(md->zwp_offset[zno], zwp_offset);
+	}
+
+	switch (bio_op(clone)) {
+	case REQ_OP_ZONE_RESET:
+	case REQ_OP_ZONE_FINISH:
+		return true;
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE:
+		/* Writes must be aligned to the zone write pointer */
+		if ((clone->bi_iter.bi_sector & (zsectors - 1)) != zwp_offset)
+			return false;
+		break;
+	case REQ_OP_ZONE_APPEND:
+		/*
+		 * Change zone append operations into a non-mergeable regular
+		 * writes directed at the current write pointer position of the
+		 * target zone.
+		 */
+		clone->bi_opf = REQ_OP_WRITE | REQ_NOMERGE |
+			(clone->bi_opf & (~REQ_OP_MASK));
+		clone->bi_iter.bi_sector += zwp_offset;
+		break;
+	default:
+		DMWARN_LIMIT("Invalid BIO operation");
+		return false;
+	}
+
+	/* Cannot write to a full zone */
+	if (zwp_offset >= zsectors)
+		return false;
+
+	return true;
+}
+
+/*
+ * Second phase of BIO mapping for targets with zone append emulation:
+ * update the zone write pointer offset array to account for the additional
+ * data written to a zone. Note that at this point, the remapped clone BIO
+ * may already have completed, so we do not touch it.
+ */
+static blk_status_t dm_zone_map_bio_end(struct mapped_device *md, unsigned int zno,
+					struct orig_bio_details *orig_bio_details,
+					unsigned int nr_sectors)
+{
+	unsigned int zwp_offset = READ_ONCE(md->zwp_offset[zno]);
+
+	/* The clone BIO may already have been completed and failed */
+	if (zwp_offset == DM_ZONE_INVALID_WP_OFST)
+		return BLK_STS_IOERR;
+
+	/* Update the zone wp offset */
+	switch (orig_bio_details->op) {
+	case REQ_OP_ZONE_RESET:
+		WRITE_ONCE(md->zwp_offset[zno], 0);
+		return BLK_STS_OK;
+	case REQ_OP_ZONE_FINISH:
+		WRITE_ONCE(md->zwp_offset[zno],
+			   bdev_zone_sectors(md->disk->part0));
+		return BLK_STS_OK;
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE:
+		WRITE_ONCE(md->zwp_offset[zno], zwp_offset + nr_sectors);
+		return BLK_STS_OK;
+	case REQ_OP_ZONE_APPEND:
+		/*
+		 * Check that the target did not truncate the write operation
+		 * emulating a zone append.
+		 */
+		if (nr_sectors != orig_bio_details->nr_sectors) {
+			DMWARN_LIMIT("Truncated write for zone append");
+			return BLK_STS_IOERR;
+		}
+		WRITE_ONCE(md->zwp_offset[zno], zwp_offset + nr_sectors);
+		return BLK_STS_OK;
+	default:
+		DMWARN_LIMIT("Invalid BIO operation");
+		return BLK_STS_IOERR;
+	}
+}
+
+static inline void dm_zone_lock(struct gendisk *disk, unsigned int zno,
+				struct bio *clone)
+{
+	if (WARN_ON_ONCE(bio_flagged(clone, BIO_ZONE_WRITE_LOCKED)))
+		return;
+
+	wait_on_bit_lock_io(disk->seq_zones_wlock, zno, TASK_UNINTERRUPTIBLE);
+	bio_set_flag(clone, BIO_ZONE_WRITE_LOCKED);
+}
+
+static inline void dm_zone_unlock(struct gendisk *disk, unsigned int zno,
+				  struct bio *clone)
+{
+	if (!bio_flagged(clone, BIO_ZONE_WRITE_LOCKED))
+		return;
+
+	WARN_ON_ONCE(!test_bit(zno, disk->seq_zones_wlock));
+	clear_bit_unlock(zno, disk->seq_zones_wlock);
+	smp_mb__after_atomic();
+	wake_up_bit(disk->seq_zones_wlock, zno);
+
+	bio_clear_flag(clone, BIO_ZONE_WRITE_LOCKED);
+}
+
+static bool dm_need_zone_wp_tracking(struct bio *bio)
+{
+	/*
+	 * Special processing is not needed for operations that do not need the
+	 * zone write lock, that is, all operations that target conventional
+	 * zones and all operations that do not modify directly a sequential
+	 * zone write pointer.
+	 */
+	if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
+		return false;
+	switch (bio_op(bio)) {
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE:
+	case REQ_OP_ZONE_RESET:
+	case REQ_OP_ZONE_FINISH:
+	case REQ_OP_ZONE_APPEND:
+		return bio_zone_is_seq(bio);
+	default:
+		return false;
+	}
+}
+
+/*
+ * Special IO mapping for targets needing zone append emulation.
+ */
+int dm_zone_map_bio(struct dm_target_io *tio)
+{
+	struct dm_io *io = tio->io;
+	struct dm_target *ti = tio->ti;
+	struct mapped_device *md = io->md;
+	struct bio *clone = &tio->clone;
+	struct orig_bio_details orig_bio_details;
+	unsigned int zno;
+	blk_status_t sts;
+	int r;
+
+	/*
+	 * IOs that do not change a zone write pointer do not need
+	 * any additional special processing.
+	 */
+	if (!dm_need_zone_wp_tracking(clone))
+		return ti->type->map(ti, clone);
+
+	/* Lock the target zone */
+	zno = bio_zone_no(clone);
+	dm_zone_lock(md->disk, zno, clone);
+
+	orig_bio_details.nr_sectors = bio_sectors(clone);
+	orig_bio_details.op = bio_op(clone);
+
+	/*
+	 * Check that the bio and the target zone write pointer offset are
+	 * both valid, and if the bio is a zone append, remap it to a write.
+	 */
+	if (!dm_zone_map_bio_begin(md, zno, clone)) {
+		dm_zone_unlock(md->disk, zno, clone);
+		return DM_MAPIO_KILL;
+	}
+
+	/* Let the target do its work */
+	r = ti->type->map(ti, clone);
+	switch (r) {
+	case DM_MAPIO_SUBMITTED:
+		/*
+		 * The target submitted the clone BIO. The target zone will
+		 * be unlocked on completion of the clone.
+		 */
+		sts = dm_zone_map_bio_end(md, zno, &orig_bio_details,
+					  *tio->len_ptr);
+		break;
+	case DM_MAPIO_REMAPPED:
+		/*
+		 * The target only remapped the clone BIO. In case of error,
+		 * unlock the target zone here as the clone will not be
+		 * submitted.
+		 */
+		sts = dm_zone_map_bio_end(md, zno, &orig_bio_details,
+					  *tio->len_ptr);
+		if (sts != BLK_STS_OK)
+			dm_zone_unlock(md->disk, zno, clone);
+		break;
+	case DM_MAPIO_REQUEUE:
+	case DM_MAPIO_KILL:
+	default:
+		dm_zone_unlock(md->disk, zno, clone);
+		sts = BLK_STS_IOERR;
+		break;
+	}
+
+	if (sts != BLK_STS_OK)
+		return DM_MAPIO_KILL;
+
+	return r;
+}
+
+/*
+ * IO completion callback called from clone_endio().
+ */
+void dm_zone_endio(struct dm_io *io, struct bio *clone)
+{
+	struct mapped_device *md = io->md;
+	struct gendisk *disk = md->disk;
+	struct bio *orig_bio = io->orig_bio;
+	unsigned int zwp_offset;
+	unsigned int zno;
+
+	/*
+	 * For targets that do not emulate zone append, we only need to
+	 * handle native zone-append bios.
+	 */
+	if (!dm_emulate_zone_append(md)) {
+		/*
+		 * Get the offset within the zone of the written sector
+		 * and add that to the original bio sector position.
+		 */
+		if (clone->bi_status == BLK_STS_OK &&
+		    bio_op(clone) == REQ_OP_ZONE_APPEND) {
+			sector_t mask =
+				(sector_t)bdev_zone_sectors(disk->part0) - 1;
+
+			orig_bio->bi_iter.bi_sector +=
+				clone->bi_iter.bi_sector & mask;
+		}
+
+		return;
+	}
+
+	/*
+	 * For targets that do emulate zone append, if the clone BIO does not
+	 * own the target zone write lock, we have nothing to do.
+	 */
+	if (!bio_flagged(clone, BIO_ZONE_WRITE_LOCKED))
+		return;
+
+	zno = bio_zone_no(orig_bio);
+
+	if (clone->bi_status != BLK_STS_OK) {
+		/*
+		 * BIOs that modify a zone write pointer may leave the zone
+		 * in an unknown state in case of failure (e.g. the write
+		 * pointer was only partially advanced). In this case, set
+		 * the target zone write pointer as invalid unless it is
+		 * already being updated.
+		 */
+		WRITE_ONCE(md->zwp_offset[zno], DM_ZONE_INVALID_WP_OFST);
+	} else if (bio_op(orig_bio) == REQ_OP_ZONE_APPEND) {
+		/*
+		 * Get the written sector for zone append operation that were
+		 * emulated using regular write operations.
+		 */
+		zwp_offset = READ_ONCE(md->zwp_offset[zno]);
+		if (WARN_ON_ONCE(zwp_offset < bio_sectors(orig_bio)))
+			WRITE_ONCE(md->zwp_offset[zno],
+				   DM_ZONE_INVALID_WP_OFST);
+		else
+			orig_bio->bi_iter.bi_sector +=
+				zwp_offset - bio_sectors(orig_bio);
+	}
+
+	dm_zone_unlock(disk, zno, clone);
+}