drivers/scsi/sd_zbc.c - kernel/msm-4.19 - Gitiles

 /*
  * SCSI Zoned Block commands
  *
  * Copyright (C) 2014-2015 SUSE Linux GmbH
  * Written by: Hannes Reinecke <hare@suse.de>
  * Modified by: Damien Le Moal <damien.lemoal@hgst.com>
  * Modified by: Shaun Tancheff <shaun.tancheff@seagate.com>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License version
  * 2 as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; see the file COPYING.  If not, write to
  * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
  * USA.
  *
  */

 #include <linux/blkdev.h>

 #include <asm/unaligned.h>

 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>

 #include "sd.h"

 /**
  * sd_zbc_parse_report - Convert a zone descriptor to a struct blk_zone,
  * @sdkp: The disk the report originated from
  * @buf: Address of the report zone descriptor
  * @zone: the destination zone structure
  *
  * All LBA sized values are converted to 512B sectors unit.
  */
 static void sd_zbc_parse_report(struct scsi_disk *sdkp, u8 *buf,
 				struct blk_zone *zone)
 {
 	struct scsi_device *sdp = sdkp->device;

 	memset(zone, 0, sizeof(struct blk_zone));

 	zone->type = buf[0] & 0x0f;
 	zone->cond = (buf[1] >> 4) & 0xf;
 	if (buf[1] & 0x01)
 		zone->reset = 1;
 	if (buf[1] & 0x02)
 		zone->non_seq = 1;

 	zone->len = logical_to_sectors(sdp, get_unaligned_be64(&buf[8]));
 	zone->start = logical_to_sectors(sdp, get_unaligned_be64(&buf[16]));
 	zone->wp = logical_to_sectors(sdp, get_unaligned_be64(&buf[24]));
 	if (zone->type != ZBC_ZONE_TYPE_CONV &&
 	    zone->cond == ZBC_ZONE_COND_FULL)
 		zone->wp = zone->start + zone->len;
 }

 /**
  * sd_zbc_report_zones - Issue a REPORT ZONES scsi command.
  * @sdkp: The target disk
  * @buf: Buffer to use for the reply
  * @buflen: the buffer size
  * @lba: Start LBA of the report
  *
  * For internal use during device validation.
  */
 static int sd_zbc_report_zones(struct scsi_disk *sdkp, unsigned char *buf,
 			       unsigned int buflen, sector_t lba)
 {
 	struct scsi_device *sdp = sdkp->device;
 	const int timeout = sdp->request_queue->rq_timeout;
 	struct scsi_sense_hdr sshdr;
 	unsigned char cmd[16];
 	unsigned int rep_len;
 	int result;

 	memset(cmd, 0, 16);
 	cmd[0] = ZBC_IN;
 	cmd[1] = ZI_REPORT_ZONES;
 	put_unaligned_be64(lba, &cmd[2]);
 	put_unaligned_be32(buflen, &cmd[10]);
 	memset(buf, 0, buflen);

 	result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
 				  buf, buflen, &sshdr,
 				  timeout, SD_MAX_RETRIES, NULL);
 	if (result) {
 		sd_printk(KERN_ERR, sdkp,
 			  "REPORT ZONES lba %llu failed with %d/%d\n",
 			  (unsigned long long)lba,
 			  host_byte(result), driver_byte(result));
 		return -EIO;
 	}

 	rep_len = get_unaligned_be32(&buf[0]);
 	if (rep_len < 64) {
 		sd_printk(KERN_ERR, sdkp,
 			  "REPORT ZONES report invalid length %u\n",
 			  rep_len);
 		return -EIO;
 	}

 	return 0;
 }

 /**
  * sd_zbc_setup_report_cmnd - Prepare a REPORT ZONES scsi command
  * @cmd: The command to setup
  *
  * Call in sd_init_command() for a REQ_OP_ZONE_REPORT request.
  */
 int sd_zbc_setup_report_cmnd(struct scsi_cmnd *cmd)
 {
 	struct request *rq = cmd->request;
 	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
 	sector_t lba, sector = blk_rq_pos(rq);
 	unsigned int nr_bytes = blk_rq_bytes(rq);
 	int ret;

 	WARN_ON(nr_bytes == 0);

 	if (!sd_is_zoned(sdkp))
 		/* Not a zoned device */
 		return BLKPREP_KILL;

 	ret = scsi_init_io(cmd);
 	if (ret != BLKPREP_OK)
 		return ret;

 	cmd->cmd_len = 16;
 	memset(cmd->cmnd, 0, cmd->cmd_len);
 	cmd->cmnd[0] = ZBC_IN;
 	cmd->cmnd[1] = ZI_REPORT_ZONES;
 	lba = sectors_to_logical(sdkp->device, sector);
 	put_unaligned_be64(lba, &cmd->cmnd[2]);
 	put_unaligned_be32(nr_bytes, &cmd->cmnd[10]);
 	/* Do partial report for speeding things up */
 	cmd->cmnd[14] = ZBC_REPORT_ZONE_PARTIAL;

 	cmd->sc_data_direction = DMA_FROM_DEVICE;
 	cmd->sdb.length = nr_bytes;
 	cmd->transfersize = sdkp->device->sector_size;
 	cmd->allowed = 0;

 	/*
 	 * Report may return less bytes than requested. Make sure
 	 * to report completion on the entire initial request.
 	 */
 	rq->__data_len = nr_bytes;

 	return BLKPREP_OK;
 }

 /**
  * sd_zbc_report_zones_complete - Process a REPORT ZONES scsi command reply.
  * @scmd: The completed report zones command
  * @good_bytes: reply size in bytes
  *
  * Convert all reported zone descriptors to struct blk_zone. The conversion
  * is done in-place, directly in the request specified sg buffer.
  */
 static void sd_zbc_report_zones_complete(struct scsi_cmnd *scmd,
 					 unsigned int good_bytes)
 {
 	struct request *rq = scmd->request;
 	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
 	struct sg_mapping_iter miter;
 	struct blk_zone_report_hdr hdr;
 	struct blk_zone zone;
 	unsigned int offset, bytes = 0;
 	unsigned long flags;
 	u8 *buf;

 	if (good_bytes < 64)
 		return;

 	memset(&hdr, 0, sizeof(struct blk_zone_report_hdr));

 	sg_miter_start(&miter, scsi_sglist(scmd), scsi_sg_count(scmd),
 		       SG_MITER_TO_SG | SG_MITER_ATOMIC);

 	local_irq_save(flags);
 	while (sg_miter_next(&miter) && bytes < good_bytes) {

 		buf = miter.addr;
 		offset = 0;

 		if (bytes == 0) {
 			/* Set the report header */
 			hdr.nr_zones = min_t(unsigned int,
 					 (good_bytes - 64) / 64,
 					 get_unaligned_be32(&buf[0]) / 64);
 			memcpy(buf, &hdr, sizeof(struct blk_zone_report_hdr));
 			offset += 64;
 			bytes += 64;
 		}

 		/* Parse zone descriptors */
 		while (offset < miter.length && hdr.nr_zones) {
 			WARN_ON(offset > miter.length);
 			buf = miter.addr + offset;
 			sd_zbc_parse_report(sdkp, buf, &zone);
 			memcpy(buf, &zone, sizeof(struct blk_zone));
 			offset += 64;
 			bytes += 64;
 			hdr.nr_zones--;
 		}

 		if (!hdr.nr_zones)
 			break;

 	}
 	sg_miter_stop(&miter);
 	local_irq_restore(flags);
 }

 /**
  * sd_zbc_zone_sectors - Get the device zone size in number of 512B sectors.
  * @sdkp: The target disk
  */
 static inline sector_t sd_zbc_zone_sectors(struct scsi_disk *sdkp)
 {
 	return logical_to_sectors(sdkp->device, sdkp->zone_blocks);
 }

 /**
  * sd_zbc_setup_reset_cmnd - Prepare a RESET WRITE POINTER scsi command.
  * @cmd: the command to setup
  *
  * Called from sd_init_command() for a REQ_OP_ZONE_RESET request.
  */
 int sd_zbc_setup_reset_cmnd(struct scsi_cmnd *cmd)
 {
 	struct request *rq = cmd->request;
 	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
 	sector_t sector = blk_rq_pos(rq);
 	sector_t block = sectors_to_logical(sdkp->device, sector);

 	if (!sd_is_zoned(sdkp))
 		/* Not a zoned device */
 		return BLKPREP_KILL;

 	if (sdkp->device->changed)
 		return BLKPREP_KILL;

 	if (sector & (sd_zbc_zone_sectors(sdkp) - 1))
 		/* Unaligned request */
 		return BLKPREP_KILL;

 	cmd->cmd_len = 16;
 	memset(cmd->cmnd, 0, cmd->cmd_len);
 	cmd->cmnd[0] = ZBC_OUT;
 	cmd->cmnd[1] = ZO_RESET_WRITE_POINTER;
 	put_unaligned_be64(block, &cmd->cmnd[2]);

 	rq->timeout = SD_TIMEOUT;
 	cmd->sc_data_direction = DMA_NONE;
 	cmd->transfersize = 0;
 	cmd->allowed = 0;

 	return BLKPREP_OK;
 }

 /**
  * sd_zbc_complete - ZBC command post processing.
  * @cmd: Completed command
  * @good_bytes: Command reply bytes
  * @sshdr: command sense header
  *
  * Called from sd_done(). Process report zones reply and handle reset zone
  * and write commands errors.
  */
 void sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
 		     struct scsi_sense_hdr *sshdr)
 {
 	int result = cmd->result;
 	struct request *rq = cmd->request;

 	switch (req_op(rq)) {
 	case REQ_OP_ZONE_RESET:

 		if (result &&
 		    sshdr->sense_key == ILLEGAL_REQUEST &&
 		    sshdr->asc == 0x24)
 			/*
 			 * INVALID FIELD IN CDB error: reset of a conventional
 			 * zone was attempted. Nothing to worry about, so be
 			 * quiet about the error.
 			 */
 			rq->rq_flags |= RQF_QUIET;
 		break;

 	case REQ_OP_WRITE:
 	case REQ_OP_WRITE_ZEROES:
 	case REQ_OP_WRITE_SAME:

 		if (result &&
 		    sshdr->sense_key == ILLEGAL_REQUEST &&
 		    sshdr->asc == 0x21)
 			/*
 			 * INVALID ADDRESS FOR WRITE error: It is unlikely that
 			 * retrying write requests failed with any kind of
 			 * alignement error will result in success. So don't.
 			 */
 			cmd->allowed = 0;
 		break;

 	case REQ_OP_ZONE_REPORT:

 		if (!result)
 			sd_zbc_report_zones_complete(cmd, good_bytes);
 		break;

 	}
 }

 /**
  * sd_zbc_read_zoned_characteristics - Read zoned block device characteristics
  * @sdkp: Target disk
  * @buf: Buffer where to store the VPD page data
  *
  * Read VPD page B6.
  */
 static int sd_zbc_read_zoned_characteristics(struct scsi_disk *sdkp,
 					     unsigned char *buf)
 {

 	if (scsi_get_vpd_page(sdkp->device, 0xb6, buf, 64)) {
 		sd_printk(KERN_NOTICE, sdkp,
 			  "Unconstrained-read check failed\n");
 		return -ENODEV;
 	}

 	if (sdkp->device->type != TYPE_ZBC) {
 		/* Host-aware */
 		sdkp->urswrz = 1;
 		sdkp->zones_optimal_open = get_unaligned_be32(&buf[8]);
 		sdkp->zones_optimal_nonseq = get_unaligned_be32(&buf[12]);
 		sdkp->zones_max_open = 0;
 	} else {
 		/* Host-managed */
 		sdkp->urswrz = buf[4] & 1;
 		sdkp->zones_optimal_open = 0;
 		sdkp->zones_optimal_nonseq = 0;
 		sdkp->zones_max_open = get_unaligned_be32(&buf[16]);
 	}

 	return 0;
 }

 /**
  * sd_zbc_check_capacity - Check reported capacity.
  * @sdkp: Target disk
  * @buf: Buffer to use for commands
  *
  * ZBC drive may report only the capacity of the first conventional zones at
  * LBA 0. This is indicated by the RC_BASIS field of the read capacity reply.
  * Check this here. If the disk reported only its conventional zones capacity,
  * get the total capacity by doing a report zones.
  */
 static int sd_zbc_check_capacity(struct scsi_disk *sdkp, unsigned char *buf)
 {
 	sector_t lba;
 	int ret;

 	if (sdkp->rc_basis != 0)
 		return 0;

 	/* Do a report zone to get the maximum LBA to check capacity */
 	ret = sd_zbc_report_zones(sdkp, buf, SD_BUF_SIZE, 0);
 	if (ret)
 		return ret;

 	/* The max_lba field is the capacity of this device */
 	lba = get_unaligned_be64(&buf[8]);
 	if (lba + 1 == sdkp->capacity)
 		return 0;

 	if (sdkp->first_scan)
 		sd_printk(KERN_WARNING, sdkp,
 			  "Changing capacity from %llu to max LBA+1 %llu\n",
 			  (unsigned long long)sdkp->capacity,
 			  (unsigned long long)lba + 1);
 	sdkp->capacity = lba + 1;

 	return 0;
 }

 #define SD_ZBC_BUF_SIZE 131072U

 /**
  * sd_zbc_check_zone_size - Check the device zone sizes
  * @sdkp: Target disk
  *
  * Check that all zones of the device are equal. The last zone can however
  * be smaller. The zone size must also be a power of two number of LBAs.
  *
  * Returns the zone size in bytes upon success or an error code upon failure.
  */
 static s64 sd_zbc_check_zone_size(struct scsi_disk *sdkp)
 {
 	u64 zone_blocks = 0;
 	sector_t block = 0;
 	unsigned char *buf;
 	unsigned char *rec;
 	unsigned int buf_len;
 	unsigned int list_length;
 	int ret;
 	u8 same;

 	/* Get a buffer */
 	buf = kmalloc(SD_ZBC_BUF_SIZE, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	/* Do a report zone to get the same field */
 	ret = sd_zbc_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, 0);
 	if (ret)
 		goto out_free;

 	same = buf[4] & 0x0f;
 	if (same > 0) {
 		rec = &buf[64];
 		zone_blocks = get_unaligned_be64(&rec[8]);
 		goto out;
 	}

 	/*
 	 * Check the size of all zones: all zones must be of
 	 * equal size, except the last zone which can be smaller
 	 * than other zones.
 	 */
 	do {

 		/* Parse REPORT ZONES header */
 		list_length = get_unaligned_be32(&buf[0]) + 64;
 		rec = buf + 64;
 		buf_len = min(list_length, SD_ZBC_BUF_SIZE);

 		/* Parse zone descriptors */
 		while (rec < buf + buf_len) {
 			u64 this_zone_blocks = get_unaligned_be64(&rec[8]);

 			if (zone_blocks == 0) {
 				zone_blocks = this_zone_blocks;
 			} else if (this_zone_blocks != zone_blocks &&
 				   (block + this_zone_blocks < sdkp->capacity
 				    || this_zone_blocks > zone_blocks)) {
 				this_zone_blocks = 0;
 				goto out;
 			}
 			block += this_zone_blocks;
 			rec += 64;
 		}

 		if (block < sdkp->capacity) {
 			ret = sd_zbc_report_zones(sdkp, buf,
 						  SD_ZBC_BUF_SIZE, block);
 			if (ret)
 				goto out_free;
 		}

 	} while (block < sdkp->capacity);

 out:
 	if (!zone_blocks) {
 		if (sdkp->first_scan)
 			sd_printk(KERN_NOTICE, sdkp,
 				  "Devices with non constant zone "
 				  "size are not supported\n");
 		ret = -ENODEV;
 	} else if (!is_power_of_2(zone_blocks)) {
 		if (sdkp->first_scan)
 			sd_printk(KERN_NOTICE, sdkp,
 				  "Devices with non power of 2 zone "
 				  "size are not supported\n");
 		ret = -ENODEV;
 	} else if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
 		if (sdkp->first_scan)
 			sd_printk(KERN_NOTICE, sdkp,
 				  "Zone size too large\n");
 		ret = -ENODEV;
 	} else {
 		ret = zone_blocks;
 	}

 out_free:
 	kfree(buf);

 	return ret;
 }

 /**
  * sd_zbc_alloc_zone_bitmap - Allocate a zone bitmap (one bit per zone).
  * @nr_zones: Number of zones to allocate space for.
  * @numa_node: NUMA node to allocate the memory from.
  */
 static inline unsigned long *
 sd_zbc_alloc_zone_bitmap(u32 nr_zones, int numa_node)
 {
 	return kzalloc_node(BITS_TO_LONGS(nr_zones) * sizeof(unsigned long),
 			    GFP_KERNEL, numa_node);
 }

 /**
  * sd_zbc_get_seq_zones - Parse report zones reply to identify sequential zones
  * @sdkp: disk used
  * @buf: report reply buffer
  * @buflen: length of @buf
  * @zone_shift: logarithm base 2 of the number of blocks in a zone
  * @seq_zones_bitmap: bitmap of sequential zones to set
  *
  * Parse reported zone descriptors in @buf to identify sequential zones and
  * set the reported zone bit in @seq_zones_bitmap accordingly.
  * Since read-only and offline zones cannot be written, do not
  * mark them as sequential in the bitmap.
  * Return the LBA after the last zone reported.
  */
 static sector_t sd_zbc_get_seq_zones(struct scsi_disk *sdkp, unsigned char *buf,
 				     unsigned int buflen, u32 zone_shift,
 				     unsigned long *seq_zones_bitmap)
 {
 	sector_t lba, next_lba = sdkp->capacity;
 	unsigned int buf_len, list_length;
 	unsigned char *rec;
 	u8 type, cond;

 	list_length = get_unaligned_be32(&buf[0]) + 64;
 	buf_len = min(list_length, buflen);
 	rec = buf + 64;

 	while (rec < buf + buf_len) {
 		type = rec[0] & 0x0f;
 		cond = (rec[1] >> 4) & 0xf;
 		lba = get_unaligned_be64(&rec[16]);
 		if (type != ZBC_ZONE_TYPE_CONV &&
 		    cond != ZBC_ZONE_COND_READONLY &&
 		    cond != ZBC_ZONE_COND_OFFLINE)
 			set_bit(lba >> zone_shift, seq_zones_bitmap);
 		next_lba = lba + get_unaligned_be64(&rec[8]);
 		rec += 64;
 	}

 	return next_lba;
 }

 /**
  * sd_zbc_setup_seq_zones_bitmap - Initialize a seq zone bitmap.
  * @sdkp: target disk
  * @zone_shift: logarithm base 2 of the number of blocks in a zone
  * @nr_zones: number of zones to set up a seq zone bitmap for
  *
  * Allocate a zone bitmap and initialize it by identifying sequential zones.
  */
 static unsigned long *
 sd_zbc_setup_seq_zones_bitmap(struct scsi_disk *sdkp, u32 zone_shift,
 			      u32 nr_zones)
 {
 	struct request_queue *q = sdkp->disk->queue;
 	unsigned long *seq_zones_bitmap;
 	sector_t lba = 0;
 	unsigned char *buf;
 	int ret = -ENOMEM;

 	seq_zones_bitmap = sd_zbc_alloc_zone_bitmap(nr_zones, q->node);
 	if (!seq_zones_bitmap)
 		return ERR_PTR(-ENOMEM);

 	buf = kmalloc(SD_ZBC_BUF_SIZE, GFP_KERNEL);
 	if (!buf)
 		goto out;

 	while (lba < sdkp->capacity) {
 		ret = sd_zbc_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, lba);
 		if (ret)
 			goto out;
 		lba = sd_zbc_get_seq_zones(sdkp, buf, SD_ZBC_BUF_SIZE,
 					   zone_shift, seq_zones_bitmap);
 	}

 	if (lba != sdkp->capacity) {
 		/* Something went wrong */
 		ret = -EIO;
 	}

 out:
 	kfree(buf);
 	if (ret) {
 		kfree(seq_zones_bitmap);
 		return ERR_PTR(ret);
 	}
 	return seq_zones_bitmap;
 }

 static void sd_zbc_cleanup(struct scsi_disk *sdkp)
 {
 	struct request_queue *q = sdkp->disk->queue;

 	kfree(q->seq_zones_bitmap);
 	q->seq_zones_bitmap = NULL;

 	kfree(q->seq_zones_wlock);
 	q->seq_zones_wlock = NULL;

 	q->nr_zones = 0;
 }

 static int sd_zbc_setup(struct scsi_disk *sdkp, u32 zone_blocks)
 {
 	struct request_queue *q = sdkp->disk->queue;
 	u32 zone_shift = ilog2(zone_blocks);
 	u32 nr_zones;
 	int ret;

 	/* chunk_sectors indicates the zone size */
 	blk_queue_chunk_sectors(q,
 			logical_to_sectors(sdkp->device, zone_blocks));
 	nr_zones = round_up(sdkp->capacity, zone_blocks) >> zone_shift;

 	/*
 	 * Initialize the device request queue information if the number
 	 * of zones changed.
 	 */
 	if (nr_zones != sdkp->nr_zones || nr_zones != q->nr_zones) {
 		unsigned long *seq_zones_wlock = NULL, *seq_zones_bitmap = NULL;
 		size_t zone_bitmap_size;

 		if (nr_zones) {
 			seq_zones_wlock = sd_zbc_alloc_zone_bitmap(nr_zones,
 								   q->node);
 			if (!seq_zones_wlock) {
 				ret = -ENOMEM;
 				goto err;
 			}

 			seq_zones_bitmap = sd_zbc_setup_seq_zones_bitmap(sdkp,
 							zone_shift, nr_zones);
 			if (IS_ERR(seq_zones_bitmap)) {
 				ret = PTR_ERR(seq_zones_bitmap);
 				kfree(seq_zones_wlock);
 				goto err;
 			}
 		}
 		zone_bitmap_size = BITS_TO_LONGS(nr_zones) *
 			sizeof(unsigned long);
 		blk_mq_freeze_queue(q);
 		if (q->nr_zones != nr_zones) {
 			/* READ16/WRITE16 is mandatory for ZBC disks */
 			sdkp->device->use_16_for_rw = 1;
 			sdkp->device->use_10_for_rw = 0;

 			sdkp->zone_blocks = zone_blocks;
 			sdkp->zone_shift = zone_shift;
 			sdkp->nr_zones = nr_zones;
 			q->nr_zones = nr_zones;
 			swap(q->seq_zones_wlock, seq_zones_wlock);
 			swap(q->seq_zones_bitmap, seq_zones_bitmap);
 		} else if (memcmp(q->seq_zones_bitmap, seq_zones_bitmap,
 				  zone_bitmap_size) != 0) {
 			memcpy(q->seq_zones_bitmap, seq_zones_bitmap,
 			       zone_bitmap_size);
 		}
 		blk_mq_unfreeze_queue(q);
 		kfree(seq_zones_wlock);
 		kfree(seq_zones_bitmap);
 	}

 	return 0;

 err:
 	sd_zbc_cleanup(sdkp);
 	return ret;
 }

 int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
 {
 	int64_t zone_blocks;
 	int ret;

 	if (!sd_is_zoned(sdkp))
 		/*
 		 * Device managed or normal SCSI disk,
 		 * no special handling required
 		 */
 		return 0;

 	/* Get zoned block device characteristics */
 	ret = sd_zbc_read_zoned_characteristics(sdkp, buf);
 	if (ret)
 		goto err;

 	/*
 	 * Check for unconstrained reads: host-managed devices with
 	 * constrained reads (drives failing read after write pointer)
 	 * are not supported.
 	 */
 	if (!sdkp->urswrz) {
 		if (sdkp->first_scan)
 			sd_printk(KERN_NOTICE, sdkp,
 			  "constrained reads devices are not supported\n");
 		ret = -ENODEV;
 		goto err;
 	}

 	/* Check capacity */
 	ret = sd_zbc_check_capacity(sdkp, buf);
 	if (ret)
 		goto err;

 	/*
 	 * Check zone size: only devices with a constant zone size (except
 	 * an eventual last runt zone) that is a power of 2 are supported.
 	 */
 	zone_blocks = sd_zbc_check_zone_size(sdkp);
 	ret = -EFBIG;
 	if (zone_blocks != (u32)zone_blocks)
 		goto err;
 	ret = zone_blocks;
 	if (ret < 0)
 		goto err;

 	/* The drive satisfies the kernel restrictions: set it up */
 	ret = sd_zbc_setup(sdkp, zone_blocks);
 	if (ret)
 		goto err;

 	return 0;

 err:
 	sdkp->capacity = 0;
 	sd_zbc_cleanup(sdkp);

 	return ret;
 }

 void sd_zbc_remove(struct scsi_disk *sdkp)
 {
 	sd_zbc_cleanup(sdkp);
 }

 void sd_zbc_print_zones(struct scsi_disk *sdkp)
 {
 	if (!sd_is_zoned(sdkp) || !sdkp->capacity)
 		return;

 	if (sdkp->capacity & (sdkp->zone_blocks - 1))
 		sd_printk(KERN_NOTICE, sdkp,
 			  "%u zones of %u logical blocks + 1 runt zone\n",
 			  sdkp->nr_zones - 1,
 			  sdkp->zone_blocks);
 	else
 		sd_printk(KERN_NOTICE, sdkp,
 			  "%u zones of %u logical blocks\n",
 			  sdkp->nr_zones,
 			  sdkp->zone_blocks);
 }
	/*
	* SCSI Zoned Block commands
	*
	* Copyright (C) 2014-2015 SUSE Linux GmbH
	* Written by: Hannes Reinecke <hare@suse.de>
	* Modified by: Damien Le Moal <damien.lemoal@hgst.com>
	* Modified by: Shaun Tancheff <shaun.tancheff@seagate.com>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License version
	* 2 as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; see the file COPYING. If not, write to
	* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
	* USA.
	*
	*/

	#include <linux/blkdev.h>

	#include <asm/unaligned.h>

	#include <scsi/scsi.h>
	#include <scsi/scsi_cmnd.h>

	#include "sd.h"

	/**
	* sd_zbc_parse_report - Convert a zone descriptor to a struct blk_zone,
	* @sdkp: The disk the report originated from
	* @buf: Address of the report zone descriptor
	* @zone: the destination zone structure
	*
	* All LBA sized values are converted to 512B sectors unit.
	*/
	static void sd_zbc_parse_report(struct scsi_disk sdkp, u8 buf,
	struct blk_zone *zone)
	{
	struct scsi_device *sdp = sdkp->device;

	memset(zone, 0, sizeof(struct blk_zone));

	zone->type = buf[0] & 0x0f;
	zone->cond = (buf[1] >> 4) & 0xf;
	if (buf[1] & 0x01)
	zone->reset = 1;
	if (buf[1] & 0x02)
	zone->non_seq = 1;

	zone->len = logical_to_sectors(sdp, get_unaligned_be64(&buf[8]));
	zone->start = logical_to_sectors(sdp, get_unaligned_be64(&buf[16]));
	zone->wp = logical_to_sectors(sdp, get_unaligned_be64(&buf[24]));
	if (zone->type != ZBC_ZONE_TYPE_CONV &&
	zone->cond == ZBC_ZONE_COND_FULL)
	zone->wp = zone->start + zone->len;
	}

	/**
	* sd_zbc_report_zones - Issue a REPORT ZONES scsi command.
	* @sdkp: The target disk
	* @buf: Buffer to use for the reply
	* @buflen: the buffer size
	* @lba: Start LBA of the report
	*
	* For internal use during device validation.
	*/
	static int sd_zbc_report_zones(struct scsi_disk sdkp, unsigned char buf,
	unsigned int buflen, sector_t lba)
	{
	struct scsi_device *sdp = sdkp->device;
	const int timeout = sdp->request_queue->rq_timeout;
	struct scsi_sense_hdr sshdr;
	unsigned char cmd[16];
	unsigned int rep_len;
	int result;

	memset(cmd, 0, 16);
	cmd[0] = ZBC_IN;
	cmd[1] = ZI_REPORT_ZONES;
	put_unaligned_be64(lba, &cmd[2]);
	put_unaligned_be32(buflen, &cmd[10]);
	memset(buf, 0, buflen);

	result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
	buf, buflen, &sshdr,
	timeout, SD_MAX_RETRIES, NULL);
	if (result) {
	sd_printk(KERN_ERR, sdkp,
	"REPORT ZONES lba %llu failed with %d/%d\n",
	(unsigned long long)lba,
	host_byte(result), driver_byte(result));
	return -EIO;
	}

	rep_len = get_unaligned_be32(&buf[0]);
	if (rep_len < 64) {
	sd_printk(KERN_ERR, sdkp,
	"REPORT ZONES report invalid length %u\n",
	rep_len);
	return -EIO;
	}

	return 0;
	}

	/**
	* sd_zbc_setup_report_cmnd - Prepare a REPORT ZONES scsi command
	* @cmd: The command to setup
	*
	* Call in sd_init_command() for a REQ_OP_ZONE_REPORT request.
	*/
	int sd_zbc_setup_report_cmnd(struct scsi_cmnd *cmd)
	{
	struct request *rq = cmd->request;
	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
	sector_t lba, sector = blk_rq_pos(rq);
	unsigned int nr_bytes = blk_rq_bytes(rq);
	int ret;

	WARN_ON(nr_bytes == 0);

	if (!sd_is_zoned(sdkp))
	/* Not a zoned device */
	return BLKPREP_KILL;

	ret = scsi_init_io(cmd);
	if (ret != BLKPREP_OK)
	return ret;

	cmd->cmd_len = 16;
	memset(cmd->cmnd, 0, cmd->cmd_len);
	cmd->cmnd[0] = ZBC_IN;
	cmd->cmnd[1] = ZI_REPORT_ZONES;
	lba = sectors_to_logical(sdkp->device, sector);
	put_unaligned_be64(lba, &cmd->cmnd[2]);
	put_unaligned_be32(nr_bytes, &cmd->cmnd[10]);
	/* Do partial report for speeding things up */
	cmd->cmnd[14] = ZBC_REPORT_ZONE_PARTIAL;

	cmd->sc_data_direction = DMA_FROM_DEVICE;
	cmd->sdb.length = nr_bytes;
	cmd->transfersize = sdkp->device->sector_size;
	cmd->allowed = 0;

	/*
	* Report may return less bytes than requested. Make sure
	* to report completion on the entire initial request.
	*/
	rq->__data_len = nr_bytes;

	return BLKPREP_OK;
	}

	/**
	* sd_zbc_report_zones_complete - Process a REPORT ZONES scsi command reply.
	* @scmd: The completed report zones command
	* @good_bytes: reply size in bytes
	*
	* Convert all reported zone descriptors to struct blk_zone. The conversion
	* is done in-place, directly in the request specified sg buffer.
	*/
	static void sd_zbc_report_zones_complete(struct scsi_cmnd *scmd,
	unsigned int good_bytes)
	{
	struct request *rq = scmd->request;
	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
	struct sg_mapping_iter miter;
	struct blk_zone_report_hdr hdr;
	struct blk_zone zone;
	unsigned int offset, bytes = 0;
	unsigned long flags;
	u8 *buf;

	if (good_bytes < 64)
	return;

	memset(&hdr, 0, sizeof(struct blk_zone_report_hdr));

	sg_miter_start(&miter, scsi_sglist(scmd), scsi_sg_count(scmd),
	SG_MITER_TO_SG \| SG_MITER_ATOMIC);

	local_irq_save(flags);
	while (sg_miter_next(&miter) && bytes < good_bytes) {

	buf = miter.addr;
	offset = 0;

	if (bytes == 0) {
	/* Set the report header */
	hdr.nr_zones = min_t(unsigned int,
	(good_bytes - 64) / 64,
	get_unaligned_be32(&buf[0]) / 64);
	memcpy(buf, &hdr, sizeof(struct blk_zone_report_hdr));
	offset += 64;
	bytes += 64;
	}

	/* Parse zone descriptors */
	while (offset < miter.length && hdr.nr_zones) {
	WARN_ON(offset > miter.length);
	buf = miter.addr + offset;
	sd_zbc_parse_report(sdkp, buf, &zone);
	memcpy(buf, &zone, sizeof(struct blk_zone));
	offset += 64;
	bytes += 64;
	hdr.nr_zones--;
	}

	if (!hdr.nr_zones)
	break;

	}
	sg_miter_stop(&miter);
	local_irq_restore(flags);
	}

	/**
	* sd_zbc_zone_sectors - Get the device zone size in number of 512B sectors.
	* @sdkp: The target disk
	*/
	static inline sector_t sd_zbc_zone_sectors(struct scsi_disk *sdkp)
	{
	return logical_to_sectors(sdkp->device, sdkp->zone_blocks);
	}

	/**
	* sd_zbc_setup_reset_cmnd - Prepare a RESET WRITE POINTER scsi command.
	* @cmd: the command to setup
	*
	* Called from sd_init_command() for a REQ_OP_ZONE_RESET request.
	*/
	int sd_zbc_setup_reset_cmnd(struct scsi_cmnd *cmd)
	{
	struct request *rq = cmd->request;
	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
	sector_t sector = blk_rq_pos(rq);
	sector_t block = sectors_to_logical(sdkp->device, sector);

	if (!sd_is_zoned(sdkp))
	/* Not a zoned device */
	return BLKPREP_KILL;

	if (sdkp->device->changed)
	return BLKPREP_KILL;

	if (sector & (sd_zbc_zone_sectors(sdkp) - 1))
	/* Unaligned request */
	return BLKPREP_KILL;

	cmd->cmd_len = 16;
	memset(cmd->cmnd, 0, cmd->cmd_len);
	cmd->cmnd[0] = ZBC_OUT;
	cmd->cmnd[1] = ZO_RESET_WRITE_POINTER;
	put_unaligned_be64(block, &cmd->cmnd[2]);

	rq->timeout = SD_TIMEOUT;
	cmd->sc_data_direction = DMA_NONE;
	cmd->transfersize = 0;
	cmd->allowed = 0;

	return BLKPREP_OK;
	}

	/**
	* sd_zbc_complete - ZBC command post processing.
	* @cmd: Completed command
	* @good_bytes: Command reply bytes
	* @sshdr: command sense header
	*
	* Called from sd_done(). Process report zones reply and handle reset zone
	* and write commands errors.
	*/
	void sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
	struct scsi_sense_hdr *sshdr)
	{
	int result = cmd->result;
	struct request *rq = cmd->request;

	switch (req_op(rq)) {
	case REQ_OP_ZONE_RESET:

	if (result &&
	sshdr->sense_key == ILLEGAL_REQUEST &&
	sshdr->asc == 0x24)
	/*
	* INVALID FIELD IN CDB error: reset of a conventional
	* zone was attempted. Nothing to worry about, so be
	* quiet about the error.
	*/
	rq->rq_flags \|= RQF_QUIET;
	break;

	case REQ_OP_WRITE:
	case REQ_OP_WRITE_ZEROES:
	case REQ_OP_WRITE_SAME:

	if (result &&
	sshdr->sense_key == ILLEGAL_REQUEST &&
	sshdr->asc == 0x21)
	/*
	* INVALID ADDRESS FOR WRITE error: It is unlikely that
	* retrying write requests failed with any kind of
	* alignement error will result in success. So don't.
	*/
	cmd->allowed = 0;
	break;

	case REQ_OP_ZONE_REPORT:

	if (!result)
	sd_zbc_report_zones_complete(cmd, good_bytes);
	break;

	}
	}

	/**
	* sd_zbc_read_zoned_characteristics - Read zoned block device characteristics
	* @sdkp: Target disk
	* @buf: Buffer where to store the VPD page data
	*
	* Read VPD page B6.
	*/
	static int sd_zbc_read_zoned_characteristics(struct scsi_disk *sdkp,
	unsigned char *buf)
	{

	if (scsi_get_vpd_page(sdkp->device, 0xb6, buf, 64)) {
	sd_printk(KERN_NOTICE, sdkp,
	"Unconstrained-read check failed\n");
	return -ENODEV;
	}

	if (sdkp->device->type != TYPE_ZBC) {
	/* Host-aware */
	sdkp->urswrz = 1;
	sdkp->zones_optimal_open = get_unaligned_be32(&buf[8]);
	sdkp->zones_optimal_nonseq = get_unaligned_be32(&buf[12]);
	sdkp->zones_max_open = 0;
	} else {
	/* Host-managed */
	sdkp->urswrz = buf[4] & 1;
	sdkp->zones_optimal_open = 0;
	sdkp->zones_optimal_nonseq = 0;
	sdkp->zones_max_open = get_unaligned_be32(&buf[16]);
	}

	return 0;
	}

	/**
	* sd_zbc_check_capacity - Check reported capacity.
	* @sdkp: Target disk
	* @buf: Buffer to use for commands
	*
	* ZBC drive may report only the capacity of the first conventional zones at
	* LBA 0. This is indicated by the RC_BASIS field of the read capacity reply.
	* Check this here. If the disk reported only its conventional zones capacity,
	* get the total capacity by doing a report zones.
	*/
	static int sd_zbc_check_capacity(struct scsi_disk sdkp, unsigned char buf)
	{
	sector_t lba;
	int ret;

	if (sdkp->rc_basis != 0)
	return 0;

	/* Do a report zone to get the maximum LBA to check capacity */
	ret = sd_zbc_report_zones(sdkp, buf, SD_BUF_SIZE, 0);
	if (ret)
	return ret;

	/* The max_lba field is the capacity of this device */
	lba = get_unaligned_be64(&buf[8]);
	if (lba + 1 == sdkp->capacity)
	return 0;

	if (sdkp->first_scan)
	sd_printk(KERN_WARNING, sdkp,
	"Changing capacity from %llu to max LBA+1 %llu\n",
	(unsigned long long)sdkp->capacity,
	(unsigned long long)lba + 1);
	sdkp->capacity = lba + 1;

	return 0;
	}

	#define SD_ZBC_BUF_SIZE 131072U

	/**
	* sd_zbc_check_zone_size - Check the device zone sizes
	* @sdkp: Target disk
	*
	* Check that all zones of the device are equal. The last zone can however
	* be smaller. The zone size must also be a power of two number of LBAs.
	*
	* Returns the zone size in bytes upon success or an error code upon failure.
	*/
	static s64 sd_zbc_check_zone_size(struct scsi_disk *sdkp)
	{
	u64 zone_blocks = 0;
	sector_t block = 0;
	unsigned char *buf;
	unsigned char *rec;
	unsigned int buf_len;
	unsigned int list_length;
	int ret;
	u8 same;

	/* Get a buffer */
	buf = kmalloc(SD_ZBC_BUF_SIZE, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	/* Do a report zone to get the same field */
	ret = sd_zbc_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, 0);
	if (ret)
	goto out_free;

	same = buf[4] & 0x0f;
	if (same > 0) {
	rec = &buf[64];
	zone_blocks = get_unaligned_be64(&rec[8]);
	goto out;
	}

	/*
	* Check the size of all zones: all zones must be of
	* equal size, except the last zone which can be smaller
	* than other zones.
	*/
	do {

	/* Parse REPORT ZONES header */
	list_length = get_unaligned_be32(&buf[0]) + 64;
	rec = buf + 64;
	buf_len = min(list_length, SD_ZBC_BUF_SIZE);

	/* Parse zone descriptors */
	while (rec < buf + buf_len) {
	u64 this_zone_blocks = get_unaligned_be64(&rec[8]);

	if (zone_blocks == 0) {
	zone_blocks = this_zone_blocks;
	} else if (this_zone_blocks != zone_blocks &&
	(block + this_zone_blocks < sdkp->capacity
	\|\| this_zone_blocks > zone_blocks)) {
	this_zone_blocks = 0;
	goto out;
	}
	block += this_zone_blocks;
	rec += 64;
	}

	if (block < sdkp->capacity) {
	ret = sd_zbc_report_zones(sdkp, buf,
	SD_ZBC_BUF_SIZE, block);
	if (ret)
	goto out_free;
	}

	} while (block < sdkp->capacity);

	out:
	if (!zone_blocks) {
	if (sdkp->first_scan)
	sd_printk(KERN_NOTICE, sdkp,
	"Devices with non constant zone "
	"size are not supported\n");
	ret = -ENODEV;
	} else if (!is_power_of_2(zone_blocks)) {
	if (sdkp->first_scan)
	sd_printk(KERN_NOTICE, sdkp,
	"Devices with non power of 2 zone "
	"size are not supported\n");
	ret = -ENODEV;
	} else if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
	if (sdkp->first_scan)
	sd_printk(KERN_NOTICE, sdkp,
	"Zone size too large\n");
	ret = -ENODEV;
	} else {
	ret = zone_blocks;
	}

	out_free:
	kfree(buf);

	return ret;
	}

	/**
	* sd_zbc_alloc_zone_bitmap - Allocate a zone bitmap (one bit per zone).
	* @nr_zones: Number of zones to allocate space for.
	* @numa_node: NUMA node to allocate the memory from.
	*/
	static inline unsigned long *
	sd_zbc_alloc_zone_bitmap(u32 nr_zones, int numa_node)
	{
	return kzalloc_node(BITS_TO_LONGS(nr_zones) * sizeof(unsigned long),
	GFP_KERNEL, numa_node);
	}

	/**
	* sd_zbc_get_seq_zones - Parse report zones reply to identify sequential zones
	* @sdkp: disk used
	* @buf: report reply buffer
	* @buflen: length of @buf
	* @zone_shift: logarithm base 2 of the number of blocks in a zone
	* @seq_zones_bitmap: bitmap of sequential zones to set
	*
	* Parse reported zone descriptors in @buf to identify sequential zones and
	* set the reported zone bit in @seq_zones_bitmap accordingly.
	* Since read-only and offline zones cannot be written, do not
	* mark them as sequential in the bitmap.
	* Return the LBA after the last zone reported.
	*/
	static sector_t sd_zbc_get_seq_zones(struct scsi_disk sdkp, unsigned char buf,
	unsigned int buflen, u32 zone_shift,
	unsigned long *seq_zones_bitmap)
	{
	sector_t lba, next_lba = sdkp->capacity;
	unsigned int buf_len, list_length;
	unsigned char *rec;
	u8 type, cond;

	list_length = get_unaligned_be32(&buf[0]) + 64;
	buf_len = min(list_length, buflen);
	rec = buf + 64;

	while (rec < buf + buf_len) {
	type = rec[0] & 0x0f;
	cond = (rec[1] >> 4) & 0xf;
	lba = get_unaligned_be64(&rec[16]);
	if (type != ZBC_ZONE_TYPE_CONV &&
	cond != ZBC_ZONE_COND_READONLY &&
	cond != ZBC_ZONE_COND_OFFLINE)
	set_bit(lba >> zone_shift, seq_zones_bitmap);
	next_lba = lba + get_unaligned_be64(&rec[8]);
	rec += 64;
	}

	return next_lba;
	}

	/**
	* sd_zbc_setup_seq_zones_bitmap - Initialize a seq zone bitmap.
	* @sdkp: target disk
	* @zone_shift: logarithm base 2 of the number of blocks in a zone
	* @nr_zones: number of zones to set up a seq zone bitmap for
	*
	* Allocate a zone bitmap and initialize it by identifying sequential zones.
	*/
	static unsigned long *
	sd_zbc_setup_seq_zones_bitmap(struct scsi_disk *sdkp, u32 zone_shift,
	u32 nr_zones)
	{
	struct request_queue *q = sdkp->disk->queue;
	unsigned long *seq_zones_bitmap;
	sector_t lba = 0;
	unsigned char *buf;
	int ret = -ENOMEM;

	seq_zones_bitmap = sd_zbc_alloc_zone_bitmap(nr_zones, q->node);
	if (!seq_zones_bitmap)
	return ERR_PTR(-ENOMEM);

	buf = kmalloc(SD_ZBC_BUF_SIZE, GFP_KERNEL);
	if (!buf)
	goto out;

	while (lba < sdkp->capacity) {
	ret = sd_zbc_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, lba);
	if (ret)
	goto out;
	lba = sd_zbc_get_seq_zones(sdkp, buf, SD_ZBC_BUF_SIZE,
	zone_shift, seq_zones_bitmap);
	}

	if (lba != sdkp->capacity) {
	/* Something went wrong */
	ret = -EIO;
	}

	out:
	kfree(buf);
	if (ret) {
	kfree(seq_zones_bitmap);
	return ERR_PTR(ret);
	}
	return seq_zones_bitmap;
	}

	static void sd_zbc_cleanup(struct scsi_disk *sdkp)
	{
	struct request_queue *q = sdkp->disk->queue;

	kfree(q->seq_zones_bitmap);
	q->seq_zones_bitmap = NULL;

	kfree(q->seq_zones_wlock);
	q->seq_zones_wlock = NULL;

	q->nr_zones = 0;
	}

	static int sd_zbc_setup(struct scsi_disk *sdkp, u32 zone_blocks)
	{
	struct request_queue *q = sdkp->disk->queue;
	u32 zone_shift = ilog2(zone_blocks);
	u32 nr_zones;
	int ret;

	/* chunk_sectors indicates the zone size */
	blk_queue_chunk_sectors(q,
	logical_to_sectors(sdkp->device, zone_blocks));
	nr_zones = round_up(sdkp->capacity, zone_blocks) >> zone_shift;

	/*
	* Initialize the device request queue information if the number
	* of zones changed.
	*/
	if (nr_zones != sdkp->nr_zones \|\| nr_zones != q->nr_zones) {
	unsigned long seq_zones_wlock = NULL, seq_zones_bitmap = NULL;
	size_t zone_bitmap_size;

	if (nr_zones) {
	seq_zones_wlock = sd_zbc_alloc_zone_bitmap(nr_zones,
	q->node);
	if (!seq_zones_wlock) {
	ret = -ENOMEM;
	goto err;
	}

	seq_zones_bitmap = sd_zbc_setup_seq_zones_bitmap(sdkp,
	zone_shift, nr_zones);
	if (IS_ERR(seq_zones_bitmap)) {
	ret = PTR_ERR(seq_zones_bitmap);
	kfree(seq_zones_wlock);
	goto err;
	}
	}
	zone_bitmap_size = BITS_TO_LONGS(nr_zones) *
	sizeof(unsigned long);
	blk_mq_freeze_queue(q);
	if (q->nr_zones != nr_zones) {
	/* READ16/WRITE16 is mandatory for ZBC disks */
	sdkp->device->use_16_for_rw = 1;
	sdkp->device->use_10_for_rw = 0;

	sdkp->zone_blocks = zone_blocks;
	sdkp->zone_shift = zone_shift;
	sdkp->nr_zones = nr_zones;
	q->nr_zones = nr_zones;
	swap(q->seq_zones_wlock, seq_zones_wlock);
	swap(q->seq_zones_bitmap, seq_zones_bitmap);
	} else if (memcmp(q->seq_zones_bitmap, seq_zones_bitmap,
	zone_bitmap_size) != 0) {
	memcpy(q->seq_zones_bitmap, seq_zones_bitmap,
	zone_bitmap_size);
	}
	blk_mq_unfreeze_queue(q);
	kfree(seq_zones_wlock);
	kfree(seq_zones_bitmap);
	}

	return 0;

	err:
	sd_zbc_cleanup(sdkp);
	return ret;
	}

	int sd_zbc_read_zones(struct scsi_disk sdkp, unsigned char buf)
	{
	int64_t zone_blocks;
	int ret;

	if (!sd_is_zoned(sdkp))
	/*
	* Device managed or normal SCSI disk,
	* no special handling required
	*/
	return 0;

	/* Get zoned block device characteristics */
	ret = sd_zbc_read_zoned_characteristics(sdkp, buf);
	if (ret)
	goto err;

	/*
	* Check for unconstrained reads: host-managed devices with
	* constrained reads (drives failing read after write pointer)
	* are not supported.
	*/
	if (!sdkp->urswrz) {
	if (sdkp->first_scan)
	sd_printk(KERN_NOTICE, sdkp,
	"constrained reads devices are not supported\n");
	ret = -ENODEV;
	goto err;
	}

	/* Check capacity */
	ret = sd_zbc_check_capacity(sdkp, buf);
	if (ret)
	goto err;

	/*
	* Check zone size: only devices with a constant zone size (except
	* an eventual last runt zone) that is a power of 2 are supported.
	*/
	zone_blocks = sd_zbc_check_zone_size(sdkp);
	ret = -EFBIG;
	if (zone_blocks != (u32)zone_blocks)
	goto err;
	ret = zone_blocks;
	if (ret < 0)
	goto err;

	/* The drive satisfies the kernel restrictions: set it up */
	ret = sd_zbc_setup(sdkp, zone_blocks);
	if (ret)
	goto err;

	return 0;

	err:
	sdkp->capacity = 0;
	sd_zbc_cleanup(sdkp);

	return ret;
	}

	void sd_zbc_remove(struct scsi_disk *sdkp)
	{
	sd_zbc_cleanup(sdkp);
	}

	void sd_zbc_print_zones(struct scsi_disk *sdkp)
	{
	if (!sd_is_zoned(sdkp) \|\| !sdkp->capacity)
	return;

	if (sdkp->capacity & (sdkp->zone_blocks - 1))
	sd_printk(KERN_NOTICE, sdkp,
	"%u zones of %u logical blocks + 1 runt zone\n",
	sdkp->nr_zones - 1,
	sdkp->zone_blocks);
	else
	sd_printk(KERN_NOTICE, sdkp,
	"%u zones of %u logical blocks\n",
	sdkp->nr_zones,
	sdkp->zone_blocks);
	}