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86db1e29
JA
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 */
70dd5bf3 10#include <linux/gcd.h>
2cda2728 11#include <linux/lcm.h>
ad5ebd2f 12#include <linux/jiffies.h>
5a0e3ad6 13#include <linux/gfp.h>
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14
15#include "blk.h"
87760e5e 16#include "blk-wbt.h"
86db1e29 17
6728cb0e 18unsigned long blk_max_low_pfn;
86db1e29 19EXPORT_SYMBOL(blk_max_low_pfn);
6728cb0e
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20
21unsigned long blk_max_pfn;
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22
23/**
24 * blk_queue_prep_rq - set a prepare_request function for queue
25 * @q: queue
26 * @pfn: prepare_request function
27 *
28 * It's possible for a queue to register a prepare_request callback which
29 * is invoked before the request is handed to the request_fn. The goal of
30 * the function is to prepare a request for I/O, it can be used to build a
31 * cdb from the request data for instance.
32 *
33 */
34void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
35{
36 q->prep_rq_fn = pfn;
37}
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38EXPORT_SYMBOL(blk_queue_prep_rq);
39
28018c24
JB
40/**
41 * blk_queue_unprep_rq - set an unprepare_request function for queue
42 * @q: queue
43 * @ufn: unprepare_request function
44 *
45 * It's possible for a queue to register an unprepare_request callback
46 * which is invoked before the request is finally completed. The goal
47 * of the function is to deallocate any data that was allocated in the
48 * prepare_request callback.
49 *
50 */
51void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn)
52{
53 q->unprep_rq_fn = ufn;
54}
55EXPORT_SYMBOL(blk_queue_unprep_rq);
56
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57void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
58{
59 q->softirq_done_fn = fn;
60}
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61EXPORT_SYMBOL(blk_queue_softirq_done);
62
242f9dcb
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63void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
64{
65 q->rq_timeout = timeout;
66}
67EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
68
69void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn)
70{
71 q->rq_timed_out_fn = fn;
72}
73EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out);
74
ef9e3fac
KU
75void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn)
76{
77 q->lld_busy_fn = fn;
78}
79EXPORT_SYMBOL_GPL(blk_queue_lld_busy);
80
e475bba2
MP
81/**
82 * blk_set_default_limits - reset limits to default values
f740f5ca 83 * @lim: the queue_limits structure to reset
e475bba2
MP
84 *
85 * Description:
b1bd055d 86 * Returns a queue_limit struct to its default state.
e475bba2
MP
87 */
88void blk_set_default_limits(struct queue_limits *lim)
89{
8a78362c 90 lim->max_segments = BLK_MAX_SEGMENTS;
13f05c8d 91 lim->max_integrity_segments = 0;
e475bba2 92 lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
03100aad 93 lim->virt_boundary_mask = 0;
eb28d31b 94 lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
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KB
95 lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
96 lim->max_dev_sectors = 0;
762380ad 97 lim->chunk_sectors = 0;
4363ac7c 98 lim->max_write_same_sectors = 0;
a6f0788e 99 lim->max_write_zeroes_sectors = 0;
86b37281 100 lim->max_discard_sectors = 0;
0034af03 101 lim->max_hw_discard_sectors = 0;
86b37281
MP
102 lim->discard_granularity = 0;
103 lim->discard_alignment = 0;
104 lim->discard_misaligned = 0;
b1bd055d 105 lim->discard_zeroes_data = 0;
e475bba2 106 lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
3a02c8e8 107 lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
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MP
108 lim->alignment_offset = 0;
109 lim->io_opt = 0;
110 lim->misaligned = 0;
e692cb66 111 lim->cluster = 1;
797476b8 112 lim->zoned = BLK_ZONED_NONE;
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MP
113}
114EXPORT_SYMBOL(blk_set_default_limits);
115
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116/**
117 * blk_set_stacking_limits - set default limits for stacking devices
118 * @lim: the queue_limits structure to reset
119 *
120 * Description:
121 * Returns a queue_limit struct to its default state. Should be used
122 * by stacking drivers like DM that have no internal limits.
123 */
124void blk_set_stacking_limits(struct queue_limits *lim)
125{
126 blk_set_default_limits(lim);
127
128 /* Inherit limits from component devices */
129 lim->discard_zeroes_data = 1;
130 lim->max_segments = USHRT_MAX;
131 lim->max_hw_sectors = UINT_MAX;
d82ae52e 132 lim->max_segment_size = UINT_MAX;
fe86cdce 133 lim->max_sectors = UINT_MAX;
ca369d51 134 lim->max_dev_sectors = UINT_MAX;
4363ac7c 135 lim->max_write_same_sectors = UINT_MAX;
a6f0788e 136 lim->max_write_zeroes_sectors = UINT_MAX;
b1bd055d
MP
137}
138EXPORT_SYMBOL(blk_set_stacking_limits);
139
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140/**
141 * blk_queue_make_request - define an alternate make_request function for a device
142 * @q: the request queue for the device to be affected
143 * @mfn: the alternate make_request function
144 *
145 * Description:
146 * The normal way for &struct bios to be passed to a device
147 * driver is for them to be collected into requests on a request
148 * queue, and then to allow the device driver to select requests
149 * off that queue when it is ready. This works well for many block
150 * devices. However some block devices (typically virtual devices
151 * such as md or lvm) do not benefit from the processing on the
152 * request queue, and are served best by having the requests passed
153 * directly to them. This can be achieved by providing a function
154 * to blk_queue_make_request().
155 *
156 * Caveat:
157 * The driver that does this *must* be able to deal appropriately
158 * with buffers in "highmemory". This can be accomplished by either calling
159 * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
160 * blk_queue_bounce() to create a buffer in normal memory.
161 **/
6728cb0e 162void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
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163{
164 /*
165 * set defaults
166 */
167 q->nr_requests = BLKDEV_MAX_RQ;
0e435ac2 168
86db1e29 169 q->make_request_fn = mfn;
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170 blk_queue_dma_alignment(q, 511);
171 blk_queue_congestion_threshold(q);
172 q->nr_batching = BLK_BATCH_REQ;
173
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MP
174 blk_set_default_limits(&q->limits);
175
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176 /*
177 * by default assume old behaviour and bounce for any highmem page
178 */
179 blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
180}
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181EXPORT_SYMBOL(blk_queue_make_request);
182
183/**
184 * blk_queue_bounce_limit - set bounce buffer limit for queue
cd0aca2d 185 * @q: the request queue for the device
9f7e45d8 186 * @max_addr: the maximum address the device can handle
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187 *
188 * Description:
189 * Different hardware can have different requirements as to what pages
190 * it can do I/O directly to. A low level driver can call
191 * blk_queue_bounce_limit to have lower memory pages allocated as bounce
9f7e45d8 192 * buffers for doing I/O to pages residing above @max_addr.
86db1e29 193 **/
9f7e45d8 194void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr)
86db1e29 195{
9f7e45d8 196 unsigned long b_pfn = max_addr >> PAGE_SHIFT;
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197 int dma = 0;
198
199 q->bounce_gfp = GFP_NOIO;
200#if BITS_PER_LONG == 64
cd0aca2d
TH
201 /*
202 * Assume anything <= 4GB can be handled by IOMMU. Actually
203 * some IOMMUs can handle everything, but I don't know of a
204 * way to test this here.
205 */
206 if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
86db1e29 207 dma = 1;
efb012b3 208 q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
86db1e29 209#else
6728cb0e 210 if (b_pfn < blk_max_low_pfn)
86db1e29 211 dma = 1;
c49825fa 212 q->limits.bounce_pfn = b_pfn;
260a67a9 213#endif
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214 if (dma) {
215 init_emergency_isa_pool();
216 q->bounce_gfp = GFP_NOIO | GFP_DMA;
260a67a9 217 q->limits.bounce_pfn = b_pfn;
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218 }
219}
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220EXPORT_SYMBOL(blk_queue_bounce_limit);
221
222/**
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MP
223 * blk_queue_max_hw_sectors - set max sectors for a request for this queue
224 * @q: the request queue for the device
2800aac1 225 * @max_hw_sectors: max hardware sectors in the usual 512b unit
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226 *
227 * Description:
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MP
228 * Enables a low level driver to set a hard upper limit,
229 * max_hw_sectors, on the size of requests. max_hw_sectors is set by
4f258a46
MP
230 * the device driver based upon the capabilities of the I/O
231 * controller.
2800aac1 232 *
ca369d51
MP
233 * max_dev_sectors is a hard limit imposed by the storage device for
234 * READ/WRITE requests. It is set by the disk driver.
235 *
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MP
236 * max_sectors is a soft limit imposed by the block layer for
237 * filesystem type requests. This value can be overridden on a
238 * per-device basis in /sys/block/<device>/queue/max_sectors_kb.
239 * The soft limit can not exceed max_hw_sectors.
86db1e29 240 **/
ca369d51 241void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
86db1e29 242{
ca369d51
MP
243 struct queue_limits *limits = &q->limits;
244 unsigned int max_sectors;
245
09cbfeaf
KS
246 if ((max_hw_sectors << 9) < PAGE_SIZE) {
247 max_hw_sectors = 1 << (PAGE_SHIFT - 9);
24c03d47 248 printk(KERN_INFO "%s: set to minimum %d\n",
2800aac1 249 __func__, max_hw_sectors);
86db1e29
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250 }
251
30e2bc08 252 limits->max_hw_sectors = max_hw_sectors;
ca369d51
MP
253 max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors);
254 max_sectors = min_t(unsigned int, max_sectors, BLK_DEF_MAX_SECTORS);
255 limits->max_sectors = max_sectors;
9491ae4a 256 q->backing_dev_info.io_pages = max_sectors >> (PAGE_SHIFT - 9);
86db1e29 257}
086fa5ff 258EXPORT_SYMBOL(blk_queue_max_hw_sectors);
86db1e29 259
762380ad
JA
260/**
261 * blk_queue_chunk_sectors - set size of the chunk for this queue
262 * @q: the request queue for the device
263 * @chunk_sectors: chunk sectors in the usual 512b unit
264 *
265 * Description:
266 * If a driver doesn't want IOs to cross a given chunk size, it can set
267 * this limit and prevent merging across chunks. Note that the chunk size
58a4915a
JA
268 * must currently be a power-of-2 in sectors. Also note that the block
269 * layer must accept a page worth of data at any offset. So if the
270 * crossing of chunks is a hard limitation in the driver, it must still be
271 * prepared to split single page bios.
762380ad
JA
272 **/
273void blk_queue_chunk_sectors(struct request_queue *q, unsigned int chunk_sectors)
274{
275 BUG_ON(!is_power_of_2(chunk_sectors));
276 q->limits.chunk_sectors = chunk_sectors;
277}
278EXPORT_SYMBOL(blk_queue_chunk_sectors);
279
67efc925
CH
280/**
281 * blk_queue_max_discard_sectors - set max sectors for a single discard
282 * @q: the request queue for the device
c7ebf065 283 * @max_discard_sectors: maximum number of sectors to discard
67efc925
CH
284 **/
285void blk_queue_max_discard_sectors(struct request_queue *q,
286 unsigned int max_discard_sectors)
287{
0034af03 288 q->limits.max_hw_discard_sectors = max_discard_sectors;
67efc925
CH
289 q->limits.max_discard_sectors = max_discard_sectors;
290}
291EXPORT_SYMBOL(blk_queue_max_discard_sectors);
292
4363ac7c
MP
293/**
294 * blk_queue_max_write_same_sectors - set max sectors for a single write same
295 * @q: the request queue for the device
296 * @max_write_same_sectors: maximum number of sectors to write per command
297 **/
298void blk_queue_max_write_same_sectors(struct request_queue *q,
299 unsigned int max_write_same_sectors)
300{
301 q->limits.max_write_same_sectors = max_write_same_sectors;
302}
303EXPORT_SYMBOL(blk_queue_max_write_same_sectors);
304
a6f0788e
CK
305/**
306 * blk_queue_max_write_zeroes_sectors - set max sectors for a single
307 * write zeroes
308 * @q: the request queue for the device
309 * @max_write_zeroes_sectors: maximum number of sectors to write per command
310 **/
311void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
312 unsigned int max_write_zeroes_sectors)
313{
314 q->limits.max_write_zeroes_sectors = max_write_zeroes_sectors;
315}
316EXPORT_SYMBOL(blk_queue_max_write_zeroes_sectors);
317
86db1e29 318/**
8a78362c 319 * blk_queue_max_segments - set max hw segments for a request for this queue
86db1e29
JA
320 * @q: the request queue for the device
321 * @max_segments: max number of segments
322 *
323 * Description:
324 * Enables a low level driver to set an upper limit on the number of
8a78362c 325 * hw data segments in a request.
86db1e29 326 **/
8a78362c 327void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
86db1e29
JA
328{
329 if (!max_segments) {
330 max_segments = 1;
24c03d47
HH
331 printk(KERN_INFO "%s: set to minimum %d\n",
332 __func__, max_segments);
86db1e29
JA
333 }
334
8a78362c 335 q->limits.max_segments = max_segments;
86db1e29 336}
8a78362c 337EXPORT_SYMBOL(blk_queue_max_segments);
86db1e29
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338
339/**
340 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
341 * @q: the request queue for the device
342 * @max_size: max size of segment in bytes
343 *
344 * Description:
345 * Enables a low level driver to set an upper limit on the size of a
346 * coalesced segment
347 **/
348void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
349{
09cbfeaf
KS
350 if (max_size < PAGE_SIZE) {
351 max_size = PAGE_SIZE;
24c03d47
HH
352 printk(KERN_INFO "%s: set to minimum %d\n",
353 __func__, max_size);
86db1e29
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354 }
355
025146e1 356 q->limits.max_segment_size = max_size;
86db1e29 357}
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358EXPORT_SYMBOL(blk_queue_max_segment_size);
359
360/**
e1defc4f 361 * blk_queue_logical_block_size - set logical block size for the queue
86db1e29 362 * @q: the request queue for the device
e1defc4f 363 * @size: the logical block size, in bytes
86db1e29
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364 *
365 * Description:
e1defc4f
MP
366 * This should be set to the lowest possible block size that the
367 * storage device can address. The default of 512 covers most
368 * hardware.
86db1e29 369 **/
e1defc4f 370void blk_queue_logical_block_size(struct request_queue *q, unsigned short size)
86db1e29 371{
025146e1 372 q->limits.logical_block_size = size;
c72758f3
MP
373
374 if (q->limits.physical_block_size < size)
375 q->limits.physical_block_size = size;
376
377 if (q->limits.io_min < q->limits.physical_block_size)
378 q->limits.io_min = q->limits.physical_block_size;
86db1e29 379}
e1defc4f 380EXPORT_SYMBOL(blk_queue_logical_block_size);
86db1e29 381
c72758f3
MP
382/**
383 * blk_queue_physical_block_size - set physical block size for the queue
384 * @q: the request queue for the device
385 * @size: the physical block size, in bytes
386 *
387 * Description:
388 * This should be set to the lowest possible sector size that the
389 * hardware can operate on without reverting to read-modify-write
390 * operations.
391 */
892b6f90 392void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
c72758f3
MP
393{
394 q->limits.physical_block_size = size;
395
396 if (q->limits.physical_block_size < q->limits.logical_block_size)
397 q->limits.physical_block_size = q->limits.logical_block_size;
398
399 if (q->limits.io_min < q->limits.physical_block_size)
400 q->limits.io_min = q->limits.physical_block_size;
401}
402EXPORT_SYMBOL(blk_queue_physical_block_size);
403
404/**
405 * blk_queue_alignment_offset - set physical block alignment offset
406 * @q: the request queue for the device
8ebf9756 407 * @offset: alignment offset in bytes
c72758f3
MP
408 *
409 * Description:
410 * Some devices are naturally misaligned to compensate for things like
411 * the legacy DOS partition table 63-sector offset. Low-level drivers
412 * should call this function for devices whose first sector is not
413 * naturally aligned.
414 */
415void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
416{
417 q->limits.alignment_offset =
418 offset & (q->limits.physical_block_size - 1);
419 q->limits.misaligned = 0;
420}
421EXPORT_SYMBOL(blk_queue_alignment_offset);
422
7c958e32
MP
423/**
424 * blk_limits_io_min - set minimum request size for a device
425 * @limits: the queue limits
426 * @min: smallest I/O size in bytes
427 *
428 * Description:
429 * Some devices have an internal block size bigger than the reported
430 * hardware sector size. This function can be used to signal the
431 * smallest I/O the device can perform without incurring a performance
432 * penalty.
433 */
434void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
435{
436 limits->io_min = min;
437
438 if (limits->io_min < limits->logical_block_size)
439 limits->io_min = limits->logical_block_size;
440
441 if (limits->io_min < limits->physical_block_size)
442 limits->io_min = limits->physical_block_size;
443}
444EXPORT_SYMBOL(blk_limits_io_min);
445
c72758f3
MP
446/**
447 * blk_queue_io_min - set minimum request size for the queue
448 * @q: the request queue for the device
8ebf9756 449 * @min: smallest I/O size in bytes
c72758f3
MP
450 *
451 * Description:
7e5f5fb0
MP
452 * Storage devices may report a granularity or preferred minimum I/O
453 * size which is the smallest request the device can perform without
454 * incurring a performance penalty. For disk drives this is often the
455 * physical block size. For RAID arrays it is often the stripe chunk
456 * size. A properly aligned multiple of minimum_io_size is the
457 * preferred request size for workloads where a high number of I/O
458 * operations is desired.
c72758f3
MP
459 */
460void blk_queue_io_min(struct request_queue *q, unsigned int min)
461{
7c958e32 462 blk_limits_io_min(&q->limits, min);
c72758f3
MP
463}
464EXPORT_SYMBOL(blk_queue_io_min);
465
3c5820c7
MP
466/**
467 * blk_limits_io_opt - set optimal request size for a device
468 * @limits: the queue limits
469 * @opt: smallest I/O size in bytes
470 *
471 * Description:
472 * Storage devices may report an optimal I/O size, which is the
473 * device's preferred unit for sustained I/O. This is rarely reported
474 * for disk drives. For RAID arrays it is usually the stripe width or
475 * the internal track size. A properly aligned multiple of
476 * optimal_io_size is the preferred request size for workloads where
477 * sustained throughput is desired.
478 */
479void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
480{
481 limits->io_opt = opt;
482}
483EXPORT_SYMBOL(blk_limits_io_opt);
484
c72758f3
MP
485/**
486 * blk_queue_io_opt - set optimal request size for the queue
487 * @q: the request queue for the device
8ebf9756 488 * @opt: optimal request size in bytes
c72758f3
MP
489 *
490 * Description:
7e5f5fb0
MP
491 * Storage devices may report an optimal I/O size, which is the
492 * device's preferred unit for sustained I/O. This is rarely reported
493 * for disk drives. For RAID arrays it is usually the stripe width or
494 * the internal track size. A properly aligned multiple of
495 * optimal_io_size is the preferred request size for workloads where
496 * sustained throughput is desired.
c72758f3
MP
497 */
498void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
499{
3c5820c7 500 blk_limits_io_opt(&q->limits, opt);
c72758f3
MP
501}
502EXPORT_SYMBOL(blk_queue_io_opt);
503
86db1e29
JA
504/**
505 * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
506 * @t: the stacking driver (top)
507 * @b: the underlying device (bottom)
508 **/
509void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
510{
fef24667 511 blk_stack_limits(&t->limits, &b->limits, 0);
86db1e29 512}
86db1e29
JA
513EXPORT_SYMBOL(blk_queue_stack_limits);
514
c72758f3
MP
515/**
516 * blk_stack_limits - adjust queue_limits for stacked devices
81744ee4
MP
517 * @t: the stacking driver limits (top device)
518 * @b: the underlying queue limits (bottom, component device)
e03a72e1 519 * @start: first data sector within component device
c72758f3
MP
520 *
521 * Description:
81744ee4
MP
522 * This function is used by stacking drivers like MD and DM to ensure
523 * that all component devices have compatible block sizes and
524 * alignments. The stacking driver must provide a queue_limits
525 * struct (top) and then iteratively call the stacking function for
526 * all component (bottom) devices. The stacking function will
527 * attempt to combine the values and ensure proper alignment.
528 *
529 * Returns 0 if the top and bottom queue_limits are compatible. The
530 * top device's block sizes and alignment offsets may be adjusted to
531 * ensure alignment with the bottom device. If no compatible sizes
532 * and alignments exist, -1 is returned and the resulting top
533 * queue_limits will have the misaligned flag set to indicate that
534 * the alignment_offset is undefined.
c72758f3
MP
535 */
536int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
e03a72e1 537 sector_t start)
c72758f3 538{
e03a72e1 539 unsigned int top, bottom, alignment, ret = 0;
86b37281 540
c72758f3
MP
541 t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
542 t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
ca369d51 543 t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_sectors);
4363ac7c
MP
544 t->max_write_same_sectors = min(t->max_write_same_sectors,
545 b->max_write_same_sectors);
a6f0788e
CK
546 t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors,
547 b->max_write_zeroes_sectors);
77634f33 548 t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn);
c72758f3
MP
549
550 t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
551 b->seg_boundary_mask);
03100aad
KB
552 t->virt_boundary_mask = min_not_zero(t->virt_boundary_mask,
553 b->virt_boundary_mask);
c72758f3 554
8a78362c 555 t->max_segments = min_not_zero(t->max_segments, b->max_segments);
13f05c8d
MP
556 t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
557 b->max_integrity_segments);
c72758f3
MP
558
559 t->max_segment_size = min_not_zero(t->max_segment_size,
560 b->max_segment_size);
561
fe0b393f
MP
562 t->misaligned |= b->misaligned;
563
e03a72e1 564 alignment = queue_limit_alignment_offset(b, start);
9504e086 565
81744ee4
MP
566 /* Bottom device has different alignment. Check that it is
567 * compatible with the current top alignment.
568 */
9504e086
MP
569 if (t->alignment_offset != alignment) {
570
571 top = max(t->physical_block_size, t->io_min)
572 + t->alignment_offset;
81744ee4 573 bottom = max(b->physical_block_size, b->io_min) + alignment;
9504e086 574
81744ee4 575 /* Verify that top and bottom intervals line up */
b8839b8c 576 if (max(top, bottom) % min(top, bottom)) {
9504e086 577 t->misaligned = 1;
fe0b393f
MP
578 ret = -1;
579 }
9504e086
MP
580 }
581
c72758f3
MP
582 t->logical_block_size = max(t->logical_block_size,
583 b->logical_block_size);
584
585 t->physical_block_size = max(t->physical_block_size,
586 b->physical_block_size);
587
588 t->io_min = max(t->io_min, b->io_min);
e9637415 589 t->io_opt = lcm_not_zero(t->io_opt, b->io_opt);
9504e086 590
e692cb66 591 t->cluster &= b->cluster;
98262f27 592 t->discard_zeroes_data &= b->discard_zeroes_data;
c72758f3 593
81744ee4 594 /* Physical block size a multiple of the logical block size? */
9504e086
MP
595 if (t->physical_block_size & (t->logical_block_size - 1)) {
596 t->physical_block_size = t->logical_block_size;
c72758f3 597 t->misaligned = 1;
fe0b393f 598 ret = -1;
86b37281
MP
599 }
600
81744ee4 601 /* Minimum I/O a multiple of the physical block size? */
9504e086
MP
602 if (t->io_min & (t->physical_block_size - 1)) {
603 t->io_min = t->physical_block_size;
604 t->misaligned = 1;
fe0b393f 605 ret = -1;
c72758f3
MP
606 }
607
81744ee4 608 /* Optimal I/O a multiple of the physical block size? */
9504e086
MP
609 if (t->io_opt & (t->physical_block_size - 1)) {
610 t->io_opt = 0;
611 t->misaligned = 1;
fe0b393f 612 ret = -1;
9504e086 613 }
c72758f3 614
c78afc62
KO
615 t->raid_partial_stripes_expensive =
616 max(t->raid_partial_stripes_expensive,
617 b->raid_partial_stripes_expensive);
618
81744ee4 619 /* Find lowest common alignment_offset */
e9637415 620 t->alignment_offset = lcm_not_zero(t->alignment_offset, alignment)
b8839b8c 621 % max(t->physical_block_size, t->io_min);
86b37281 622
81744ee4 623 /* Verify that new alignment_offset is on a logical block boundary */
fe0b393f 624 if (t->alignment_offset & (t->logical_block_size - 1)) {
c72758f3 625 t->misaligned = 1;
fe0b393f
MP
626 ret = -1;
627 }
c72758f3 628
9504e086
MP
629 /* Discard alignment and granularity */
630 if (b->discard_granularity) {
e03a72e1 631 alignment = queue_limit_discard_alignment(b, start);
9504e086
MP
632
633 if (t->discard_granularity != 0 &&
634 t->discard_alignment != alignment) {
635 top = t->discard_granularity + t->discard_alignment;
636 bottom = b->discard_granularity + alignment;
70dd5bf3 637
9504e086 638 /* Verify that top and bottom intervals line up */
8dd2cb7e 639 if ((max(top, bottom) % min(top, bottom)) != 0)
9504e086
MP
640 t->discard_misaligned = 1;
641 }
642
81744ee4
MP
643 t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
644 b->max_discard_sectors);
0034af03
JA
645 t->max_hw_discard_sectors = min_not_zero(t->max_hw_discard_sectors,
646 b->max_hw_discard_sectors);
9504e086
MP
647 t->discard_granularity = max(t->discard_granularity,
648 b->discard_granularity);
e9637415 649 t->discard_alignment = lcm_not_zero(t->discard_alignment, alignment) %
8dd2cb7e 650 t->discard_granularity;
9504e086 651 }
70dd5bf3 652
987b3b26
HR
653 if (b->chunk_sectors)
654 t->chunk_sectors = min_not_zero(t->chunk_sectors,
655 b->chunk_sectors);
656
fe0b393f 657 return ret;
c72758f3 658}
5d85d324 659EXPORT_SYMBOL(blk_stack_limits);
c72758f3 660
17be8c24
MP
661/**
662 * bdev_stack_limits - adjust queue limits for stacked drivers
663 * @t: the stacking driver limits (top device)
664 * @bdev: the component block_device (bottom)
665 * @start: first data sector within component device
666 *
667 * Description:
668 * Merges queue limits for a top device and a block_device. Returns
669 * 0 if alignment didn't change. Returns -1 if adding the bottom
670 * device caused misalignment.
671 */
672int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
673 sector_t start)
674{
675 struct request_queue *bq = bdev_get_queue(bdev);
676
677 start += get_start_sect(bdev);
678
e03a72e1 679 return blk_stack_limits(t, &bq->limits, start);
17be8c24
MP
680}
681EXPORT_SYMBOL(bdev_stack_limits);
682
c72758f3
MP
683/**
684 * disk_stack_limits - adjust queue limits for stacked drivers
77634f33 685 * @disk: MD/DM gendisk (top)
c72758f3
MP
686 * @bdev: the underlying block device (bottom)
687 * @offset: offset to beginning of data within component device
688 *
689 * Description:
e03a72e1
MP
690 * Merges the limits for a top level gendisk and a bottom level
691 * block_device.
c72758f3
MP
692 */
693void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
694 sector_t offset)
695{
696 struct request_queue *t = disk->queue;
c72758f3 697
e03a72e1 698 if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {
c72758f3
MP
699 char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
700
701 disk_name(disk, 0, top);
702 bdevname(bdev, bottom);
703
704 printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",
705 top, bottom);
706 }
c72758f3
MP
707}
708EXPORT_SYMBOL(disk_stack_limits);
709
e3790c7d
TH
710/**
711 * blk_queue_dma_pad - set pad mask
712 * @q: the request queue for the device
713 * @mask: pad mask
714 *
27f8221a 715 * Set dma pad mask.
e3790c7d 716 *
27f8221a
FT
717 * Appending pad buffer to a request modifies the last entry of a
718 * scatter list such that it includes the pad buffer.
e3790c7d
TH
719 **/
720void blk_queue_dma_pad(struct request_queue *q, unsigned int mask)
721{
722 q->dma_pad_mask = mask;
723}
724EXPORT_SYMBOL(blk_queue_dma_pad);
725
27f8221a
FT
726/**
727 * blk_queue_update_dma_pad - update pad mask
728 * @q: the request queue for the device
729 * @mask: pad mask
730 *
731 * Update dma pad mask.
732 *
733 * Appending pad buffer to a request modifies the last entry of a
734 * scatter list such that it includes the pad buffer.
735 **/
736void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask)
737{
738 if (mask > q->dma_pad_mask)
739 q->dma_pad_mask = mask;
740}
741EXPORT_SYMBOL(blk_queue_update_dma_pad);
742
86db1e29
JA
743/**
744 * blk_queue_dma_drain - Set up a drain buffer for excess dma.
86db1e29 745 * @q: the request queue for the device
2fb98e84 746 * @dma_drain_needed: fn which returns non-zero if drain is necessary
86db1e29
JA
747 * @buf: physically contiguous buffer
748 * @size: size of the buffer in bytes
749 *
750 * Some devices have excess DMA problems and can't simply discard (or
751 * zero fill) the unwanted piece of the transfer. They have to have a
752 * real area of memory to transfer it into. The use case for this is
753 * ATAPI devices in DMA mode. If the packet command causes a transfer
754 * bigger than the transfer size some HBAs will lock up if there
755 * aren't DMA elements to contain the excess transfer. What this API
756 * does is adjust the queue so that the buf is always appended
757 * silently to the scatterlist.
758 *
8a78362c
MP
759 * Note: This routine adjusts max_hw_segments to make room for appending
760 * the drain buffer. If you call blk_queue_max_segments() after calling
761 * this routine, you must set the limit to one fewer than your device
762 * can support otherwise there won't be room for the drain buffer.
86db1e29 763 */
448da4d2 764int blk_queue_dma_drain(struct request_queue *q,
2fb98e84
TH
765 dma_drain_needed_fn *dma_drain_needed,
766 void *buf, unsigned int size)
86db1e29 767{
8a78362c 768 if (queue_max_segments(q) < 2)
86db1e29
JA
769 return -EINVAL;
770 /* make room for appending the drain */
8a78362c 771 blk_queue_max_segments(q, queue_max_segments(q) - 1);
2fb98e84 772 q->dma_drain_needed = dma_drain_needed;
86db1e29
JA
773 q->dma_drain_buffer = buf;
774 q->dma_drain_size = size;
775
776 return 0;
777}
86db1e29
JA
778EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
779
780/**
781 * blk_queue_segment_boundary - set boundary rules for segment merging
782 * @q: the request queue for the device
783 * @mask: the memory boundary mask
784 **/
785void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
786{
09cbfeaf
KS
787 if (mask < PAGE_SIZE - 1) {
788 mask = PAGE_SIZE - 1;
24c03d47
HH
789 printk(KERN_INFO "%s: set to minimum %lx\n",
790 __func__, mask);
86db1e29
JA
791 }
792
025146e1 793 q->limits.seg_boundary_mask = mask;
86db1e29 794}
86db1e29
JA
795EXPORT_SYMBOL(blk_queue_segment_boundary);
796
03100aad
KB
797/**
798 * blk_queue_virt_boundary - set boundary rules for bio merging
799 * @q: the request queue for the device
800 * @mask: the memory boundary mask
801 **/
802void blk_queue_virt_boundary(struct request_queue *q, unsigned long mask)
803{
804 q->limits.virt_boundary_mask = mask;
805}
806EXPORT_SYMBOL(blk_queue_virt_boundary);
807
86db1e29
JA
808/**
809 * blk_queue_dma_alignment - set dma length and memory alignment
810 * @q: the request queue for the device
811 * @mask: alignment mask
812 *
813 * description:
710027a4 814 * set required memory and length alignment for direct dma transactions.
8feb4d20 815 * this is used when building direct io requests for the queue.
86db1e29
JA
816 *
817 **/
818void blk_queue_dma_alignment(struct request_queue *q, int mask)
819{
820 q->dma_alignment = mask;
821}
86db1e29
JA
822EXPORT_SYMBOL(blk_queue_dma_alignment);
823
824/**
825 * blk_queue_update_dma_alignment - update dma length and memory alignment
826 * @q: the request queue for the device
827 * @mask: alignment mask
828 *
829 * description:
710027a4 830 * update required memory and length alignment for direct dma transactions.
86db1e29
JA
831 * If the requested alignment is larger than the current alignment, then
832 * the current queue alignment is updated to the new value, otherwise it
833 * is left alone. The design of this is to allow multiple objects
834 * (driver, device, transport etc) to set their respective
835 * alignments without having them interfere.
836 *
837 **/
838void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
839{
840 BUG_ON(mask > PAGE_SIZE);
841
842 if (mask > q->dma_alignment)
843 q->dma_alignment = mask;
844}
86db1e29
JA
845EXPORT_SYMBOL(blk_queue_update_dma_alignment);
846
f3876930 847void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
848{
c888a8f9
JA
849 spin_lock_irq(q->queue_lock);
850 if (queueable)
851 clear_bit(QUEUE_FLAG_FLUSH_NQ, &q->queue_flags);
852 else
853 set_bit(QUEUE_FLAG_FLUSH_NQ, &q->queue_flags);
854 spin_unlock_irq(q->queue_lock);
f3876930 855}
856EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
857
d278d4a8
JA
858/**
859 * blk_set_queue_depth - tell the block layer about the device queue depth
860 * @q: the request queue for the device
861 * @depth: queue depth
862 *
863 */
864void blk_set_queue_depth(struct request_queue *q, unsigned int depth)
865{
866 q->queue_depth = depth;
87760e5e 867 wbt_set_queue_depth(q->rq_wb, depth);
d278d4a8
JA
868}
869EXPORT_SYMBOL(blk_set_queue_depth);
870
93e9d8e8
JA
871/**
872 * blk_queue_write_cache - configure queue's write cache
873 * @q: the request queue for the device
874 * @wc: write back cache on or off
875 * @fua: device supports FUA writes, if true
876 *
877 * Tell the block layer about the write cache of @q.
878 */
879void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
880{
881 spin_lock_irq(q->queue_lock);
c888a8f9 882 if (wc)
93e9d8e8 883 queue_flag_set(QUEUE_FLAG_WC, q);
c888a8f9 884 else
93e9d8e8 885 queue_flag_clear(QUEUE_FLAG_WC, q);
c888a8f9 886 if (fua)
93e9d8e8 887 queue_flag_set(QUEUE_FLAG_FUA, q);
c888a8f9 888 else
93e9d8e8
JA
889 queue_flag_clear(QUEUE_FLAG_FUA, q);
890 spin_unlock_irq(q->queue_lock);
87760e5e
JA
891
892 wbt_set_write_cache(q->rq_wb, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
93e9d8e8
JA
893}
894EXPORT_SYMBOL_GPL(blk_queue_write_cache);
895
aeb3d3a8 896static int __init blk_settings_init(void)
86db1e29
JA
897{
898 blk_max_low_pfn = max_low_pfn - 1;
899 blk_max_pfn = max_pfn - 1;
900 return 0;
901}
902subsys_initcall(blk_settings_init);