xref: /openbmc/linux/drivers/scsi/sd_zbc.c (revision 08283d30)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * SCSI Zoned Block commands
4  *
5  * Copyright (C) 2014-2015 SUSE Linux GmbH
6  * Written by: Hannes Reinecke <hare@suse.de>
7  * Modified by: Damien Le Moal <damien.lemoal@hgst.com>
8  * Modified by: Shaun Tancheff <shaun.tancheff@seagate.com>
9  */
10 
11 #include <linux/blkdev.h>
12 #include <linux/vmalloc.h>
13 #include <linux/sched/mm.h>
14 
15 #include <asm/unaligned.h>
16 
17 #include <scsi/scsi.h>
18 #include <scsi/scsi_cmnd.h>
19 
20 #include "sd.h"
21 
22 /**
23  * sd_zbc_parse_report - Convert a zone descriptor to a struct blk_zone,
24  * @sdkp: The disk the report originated from
25  * @buf: Address of the report zone descriptor
26  * @zone: the destination zone structure
27  *
28  * All LBA sized values are converted to 512B sectors unit.
29  */
30 static void sd_zbc_parse_report(struct scsi_disk *sdkp, u8 *buf,
31 				struct blk_zone *zone)
32 {
33 	struct scsi_device *sdp = sdkp->device;
34 
35 	memset(zone, 0, sizeof(struct blk_zone));
36 
37 	zone->type = buf[0] & 0x0f;
38 	zone->cond = (buf[1] >> 4) & 0xf;
39 	if (buf[1] & 0x01)
40 		zone->reset = 1;
41 	if (buf[1] & 0x02)
42 		zone->non_seq = 1;
43 
44 	zone->len = logical_to_sectors(sdp, get_unaligned_be64(&buf[8]));
45 	zone->start = logical_to_sectors(sdp, get_unaligned_be64(&buf[16]));
46 	zone->wp = logical_to_sectors(sdp, get_unaligned_be64(&buf[24]));
47 	if (zone->type != ZBC_ZONE_TYPE_CONV &&
48 	    zone->cond == ZBC_ZONE_COND_FULL)
49 		zone->wp = zone->start + zone->len;
50 }
51 
52 /**
53  * sd_zbc_do_report_zones - Issue a REPORT ZONES scsi command.
54  * @sdkp: The target disk
55  * @buf: vmalloc-ed buffer to use for the reply
56  * @buflen: the buffer size
57  * @lba: Start LBA of the report
58  * @partial: Do partial report
59  *
60  * For internal use during device validation.
61  * Using partial=true can significantly speed up execution of a report zones
62  * command because the disk does not have to count all possible report matching
63  * zones and will only report the count of zones fitting in the command reply
64  * buffer.
65  */
66 static int sd_zbc_do_report_zones(struct scsi_disk *sdkp, unsigned char *buf,
67 				  unsigned int buflen, sector_t lba,
68 				  bool partial)
69 {
70 	struct scsi_device *sdp = sdkp->device;
71 	const int timeout = sdp->request_queue->rq_timeout;
72 	struct scsi_sense_hdr sshdr;
73 	unsigned char cmd[16];
74 	unsigned int rep_len;
75 	int result;
76 
77 	memset(cmd, 0, 16);
78 	cmd[0] = ZBC_IN;
79 	cmd[1] = ZI_REPORT_ZONES;
80 	put_unaligned_be64(lba, &cmd[2]);
81 	put_unaligned_be32(buflen, &cmd[10]);
82 	if (partial)
83 		cmd[14] = ZBC_REPORT_ZONE_PARTIAL;
84 
85 	result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
86 				  buf, buflen, &sshdr,
87 				  timeout, SD_MAX_RETRIES, NULL);
88 	if (result) {
89 		sd_printk(KERN_ERR, sdkp,
90 			  "REPORT ZONES lba %llu failed with %d/%d\n",
91 			  (unsigned long long)lba,
92 			  host_byte(result), driver_byte(result));
93 		return -EIO;
94 	}
95 
96 	rep_len = get_unaligned_be32(&buf[0]);
97 	if (rep_len < 64) {
98 		sd_printk(KERN_ERR, sdkp,
99 			  "REPORT ZONES report invalid length %u\n",
100 			  rep_len);
101 		return -EIO;
102 	}
103 
104 	return 0;
105 }
106 
107 /*
108  * Maximum number of zones to get with one report zones command.
109  */
110 #define SD_ZBC_REPORT_MAX_ZONES		8192U
111 
112 /**
113  * Allocate a buffer for report zones reply.
114  * @sdkp: The target disk
115  * @nr_zones: Maximum number of zones to report
116  * @buflen: Size of the buffer allocated
117  *
118  * Try to allocate a reply buffer for the number of requested zones.
119  * The size of the buffer allocated may be smaller than requested to
120  * satify the device constraint (max_hw_sectors, max_segments, etc).
121  *
122  * Return the address of the allocated buffer and update @buflen with
123  * the size of the allocated buffer.
124  */
125 static void *sd_zbc_alloc_report_buffer(struct scsi_disk *sdkp,
126 					unsigned int nr_zones, size_t *buflen)
127 {
128 	struct request_queue *q = sdkp->disk->queue;
129 	size_t bufsize;
130 	void *buf;
131 
132 	/*
133 	 * Report zone buffer size should be at most 64B times the number of
134 	 * zones requested plus the 64B reply header, but should be at least
135 	 * SECTOR_SIZE for ATA devices.
136 	 * Make sure that this size does not exceed the hardware capabilities.
137 	 * Furthermore, since the report zone command cannot be split, make
138 	 * sure that the allocated buffer can always be mapped by limiting the
139 	 * number of pages allocated to the HBA max segments limit.
140 	 */
141 	nr_zones = min(nr_zones, SD_ZBC_REPORT_MAX_ZONES);
142 	bufsize = roundup((nr_zones + 1) * 64, 512);
143 	bufsize = min_t(size_t, bufsize,
144 			queue_max_hw_sectors(q) << SECTOR_SHIFT);
145 	bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
146 
147 	buf = vzalloc(bufsize);
148 	if (buf)
149 		*buflen = bufsize;
150 
151 	return buf;
152 }
153 
154 /**
155  * sd_zbc_report_zones - Disk report zones operation.
156  * @disk: The target disk
157  * @sector: Start 512B sector of the report
158  * @zones: Array of zone descriptors
159  * @nr_zones: Number of descriptors in the array
160  *
161  * Execute a report zones command on the target disk.
162  */
163 int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
164 			struct blk_zone *zones, unsigned int *nr_zones)
165 {
166 	struct scsi_disk *sdkp = scsi_disk(disk);
167 	unsigned int i, nrz = *nr_zones;
168 	unsigned char *buf;
169 	size_t buflen = 0, offset = 0;
170 	int ret = 0;
171 
172 	if (!sd_is_zoned(sdkp))
173 		/* Not a zoned device */
174 		return -EOPNOTSUPP;
175 
176 	buf = sd_zbc_alloc_report_buffer(sdkp, nrz, &buflen);
177 	if (!buf)
178 		return -ENOMEM;
179 
180 	ret = sd_zbc_do_report_zones(sdkp, buf, buflen,
181 			sectors_to_logical(sdkp->device, sector), true);
182 	if (ret)
183 		goto out;
184 
185 	nrz = min(nrz, get_unaligned_be32(&buf[0]) / 64);
186 	for (i = 0; i < nrz; i++) {
187 		offset += 64;
188 		sd_zbc_parse_report(sdkp, buf + offset, zones);
189 		zones++;
190 	}
191 
192 	*nr_zones = nrz;
193 
194 out:
195 	kvfree(buf);
196 
197 	return ret;
198 }
199 
200 /**
201  * sd_zbc_zone_sectors - Get the device zone size in number of 512B sectors.
202  * @sdkp: The target disk
203  */
204 static inline sector_t sd_zbc_zone_sectors(struct scsi_disk *sdkp)
205 {
206 	return logical_to_sectors(sdkp->device, sdkp->zone_blocks);
207 }
208 
209 /**
210  * sd_zbc_setup_reset_cmnd - Prepare a RESET WRITE POINTER scsi command.
211  * @cmd: the command to setup
212  * @all: Reset all zones control.
213  *
214  * Called from sd_init_command() for a REQ_OP_ZONE_RESET request.
215  */
216 blk_status_t sd_zbc_setup_reset_cmnd(struct scsi_cmnd *cmd, bool all)
217 {
218 	struct request *rq = cmd->request;
219 	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
220 	sector_t sector = blk_rq_pos(rq);
221 	sector_t block = sectors_to_logical(sdkp->device, sector);
222 
223 	if (!sd_is_zoned(sdkp))
224 		/* Not a zoned device */
225 		return BLK_STS_IOERR;
226 
227 	if (sdkp->device->changed)
228 		return BLK_STS_IOERR;
229 
230 	if (sector & (sd_zbc_zone_sectors(sdkp) - 1))
231 		/* Unaligned request */
232 		return BLK_STS_IOERR;
233 
234 	cmd->cmd_len = 16;
235 	memset(cmd->cmnd, 0, cmd->cmd_len);
236 	cmd->cmnd[0] = ZBC_OUT;
237 	cmd->cmnd[1] = ZO_RESET_WRITE_POINTER;
238 	if (all)
239 		cmd->cmnd[14] = 0x1;
240 	else
241 		put_unaligned_be64(block, &cmd->cmnd[2]);
242 
243 	rq->timeout = SD_TIMEOUT;
244 	cmd->sc_data_direction = DMA_NONE;
245 	cmd->transfersize = 0;
246 	cmd->allowed = 0;
247 
248 	return BLK_STS_OK;
249 }
250 
251 /**
252  * sd_zbc_complete - ZBC command post processing.
253  * @cmd: Completed command
254  * @good_bytes: Command reply bytes
255  * @sshdr: command sense header
256  *
257  * Called from sd_done(). Process report zones reply and handle reset zone
258  * and write commands errors.
259  */
260 void sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
261 		     struct scsi_sense_hdr *sshdr)
262 {
263 	int result = cmd->result;
264 	struct request *rq = cmd->request;
265 
266 	switch (req_op(rq)) {
267 	case REQ_OP_ZONE_RESET:
268 	case REQ_OP_ZONE_RESET_ALL:
269 
270 		if (result &&
271 		    sshdr->sense_key == ILLEGAL_REQUEST &&
272 		    sshdr->asc == 0x24)
273 			/*
274 			 * INVALID FIELD IN CDB error: reset of a conventional
275 			 * zone was attempted. Nothing to worry about, so be
276 			 * quiet about the error.
277 			 */
278 			rq->rq_flags |= RQF_QUIET;
279 		break;
280 
281 	case REQ_OP_WRITE:
282 	case REQ_OP_WRITE_ZEROES:
283 	case REQ_OP_WRITE_SAME:
284 		break;
285 	}
286 }
287 
288 /**
289  * sd_zbc_check_zoned_characteristics - Check zoned block device characteristics
290  * @sdkp: Target disk
291  * @buf: Buffer where to store the VPD page data
292  *
293  * Read VPD page B6, get information and check that reads are unconstrained.
294  */
295 static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
296 					      unsigned char *buf)
297 {
298 
299 	if (scsi_get_vpd_page(sdkp->device, 0xb6, buf, 64)) {
300 		sd_printk(KERN_NOTICE, sdkp,
301 			  "Read zoned characteristics VPD page failed\n");
302 		return -ENODEV;
303 	}
304 
305 	if (sdkp->device->type != TYPE_ZBC) {
306 		/* Host-aware */
307 		sdkp->urswrz = 1;
308 		sdkp->zones_optimal_open = get_unaligned_be32(&buf[8]);
309 		sdkp->zones_optimal_nonseq = get_unaligned_be32(&buf[12]);
310 		sdkp->zones_max_open = 0;
311 	} else {
312 		/* Host-managed */
313 		sdkp->urswrz = buf[4] & 1;
314 		sdkp->zones_optimal_open = 0;
315 		sdkp->zones_optimal_nonseq = 0;
316 		sdkp->zones_max_open = get_unaligned_be32(&buf[16]);
317 	}
318 
319 	/*
320 	 * Check for unconstrained reads: host-managed devices with
321 	 * constrained reads (drives failing read after write pointer)
322 	 * are not supported.
323 	 */
324 	if (!sdkp->urswrz) {
325 		if (sdkp->first_scan)
326 			sd_printk(KERN_NOTICE, sdkp,
327 			  "constrained reads devices are not supported\n");
328 		return -ENODEV;
329 	}
330 
331 	return 0;
332 }
333 
334 /**
335  * sd_zbc_check_zones - Check the device capacity and zone sizes
336  * @sdkp: Target disk
337  *
338  * Check that the device capacity as reported by READ CAPACITY matches the
339  * max_lba value (plus one)of the report zones command reply. Also check that
340  * all zones of the device have an equal size, only allowing the last zone of
341  * the disk to have a smaller size (runt zone). The zone size must also be a
342  * power of two.
343  *
344  * Returns the zone size in number of blocks upon success or an error code
345  * upon failure.
346  */
347 static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
348 {
349 	size_t bufsize, buflen;
350 	unsigned int noio_flag;
351 	u64 zone_blocks = 0;
352 	sector_t max_lba, block = 0;
353 	unsigned char *buf;
354 	unsigned char *rec;
355 	int ret;
356 	u8 same;
357 
358 	/* Do all memory allocations as if GFP_NOIO was specified */
359 	noio_flag = memalloc_noio_save();
360 
361 	/* Get a buffer */
362 	buf = sd_zbc_alloc_report_buffer(sdkp, SD_ZBC_REPORT_MAX_ZONES,
363 					 &bufsize);
364 	if (!buf) {
365 		ret = -ENOMEM;
366 		goto out;
367 	}
368 
369 	/* Do a report zone to get max_lba and the same field */
370 	ret = sd_zbc_do_report_zones(sdkp, buf, bufsize, 0, false);
371 	if (ret)
372 		goto out_free;
373 
374 	if (sdkp->rc_basis == 0) {
375 		/* The max_lba field is the capacity of this device */
376 		max_lba = get_unaligned_be64(&buf[8]);
377 		if (sdkp->capacity != max_lba + 1) {
378 			if (sdkp->first_scan)
379 				sd_printk(KERN_WARNING, sdkp,
380 					"Changing capacity from %llu to max LBA+1 %llu\n",
381 					(unsigned long long)sdkp->capacity,
382 					(unsigned long long)max_lba + 1);
383 			sdkp->capacity = max_lba + 1;
384 		}
385 	}
386 
387 	/*
388 	 * Check same field: for any value other than 0, we know that all zones
389 	 * have the same size.
390 	 */
391 	same = buf[4] & 0x0f;
392 	if (same > 0) {
393 		rec = &buf[64];
394 		zone_blocks = get_unaligned_be64(&rec[8]);
395 		goto out;
396 	}
397 
398 	/*
399 	 * Check the size of all zones: all zones must be of
400 	 * equal size, except the last zone which can be smaller
401 	 * than other zones.
402 	 */
403 	do {
404 
405 		/* Parse REPORT ZONES header */
406 		buflen = min_t(size_t, get_unaligned_be32(&buf[0]) + 64,
407 			       bufsize);
408 		rec = buf + 64;
409 
410 		/* Parse zone descriptors */
411 		while (rec < buf + buflen) {
412 			u64 this_zone_blocks = get_unaligned_be64(&rec[8]);
413 
414 			if (zone_blocks == 0) {
415 				zone_blocks = this_zone_blocks;
416 			} else if (this_zone_blocks != zone_blocks &&
417 				   (block + this_zone_blocks < sdkp->capacity
418 				    || this_zone_blocks > zone_blocks)) {
419 				zone_blocks = 0;
420 				goto out;
421 			}
422 			block += this_zone_blocks;
423 			rec += 64;
424 		}
425 
426 		if (block < sdkp->capacity) {
427 			ret = sd_zbc_do_report_zones(sdkp, buf, bufsize, block,
428 						     true);
429 			if (ret)
430 				goto out_free;
431 		}
432 
433 	} while (block < sdkp->capacity);
434 
435 out:
436 	if (!zone_blocks) {
437 		if (sdkp->first_scan)
438 			sd_printk(KERN_NOTICE, sdkp,
439 				  "Devices with non constant zone "
440 				  "size are not supported\n");
441 		ret = -ENODEV;
442 	} else if (!is_power_of_2(zone_blocks)) {
443 		if (sdkp->first_scan)
444 			sd_printk(KERN_NOTICE, sdkp,
445 				  "Devices with non power of 2 zone "
446 				  "size are not supported\n");
447 		ret = -ENODEV;
448 	} else if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
449 		if (sdkp->first_scan)
450 			sd_printk(KERN_NOTICE, sdkp,
451 				  "Zone size too large\n");
452 		ret = -EFBIG;
453 	} else {
454 		*zblocks = zone_blocks;
455 		ret = 0;
456 	}
457 
458 out_free:
459 	memalloc_noio_restore(noio_flag);
460 	kvfree(buf);
461 
462 	return ret;
463 }
464 
465 int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
466 {
467 	struct gendisk *disk = sdkp->disk;
468 	unsigned int nr_zones;
469 	u32 zone_blocks = 0;
470 	int ret;
471 
472 	if (!sd_is_zoned(sdkp))
473 		/*
474 		 * Device managed or normal SCSI disk,
475 		 * no special handling required
476 		 */
477 		return 0;
478 
479 	/* Check zoned block device characteristics (unconstrained reads) */
480 	ret = sd_zbc_check_zoned_characteristics(sdkp, buf);
481 	if (ret)
482 		goto err;
483 
484 	/*
485 	 * Check zone size: only devices with a constant zone size (except
486 	 * an eventual last runt zone) that is a power of 2 are supported.
487 	 */
488 	ret = sd_zbc_check_zones(sdkp, &zone_blocks);
489 	if (ret != 0)
490 		goto err;
491 
492 	/* The drive satisfies the kernel restrictions: set it up */
493 	blk_queue_chunk_sectors(sdkp->disk->queue,
494 			logical_to_sectors(sdkp->device, zone_blocks));
495 	blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, sdkp->disk->queue);
496 	blk_queue_required_elevator_features(sdkp->disk->queue,
497 					     ELEVATOR_F_ZBD_SEQ_WRITE);
498 	nr_zones = round_up(sdkp->capacity, zone_blocks) >> ilog2(zone_blocks);
499 
500 	/* READ16/WRITE16 is mandatory for ZBC disks */
501 	sdkp->device->use_16_for_rw = 1;
502 	sdkp->device->use_10_for_rw = 0;
503 
504 	/*
505 	 * Revalidate the disk zone bitmaps once the block device capacity is
506 	 * set on the second revalidate execution during disk scan and if
507 	 * something changed when executing a normal revalidate.
508 	 */
509 	if (sdkp->first_scan) {
510 		sdkp->zone_blocks = zone_blocks;
511 		sdkp->nr_zones = nr_zones;
512 		return 0;
513 	}
514 
515 	if (sdkp->zone_blocks != zone_blocks ||
516 	    sdkp->nr_zones != nr_zones ||
517 	    disk->queue->nr_zones != nr_zones) {
518 		ret = blk_revalidate_disk_zones(disk);
519 		if (ret != 0)
520 			goto err;
521 		sdkp->zone_blocks = zone_blocks;
522 		sdkp->nr_zones = nr_zones;
523 	}
524 
525 	return 0;
526 
527 err:
528 	sdkp->capacity = 0;
529 
530 	return ret;
531 }
532 
533 void sd_zbc_print_zones(struct scsi_disk *sdkp)
534 {
535 	if (!sd_is_zoned(sdkp) || !sdkp->capacity)
536 		return;
537 
538 	if (sdkp->capacity & (sdkp->zone_blocks - 1))
539 		sd_printk(KERN_NOTICE, sdkp,
540 			  "%u zones of %u logical blocks + 1 runt zone\n",
541 			  sdkp->nr_zones - 1,
542 			  sdkp->zone_blocks);
543 	else
544 		sd_printk(KERN_NOTICE, sdkp,
545 			  "%u zones of %u logical blocks\n",
546 			  sdkp->nr_zones,
547 			  sdkp->zone_blocks);
548 }
549