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1/*
2 * Functions related to setting various queue properties from drivers
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/init.h>
7#include <linux/bio.h>
8#include <linux/blkdev.h>
9#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
10#include <linux/gcd.h>
11#include <linux/lcm.h>
12#include <linux/jiffies.h>
13#include <linux/gfp.h>
14
15#include "blk.h"
16
17unsigned long blk_max_low_pfn;
18EXPORT_SYMBOL(blk_max_low_pfn);
19
20unsigned long blk_max_pfn;
21
22/**
23 * blk_queue_prep_rq - set a prepare_request function for queue
24 * @q: queue
25 * @pfn: prepare_request function
26 *
27 * It's possible for a queue to register a prepare_request callback which
28 * is invoked before the request is handed to the request_fn. The goal of
29 * the function is to prepare a request for I/O, it can be used to build a
30 * cdb from the request data for instance.
31 *
32 */
33void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
34{
35 q->prep_rq_fn = pfn;
36}
37EXPORT_SYMBOL(blk_queue_prep_rq);
38
39/**
40 * blk_queue_unprep_rq - set an unprepare_request function for queue
41 * @q: queue
42 * @ufn: unprepare_request function
43 *
44 * It's possible for a queue to register an unprepare_request callback
45 * which is invoked before the request is finally completed. The goal
46 * of the function is to deallocate any data that was allocated in the
47 * prepare_request callback.
48 *
49 */
50void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn)
51{
52 q->unprep_rq_fn = ufn;
53}
54EXPORT_SYMBOL(blk_queue_unprep_rq);
55
56/**
57 * blk_queue_merge_bvec - set a merge_bvec function for queue
58 * @q: queue
59 * @mbfn: merge_bvec_fn
60 *
61 * Usually queues have static limitations on the max sectors or segments that
62 * we can put in a request. Stacking drivers may have some settings that
63 * are dynamic, and thus we have to query the queue whether it is ok to
64 * add a new bio_vec to a bio at a given offset or not. If the block device
65 * has such limitations, it needs to register a merge_bvec_fn to control
66 * the size of bio's sent to it. Note that a block device *must* allow a
67 * single page to be added to an empty bio. The block device driver may want
68 * to use the bio_split() function to deal with these bio's. By default
69 * no merge_bvec_fn is defined for a queue, and only the fixed limits are
70 * honored.
71 */
72void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
73{
74 q->merge_bvec_fn = mbfn;
75}
76EXPORT_SYMBOL(blk_queue_merge_bvec);
77
78void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
79{
80 q->softirq_done_fn = fn;
81}
82EXPORT_SYMBOL(blk_queue_softirq_done);
83
84void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
85{
86 q->rq_timeout = timeout;
87}
88EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
89
90void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn)
91{
92 q->rq_timed_out_fn = fn;
93}
94EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out);
95
96void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn)
97{
98 q->lld_busy_fn = fn;
99}
100EXPORT_SYMBOL_GPL(blk_queue_lld_busy);
101
102/**
103 * blk_set_default_limits - reset limits to default values
104 * @lim: the queue_limits structure to reset
105 *
106 * Description:
107 * Returns a queue_limit struct to its default state.
108 */
109void blk_set_default_limits(struct queue_limits *lim)
110{
111 lim->max_segments = BLK_MAX_SEGMENTS;
112 lim->max_integrity_segments = 0;
113 lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
114 lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
115 lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
116 lim->max_write_same_sectors = 0;
117 lim->max_discard_sectors = 0;
118 lim->discard_granularity = 0;
119 lim->discard_alignment = 0;
120 lim->discard_misaligned = 0;
121 lim->discard_zeroes_data = 0;
122 lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
123 lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
124 lim->alignment_offset = 0;
125 lim->io_opt = 0;
126 lim->misaligned = 0;
127 lim->cluster = 1;
128}
129EXPORT_SYMBOL(blk_set_default_limits);
130
131/**
132 * blk_set_stacking_limits - set default limits for stacking devices
133 * @lim: the queue_limits structure to reset
134 *
135 * Description:
136 * Returns a queue_limit struct to its default state. Should be used
137 * by stacking drivers like DM that have no internal limits.
138 */
139void blk_set_stacking_limits(struct queue_limits *lim)
140{
141 blk_set_default_limits(lim);
142
143 /* Inherit limits from component devices */
144 lim->discard_zeroes_data = 1;
145 lim->max_segments = USHRT_MAX;
146 lim->max_hw_sectors = UINT_MAX;
147 lim->max_segment_size = UINT_MAX;
148 lim->max_sectors = UINT_MAX;
149 lim->max_write_same_sectors = UINT_MAX;
150}
151EXPORT_SYMBOL(blk_set_stacking_limits);
152
153/**
154 * blk_queue_make_request - define an alternate make_request function for a device
155 * @q: the request queue for the device to be affected
156 * @mfn: the alternate make_request function
157 *
158 * Description:
159 * The normal way for &struct bios to be passed to a device
160 * driver is for them to be collected into requests on a request
161 * queue, and then to allow the device driver to select requests
162 * off that queue when it is ready. This works well for many block
163 * devices. However some block devices (typically virtual devices
164 * such as md or lvm) do not benefit from the processing on the
165 * request queue, and are served best by having the requests passed
166 * directly to them. This can be achieved by providing a function
167 * to blk_queue_make_request().
168 *
169 * Caveat:
170 * The driver that does this *must* be able to deal appropriately
171 * with buffers in "highmemory". This can be accomplished by either calling
172 * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
173 * blk_queue_bounce() to create a buffer in normal memory.
174 **/
175void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
176{
177 /*
178 * set defaults
179 */
180 q->nr_requests = BLKDEV_MAX_RQ;
181
182 q->make_request_fn = mfn;
183 blk_queue_dma_alignment(q, 511);
184 blk_queue_congestion_threshold(q);
185 q->nr_batching = BLK_BATCH_REQ;
186
187 blk_set_default_limits(&q->limits);
188
189 /*
190 * by default assume old behaviour and bounce for any highmem page
191 */
192 blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
193}
194EXPORT_SYMBOL(blk_queue_make_request);
195
196/**
197 * blk_queue_bounce_limit - set bounce buffer limit for queue
198 * @q: the request queue for the device
199 * @max_addr: the maximum address the device can handle
200 *
201 * Description:
202 * Different hardware can have different requirements as to what pages
203 * it can do I/O directly to. A low level driver can call
204 * blk_queue_bounce_limit to have lower memory pages allocated as bounce
205 * buffers for doing I/O to pages residing above @max_addr.
206 **/
207void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr)
208{
209 unsigned long b_pfn = max_addr >> PAGE_SHIFT;
210 int dma = 0;
211
212 q->bounce_gfp = GFP_NOIO;
213#if BITS_PER_LONG == 64
214 /*
215 * Assume anything <= 4GB can be handled by IOMMU. Actually
216 * some IOMMUs can handle everything, but I don't know of a
217 * way to test this here.
218 */
219 if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
220 dma = 1;
221 q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
222#else
223 if (b_pfn < blk_max_low_pfn)
224 dma = 1;
225 q->limits.bounce_pfn = b_pfn;
226#endif
227 if (dma) {
228 init_emergency_isa_pool();
229 q->bounce_gfp = GFP_NOIO | GFP_DMA;
230 q->limits.bounce_pfn = b_pfn;
231 }
232}
233EXPORT_SYMBOL(blk_queue_bounce_limit);
234
235/**
236 * blk_limits_max_hw_sectors - set hard and soft limit of max sectors for request
237 * @limits: the queue limits
238 * @max_hw_sectors: max hardware sectors in the usual 512b unit
239 *
240 * Description:
241 * Enables a low level driver to set a hard upper limit,
242 * max_hw_sectors, on the size of requests. max_hw_sectors is set by
243 * the device driver based upon the combined capabilities of I/O
244 * controller and storage device.
245 *
246 * max_sectors is a soft limit imposed by the block layer for
247 * filesystem type requests. This value can be overridden on a
248 * per-device basis in /sys/block/<device>/queue/max_sectors_kb.
249 * The soft limit can not exceed max_hw_sectors.
250 **/
251void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_sectors)
252{
253 if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) {
254 max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
255 printk(KERN_INFO "%s: set to minimum %d\n",
256 __func__, max_hw_sectors);
257 }
258
259 limits->max_hw_sectors = max_hw_sectors;
260 limits->max_sectors = min_t(unsigned int, max_hw_sectors,
261 BLK_DEF_MAX_SECTORS);
262}
263EXPORT_SYMBOL(blk_limits_max_hw_sectors);
264
265/**
266 * blk_queue_max_hw_sectors - set max sectors for a request for this queue
267 * @q: the request queue for the device
268 * @max_hw_sectors: max hardware sectors in the usual 512b unit
269 *
270 * Description:
271 * See description for blk_limits_max_hw_sectors().
272 **/
273void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
274{
275 blk_limits_max_hw_sectors(&q->limits, max_hw_sectors);
276}
277EXPORT_SYMBOL(blk_queue_max_hw_sectors);
278
279/**
280 * blk_queue_max_discard_sectors - set max sectors for a single discard
281 * @q: the request queue for the device
282 * @max_discard_sectors: maximum number of sectors to discard
283 **/
284void blk_queue_max_discard_sectors(struct request_queue *q,
285 unsigned int max_discard_sectors)
286{
287 q->limits.max_discard_sectors = max_discard_sectors;
288}
289EXPORT_SYMBOL(blk_queue_max_discard_sectors);
290
291/**
292 * blk_queue_max_write_same_sectors - set max sectors for a single write same
293 * @q: the request queue for the device
294 * @max_write_same_sectors: maximum number of sectors to write per command
295 **/
296void blk_queue_max_write_same_sectors(struct request_queue *q,
297 unsigned int max_write_same_sectors)
298{
299 q->limits.max_write_same_sectors = max_write_same_sectors;
300}
301EXPORT_SYMBOL(blk_queue_max_write_same_sectors);
302
303/**
304 * blk_queue_max_segments - set max hw segments for a request for this queue
305 * @q: the request queue for the device
306 * @max_segments: max number of segments
307 *
308 * Description:
309 * Enables a low level driver to set an upper limit on the number of
310 * hw data segments in a request.
311 **/
312void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
313{
314 if (!max_segments) {
315 max_segments = 1;
316 printk(KERN_INFO "%s: set to minimum %d\n",
317 __func__, max_segments);
318 }
319
320 q->limits.max_segments = max_segments;
321}
322EXPORT_SYMBOL(blk_queue_max_segments);
323
324/**
325 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
326 * @q: the request queue for the device
327 * @max_size: max size of segment in bytes
328 *
329 * Description:
330 * Enables a low level driver to set an upper limit on the size of a
331 * coalesced segment
332 **/
333void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
334{
335 if (max_size < PAGE_CACHE_SIZE) {
336 max_size = PAGE_CACHE_SIZE;
337 printk(KERN_INFO "%s: set to minimum %d\n",
338 __func__, max_size);
339 }
340
341 q->limits.max_segment_size = max_size;
342}
343EXPORT_SYMBOL(blk_queue_max_segment_size);
344
345/**
346 * blk_queue_logical_block_size - set logical block size for the queue
347 * @q: the request queue for the device
348 * @size: the logical block size, in bytes
349 *
350 * Description:
351 * This should be set to the lowest possible block size that the
352 * storage device can address. The default of 512 covers most
353 * hardware.
354 **/
355void blk_queue_logical_block_size(struct request_queue *q, unsigned short size)
356{
357 q->limits.logical_block_size = size;
358
359 if (q->limits.physical_block_size < size)
360 q->limits.physical_block_size = size;
361
362 if (q->limits.io_min < q->limits.physical_block_size)
363 q->limits.io_min = q->limits.physical_block_size;
364}
365EXPORT_SYMBOL(blk_queue_logical_block_size);
366
367/**
368 * blk_queue_physical_block_size - set physical block size for the queue
369 * @q: the request queue for the device
370 * @size: the physical block size, in bytes
371 *
372 * Description:
373 * This should be set to the lowest possible sector size that the
374 * hardware can operate on without reverting to read-modify-write
375 * operations.
376 */
377void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
378{
379 q->limits.physical_block_size = size;
380
381 if (q->limits.physical_block_size < q->limits.logical_block_size)
382 q->limits.physical_block_size = q->limits.logical_block_size;
383
384 if (q->limits.io_min < q->limits.physical_block_size)
385 q->limits.io_min = q->limits.physical_block_size;
386}
387EXPORT_SYMBOL(blk_queue_physical_block_size);
388
389/**
390 * blk_queue_alignment_offset - set physical block alignment offset
391 * @q: the request queue for the device
392 * @offset: alignment offset in bytes
393 *
394 * Description:
395 * Some devices are naturally misaligned to compensate for things like
396 * the legacy DOS partition table 63-sector offset. Low-level drivers
397 * should call this function for devices whose first sector is not
398 * naturally aligned.
399 */
400void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
401{
402 q->limits.alignment_offset =
403 offset & (q->limits.physical_block_size - 1);
404 q->limits.misaligned = 0;
405}
406EXPORT_SYMBOL(blk_queue_alignment_offset);
407
408/**
409 * blk_limits_io_min - set minimum request size for a device
410 * @limits: the queue limits
411 * @min: smallest I/O size in bytes
412 *
413 * Description:
414 * Some devices have an internal block size bigger than the reported
415 * hardware sector size. This function can be used to signal the
416 * smallest I/O the device can perform without incurring a performance
417 * penalty.
418 */
419void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
420{
421 limits->io_min = min;
422
423 if (limits->io_min < limits->logical_block_size)
424 limits->io_min = limits->logical_block_size;
425
426 if (limits->io_min < limits->physical_block_size)
427 limits->io_min = limits->physical_block_size;
428}
429EXPORT_SYMBOL(blk_limits_io_min);
430
431/**
432 * blk_queue_io_min - set minimum request size for the queue
433 * @q: the request queue for the device
434 * @min: smallest I/O size in bytes
435 *
436 * Description:
437 * Storage devices may report a granularity or preferred minimum I/O
438 * size which is the smallest request the device can perform without
439 * incurring a performance penalty. For disk drives this is often the
440 * physical block size. For RAID arrays it is often the stripe chunk
441 * size. A properly aligned multiple of minimum_io_size is the
442 * preferred request size for workloads where a high number of I/O
443 * operations is desired.
444 */
445void blk_queue_io_min(struct request_queue *q, unsigned int min)
446{
447 blk_limits_io_min(&q->limits, min);
448}
449EXPORT_SYMBOL(blk_queue_io_min);
450
451/**
452 * blk_limits_io_opt - set optimal request size for a device
453 * @limits: the queue limits
454 * @opt: smallest I/O size in bytes
455 *
456 * Description:
457 * Storage devices may report an optimal I/O size, which is the
458 * device's preferred unit for sustained I/O. This is rarely reported
459 * for disk drives. For RAID arrays it is usually the stripe width or
460 * the internal track size. A properly aligned multiple of
461 * optimal_io_size is the preferred request size for workloads where
462 * sustained throughput is desired.
463 */
464void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
465{
466 limits->io_opt = opt;
467}
468EXPORT_SYMBOL(blk_limits_io_opt);
469
470/**
471 * blk_queue_io_opt - set optimal request size for the queue
472 * @q: the request queue for the device
473 * @opt: optimal request size in bytes
474 *
475 * Description:
476 * Storage devices may report an optimal I/O size, which is the
477 * device's preferred unit for sustained I/O. This is rarely reported
478 * for disk drives. For RAID arrays it is usually the stripe width or
479 * the internal track size. A properly aligned multiple of
480 * optimal_io_size is the preferred request size for workloads where
481 * sustained throughput is desired.
482 */
483void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
484{
485 blk_limits_io_opt(&q->limits, opt);
486}
487EXPORT_SYMBOL(blk_queue_io_opt);
488
489/**
490 * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
491 * @t: the stacking driver (top)
492 * @b: the underlying device (bottom)
493 **/
494void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
495{
496 blk_stack_limits(&t->limits, &b->limits, 0);
497}
498EXPORT_SYMBOL(blk_queue_stack_limits);
499
500/**
501 * blk_stack_limits - adjust queue_limits for stacked devices
502 * @t: the stacking driver limits (top device)
503 * @b: the underlying queue limits (bottom, component device)
504 * @start: first data sector within component device
505 *
506 * Description:
507 * This function is used by stacking drivers like MD and DM to ensure
508 * that all component devices have compatible block sizes and
509 * alignments. The stacking driver must provide a queue_limits
510 * struct (top) and then iteratively call the stacking function for
511 * all component (bottom) devices. The stacking function will
512 * attempt to combine the values and ensure proper alignment.
513 *
514 * Returns 0 if the top and bottom queue_limits are compatible. The
515 * top device's block sizes and alignment offsets may be adjusted to
516 * ensure alignment with the bottom device. If no compatible sizes
517 * and alignments exist, -1 is returned and the resulting top
518 * queue_limits will have the misaligned flag set to indicate that
519 * the alignment_offset is undefined.
520 */
521int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
522 sector_t start)
523{
524 unsigned int top, bottom, alignment, ret = 0;
525
526 t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
527 t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
528 t->max_write_same_sectors = min(t->max_write_same_sectors,
529 b->max_write_same_sectors);
530 t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn);
531
532 t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
533 b->seg_boundary_mask);
534
535 t->max_segments = min_not_zero(t->max_segments, b->max_segments);
536 t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
537 b->max_integrity_segments);
538
539 t->max_segment_size = min_not_zero(t->max_segment_size,
540 b->max_segment_size);
541
542 t->misaligned |= b->misaligned;
543
544 alignment = queue_limit_alignment_offset(b, start);
545
546 /* Bottom device has different alignment. Check that it is
547 * compatible with the current top alignment.
548 */
549 if (t->alignment_offset != alignment) {
550
551 top = max(t->physical_block_size, t->io_min)
552 + t->alignment_offset;
553 bottom = max(b->physical_block_size, b->io_min) + alignment;
554
555 /* Verify that top and bottom intervals line up */
556 if (max(top, bottom) & (min(top, bottom) - 1)) {
557 t->misaligned = 1;
558 ret = -1;
559 }
560 }
561
562 t->logical_block_size = max(t->logical_block_size,
563 b->logical_block_size);
564
565 t->physical_block_size = max(t->physical_block_size,
566 b->physical_block_size);
567
568 t->io_min = max(t->io_min, b->io_min);
569 t->io_opt = lcm(t->io_opt, b->io_opt);
570
571 t->cluster &= b->cluster;
572 t->discard_zeroes_data &= b->discard_zeroes_data;
573
574 /* Physical block size a multiple of the logical block size? */
575 if (t->physical_block_size & (t->logical_block_size - 1)) {
576 t->physical_block_size = t->logical_block_size;
577 t->misaligned = 1;
578 ret = -1;
579 }
580
581 /* Minimum I/O a multiple of the physical block size? */
582 if (t->io_min & (t->physical_block_size - 1)) {
583 t->io_min = t->physical_block_size;
584 t->misaligned = 1;
585 ret = -1;
586 }
587
588 /* Optimal I/O a multiple of the physical block size? */
589 if (t->io_opt & (t->physical_block_size - 1)) {
590 t->io_opt = 0;
591 t->misaligned = 1;
592 ret = -1;
593 }
594
595 t->raid_partial_stripes_expensive =
596 max(t->raid_partial_stripes_expensive,
597 b->raid_partial_stripes_expensive);
598
599 /* Find lowest common alignment_offset */
600 t->alignment_offset = lcm(t->alignment_offset, alignment)
601 & (max(t->physical_block_size, t->io_min) - 1);
602
603 /* Verify that new alignment_offset is on a logical block boundary */
604 if (t->alignment_offset & (t->logical_block_size - 1)) {
605 t->misaligned = 1;
606 ret = -1;
607 }
608
609 /* Discard alignment and granularity */
610 if (b->discard_granularity) {
611 alignment = queue_limit_discard_alignment(b, start);
612
613 if (t->discard_granularity != 0 &&
614 t->discard_alignment != alignment) {
615 top = t->discard_granularity + t->discard_alignment;
616 bottom = b->discard_granularity + alignment;
617
618 /* Verify that top and bottom intervals line up */
619 if ((max(top, bottom) % min(top, bottom)) != 0)
620 t->discard_misaligned = 1;
621 }
622
623 t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
624 b->max_discard_sectors);
625 t->discard_granularity = max(t->discard_granularity,
626 b->discard_granularity);
627 t->discard_alignment = lcm(t->discard_alignment, alignment) %
628 t->discard_granularity;
629 }
630
631 return ret;
632}
633EXPORT_SYMBOL(blk_stack_limits);
634
635/**
636 * bdev_stack_limits - adjust queue limits for stacked drivers
637 * @t: the stacking driver limits (top device)
638 * @bdev: the component block_device (bottom)
639 * @start: first data sector within component device
640 *
641 * Description:
642 * Merges queue limits for a top device and a block_device. Returns
643 * 0 if alignment didn't change. Returns -1 if adding the bottom
644 * device caused misalignment.
645 */
646int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
647 sector_t start)
648{
649 struct request_queue *bq = bdev_get_queue(bdev);
650
651 start += get_start_sect(bdev);
652
653 return blk_stack_limits(t, &bq->limits, start);
654}
655EXPORT_SYMBOL(bdev_stack_limits);
656
657/**
658 * disk_stack_limits - adjust queue limits for stacked drivers
659 * @disk: MD/DM gendisk (top)
660 * @bdev: the underlying block device (bottom)
661 * @offset: offset to beginning of data within component device
662 *
663 * Description:
664 * Merges the limits for a top level gendisk and a bottom level
665 * block_device.
666 */
667void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
668 sector_t offset)
669{
670 struct request_queue *t = disk->queue;
671
672 if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {
673 char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
674
675 disk_name(disk, 0, top);
676 bdevname(bdev, bottom);
677
678 printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",
679 top, bottom);
680 }
681}
682EXPORT_SYMBOL(disk_stack_limits);
683
684/**
685 * blk_queue_dma_pad - set pad mask
686 * @q: the request queue for the device
687 * @mask: pad mask
688 *
689 * Set dma pad mask.
690 *
691 * Appending pad buffer to a request modifies the last entry of a
692 * scatter list such that it includes the pad buffer.
693 **/
694void blk_queue_dma_pad(struct request_queue *q, unsigned int mask)
695{
696 q->dma_pad_mask = mask;
697}
698EXPORT_SYMBOL(blk_queue_dma_pad);
699
700/**
701 * blk_queue_update_dma_pad - update pad mask
702 * @q: the request queue for the device
703 * @mask: pad mask
704 *
705 * Update dma pad mask.
706 *
707 * Appending pad buffer to a request modifies the last entry of a
708 * scatter list such that it includes the pad buffer.
709 **/
710void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask)
711{
712 if (mask > q->dma_pad_mask)
713 q->dma_pad_mask = mask;
714}
715EXPORT_SYMBOL(blk_queue_update_dma_pad);
716
717/**
718 * blk_queue_dma_drain - Set up a drain buffer for excess dma.
719 * @q: the request queue for the device
720 * @dma_drain_needed: fn which returns non-zero if drain is necessary
721 * @buf: physically contiguous buffer
722 * @size: size of the buffer in bytes
723 *
724 * Some devices have excess DMA problems and can't simply discard (or
725 * zero fill) the unwanted piece of the transfer. They have to have a
726 * real area of memory to transfer it into. The use case for this is
727 * ATAPI devices in DMA mode. If the packet command causes a transfer
728 * bigger than the transfer size some HBAs will lock up if there
729 * aren't DMA elements to contain the excess transfer. What this API
730 * does is adjust the queue so that the buf is always appended
731 * silently to the scatterlist.
732 *
733 * Note: This routine adjusts max_hw_segments to make room for appending
734 * the drain buffer. If you call blk_queue_max_segments() after calling
735 * this routine, you must set the limit to one fewer than your device
736 * can support otherwise there won't be room for the drain buffer.
737 */
738int blk_queue_dma_drain(struct request_queue *q,
739 dma_drain_needed_fn *dma_drain_needed,
740 void *buf, unsigned int size)
741{
742 if (queue_max_segments(q) < 2)
743 return -EINVAL;
744 /* make room for appending the drain */
745 blk_queue_max_segments(q, queue_max_segments(q) - 1);
746 q->dma_drain_needed = dma_drain_needed;
747 q->dma_drain_buffer = buf;
748 q->dma_drain_size = size;
749
750 return 0;
751}
752EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
753
754/**
755 * blk_queue_segment_boundary - set boundary rules for segment merging
756 * @q: the request queue for the device
757 * @mask: the memory boundary mask
758 **/
759void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
760{
761 if (mask < PAGE_CACHE_SIZE - 1) {
762 mask = PAGE_CACHE_SIZE - 1;
763 printk(KERN_INFO "%s: set to minimum %lx\n",
764 __func__, mask);
765 }
766
767 q->limits.seg_boundary_mask = mask;
768}
769EXPORT_SYMBOL(blk_queue_segment_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->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->dma_alignment)
806 q->dma_alignment = mask;
807}
808EXPORT_SYMBOL(blk_queue_update_dma_alignment);
809
810/**
811 * blk_queue_flush - configure queue's cache flush capability
812 * @q: the request queue for the device
813 * @flush: 0, REQ_FLUSH or REQ_FLUSH | REQ_FUA
814 *
815 * Tell block layer cache flush capability of @q. If it supports
816 * flushing, REQ_FLUSH should be set. If it supports bypassing
817 * write cache for individual writes, REQ_FUA should be set.
818 */
819void blk_queue_flush(struct request_queue *q, unsigned int flush)
820{
821 WARN_ON_ONCE(flush & ~(REQ_FLUSH | REQ_FUA));
822
823 if (WARN_ON_ONCE(!(flush & REQ_FLUSH) && (flush & REQ_FUA)))
824 flush &= ~REQ_FUA;
825
826 q->flush_flags = flush & (REQ_FLUSH | REQ_FUA);
827}
828EXPORT_SYMBOL_GPL(blk_queue_flush);
829
830void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
831{
832 q->flush_not_queueable = !queueable;
833}
834EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
835
836static int __init blk_settings_init(void)
837{
838 blk_max_low_pfn = max_low_pfn - 1;
839 blk_max_pfn = max_pfn - 1;
840 return 0;
841}
842subsys_initcall(blk_settings_init);
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/memblock.h> /* for max_pfn/max_low_pfn */
11#include <linux/gcd.h>
12#include <linux/lcm.h>
13#include <linux/jiffies.h>
14#include <linux/gfp.h>
15#include <linux/dma-mapping.h>
16
17#include "blk.h"
18#include "blk-wbt.h"
19
20unsigned long blk_max_low_pfn;
21EXPORT_SYMBOL(blk_max_low_pfn);
22
23unsigned long blk_max_pfn;
24
25void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
26{
27 q->rq_timeout = timeout;
28}
29EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
30
31/**
32 * blk_set_default_limits - reset limits to default values
33 * @lim: the queue_limits structure to reset
34 *
35 * Description:
36 * Returns a queue_limit struct to its default state.
37 */
38void blk_set_default_limits(struct queue_limits *lim)
39{
40 lim->max_segments = BLK_MAX_SEGMENTS;
41 lim->max_discard_segments = 1;
42 lim->max_integrity_segments = 0;
43 lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
44 lim->virt_boundary_mask = 0;
45 lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
46 lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
47 lim->max_dev_sectors = 0;
48 lim->chunk_sectors = 0;
49 lim->max_write_same_sectors = 0;
50 lim->max_write_zeroes_sectors = 0;
51 lim->max_zone_append_sectors = 0;
52 lim->max_discard_sectors = 0;
53 lim->max_hw_discard_sectors = 0;
54 lim->discard_granularity = 0;
55 lim->discard_alignment = 0;
56 lim->discard_misaligned = 0;
57 lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
58 lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
59 lim->alignment_offset = 0;
60 lim->io_opt = 0;
61 lim->misaligned = 0;
62 lim->zoned = BLK_ZONED_NONE;
63}
64EXPORT_SYMBOL(blk_set_default_limits);
65
66/**
67 * blk_set_stacking_limits - set default limits for stacking devices
68 * @lim: the queue_limits structure to reset
69 *
70 * Description:
71 * Returns a queue_limit struct to its default state. Should be used
72 * by stacking drivers like DM that have no internal limits.
73 */
74void blk_set_stacking_limits(struct queue_limits *lim)
75{
76 blk_set_default_limits(lim);
77
78 /* Inherit limits from component devices */
79 lim->max_segments = USHRT_MAX;
80 lim->max_discard_segments = USHRT_MAX;
81 lim->max_hw_sectors = UINT_MAX;
82 lim->max_segment_size = UINT_MAX;
83 lim->max_sectors = UINT_MAX;
84 lim->max_dev_sectors = UINT_MAX;
85 lim->max_write_same_sectors = UINT_MAX;
86 lim->max_write_zeroes_sectors = UINT_MAX;
87 lim->max_zone_append_sectors = UINT_MAX;
88}
89EXPORT_SYMBOL(blk_set_stacking_limits);
90
91/**
92 * blk_queue_bounce_limit - set bounce buffer limit for queue
93 * @q: the request queue for the device
94 * @max_addr: the maximum address the device can handle
95 *
96 * Description:
97 * Different hardware can have different requirements as to what pages
98 * it can do I/O directly to. A low level driver can call
99 * blk_queue_bounce_limit to have lower memory pages allocated as bounce
100 * buffers for doing I/O to pages residing above @max_addr.
101 **/
102void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr)
103{
104 unsigned long b_pfn = max_addr >> PAGE_SHIFT;
105 int dma = 0;
106
107 q->bounce_gfp = GFP_NOIO;
108#if BITS_PER_LONG == 64
109 /*
110 * Assume anything <= 4GB can be handled by IOMMU. Actually
111 * some IOMMUs can handle everything, but I don't know of a
112 * way to test this here.
113 */
114 if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
115 dma = 1;
116 q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
117#else
118 if (b_pfn < blk_max_low_pfn)
119 dma = 1;
120 q->limits.bounce_pfn = b_pfn;
121#endif
122 if (dma) {
123 init_emergency_isa_pool();
124 q->bounce_gfp = GFP_NOIO | GFP_DMA;
125 q->limits.bounce_pfn = b_pfn;
126 }
127}
128EXPORT_SYMBOL(blk_queue_bounce_limit);
129
130/**
131 * blk_queue_max_hw_sectors - set max sectors for a request for this queue
132 * @q: the request queue for the device
133 * @max_hw_sectors: max hardware sectors in the usual 512b unit
134 *
135 * Description:
136 * Enables a low level driver to set a hard upper limit,
137 * max_hw_sectors, on the size of requests. max_hw_sectors is set by
138 * the device driver based upon the capabilities of the I/O
139 * controller.
140 *
141 * max_dev_sectors is a hard limit imposed by the storage device for
142 * READ/WRITE requests. It is set by the disk driver.
143 *
144 * max_sectors is a soft limit imposed by the block layer for
145 * filesystem type requests. This value can be overridden on a
146 * per-device basis in /sys/block/<device>/queue/max_sectors_kb.
147 * The soft limit can not exceed max_hw_sectors.
148 **/
149void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
150{
151 struct queue_limits *limits = &q->limits;
152 unsigned int max_sectors;
153
154 if ((max_hw_sectors << 9) < PAGE_SIZE) {
155 max_hw_sectors = 1 << (PAGE_SHIFT - 9);
156 printk(KERN_INFO "%s: set to minimum %d\n",
157 __func__, max_hw_sectors);
158 }
159
160 limits->max_hw_sectors = max_hw_sectors;
161 max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors);
162 max_sectors = min_t(unsigned int, max_sectors, BLK_DEF_MAX_SECTORS);
163 limits->max_sectors = max_sectors;
164 q->backing_dev_info->io_pages = max_sectors >> (PAGE_SHIFT - 9);
165}
166EXPORT_SYMBOL(blk_queue_max_hw_sectors);
167
168/**
169 * blk_queue_chunk_sectors - set size of the chunk for this queue
170 * @q: the request queue for the device
171 * @chunk_sectors: chunk sectors in the usual 512b unit
172 *
173 * Description:
174 * If a driver doesn't want IOs to cross a given chunk size, it can set
175 * this limit and prevent merging across chunks. Note that the chunk size
176 * must currently be a power-of-2 in sectors. Also note that the block
177 * layer must accept a page worth of data at any offset. So if the
178 * crossing of chunks is a hard limitation in the driver, it must still be
179 * prepared to split single page bios.
180 **/
181void blk_queue_chunk_sectors(struct request_queue *q, unsigned int chunk_sectors)
182{
183 BUG_ON(!is_power_of_2(chunk_sectors));
184 q->limits.chunk_sectors = chunk_sectors;
185}
186EXPORT_SYMBOL(blk_queue_chunk_sectors);
187
188/**
189 * blk_queue_max_discard_sectors - set max sectors for a single discard
190 * @q: the request queue for the device
191 * @max_discard_sectors: maximum number of sectors to discard
192 **/
193void blk_queue_max_discard_sectors(struct request_queue *q,
194 unsigned int max_discard_sectors)
195{
196 q->limits.max_hw_discard_sectors = max_discard_sectors;
197 q->limits.max_discard_sectors = max_discard_sectors;
198}
199EXPORT_SYMBOL(blk_queue_max_discard_sectors);
200
201/**
202 * blk_queue_max_write_same_sectors - set max sectors for a single write same
203 * @q: the request queue for the device
204 * @max_write_same_sectors: maximum number of sectors to write per command
205 **/
206void blk_queue_max_write_same_sectors(struct request_queue *q,
207 unsigned int max_write_same_sectors)
208{
209 q->limits.max_write_same_sectors = max_write_same_sectors;
210}
211EXPORT_SYMBOL(blk_queue_max_write_same_sectors);
212
213/**
214 * blk_queue_max_write_zeroes_sectors - set max sectors for a single
215 * write zeroes
216 * @q: the request queue for the device
217 * @max_write_zeroes_sectors: maximum number of sectors to write per command
218 **/
219void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
220 unsigned int max_write_zeroes_sectors)
221{
222 q->limits.max_write_zeroes_sectors = max_write_zeroes_sectors;
223}
224EXPORT_SYMBOL(blk_queue_max_write_zeroes_sectors);
225
226/**
227 * blk_queue_max_zone_append_sectors - set max sectors for a single zone append
228 * @q: the request queue for the device
229 * @max_zone_append_sectors: maximum number of sectors to write per command
230 **/
231void blk_queue_max_zone_append_sectors(struct request_queue *q,
232 unsigned int max_zone_append_sectors)
233{
234 unsigned int max_sectors;
235
236 if (WARN_ON(!blk_queue_is_zoned(q)))
237 return;
238
239 max_sectors = min(q->limits.max_hw_sectors, max_zone_append_sectors);
240 max_sectors = min(q->limits.chunk_sectors, max_sectors);
241
242 /*
243 * Signal eventual driver bugs resulting in the max_zone_append sectors limit
244 * being 0 due to a 0 argument, the chunk_sectors limit (zone size) not set,
245 * or the max_hw_sectors limit not set.
246 */
247 WARN_ON(!max_sectors);
248
249 q->limits.max_zone_append_sectors = max_sectors;
250}
251EXPORT_SYMBOL_GPL(blk_queue_max_zone_append_sectors);
252
253/**
254 * blk_queue_max_segments - set max hw segments for a request for this queue
255 * @q: the request queue for the device
256 * @max_segments: max number of segments
257 *
258 * Description:
259 * Enables a low level driver to set an upper limit on the number of
260 * hw data segments in a request.
261 **/
262void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
263{
264 if (!max_segments) {
265 max_segments = 1;
266 printk(KERN_INFO "%s: set to minimum %d\n",
267 __func__, max_segments);
268 }
269
270 q->limits.max_segments = max_segments;
271}
272EXPORT_SYMBOL(blk_queue_max_segments);
273
274/**
275 * blk_queue_max_discard_segments - set max segments for discard requests
276 * @q: the request queue for the device
277 * @max_segments: max number of segments
278 *
279 * Description:
280 * Enables a low level driver to set an upper limit on the number of
281 * segments in a discard request.
282 **/
283void blk_queue_max_discard_segments(struct request_queue *q,
284 unsigned short max_segments)
285{
286 q->limits.max_discard_segments = max_segments;
287}
288EXPORT_SYMBOL_GPL(blk_queue_max_discard_segments);
289
290/**
291 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
292 * @q: the request queue for the device
293 * @max_size: max size of segment in bytes
294 *
295 * Description:
296 * Enables a low level driver to set an upper limit on the size of a
297 * coalesced segment
298 **/
299void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
300{
301 if (max_size < PAGE_SIZE) {
302 max_size = PAGE_SIZE;
303 printk(KERN_INFO "%s: set to minimum %d\n",
304 __func__, max_size);
305 }
306
307 /* see blk_queue_virt_boundary() for the explanation */
308 WARN_ON_ONCE(q->limits.virt_boundary_mask);
309
310 q->limits.max_segment_size = max_size;
311}
312EXPORT_SYMBOL(blk_queue_max_segment_size);
313
314/**
315 * blk_queue_logical_block_size - set logical block size for the queue
316 * @q: the request queue for the device
317 * @size: the logical block size, in bytes
318 *
319 * Description:
320 * This should be set to the lowest possible block size that the
321 * storage device can address. The default of 512 covers most
322 * hardware.
323 **/
324void blk_queue_logical_block_size(struct request_queue *q, unsigned int size)
325{
326 q->limits.logical_block_size = size;
327
328 if (q->limits.physical_block_size < size)
329 q->limits.physical_block_size = size;
330
331 if (q->limits.io_min < q->limits.physical_block_size)
332 q->limits.io_min = q->limits.physical_block_size;
333}
334EXPORT_SYMBOL(blk_queue_logical_block_size);
335
336/**
337 * blk_queue_physical_block_size - set physical block size for the queue
338 * @q: the request queue for the device
339 * @size: the physical block size, in bytes
340 *
341 * Description:
342 * This should be set to the lowest possible sector size that the
343 * hardware can operate on without reverting to read-modify-write
344 * operations.
345 */
346void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
347{
348 q->limits.physical_block_size = size;
349
350 if (q->limits.physical_block_size < q->limits.logical_block_size)
351 q->limits.physical_block_size = q->limits.logical_block_size;
352
353 if (q->limits.io_min < q->limits.physical_block_size)
354 q->limits.io_min = q->limits.physical_block_size;
355}
356EXPORT_SYMBOL(blk_queue_physical_block_size);
357
358/**
359 * blk_queue_alignment_offset - set physical block alignment offset
360 * @q: the request queue for the device
361 * @offset: alignment offset in bytes
362 *
363 * Description:
364 * Some devices are naturally misaligned to compensate for things like
365 * the legacy DOS partition table 63-sector offset. Low-level drivers
366 * should call this function for devices whose first sector is not
367 * naturally aligned.
368 */
369void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
370{
371 q->limits.alignment_offset =
372 offset & (q->limits.physical_block_size - 1);
373 q->limits.misaligned = 0;
374}
375EXPORT_SYMBOL(blk_queue_alignment_offset);
376
377/**
378 * blk_limits_io_min - set minimum request size for a device
379 * @limits: the queue limits
380 * @min: smallest I/O size in bytes
381 *
382 * Description:
383 * Some devices have an internal block size bigger than the reported
384 * hardware sector size. This function can be used to signal the
385 * smallest I/O the device can perform without incurring a performance
386 * penalty.
387 */
388void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
389{
390 limits->io_min = min;
391
392 if (limits->io_min < limits->logical_block_size)
393 limits->io_min = limits->logical_block_size;
394
395 if (limits->io_min < limits->physical_block_size)
396 limits->io_min = limits->physical_block_size;
397}
398EXPORT_SYMBOL(blk_limits_io_min);
399
400/**
401 * blk_queue_io_min - set minimum request size for the queue
402 * @q: the request queue for the device
403 * @min: smallest I/O size in bytes
404 *
405 * Description:
406 * Storage devices may report a granularity or preferred minimum I/O
407 * size which is the smallest request the device can perform without
408 * incurring a performance penalty. For disk drives this is often the
409 * physical block size. For RAID arrays it is often the stripe chunk
410 * size. A properly aligned multiple of minimum_io_size is the
411 * preferred request size for workloads where a high number of I/O
412 * operations is desired.
413 */
414void blk_queue_io_min(struct request_queue *q, unsigned int min)
415{
416 blk_limits_io_min(&q->limits, min);
417}
418EXPORT_SYMBOL(blk_queue_io_min);
419
420/**
421 * blk_limits_io_opt - set optimal request size for a device
422 * @limits: the queue limits
423 * @opt: smallest I/O size in bytes
424 *
425 * Description:
426 * Storage devices may report an optimal I/O size, which is the
427 * device's preferred unit for sustained I/O. This is rarely reported
428 * for disk drives. For RAID arrays it is usually the stripe width or
429 * the internal track size. A properly aligned multiple of
430 * optimal_io_size is the preferred request size for workloads where
431 * sustained throughput is desired.
432 */
433void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
434{
435 limits->io_opt = opt;
436}
437EXPORT_SYMBOL(blk_limits_io_opt);
438
439/**
440 * blk_queue_io_opt - set optimal request size for the queue
441 * @q: the request queue for the device
442 * @opt: optimal request size in bytes
443 *
444 * Description:
445 * Storage devices may report an optimal I/O size, which is the
446 * device's preferred unit for sustained I/O. This is rarely reported
447 * for disk drives. For RAID arrays it is usually the stripe width or
448 * the internal track size. A properly aligned multiple of
449 * optimal_io_size is the preferred request size for workloads where
450 * sustained throughput is desired.
451 */
452void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
453{
454 blk_limits_io_opt(&q->limits, opt);
455}
456EXPORT_SYMBOL(blk_queue_io_opt);
457
458/**
459 * blk_stack_limits - adjust queue_limits for stacked devices
460 * @t: the stacking driver limits (top device)
461 * @b: the underlying queue limits (bottom, component device)
462 * @start: first data sector within component device
463 *
464 * Description:
465 * This function is used by stacking drivers like MD and DM to ensure
466 * that all component devices have compatible block sizes and
467 * alignments. The stacking driver must provide a queue_limits
468 * struct (top) and then iteratively call the stacking function for
469 * all component (bottom) devices. The stacking function will
470 * attempt to combine the values and ensure proper alignment.
471 *
472 * Returns 0 if the top and bottom queue_limits are compatible. The
473 * top device's block sizes and alignment offsets may be adjusted to
474 * ensure alignment with the bottom device. If no compatible sizes
475 * and alignments exist, -1 is returned and the resulting top
476 * queue_limits will have the misaligned flag set to indicate that
477 * the alignment_offset is undefined.
478 */
479int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
480 sector_t start)
481{
482 unsigned int top, bottom, alignment, ret = 0;
483
484 t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
485 t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
486 t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_sectors);
487 t->max_write_same_sectors = min(t->max_write_same_sectors,
488 b->max_write_same_sectors);
489 t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors,
490 b->max_write_zeroes_sectors);
491 t->max_zone_append_sectors = min(t->max_zone_append_sectors,
492 b->max_zone_append_sectors);
493 t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn);
494
495 t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
496 b->seg_boundary_mask);
497 t->virt_boundary_mask = min_not_zero(t->virt_boundary_mask,
498 b->virt_boundary_mask);
499
500 t->max_segments = min_not_zero(t->max_segments, b->max_segments);
501 t->max_discard_segments = min_not_zero(t->max_discard_segments,
502 b->max_discard_segments);
503 t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
504 b->max_integrity_segments);
505
506 t->max_segment_size = min_not_zero(t->max_segment_size,
507 b->max_segment_size);
508
509 t->misaligned |= b->misaligned;
510
511 alignment = queue_limit_alignment_offset(b, start);
512
513 /* Bottom device has different alignment. Check that it is
514 * compatible with the current top alignment.
515 */
516 if (t->alignment_offset != alignment) {
517
518 top = max(t->physical_block_size, t->io_min)
519 + t->alignment_offset;
520 bottom = max(b->physical_block_size, b->io_min) + alignment;
521
522 /* Verify that top and bottom intervals line up */
523 if (max(top, bottom) % min(top, bottom)) {
524 t->misaligned = 1;
525 ret = -1;
526 }
527 }
528
529 t->logical_block_size = max(t->logical_block_size,
530 b->logical_block_size);
531
532 t->physical_block_size = max(t->physical_block_size,
533 b->physical_block_size);
534
535 t->io_min = max(t->io_min, b->io_min);
536 t->io_opt = lcm_not_zero(t->io_opt, b->io_opt);
537
538 /* Physical block size a multiple of the logical block size? */
539 if (t->physical_block_size & (t->logical_block_size - 1)) {
540 t->physical_block_size = t->logical_block_size;
541 t->misaligned = 1;
542 ret = -1;
543 }
544
545 /* Minimum I/O a multiple of the physical block size? */
546 if (t->io_min & (t->physical_block_size - 1)) {
547 t->io_min = t->physical_block_size;
548 t->misaligned = 1;
549 ret = -1;
550 }
551
552 /* Optimal I/O a multiple of the physical block size? */
553 if (t->io_opt & (t->physical_block_size - 1)) {
554 t->io_opt = 0;
555 t->misaligned = 1;
556 ret = -1;
557 }
558
559 t->raid_partial_stripes_expensive =
560 max(t->raid_partial_stripes_expensive,
561 b->raid_partial_stripes_expensive);
562
563 /* Find lowest common alignment_offset */
564 t->alignment_offset = lcm_not_zero(t->alignment_offset, alignment)
565 % max(t->physical_block_size, t->io_min);
566
567 /* Verify that new alignment_offset is on a logical block boundary */
568 if (t->alignment_offset & (t->logical_block_size - 1)) {
569 t->misaligned = 1;
570 ret = -1;
571 }
572
573 /* Discard alignment and granularity */
574 if (b->discard_granularity) {
575 alignment = queue_limit_discard_alignment(b, start);
576
577 if (t->discard_granularity != 0 &&
578 t->discard_alignment != alignment) {
579 top = t->discard_granularity + t->discard_alignment;
580 bottom = b->discard_granularity + alignment;
581
582 /* Verify that top and bottom intervals line up */
583 if ((max(top, bottom) % min(top, bottom)) != 0)
584 t->discard_misaligned = 1;
585 }
586
587 t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
588 b->max_discard_sectors);
589 t->max_hw_discard_sectors = min_not_zero(t->max_hw_discard_sectors,
590 b->max_hw_discard_sectors);
591 t->discard_granularity = max(t->discard_granularity,
592 b->discard_granularity);
593 t->discard_alignment = lcm_not_zero(t->discard_alignment, alignment) %
594 t->discard_granularity;
595 }
596
597 if (b->chunk_sectors)
598 t->chunk_sectors = min_not_zero(t->chunk_sectors,
599 b->chunk_sectors);
600
601 t->zoned = max(t->zoned, b->zoned);
602 return ret;
603}
604EXPORT_SYMBOL(blk_stack_limits);
605
606/**
607 * disk_stack_limits - adjust queue limits for stacked drivers
608 * @disk: MD/DM gendisk (top)
609 * @bdev: the underlying block device (bottom)
610 * @offset: offset to beginning of data within component device
611 *
612 * Description:
613 * Merges the limits for a top level gendisk and a bottom level
614 * block_device.
615 */
616void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
617 sector_t offset)
618{
619 struct request_queue *t = disk->queue;
620
621 if (blk_stack_limits(&t->limits, &bdev_get_queue(bdev)->limits,
622 get_start_sect(bdev) + (offset >> 9)) < 0) {
623 char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
624
625 disk_name(disk, 0, top);
626 bdevname(bdev, bottom);
627
628 printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",
629 top, bottom);
630 }
631
632 t->backing_dev_info->io_pages =
633 t->limits.max_sectors >> (PAGE_SHIFT - 9);
634}
635EXPORT_SYMBOL(disk_stack_limits);
636
637/**
638 * blk_queue_update_dma_pad - update pad mask
639 * @q: the request queue for the device
640 * @mask: pad mask
641 *
642 * Update dma pad mask.
643 *
644 * Appending pad buffer to a request modifies the last entry of a
645 * scatter list such that it includes the pad buffer.
646 **/
647void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask)
648{
649 if (mask > q->dma_pad_mask)
650 q->dma_pad_mask = mask;
651}
652EXPORT_SYMBOL(blk_queue_update_dma_pad);
653
654/**
655 * blk_queue_segment_boundary - set boundary rules for segment merging
656 * @q: the request queue for the device
657 * @mask: the memory boundary mask
658 **/
659void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
660{
661 if (mask < PAGE_SIZE - 1) {
662 mask = PAGE_SIZE - 1;
663 printk(KERN_INFO "%s: set to minimum %lx\n",
664 __func__, mask);
665 }
666
667 q->limits.seg_boundary_mask = mask;
668}
669EXPORT_SYMBOL(blk_queue_segment_boundary);
670
671/**
672 * blk_queue_virt_boundary - set boundary rules for bio merging
673 * @q: the request queue for the device
674 * @mask: the memory boundary mask
675 **/
676void blk_queue_virt_boundary(struct request_queue *q, unsigned long mask)
677{
678 q->limits.virt_boundary_mask = mask;
679
680 /*
681 * Devices that require a virtual boundary do not support scatter/gather
682 * I/O natively, but instead require a descriptor list entry for each
683 * page (which might not be idential to the Linux PAGE_SIZE). Because
684 * of that they are not limited by our notion of "segment size".
685 */
686 if (mask)
687 q->limits.max_segment_size = UINT_MAX;
688}
689EXPORT_SYMBOL(blk_queue_virt_boundary);
690
691/**
692 * blk_queue_dma_alignment - set dma length and memory alignment
693 * @q: the request queue for the device
694 * @mask: alignment mask
695 *
696 * description:
697 * set required memory and length alignment for direct dma transactions.
698 * this is used when building direct io requests for the queue.
699 *
700 **/
701void blk_queue_dma_alignment(struct request_queue *q, int mask)
702{
703 q->dma_alignment = mask;
704}
705EXPORT_SYMBOL(blk_queue_dma_alignment);
706
707/**
708 * blk_queue_update_dma_alignment - update dma length and memory alignment
709 * @q: the request queue for the device
710 * @mask: alignment mask
711 *
712 * description:
713 * update required memory and length alignment for direct dma transactions.
714 * If the requested alignment is larger than the current alignment, then
715 * the current queue alignment is updated to the new value, otherwise it
716 * is left alone. The design of this is to allow multiple objects
717 * (driver, device, transport etc) to set their respective
718 * alignments without having them interfere.
719 *
720 **/
721void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
722{
723 BUG_ON(mask > PAGE_SIZE);
724
725 if (mask > q->dma_alignment)
726 q->dma_alignment = mask;
727}
728EXPORT_SYMBOL(blk_queue_update_dma_alignment);
729
730/**
731 * blk_set_queue_depth - tell the block layer about the device queue depth
732 * @q: the request queue for the device
733 * @depth: queue depth
734 *
735 */
736void blk_set_queue_depth(struct request_queue *q, unsigned int depth)
737{
738 q->queue_depth = depth;
739 rq_qos_queue_depth_changed(q);
740}
741EXPORT_SYMBOL(blk_set_queue_depth);
742
743/**
744 * blk_queue_write_cache - configure queue's write cache
745 * @q: the request queue for the device
746 * @wc: write back cache on or off
747 * @fua: device supports FUA writes, if true
748 *
749 * Tell the block layer about the write cache of @q.
750 */
751void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
752{
753 if (wc)
754 blk_queue_flag_set(QUEUE_FLAG_WC, q);
755 else
756 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
757 if (fua)
758 blk_queue_flag_set(QUEUE_FLAG_FUA, q);
759 else
760 blk_queue_flag_clear(QUEUE_FLAG_FUA, q);
761
762 wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
763}
764EXPORT_SYMBOL_GPL(blk_queue_write_cache);
765
766/**
767 * blk_queue_required_elevator_features - Set a queue required elevator features
768 * @q: the request queue for the target device
769 * @features: Required elevator features OR'ed together
770 *
771 * Tell the block layer that for the device controlled through @q, only the
772 * only elevators that can be used are those that implement at least the set of
773 * features specified by @features.
774 */
775void blk_queue_required_elevator_features(struct request_queue *q,
776 unsigned int features)
777{
778 q->required_elevator_features = features;
779}
780EXPORT_SYMBOL_GPL(blk_queue_required_elevator_features);
781
782/**
783 * blk_queue_can_use_dma_map_merging - configure queue for merging segments.
784 * @q: the request queue for the device
785 * @dev: the device pointer for dma
786 *
787 * Tell the block layer about merging the segments by dma map of @q.
788 */
789bool blk_queue_can_use_dma_map_merging(struct request_queue *q,
790 struct device *dev)
791{
792 unsigned long boundary = dma_get_merge_boundary(dev);
793
794 if (!boundary)
795 return false;
796
797 /* No need to update max_segment_size. see blk_queue_virt_boundary() */
798 blk_queue_virt_boundary(q, boundary);
799
800 return true;
801}
802EXPORT_SYMBOL_GPL(blk_queue_can_use_dma_map_merging);
803
804/**
805 * blk_queue_set_zoned - configure a disk queue zoned model.
806 * @disk: the gendisk of the queue to configure
807 * @model: the zoned model to set
808 *
809 * Set the zoned model of the request queue of @disk according to @model.
810 * When @model is BLK_ZONED_HM (host managed), this should be called only
811 * if zoned block device support is enabled (CONFIG_BLK_DEV_ZONED option).
812 * If @model specifies BLK_ZONED_HA (host aware), the effective model used
813 * depends on CONFIG_BLK_DEV_ZONED settings and on the existence of partitions
814 * on the disk.
815 */
816void blk_queue_set_zoned(struct gendisk *disk, enum blk_zoned_model model)
817{
818 switch (model) {
819 case BLK_ZONED_HM:
820 /*
821 * Host managed devices are supported only if
822 * CONFIG_BLK_DEV_ZONED is enabled.
823 */
824 WARN_ON_ONCE(!IS_ENABLED(CONFIG_BLK_DEV_ZONED));
825 break;
826 case BLK_ZONED_HA:
827 /*
828 * Host aware devices can be treated either as regular block
829 * devices (similar to drive managed devices) or as zoned block
830 * devices to take advantage of the zone command set, similarly
831 * to host managed devices. We try the latter if there are no
832 * partitions and zoned block device support is enabled, else
833 * we do nothing special as far as the block layer is concerned.
834 */
835 if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) ||
836 disk_has_partitions(disk))
837 model = BLK_ZONED_NONE;
838 break;
839 case BLK_ZONED_NONE:
840 default:
841 if (WARN_ON_ONCE(model != BLK_ZONED_NONE))
842 model = BLK_ZONED_NONE;
843 break;
844 }
845
846 disk->queue->limits.zoned = model;
847}
848EXPORT_SYMBOL_GPL(blk_queue_set_zoned);
849
850static int __init blk_settings_init(void)
851{
852 blk_max_low_pfn = max_low_pfn - 1;
853 blk_max_pfn = max_pfn - 1;
854 return 0;
855}
856subsys_initcall(blk_settings_init);