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