1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Functions related to setting various queue properties from drivers
4 */
5#include <linux/kernel.h>
6#include <linux/module.h>
7#include <linux/init.h>
8#include <linux/bio.h>
9#include <linux/blkdev.h>
10#include <linux/pagemap.h>
11#include <linux/backing-dev-defs.h>
12#include <linux/gcd.h>
13#include <linux/lcm.h>
14#include <linux/jiffies.h>
15#include <linux/gfp.h>
16#include <linux/dma-mapping.h>
17
18#include "blk.h"
19#include "blk-rq-qos.h"
20#include "blk-wbt.h"
21
22void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
23{
24 q->rq_timeout = timeout;
25}
26EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
27
28/**
29 * blk_set_default_limits - reset limits to default values
30 * @lim: the queue_limits structure to reset
31 *
32 * Description:
33 * Returns a queue_limit struct to its default state.
34 */
35void blk_set_default_limits(struct queue_limits *lim)
36{
37 lim->max_segments = BLK_MAX_SEGMENTS;
38 lim->max_discard_segments = 1;
39 lim->max_integrity_segments = 0;
40 lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
41 lim->virt_boundary_mask = 0;
42 lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
43 lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
44 lim->max_user_sectors = lim->max_dev_sectors = 0;
45 lim->chunk_sectors = 0;
46 lim->max_write_zeroes_sectors = 0;
47 lim->max_zone_append_sectors = 0;
48 lim->max_discard_sectors = 0;
49 lim->max_hw_discard_sectors = 0;
50 lim->max_secure_erase_sectors = 0;
51 lim->discard_granularity = 0;
52 lim->discard_alignment = 0;
53 lim->discard_misaligned = 0;
54 lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
55 lim->bounce = BLK_BOUNCE_NONE;
56 lim->alignment_offset = 0;
57 lim->io_opt = 0;
58 lim->misaligned = 0;
59 lim->zoned = BLK_ZONED_NONE;
60 lim->zone_write_granularity = 0;
61 lim->dma_alignment = 511;
62}
63
64/**
65 * blk_set_stacking_limits - set default limits for stacking devices
66 * @lim: the queue_limits structure to reset
67 *
68 * Description:
69 * Returns a queue_limit struct to its default state. Should be used
70 * by stacking drivers like DM that have no internal limits.
71 */
72void blk_set_stacking_limits(struct queue_limits *lim)
73{
74 blk_set_default_limits(lim);
75
76 /* Inherit limits from component devices */
77 lim->max_segments = USHRT_MAX;
78 lim->max_discard_segments = USHRT_MAX;
79 lim->max_hw_sectors = UINT_MAX;
80 lim->max_segment_size = UINT_MAX;
81 lim->max_sectors = UINT_MAX;
82 lim->max_dev_sectors = UINT_MAX;
83 lim->max_write_zeroes_sectors = UINT_MAX;
84 lim->max_zone_append_sectors = UINT_MAX;
85}
86EXPORT_SYMBOL(blk_set_stacking_limits);
87
88/**
89 * blk_queue_bounce_limit - set bounce buffer limit for queue
90 * @q: the request queue for the device
91 * @bounce: bounce limit to enforce
92 *
93 * Description:
94 * Force bouncing for ISA DMA ranges or highmem.
95 *
96 * DEPRECATED, don't use in new code.
97 **/
98void blk_queue_bounce_limit(struct request_queue *q, enum blk_bounce bounce)
99{
100 q->limits.bounce = bounce;
101}
102EXPORT_SYMBOL(blk_queue_bounce_limit);
103
104/**
105 * blk_queue_max_hw_sectors - set max sectors for a request for this queue
106 * @q: the request queue for the device
107 * @max_hw_sectors: max hardware sectors in the usual 512b unit
108 *
109 * Description:
110 * Enables a low level driver to set a hard upper limit,
111 * max_hw_sectors, on the size of requests. max_hw_sectors is set by
112 * the device driver based upon the capabilities of the I/O
113 * controller.
114 *
115 * max_dev_sectors is a hard limit imposed by the storage device for
116 * READ/WRITE requests. It is set by the disk driver.
117 *
118 * max_sectors is a soft limit imposed by the block layer for
119 * filesystem type requests. This value can be overridden on a
120 * per-device basis in /sys/block/<device>/queue/max_sectors_kb.
121 * The soft limit can not exceed max_hw_sectors.
122 **/
123void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
124{
125 struct queue_limits *limits = &q->limits;
126 unsigned int max_sectors;
127
128 if ((max_hw_sectors << 9) < PAGE_SIZE) {
129 max_hw_sectors = 1 << (PAGE_SHIFT - 9);
130 printk(KERN_INFO "%s: set to minimum %d\n",
131 __func__, max_hw_sectors);
132 }
133
134 max_hw_sectors = round_down(max_hw_sectors,
135 limits->logical_block_size >> SECTOR_SHIFT);
136 limits->max_hw_sectors = max_hw_sectors;
137
138 max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors);
139
140 if (limits->max_user_sectors)
141 max_sectors = min(max_sectors, limits->max_user_sectors);
142 else
143 max_sectors = min(max_sectors, BLK_DEF_MAX_SECTORS);
144
145 max_sectors = round_down(max_sectors,
146 limits->logical_block_size >> SECTOR_SHIFT);
147 limits->max_sectors = max_sectors;
148
149 if (!q->disk)
150 return;
151 q->disk->bdi->io_pages = max_sectors >> (PAGE_SHIFT - 9);
152}
153EXPORT_SYMBOL(blk_queue_max_hw_sectors);
154
155/**
156 * blk_queue_chunk_sectors - set size of the chunk for this queue
157 * @q: the request queue for the device
158 * @chunk_sectors: chunk sectors in the usual 512b unit
159 *
160 * Description:
161 * If a driver doesn't want IOs to cross a given chunk size, it can set
162 * this limit and prevent merging across chunks. Note that the block layer
163 * must accept a page worth of data at any offset. So if the crossing of
164 * chunks is a hard limitation in the driver, it must still be prepared
165 * to split single page bios.
166 **/
167void blk_queue_chunk_sectors(struct request_queue *q, unsigned int chunk_sectors)
168{
169 q->limits.chunk_sectors = chunk_sectors;
170}
171EXPORT_SYMBOL(blk_queue_chunk_sectors);
172
173/**
174 * blk_queue_max_discard_sectors - set max sectors for a single discard
175 * @q: the request queue for the device
176 * @max_discard_sectors: maximum number of sectors to discard
177 **/
178void blk_queue_max_discard_sectors(struct request_queue *q,
179 unsigned int max_discard_sectors)
180{
181 q->limits.max_hw_discard_sectors = max_discard_sectors;
182 q->limits.max_discard_sectors = max_discard_sectors;
183}
184EXPORT_SYMBOL(blk_queue_max_discard_sectors);
185
186/**
187 * blk_queue_max_secure_erase_sectors - set max sectors for a secure erase
188 * @q: the request queue for the device
189 * @max_sectors: maximum number of sectors to secure_erase
190 **/
191void blk_queue_max_secure_erase_sectors(struct request_queue *q,
192 unsigned int max_sectors)
193{
194 q->limits.max_secure_erase_sectors = max_sectors;
195}
196EXPORT_SYMBOL(blk_queue_max_secure_erase_sectors);
197
198/**
199 * blk_queue_max_write_zeroes_sectors - set max sectors for a single
200 * write zeroes
201 * @q: the request queue for the device
202 * @max_write_zeroes_sectors: maximum number of sectors to write per command
203 **/
204void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
205 unsigned int max_write_zeroes_sectors)
206{
207 q->limits.max_write_zeroes_sectors = max_write_zeroes_sectors;
208}
209EXPORT_SYMBOL(blk_queue_max_write_zeroes_sectors);
210
211/**
212 * blk_queue_max_zone_append_sectors - set max sectors for a single zone append
213 * @q: the request queue for the device
214 * @max_zone_append_sectors: maximum number of sectors to write per command
215 **/
216void blk_queue_max_zone_append_sectors(struct request_queue *q,
217 unsigned int max_zone_append_sectors)
218{
219 unsigned int max_sectors;
220
221 if (WARN_ON(!blk_queue_is_zoned(q)))
222 return;
223
224 max_sectors = min(q->limits.max_hw_sectors, max_zone_append_sectors);
225 max_sectors = min(q->limits.chunk_sectors, max_sectors);
226
227 /*
228 * Signal eventual driver bugs resulting in the max_zone_append sectors limit
229 * being 0 due to a 0 argument, the chunk_sectors limit (zone size) not set,
230 * or the max_hw_sectors limit not set.
231 */
232 WARN_ON(!max_sectors);
233
234 q->limits.max_zone_append_sectors = max_sectors;
235}
236EXPORT_SYMBOL_GPL(blk_queue_max_zone_append_sectors);
237
238/**
239 * blk_queue_max_segments - set max hw segments for a request for this queue
240 * @q: the request queue for the device
241 * @max_segments: max number of segments
242 *
243 * Description:
244 * Enables a low level driver to set an upper limit on the number of
245 * hw data segments in a request.
246 **/
247void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
248{
249 if (!max_segments) {
250 max_segments = 1;
251 printk(KERN_INFO "%s: set to minimum %d\n",
252 __func__, max_segments);
253 }
254
255 q->limits.max_segments = max_segments;
256}
257EXPORT_SYMBOL(blk_queue_max_segments);
258
259/**
260 * blk_queue_max_discard_segments - set max segments for discard requests
261 * @q: the request queue for the device
262 * @max_segments: max number of segments
263 *
264 * Description:
265 * Enables a low level driver to set an upper limit on the number of
266 * segments in a discard request.
267 **/
268void blk_queue_max_discard_segments(struct request_queue *q,
269 unsigned short max_segments)
270{
271 q->limits.max_discard_segments = max_segments;
272}
273EXPORT_SYMBOL_GPL(blk_queue_max_discard_segments);
274
275/**
276 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
277 * @q: the request queue for the device
278 * @max_size: max size of segment in bytes
279 *
280 * Description:
281 * Enables a low level driver to set an upper limit on the size of a
282 * coalesced segment
283 **/
284void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
285{
286 if (max_size < PAGE_SIZE) {
287 max_size = PAGE_SIZE;
288 printk(KERN_INFO "%s: set to minimum %d\n",
289 __func__, max_size);
290 }
291
292 /* see blk_queue_virt_boundary() for the explanation */
293 WARN_ON_ONCE(q->limits.virt_boundary_mask);
294
295 q->limits.max_segment_size = max_size;
296}
297EXPORT_SYMBOL(blk_queue_max_segment_size);
298
299/**
300 * blk_queue_logical_block_size - set logical block size for the queue
301 * @q: the request queue for the device
302 * @size: the logical block size, in bytes
303 *
304 * Description:
305 * This should be set to the lowest possible block size that the
306 * storage device can address. The default of 512 covers most
307 * hardware.
308 **/
309void blk_queue_logical_block_size(struct request_queue *q, unsigned int size)
310{
311 struct queue_limits *limits = &q->limits;
312
313 limits->logical_block_size = size;
314
315 if (limits->physical_block_size < size)
316 limits->physical_block_size = size;
317
318 if (limits->io_min < limits->physical_block_size)
319 limits->io_min = limits->physical_block_size;
320
321 limits->max_hw_sectors =
322 round_down(limits->max_hw_sectors, size >> SECTOR_SHIFT);
323 limits->max_sectors =
324 round_down(limits->max_sectors, size >> SECTOR_SHIFT);
325}
326EXPORT_SYMBOL(blk_queue_logical_block_size);
327
328/**
329 * blk_queue_physical_block_size - set physical block size for the queue
330 * @q: the request queue for the device
331 * @size: the physical block size, in bytes
332 *
333 * Description:
334 * This should be set to the lowest possible sector size that the
335 * hardware can operate on without reverting to read-modify-write
336 * operations.
337 */
338void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
339{
340 q->limits.physical_block_size = size;
341
342 if (q->limits.physical_block_size < q->limits.logical_block_size)
343 q->limits.physical_block_size = q->limits.logical_block_size;
344
345 if (q->limits.io_min < q->limits.physical_block_size)
346 q->limits.io_min = q->limits.physical_block_size;
347}
348EXPORT_SYMBOL(blk_queue_physical_block_size);
349
350/**
351 * blk_queue_zone_write_granularity - set zone write granularity for the queue
352 * @q: the request queue for the zoned device
353 * @size: the zone write granularity size, in bytes
354 *
355 * Description:
356 * This should be set to the lowest possible size allowing to write in
357 * sequential zones of a zoned block device.
358 */
359void blk_queue_zone_write_granularity(struct request_queue *q,
360 unsigned int size)
361{
362 if (WARN_ON_ONCE(!blk_queue_is_zoned(q)))
363 return;
364
365 q->limits.zone_write_granularity = size;
366
367 if (q->limits.zone_write_granularity < q->limits.logical_block_size)
368 q->limits.zone_write_granularity = q->limits.logical_block_size;
369}
370EXPORT_SYMBOL_GPL(blk_queue_zone_write_granularity);
371
372/**
373 * blk_queue_alignment_offset - set physical block alignment offset
374 * @q: the request queue for the device
375 * @offset: alignment offset in bytes
376 *
377 * Description:
378 * Some devices are naturally misaligned to compensate for things like
379 * the legacy DOS partition table 63-sector offset. Low-level drivers
380 * should call this function for devices whose first sector is not
381 * naturally aligned.
382 */
383void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
384{
385 q->limits.alignment_offset =
386 offset & (q->limits.physical_block_size - 1);
387 q->limits.misaligned = 0;
388}
389EXPORT_SYMBOL(blk_queue_alignment_offset);
390
391void disk_update_readahead(struct gendisk *disk)
392{
393 struct request_queue *q = disk->queue;
394
395 /*
396 * For read-ahead of large files to be effective, we need to read ahead
397 * at least twice the optimal I/O size.
398 */
399 disk->bdi->ra_pages =
400 max(queue_io_opt(q) * 2 / PAGE_SIZE, VM_READAHEAD_PAGES);
401 disk->bdi->io_pages = queue_max_sectors(q) >> (PAGE_SHIFT - 9);
402}
403EXPORT_SYMBOL_GPL(disk_update_readahead);
404
405/**
406 * blk_limits_io_min - set minimum request size for a device
407 * @limits: the queue limits
408 * @min: smallest I/O size in bytes
409 *
410 * Description:
411 * Some devices have an internal block size bigger than the reported
412 * hardware sector size. This function can be used to signal the
413 * smallest I/O the device can perform without incurring a performance
414 * penalty.
415 */
416void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
417{
418 limits->io_min = min;
419
420 if (limits->io_min < limits->logical_block_size)
421 limits->io_min = limits->logical_block_size;
422
423 if (limits->io_min < limits->physical_block_size)
424 limits->io_min = limits->physical_block_size;
425}
426EXPORT_SYMBOL(blk_limits_io_min);
427
428/**
429 * blk_queue_io_min - set minimum request size for the queue
430 * @q: the request queue for the device
431 * @min: smallest I/O size in bytes
432 *
433 * Description:
434 * Storage devices may report a granularity or preferred minimum I/O
435 * size which is the smallest request the device can perform without
436 * incurring a performance penalty. For disk drives this is often the
437 * physical block size. For RAID arrays it is often the stripe chunk
438 * size. A properly aligned multiple of minimum_io_size is the
439 * preferred request size for workloads where a high number of I/O
440 * operations is desired.
441 */
442void blk_queue_io_min(struct request_queue *q, unsigned int min)
443{
444 blk_limits_io_min(&q->limits, min);
445}
446EXPORT_SYMBOL(blk_queue_io_min);
447
448/**
449 * blk_limits_io_opt - set optimal request size for a device
450 * @limits: the queue limits
451 * @opt: smallest I/O size in bytes
452 *
453 * Description:
454 * Storage devices may report an optimal I/O size, which is the
455 * device's preferred unit for sustained I/O. This is rarely reported
456 * for disk drives. For RAID arrays it is usually the stripe width or
457 * the internal track size. A properly aligned multiple of
458 * optimal_io_size is the preferred request size for workloads where
459 * sustained throughput is desired.
460 */
461void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
462{
463 limits->io_opt = opt;
464}
465EXPORT_SYMBOL(blk_limits_io_opt);
466
467/**
468 * blk_queue_io_opt - set optimal request size for the queue
469 * @q: the request queue for the device
470 * @opt: optimal request size in bytes
471 *
472 * Description:
473 * Storage devices may report an optimal I/O size, which is the
474 * device's preferred unit for sustained I/O. This is rarely reported
475 * for disk drives. For RAID arrays it is usually the stripe width or
476 * the internal track size. A properly aligned multiple of
477 * optimal_io_size is the preferred request size for workloads where
478 * sustained throughput is desired.
479 */
480void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
481{
482 blk_limits_io_opt(&q->limits, opt);
483 if (!q->disk)
484 return;
485 q->disk->bdi->ra_pages =
486 max(queue_io_opt(q) * 2 / PAGE_SIZE, VM_READAHEAD_PAGES);
487}
488EXPORT_SYMBOL(blk_queue_io_opt);
489
490static int queue_limit_alignment_offset(const struct queue_limits *lim,
491 sector_t sector)
492{
493 unsigned int granularity = max(lim->physical_block_size, lim->io_min);
494 unsigned int alignment = sector_div(sector, granularity >> SECTOR_SHIFT)
495 << SECTOR_SHIFT;
496
497 return (granularity + lim->alignment_offset - alignment) % granularity;
498}
499
500static unsigned int queue_limit_discard_alignment(
501 const struct queue_limits *lim, sector_t sector)
502{
503 unsigned int alignment, granularity, offset;
504
505 if (!lim->max_discard_sectors)
506 return 0;
507
508 /* Why are these in bytes, not sectors? */
509 alignment = lim->discard_alignment >> SECTOR_SHIFT;
510 granularity = lim->discard_granularity >> SECTOR_SHIFT;
511 if (!granularity)
512 return 0;
513
514 /* Offset of the partition start in 'granularity' sectors */
515 offset = sector_div(sector, granularity);
516
517 /* And why do we do this modulus *again* in blkdev_issue_discard()? */
518 offset = (granularity + alignment - offset) % granularity;
519
520 /* Turn it back into bytes, gaah */
521 return offset << SECTOR_SHIFT;
522}
523
524static unsigned int blk_round_down_sectors(unsigned int sectors, unsigned int lbs)
525{
526 sectors = round_down(sectors, lbs >> SECTOR_SHIFT);
527 if (sectors < PAGE_SIZE >> SECTOR_SHIFT)
528 sectors = PAGE_SIZE >> SECTOR_SHIFT;
529 return sectors;
530}
531
532/**
533 * blk_stack_limits - adjust queue_limits for stacked devices
534 * @t: the stacking driver limits (top device)
535 * @b: the underlying queue limits (bottom, component device)
536 * @start: first data sector within component device
537 *
538 * Description:
539 * This function is used by stacking drivers like MD and DM to ensure
540 * that all component devices have compatible block sizes and
541 * alignments. The stacking driver must provide a queue_limits
542 * struct (top) and then iteratively call the stacking function for
543 * all component (bottom) devices. The stacking function will
544 * attempt to combine the values and ensure proper alignment.
545 *
546 * Returns 0 if the top and bottom queue_limits are compatible. The
547 * top device's block sizes and alignment offsets may be adjusted to
548 * ensure alignment with the bottom device. If no compatible sizes
549 * and alignments exist, -1 is returned and the resulting top
550 * queue_limits will have the misaligned flag set to indicate that
551 * the alignment_offset is undefined.
552 */
553int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
554 sector_t start)
555{
556 unsigned int top, bottom, alignment, ret = 0;
557
558 t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
559 t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
560 t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_sectors);
561 t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors,
562 b->max_write_zeroes_sectors);
563 t->max_zone_append_sectors = min(t->max_zone_append_sectors,
564 b->max_zone_append_sectors);
565 t->bounce = max(t->bounce, b->bounce);
566
567 t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
568 b->seg_boundary_mask);
569 t->virt_boundary_mask = min_not_zero(t->virt_boundary_mask,
570 b->virt_boundary_mask);
571
572 t->max_segments = min_not_zero(t->max_segments, b->max_segments);
573 t->max_discard_segments = min_not_zero(t->max_discard_segments,
574 b->max_discard_segments);
575 t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
576 b->max_integrity_segments);
577
578 t->max_segment_size = min_not_zero(t->max_segment_size,
579 b->max_segment_size);
580
581 t->misaligned |= b->misaligned;
582
583 alignment = queue_limit_alignment_offset(lim: b, sector: start);
584
585 /* Bottom device has different alignment. Check that it is
586 * compatible with the current top alignment.
587 */
588 if (t->alignment_offset != alignment) {
589
590 top = max(t->physical_block_size, t->io_min)
591 + t->alignment_offset;
592 bottom = max(b->physical_block_size, b->io_min) + alignment;
593
594 /* Verify that top and bottom intervals line up */
595 if (max(top, bottom) % min(top, bottom)) {
596 t->misaligned = 1;
597 ret = -1;
598 }
599 }
600
601 t->logical_block_size = max(t->logical_block_size,
602 b->logical_block_size);
603
604 t->physical_block_size = max(t->physical_block_size,
605 b->physical_block_size);
606
607 t->io_min = max(t->io_min, b->io_min);
608 t->io_opt = lcm_not_zero(a: t->io_opt, b: b->io_opt);
609 t->dma_alignment = max(t->dma_alignment, b->dma_alignment);
610
611 /* Set non-power-of-2 compatible chunk_sectors boundary */
612 if (b->chunk_sectors)
613 t->chunk_sectors = gcd(a: t->chunk_sectors, b: b->chunk_sectors);
614
615 /* Physical block size a multiple of the logical block size? */
616 if (t->physical_block_size & (t->logical_block_size - 1)) {
617 t->physical_block_size = t->logical_block_size;
618 t->misaligned = 1;
619 ret = -1;
620 }
621
622 /* Minimum I/O a multiple of the physical block size? */
623 if (t->io_min & (t->physical_block_size - 1)) {
624 t->io_min = t->physical_block_size;
625 t->misaligned = 1;
626 ret = -1;
627 }
628
629 /* Optimal I/O a multiple of the physical block size? */
630 if (t->io_opt & (t->physical_block_size - 1)) {
631 t->io_opt = 0;
632 t->misaligned = 1;
633 ret = -1;
634 }
635
636 /* chunk_sectors a multiple of the physical block size? */
637 if ((t->chunk_sectors << 9) & (t->physical_block_size - 1)) {
638 t->chunk_sectors = 0;
639 t->misaligned = 1;
640 ret = -1;
641 }
642
643 t->raid_partial_stripes_expensive =
644 max(t->raid_partial_stripes_expensive,
645 b->raid_partial_stripes_expensive);
646
647 /* Find lowest common alignment_offset */
648 t->alignment_offset = lcm_not_zero(a: t->alignment_offset, b: alignment)
649 % max(t->physical_block_size, t->io_min);
650
651 /* Verify that new alignment_offset is on a logical block boundary */
652 if (t->alignment_offset & (t->logical_block_size - 1)) {
653 t->misaligned = 1;
654 ret = -1;
655 }
656
657 t->max_sectors = blk_round_down_sectors(sectors: t->max_sectors, lbs: t->logical_block_size);
658 t->max_hw_sectors = blk_round_down_sectors(sectors: t->max_hw_sectors, lbs: t->logical_block_size);
659 t->max_dev_sectors = blk_round_down_sectors(sectors: t->max_dev_sectors, lbs: t->logical_block_size);
660
661 /* Discard alignment and granularity */
662 if (b->discard_granularity) {
663 alignment = queue_limit_discard_alignment(lim: b, sector: start);
664
665 if (t->discard_granularity != 0 &&
666 t->discard_alignment != alignment) {
667 top = t->discard_granularity + t->discard_alignment;
668 bottom = b->discard_granularity + alignment;
669
670 /* Verify that top and bottom intervals line up */
671 if ((max(top, bottom) % min(top, bottom)) != 0)
672 t->discard_misaligned = 1;
673 }
674
675 t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
676 b->max_discard_sectors);
677 t->max_hw_discard_sectors = min_not_zero(t->max_hw_discard_sectors,
678 b->max_hw_discard_sectors);
679 t->discard_granularity = max(t->discard_granularity,
680 b->discard_granularity);
681 t->discard_alignment = lcm_not_zero(a: t->discard_alignment, b: alignment) %
682 t->discard_granularity;
683 }
684 t->max_secure_erase_sectors = min_not_zero(t->max_secure_erase_sectors,
685 b->max_secure_erase_sectors);
686 t->zone_write_granularity = max(t->zone_write_granularity,
687 b->zone_write_granularity);
688 t->zoned = max(t->zoned, b->zoned);
689 return ret;
690}
691EXPORT_SYMBOL(blk_stack_limits);
692
693/**
694 * disk_stack_limits - adjust queue limits for stacked drivers
695 * @disk: MD/DM gendisk (top)
696 * @bdev: the underlying block device (bottom)
697 * @offset: offset to beginning of data within component device
698 *
699 * Description:
700 * Merges the limits for a top level gendisk and a bottom level
701 * block_device.
702 */
703void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
704 sector_t offset)
705{
706 struct request_queue *t = disk->queue;
707
708 if (blk_stack_limits(&t->limits, &bdev_get_queue(bdev)->limits,
709 get_start_sect(bdev) + (offset >> 9)) < 0)
710 pr_notice("%s: Warning: Device %pg is misaligned\n",
711 disk->disk_name, bdev);
712
713 disk_update_readahead(disk);
714}
715EXPORT_SYMBOL(disk_stack_limits);
716
717/**
718 * blk_queue_update_dma_pad - update pad mask
719 * @q: the request queue for the device
720 * @mask: pad mask
721 *
722 * Update dma pad mask.
723 *
724 * Appending pad buffer to a request modifies the last entry of a
725 * scatter list such that it includes the pad buffer.
726 **/
727void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask)
728{
729 if (mask > q->dma_pad_mask)
730 q->dma_pad_mask = mask;
731}
732EXPORT_SYMBOL(blk_queue_update_dma_pad);
733
734/**
735 * blk_queue_segment_boundary - set boundary rules for segment merging
736 * @q: the request queue for the device
737 * @mask: the memory boundary mask
738 **/
739void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
740{
741 if (mask < PAGE_SIZE - 1) {
742 mask = PAGE_SIZE - 1;
743 printk(KERN_INFO "%s: set to minimum %lx\n",
744 __func__, mask);
745 }
746
747 q->limits.seg_boundary_mask = mask;
748}
749EXPORT_SYMBOL(blk_queue_segment_boundary);
750
751/**
752 * blk_queue_virt_boundary - set boundary rules for bio merging
753 * @q: the request queue for the device
754 * @mask: the memory boundary mask
755 **/
756void blk_queue_virt_boundary(struct request_queue *q, unsigned long mask)
757{
758 q->limits.virt_boundary_mask = mask;
759
760 /*
761 * Devices that require a virtual boundary do not support scatter/gather
762 * I/O natively, but instead require a descriptor list entry for each
763 * page (which might not be idential to the Linux PAGE_SIZE). Because
764 * of that they are not limited by our notion of "segment size".
765 */
766 if (mask)
767 q->limits.max_segment_size = UINT_MAX;
768}
769EXPORT_SYMBOL(blk_queue_virt_boundary);
770
771/**
772 * blk_queue_dma_alignment - set dma length and memory alignment
773 * @q: the request queue for the device
774 * @mask: alignment mask
775 *
776 * description:
777 * set required memory and length alignment for direct dma transactions.
778 * this is used when building direct io requests for the queue.
779 *
780 **/
781void blk_queue_dma_alignment(struct request_queue *q, int mask)
782{
783 q->limits.dma_alignment = mask;
784}
785EXPORT_SYMBOL(blk_queue_dma_alignment);
786
787/**
788 * blk_queue_update_dma_alignment - update dma length and memory alignment
789 * @q: the request queue for the device
790 * @mask: alignment mask
791 *
792 * description:
793 * update required memory and length alignment for direct dma transactions.
794 * If the requested alignment is larger than the current alignment, then
795 * the current queue alignment is updated to the new value, otherwise it
796 * is left alone. The design of this is to allow multiple objects
797 * (driver, device, transport etc) to set their respective
798 * alignments without having them interfere.
799 *
800 **/
801void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
802{
803 BUG_ON(mask > PAGE_SIZE);
804
805 if (mask > q->limits.dma_alignment)
806 q->limits.dma_alignment = mask;
807}
808EXPORT_SYMBOL(blk_queue_update_dma_alignment);
809
810/**
811 * blk_set_queue_depth - tell the block layer about the device queue depth
812 * @q: the request queue for the device
813 * @depth: queue depth
814 *
815 */
816void blk_set_queue_depth(struct request_queue *q, unsigned int depth)
817{
818 q->queue_depth = depth;
819 rq_qos_queue_depth_changed(q);
820}
821EXPORT_SYMBOL(blk_set_queue_depth);
822
823/**
824 * blk_queue_write_cache - configure queue's write cache
825 * @q: the request queue for the device
826 * @wc: write back cache on or off
827 * @fua: device supports FUA writes, if true
828 *
829 * Tell the block layer about the write cache of @q.
830 */
831void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
832{
833 if (wc) {
834 blk_queue_flag_set(QUEUE_FLAG_HW_WC, q);
835 blk_queue_flag_set(QUEUE_FLAG_WC, q);
836 } else {
837 blk_queue_flag_clear(QUEUE_FLAG_HW_WC, q);
838 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
839 }
840 if (fua)
841 blk_queue_flag_set(QUEUE_FLAG_FUA, q);
842 else
843 blk_queue_flag_clear(QUEUE_FLAG_FUA, q);
844
845 wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
846}
847EXPORT_SYMBOL_GPL(blk_queue_write_cache);
848
849/**
850 * blk_queue_required_elevator_features - Set a queue required elevator features
851 * @q: the request queue for the target device
852 * @features: Required elevator features OR'ed together
853 *
854 * Tell the block layer that for the device controlled through @q, only the
855 * only elevators that can be used are those that implement at least the set of
856 * features specified by @features.
857 */
858void blk_queue_required_elevator_features(struct request_queue *q,
859 unsigned int features)
860{
861 q->required_elevator_features = features;
862}
863EXPORT_SYMBOL_GPL(blk_queue_required_elevator_features);
864
865/**
866 * blk_queue_can_use_dma_map_merging - configure queue for merging segments.
867 * @q: the request queue for the device
868 * @dev: the device pointer for dma
869 *
870 * Tell the block layer about merging the segments by dma map of @q.
871 */
872bool blk_queue_can_use_dma_map_merging(struct request_queue *q,
873 struct device *dev)
874{
875 unsigned long boundary = dma_get_merge_boundary(dev);
876
877 if (!boundary)
878 return false;
879
880 /* No need to update max_segment_size. see blk_queue_virt_boundary() */
881 blk_queue_virt_boundary(q, boundary);
882
883 return true;
884}
885EXPORT_SYMBOL_GPL(blk_queue_can_use_dma_map_merging);
886
887static bool disk_has_partitions(struct gendisk *disk)
888{
889 unsigned long idx;
890 struct block_device *part;
891 bool ret = false;
892
893 rcu_read_lock();
894 xa_for_each(&disk->part_tbl, idx, part) {
895 if (bdev_is_partition(bdev: part)) {
896 ret = true;
897 break;
898 }
899 }
900 rcu_read_unlock();
901
902 return ret;
903}
904
905/**
906 * disk_set_zoned - configure the zoned model for a disk
907 * @disk: the gendisk of the queue to configure
908 * @model: the zoned model to set
909 *
910 * Set the zoned model of @disk to @model.
911 *
912 * When @model is BLK_ZONED_HM (host managed), this should be called only
913 * if zoned block device support is enabled (CONFIG_BLK_DEV_ZONED option).
914 * If @model specifies BLK_ZONED_HA (host aware), the effective model used
915 * depends on CONFIG_BLK_DEV_ZONED settings and on the existence of partitions
916 * on the disk.
917 */
918void disk_set_zoned(struct gendisk *disk, enum blk_zoned_model model)
919{
920 struct request_queue *q = disk->queue;
921 unsigned int old_model = q->limits.zoned;
922
923 switch (model) {
924 case BLK_ZONED_HM:
925 /*
926 * Host managed devices are supported only if
927 * CONFIG_BLK_DEV_ZONED is enabled.
928 */
929 WARN_ON_ONCE(!IS_ENABLED(CONFIG_BLK_DEV_ZONED));
930 break;
931 case BLK_ZONED_HA:
932 /*
933 * Host aware devices can be treated either as regular block
934 * devices (similar to drive managed devices) or as zoned block
935 * devices to take advantage of the zone command set, similarly
936 * to host managed devices. We try the latter if there are no
937 * partitions and zoned block device support is enabled, else
938 * we do nothing special as far as the block layer is concerned.
939 */
940 if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) ||
941 disk_has_partitions(disk))
942 model = BLK_ZONED_NONE;
943 break;
944 case BLK_ZONED_NONE:
945 default:
946 if (WARN_ON_ONCE(model != BLK_ZONED_NONE))
947 model = BLK_ZONED_NONE;
948 break;
949 }
950
951 q->limits.zoned = model;
952 if (model != BLK_ZONED_NONE) {
953 /*
954 * Set the zone write granularity to the device logical block
955 * size by default. The driver can change this value if needed.
956 */
957 blk_queue_zone_write_granularity(q,
958 queue_logical_block_size(q));
959 } else if (old_model != BLK_ZONED_NONE) {
960 disk_clear_zone_settings(disk);
961 }
962}
963EXPORT_SYMBOL_GPL(disk_set_zoned);
964
965int bdev_alignment_offset(struct block_device *bdev)
966{
967 struct request_queue *q = bdev_get_queue(bdev);
968
969 if (q->limits.misaligned)
970 return -1;
971 if (bdev_is_partition(bdev))
972 return queue_limit_alignment_offset(lim: &q->limits,
973 sector: bdev->bd_start_sect);
974 return q->limits.alignment_offset;
975}
976EXPORT_SYMBOL_GPL(bdev_alignment_offset);
977
978unsigned int bdev_discard_alignment(struct block_device *bdev)
979{
980 struct request_queue *q = bdev_get_queue(bdev);
981
982 if (bdev_is_partition(bdev))
983 return queue_limit_discard_alignment(lim: &q->limits,
984 sector: bdev->bd_start_sect);
985 return q->limits.discard_alignment;
986}
987EXPORT_SYMBOL_GPL(bdev_discard_alignment);
988

source code of linux/block/blk-settings.c