drivers/scsi/sd_zbc.c - kernel/msm-5.4 - Gitiles

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * 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>
  */

 #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_do_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
  * @partial: Do partial report
  *
  * For internal use during device validation.
  * Using partial=true can significantly speed up execution of a report zones
  * command because the disk does not have to count all possible report matching
  * zones and will only report the count of zones fitting in the command reply
  * buffer.
  */
 static int sd_zbc_do_report_zones(struct scsi_disk *sdkp, unsigned char *buf,
 				  unsigned int buflen, sector_t lba,
 				  bool partial)
 {
 	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]);
 	if (partial)
 		cmd[14] = ZBC_REPORT_ZONE_PARTIAL;
 	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_report_zones - Disk report zones operation.
  * @disk: The target disk
  * @sector: Start 512B sector of the report
  * @zones: Array of zone descriptors
  * @nr_zones: Number of descriptors in the array
  * @gfp_mask: Memory allocation mask
  *
  * Execute a report zones command on the target disk.
  */
 int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
 			struct blk_zone *zones, unsigned int *nr_zones,
 			gfp_t gfp_mask)
 {
 	struct scsi_disk *sdkp = scsi_disk(disk);
 	unsigned int i, buflen, nrz = *nr_zones;
 	unsigned char *buf;
 	size_t offset = 0;
 	int ret = 0;

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

 	/*
 	 * Get a reply buffer for the number of requested zones plus a header,
 	 * without exceeding the device maximum command size. For ATA disks,
 	 * buffers must be aligned to 512B.
 	 */
 	buflen = min(queue_max_hw_sectors(disk->queue) << 9,
 		     roundup((nrz + 1) * 64, 512));
 	buf = kmalloc(buflen, gfp_mask);
 	if (!buf)
 		return -ENOMEM;

 	ret = sd_zbc_do_report_zones(sdkp, buf, buflen,
 			sectors_to_logical(sdkp->device, sector), true);
 	if (ret)
 		goto out_free_buf;

 	nrz = min(nrz, get_unaligned_be32(&buf[0]) / 64);
 	for (i = 0; i < nrz; i++) {
 		offset += 64;
 		sd_zbc_parse_report(sdkp, buf + offset, zones);
 		zones++;
 	}

 	*nr_zones = nrz;

 out_free_buf:
 	kfree(buf);

 	return ret;
 }

 /**
  * 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.
  */
 blk_status_t 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 BLK_STS_IOERR;

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

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

 	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 BLK_STS_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:
 		break;
 	}
 }

 /**
  * sd_zbc_check_zoned_characteristics - Check zoned block device characteristics
  * @sdkp: Target disk
  * @buf: Buffer where to store the VPD page data
  *
  * Read VPD page B6, get information and check that reads are unconstrained.
  */
 static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
 					      unsigned char *buf)
 {

 	if (scsi_get_vpd_page(sdkp->device, 0xb6, buf, 64)) {
 		sd_printk(KERN_NOTICE, sdkp,
 			  "Read zoned characteristics VPD page 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]);
 	}

 	/*
 	 * 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");
 		return -ENODEV;
 	}

 	return 0;
 }

 #define SD_ZBC_BUF_SIZE 131072U

 /**
  * sd_zbc_check_zones - Check the device capacity and zone sizes
  * @sdkp: Target disk
  *
  * Check that the device capacity as reported by READ CAPACITY matches the
  * max_lba value (plus one)of the report zones command reply. Also check that
  * all zones of the device have an equal size, only allowing the last zone of
  * the disk to have a smaller size (runt zone). The zone size must also be a
  * power of two.
  *
  * Returns the zone size in number of blocks upon success or an error code
  * upon failure.
  */
 static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
 {
 	u64 zone_blocks = 0;
 	sector_t max_lba, 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 max_lba and the same field */
 	ret = sd_zbc_do_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, 0, false);
 	if (ret)
 		goto out_free;

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

 	/*
 	 * Check same field: for any value other than 0, we know that all zones
 	 * have the same size.
 	 */
 	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)) {
 				zone_blocks = 0;
 				goto out;
 			}
 			block += this_zone_blocks;
 			rec += 64;
 		}

 		if (block < sdkp->capacity) {
 			ret = sd_zbc_do_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE,
 						     block, true);
 			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 = -EFBIG;
 	} else {
 		*zblocks = zone_blocks;
 		ret = 0;
 	}

 out_free:
 	kfree(buf);

 	return ret;
 }

 int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
 {
 	struct gendisk *disk = sdkp->disk;
 	unsigned int nr_zones;
 	u32 zone_blocks;
 	int ret;

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

 	/* Check zoned block device characteristics (unconstrained reads) */
 	ret = sd_zbc_check_zoned_characteristics(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.
 	 */
 	ret = sd_zbc_check_zones(sdkp, &zone_blocks);
 	if (ret != 0)
 		goto err;

 	/* The drive satisfies the kernel restrictions: set it up */
 	blk_queue_chunk_sectors(sdkp->disk->queue,
 			logical_to_sectors(sdkp->device, zone_blocks));
 	nr_zones = round_up(sdkp->capacity, zone_blocks) >> ilog2(zone_blocks);

 	/* READ16/WRITE16 is mandatory for ZBC disks */
 	sdkp->device->use_16_for_rw = 1;
 	sdkp->device->use_10_for_rw = 0;

 	/*
 	 * Revalidate the disk zone bitmaps once the block device capacity is
 	 * set on the second revalidate execution during disk scan and if
 	 * something changed when executing a normal revalidate.
 	 */
 	if (sdkp->first_scan) {
 		sdkp->zone_blocks = zone_blocks;
 		sdkp->nr_zones = nr_zones;
 		return 0;
 	}

 	if (sdkp->zone_blocks != zone_blocks ||
 	    sdkp->nr_zones != nr_zones ||
 	    disk->queue->nr_zones != nr_zones) {
 		ret = blk_revalidate_disk_zones(disk);
 		if (ret != 0)
 			goto err;
 		sdkp->zone_blocks = zone_blocks;
 		sdkp->nr_zones = nr_zones;
 	}

 	return 0;

 err:
 	sdkp->capacity = 0;

 	return ret;
 }

 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);
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* 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>
	*/

	#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_do_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
	* @partial: Do partial report
	*
	* For internal use during device validation.
	* Using partial=true can significantly speed up execution of a report zones
	* command because the disk does not have to count all possible report matching
	* zones and will only report the count of zones fitting in the command reply
	* buffer.
	*/
	static int sd_zbc_do_report_zones(struct scsi_disk sdkp, unsigned char buf,
	unsigned int buflen, sector_t lba,
	bool partial)
	{
	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]);
	if (partial)
	cmd[14] = ZBC_REPORT_ZONE_PARTIAL;
	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_report_zones - Disk report zones operation.
	* @disk: The target disk
	* @sector: Start 512B sector of the report
	* @zones: Array of zone descriptors
	* @nr_zones: Number of descriptors in the array
	* @gfp_mask: Memory allocation mask
	*
	* Execute a report zones command on the target disk.
	*/
	int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
	struct blk_zone zones, unsigned int nr_zones,
	gfp_t gfp_mask)
	{
	struct scsi_disk *sdkp = scsi_disk(disk);
	unsigned int i, buflen, nrz = *nr_zones;
	unsigned char *buf;
	size_t offset = 0;
	int ret = 0;

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

	/*
	* Get a reply buffer for the number of requested zones plus a header,
	* without exceeding the device maximum command size. For ATA disks,
	* buffers must be aligned to 512B.
	*/
	buflen = min(queue_max_hw_sectors(disk->queue) << 9,
	roundup((nrz + 1) * 64, 512));
	buf = kmalloc(buflen, gfp_mask);
	if (!buf)
	return -ENOMEM;

	ret = sd_zbc_do_report_zones(sdkp, buf, buflen,
	sectors_to_logical(sdkp->device, sector), true);
	if (ret)
	goto out_free_buf;

	nrz = min(nrz, get_unaligned_be32(&buf[0]) / 64);
	for (i = 0; i < nrz; i++) {
	offset += 64;
	sd_zbc_parse_report(sdkp, buf + offset, zones);
	zones++;
	}

	*nr_zones = nrz;

	out_free_buf:
	kfree(buf);

	return ret;
	}

	/**
	* 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.
	*/
	blk_status_t 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 BLK_STS_IOERR;

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

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

	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 BLK_STS_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:
	break;
	}
	}

	/**
	* sd_zbc_check_zoned_characteristics - Check zoned block device characteristics
	* @sdkp: Target disk
	* @buf: Buffer where to store the VPD page data
	*
	* Read VPD page B6, get information and check that reads are unconstrained.
	*/
	static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
	unsigned char *buf)
	{

	if (scsi_get_vpd_page(sdkp->device, 0xb6, buf, 64)) {
	sd_printk(KERN_NOTICE, sdkp,
	"Read zoned characteristics VPD page 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]);
	}

	/*
	* 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");
	return -ENODEV;
	}

	return 0;
	}

	#define SD_ZBC_BUF_SIZE 131072U

	/**
	* sd_zbc_check_zones - Check the device capacity and zone sizes
	* @sdkp: Target disk
	*
	* Check that the device capacity as reported by READ CAPACITY matches the
	* max_lba value (plus one)of the report zones command reply. Also check that
	* all zones of the device have an equal size, only allowing the last zone of
	* the disk to have a smaller size (runt zone). The zone size must also be a
	* power of two.
	*
	* Returns the zone size in number of blocks upon success or an error code
	* upon failure.
	*/
	static int sd_zbc_check_zones(struct scsi_disk sdkp, u32 zblocks)
	{
	u64 zone_blocks = 0;
	sector_t max_lba, 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 max_lba and the same field */
	ret = sd_zbc_do_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, 0, false);
	if (ret)
	goto out_free;

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

	/*
	* Check same field: for any value other than 0, we know that all zones
	* have the same size.
	*/
	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)) {
	zone_blocks = 0;
	goto out;
	}
	block += this_zone_blocks;
	rec += 64;
	}

	if (block < sdkp->capacity) {
	ret = sd_zbc_do_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE,
	block, true);
	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 = -EFBIG;
	} else {
	*zblocks = zone_blocks;
	ret = 0;
	}

	out_free:
	kfree(buf);

	return ret;
	}

	int sd_zbc_read_zones(struct scsi_disk sdkp, unsigned char buf)
	{
	struct gendisk *disk = sdkp->disk;
	unsigned int nr_zones;
	u32 zone_blocks;
	int ret;

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

	/* Check zoned block device characteristics (unconstrained reads) */
	ret = sd_zbc_check_zoned_characteristics(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.
	*/
	ret = sd_zbc_check_zones(sdkp, &zone_blocks);
	if (ret != 0)
	goto err;

	/* The drive satisfies the kernel restrictions: set it up */
	blk_queue_chunk_sectors(sdkp->disk->queue,
	logical_to_sectors(sdkp->device, zone_blocks));
	nr_zones = round_up(sdkp->capacity, zone_blocks) >> ilog2(zone_blocks);

	/* READ16/WRITE16 is mandatory for ZBC disks */
	sdkp->device->use_16_for_rw = 1;
	sdkp->device->use_10_for_rw = 0;

	/*
	* Revalidate the disk zone bitmaps once the block device capacity is
	* set on the second revalidate execution during disk scan and if
	* something changed when executing a normal revalidate.
	*/
	if (sdkp->first_scan) {
	sdkp->zone_blocks = zone_blocks;
	sdkp->nr_zones = nr_zones;
	return 0;
	}

	if (sdkp->zone_blocks != zone_blocks \|\|
	sdkp->nr_zones != nr_zones \|\|
	disk->queue->nr_zones != nr_zones) {
	ret = blk_revalidate_disk_zones(disk);
	if (ret != 0)
	goto err;
	sdkp->zone_blocks = zone_blocks;
	sdkp->nr_zones = nr_zones;
	}

	return 0;

	err:
	sdkp->capacity = 0;

	return ret;
	}

	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);
	}