summaryrefslogtreecommitdiff
path: root/drivers/scsi/sd_zbc.c
blob: 27793b9f54c06368995a7a97bf5427ec81a052e5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
/*
 * 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_zone_no - Get the number of the zone conataining a sector.
 * @sdkp: The target disk
 * @sector: 512B sector address contained in the zone
 */
static inline unsigned int sd_zbc_zone_no(struct scsi_disk *sdkp,
					  sector_t sector)
{
	return sectors_to_logical(sdkp->device, sector) >> sdkp->zone_shift;
}

/**
 * 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_write_lock_zone - Write lock a sequential zone.
 * @cmd: write command
 *
 * Called from sd_init_cmd() for write requests (standard write, write same or
 * write zeroes operations). If the request target zone is not already locked,
 * the zone is locked and BLKPREP_OK returned, allowing the request to proceed
 * through dispatch in scsi_request_fn(). Otherwise, BLKPREP_DEFER is returned,
 * forcing the request to wait for the zone to be unlocked, that is, for the
 * previously issued write request targeting the same zone to complete.
 *
 * This is called from blk_peek_request() context with the queue lock held and
 * before the request is removed from the scheduler. As a result, multiple
 * contexts executing concurrently scsi_request_fn() cannot result in write
 * sequence reordering as only a single write request per zone is allowed to
 * proceed.
 */
int sd_zbc_write_lock_zone(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 zone_sectors = sd_zbc_zone_sectors(sdkp);
	unsigned int zno = sd_zbc_zone_no(sdkp, sector);

	/*
	 * Note: Checks of the alignment of the write command on
	 * logical blocks is done in sd.c
	 */

	/* Do not allow zone boundaries crossing on host-managed drives */
	if (blk_queue_zoned_model(sdkp->disk->queue) == BLK_ZONED_HM &&
	    (sector & (zone_sectors - 1)) + blk_rq_sectors(rq) > zone_sectors)
		return BLKPREP_KILL;

	/*
	 * Do not issue more than one write at a time per
	 * zone. This solves write ordering problems due to
	 * the unlocking of the request queue in the dispatch
	 * path in the non scsi-mq case.
	 */
	if (sdkp->zones_wlock &&
	    test_and_set_bit(zno, sdkp->zones_wlock))
		return BLKPREP_DEFER;

	WARN_ON_ONCE(cmd->flags & SCMD_ZONE_WRITE_LOCK);
	cmd->flags |= SCMD_ZONE_WRITE_LOCK;

	return BLKPREP_OK;
}

/**
 * sd_zbc_write_unlock_zone - Write unlock a sequential zone.
 * @cmd: write command
 *
 * Called from sd_uninit_cmd(). Unlocking the request target zone will allow
 * dispatching the next write request for the zone.
 */
void sd_zbc_write_unlock_zone(struct scsi_cmnd *cmd)
{
	struct request *rq = cmd->request;
	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);

	if (sdkp->zones_wlock && cmd->flags & SCMD_ZONE_WRITE_LOCK) {
		unsigned int zno = sd_zbc_zone_no(sdkp, blk_rq_pos(rq));
		WARN_ON_ONCE(!test_bit(zno, sdkp->zones_wlock));
		cmd->flags &= ~SCMD_ZONE_WRITE_LOCK;
		clear_bit_unlock(zno, sdkp->zones_wlock);
		smp_mb__after_atomic();
	}
}

/**
 * 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.
 */
static int sd_zbc_check_zone_size(struct scsi_disk *sdkp)
{
	u64 zone_blocks;
	sector_t block = 0;
	unsigned char *buf;
	unsigned char *rec;
	unsigned int buf_len;
	unsigned int list_length;
	int ret;
	u8 same;

	sdkp->zone_blocks = 0;

	/* 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) {
		zone_blocks = 0;
		goto out;
	}

	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) {
			zone_blocks = get_unaligned_be64(&rec[8]);
			if (sdkp->zone_blocks == 0) {
				sdkp->zone_blocks = zone_blocks;
			} else if (zone_blocks != sdkp->zone_blocks &&
				   (block + zone_blocks < sdkp->capacity
				    || zone_blocks > sdkp->zone_blocks)) {
				zone_blocks = 0;
				goto out;
			}
			block += zone_blocks;
			rec += 64;
		}

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

	} while (block < sdkp->capacity);

	zone_blocks = sdkp->zone_blocks;

out:
	kfree(buf);

	if (!zone_blocks) {
		if (sdkp->first_scan)
			sd_printk(KERN_NOTICE, sdkp,
				  "Devices with non constant zone "
				  "size are not supported\n");
		return -ENODEV;
	}

	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");
		return -ENODEV;
	}

	if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
		if (sdkp->first_scan)
			sd_printk(KERN_NOTICE, sdkp,
				  "Zone size too large\n");
		return -ENODEV;
	}

	sdkp->zone_blocks = zone_blocks;
	sdkp->zone_shift = ilog2(zone_blocks);

	return 0;
}

static int sd_zbc_setup(struct scsi_disk *sdkp)
{

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

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

	if (!sdkp->zones_wlock) {
		sdkp->zones_wlock = kcalloc(BITS_TO_LONGS(sdkp->nr_zones),
					    sizeof(unsigned long),
					    GFP_KERNEL);
		if (!sdkp->zones_wlock)
			return -ENOMEM;
	}

	return 0;
}

int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
{
	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.
	 */
	ret = sd_zbc_check_zone_size(sdkp);
	if (ret)
		goto err;

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

	return 0;

err:
	sdkp->capacity = 0;

	return ret;
}

void sd_zbc_remove(struct scsi_disk *sdkp)
{
	kfree(sdkp->zones_wlock);
	sdkp->zones_wlock = NULL;
}

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);
}