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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 | ||
17 | unsigned long blk_max_low_pfn; | |
18 | EXPORT_SYMBOL(blk_max_low_pfn); | |
19 | ||
20 | unsigned 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 | */ | |
33 | void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn) | |
34 | { | |
35 | q->prep_rq_fn = pfn; | |
36 | } | |
37 | EXPORT_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 | */ | |
50 | void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn) | |
51 | { | |
52 | q->unprep_rq_fn = ufn; | |
53 | } | |
54 | EXPORT_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 | */ | |
72 | void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn) | |
73 | { | |
74 | q->merge_bvec_fn = mbfn; | |
75 | } | |
76 | EXPORT_SYMBOL(blk_queue_merge_bvec); | |
77 | ||
78 | void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn) | |
79 | { | |
80 | q->softirq_done_fn = fn; | |
81 | } | |
82 | EXPORT_SYMBOL(blk_queue_softirq_done); | |
83 | ||
84 | void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout) | |
85 | { | |
86 | q->rq_timeout = timeout; | |
87 | } | |
88 | EXPORT_SYMBOL_GPL(blk_queue_rq_timeout); | |
89 | ||
90 | void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn) | |
91 | { | |
92 | q->rq_timed_out_fn = fn; | |
93 | } | |
94 | EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out); | |
95 | ||
96 | void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn) | |
97 | { | |
98 | q->lld_busy_fn = fn; | |
99 | } | |
100 | EXPORT_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 | */ | |
109 | void 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_discard_sectors = 0; | |
117 | lim->discard_granularity = 0; | |
118 | lim->discard_alignment = 0; | |
119 | lim->discard_misaligned = 0; | |
120 | lim->discard_zeroes_data = 0; | |
121 | lim->logical_block_size = lim->physical_block_size = lim->io_min = 512; | |
122 | lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT); | |
123 | lim->alignment_offset = 0; | |
124 | lim->io_opt = 0; | |
125 | lim->misaligned = 0; | |
126 | lim->cluster = 1; | |
127 | } | |
128 | EXPORT_SYMBOL(blk_set_default_limits); | |
129 | ||
130 | /** | |
131 | * blk_set_stacking_limits - set default limits for stacking devices | |
132 | * @lim: the queue_limits structure to reset | |
133 | * | |
134 | * Description: | |
135 | * Returns a queue_limit struct to its default state. Should be used | |
136 | * by stacking drivers like DM that have no internal limits. | |
137 | */ | |
138 | void blk_set_stacking_limits(struct queue_limits *lim) | |
139 | { | |
140 | blk_set_default_limits(lim); | |
141 | ||
142 | /* Inherit limits from component devices */ | |
143 | lim->discard_zeroes_data = 1; | |
144 | lim->max_segments = USHRT_MAX; | |
145 | lim->max_hw_sectors = UINT_MAX; | |
146 | lim->max_sectors = UINT_MAX; | |
147 | } | |
148 | EXPORT_SYMBOL(blk_set_stacking_limits); | |
149 | ||
150 | /** | |
151 | * blk_queue_make_request - define an alternate make_request function for a device | |
152 | * @q: the request queue for the device to be affected | |
153 | * @mfn: the alternate make_request function | |
154 | * | |
155 | * Description: | |
156 | * The normal way for &struct bios to be passed to a device | |
157 | * driver is for them to be collected into requests on a request | |
158 | * queue, and then to allow the device driver to select requests | |
159 | * off that queue when it is ready. This works well for many block | |
160 | * devices. However some block devices (typically virtual devices | |
161 | * such as md or lvm) do not benefit from the processing on the | |
162 | * request queue, and are served best by having the requests passed | |
163 | * directly to them. This can be achieved by providing a function | |
164 | * to blk_queue_make_request(). | |
165 | * | |
166 | * Caveat: | |
167 | * The driver that does this *must* be able to deal appropriately | |
168 | * with buffers in "highmemory". This can be accomplished by either calling | |
169 | * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling | |
170 | * blk_queue_bounce() to create a buffer in normal memory. | |
171 | **/ | |
172 | void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn) | |
173 | { | |
174 | /* | |
175 | * set defaults | |
176 | */ | |
177 | q->nr_requests = BLKDEV_MAX_RQ; | |
178 | ||
179 | q->make_request_fn = mfn; | |
180 | blk_queue_dma_alignment(q, 511); | |
181 | blk_queue_congestion_threshold(q); | |
182 | q->nr_batching = BLK_BATCH_REQ; | |
183 | ||
184 | blk_set_default_limits(&q->limits); | |
185 | ||
186 | /* | |
187 | * by default assume old behaviour and bounce for any highmem page | |
188 | */ | |
189 | blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH); | |
190 | } | |
191 | EXPORT_SYMBOL(blk_queue_make_request); | |
192 | ||
193 | /** | |
194 | * blk_queue_bounce_limit - set bounce buffer limit for queue | |
195 | * @q: the request queue for the device | |
196 | * @dma_mask: the maximum address the device can handle | |
197 | * | |
198 | * Description: | |
199 | * Different hardware can have different requirements as to what pages | |
200 | * it can do I/O directly to. A low level driver can call | |
201 | * blk_queue_bounce_limit to have lower memory pages allocated as bounce | |
202 | * buffers for doing I/O to pages residing above @dma_mask. | |
203 | **/ | |
204 | void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask) | |
205 | { | |
206 | unsigned long b_pfn = dma_mask >> PAGE_SHIFT; | |
207 | int dma = 0; | |
208 | ||
209 | q->bounce_gfp = GFP_NOIO; | |
210 | #if BITS_PER_LONG == 64 | |
211 | /* | |
212 | * Assume anything <= 4GB can be handled by IOMMU. Actually | |
213 | * some IOMMUs can handle everything, but I don't know of a | |
214 | * way to test this here. | |
215 | */ | |
216 | if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT)) | |
217 | dma = 1; | |
218 | q->limits.bounce_pfn = max(max_low_pfn, b_pfn); | |
219 | #else | |
220 | if (b_pfn < blk_max_low_pfn) | |
221 | dma = 1; | |
222 | q->limits.bounce_pfn = b_pfn; | |
223 | #endif | |
224 | if (dma) { | |
225 | init_emergency_isa_pool(); | |
226 | q->bounce_gfp = GFP_NOIO | GFP_DMA; | |
227 | q->limits.bounce_pfn = b_pfn; | |
228 | } | |
229 | } | |
230 | EXPORT_SYMBOL(blk_queue_bounce_limit); | |
231 | ||
232 | /** | |
233 | * blk_limits_max_hw_sectors - set hard and soft limit of max sectors for request | |
234 | * @limits: the queue limits | |
235 | * @max_hw_sectors: max hardware sectors in the usual 512b unit | |
236 | * | |
237 | * Description: | |
238 | * Enables a low level driver to set a hard upper limit, | |
239 | * max_hw_sectors, on the size of requests. max_hw_sectors is set by | |
240 | * the device driver based upon the combined capabilities of I/O | |
241 | * controller and storage device. | |
242 | * | |
243 | * max_sectors is a soft limit imposed by the block layer for | |
244 | * filesystem type requests. This value can be overridden on a | |
245 | * per-device basis in /sys/block/<device>/queue/max_sectors_kb. | |
246 | * The soft limit can not exceed max_hw_sectors. | |
247 | **/ | |
248 | void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_sectors) | |
249 | { | |
250 | if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) { | |
251 | max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9); | |
252 | printk(KERN_INFO "%s: set to minimum %d\n", | |
253 | __func__, max_hw_sectors); | |
254 | } | |
255 | ||
256 | limits->max_hw_sectors = max_hw_sectors; | |
257 | limits->max_sectors = min_t(unsigned int, max_hw_sectors, | |
258 | BLK_DEF_MAX_SECTORS); | |
259 | } | |
260 | EXPORT_SYMBOL(blk_limits_max_hw_sectors); | |
261 | ||
262 | /** | |
263 | * blk_queue_max_hw_sectors - set max sectors for a request for this queue | |
264 | * @q: the request queue for the device | |
265 | * @max_hw_sectors: max hardware sectors in the usual 512b unit | |
266 | * | |
267 | * Description: | |
268 | * See description for blk_limits_max_hw_sectors(). | |
269 | **/ | |
270 | void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors) | |
271 | { | |
272 | blk_limits_max_hw_sectors(&q->limits, max_hw_sectors); | |
273 | } | |
274 | EXPORT_SYMBOL(blk_queue_max_hw_sectors); | |
275 | ||
276 | /** | |
277 | * blk_queue_max_discard_sectors - set max sectors for a single discard | |
278 | * @q: the request queue for the device | |
279 | * @max_discard_sectors: maximum number of sectors to discard | |
280 | **/ | |
281 | void blk_queue_max_discard_sectors(struct request_queue *q, | |
282 | unsigned int max_discard_sectors) | |
283 | { | |
284 | q->limits.max_discard_sectors = max_discard_sectors; | |
285 | } | |
286 | EXPORT_SYMBOL(blk_queue_max_discard_sectors); | |
287 | ||
288 | /** | |
289 | * blk_queue_max_segments - set max hw segments for a request for this queue | |
290 | * @q: the request queue for the device | |
291 | * @max_segments: max number of segments | |
292 | * | |
293 | * Description: | |
294 | * Enables a low level driver to set an upper limit on the number of | |
295 | * hw data segments in a request. | |
296 | **/ | |
297 | void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments) | |
298 | { | |
299 | if (!max_segments) { | |
300 | max_segments = 1; | |
301 | printk(KERN_INFO "%s: set to minimum %d\n", | |
302 | __func__, max_segments); | |
303 | } | |
304 | ||
305 | q->limits.max_segments = max_segments; | |
306 | } | |
307 | EXPORT_SYMBOL(blk_queue_max_segments); | |
308 | ||
309 | /** | |
310 | * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg | |
311 | * @q: the request queue for the device | |
312 | * @max_size: max size of segment in bytes | |
313 | * | |
314 | * Description: | |
315 | * Enables a low level driver to set an upper limit on the size of a | |
316 | * coalesced segment | |
317 | **/ | |
318 | void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size) | |
319 | { | |
320 | if (max_size < PAGE_CACHE_SIZE) { | |
321 | max_size = PAGE_CACHE_SIZE; | |
322 | printk(KERN_INFO "%s: set to minimum %d\n", | |
323 | __func__, max_size); | |
324 | } | |
325 | ||
326 | q->limits.max_segment_size = max_size; | |
327 | } | |
328 | EXPORT_SYMBOL(blk_queue_max_segment_size); | |
329 | ||
330 | /** | |
331 | * blk_queue_logical_block_size - set logical block size for the queue | |
332 | * @q: the request queue for the device | |
333 | * @size: the logical block size, in bytes | |
334 | * | |
335 | * Description: | |
336 | * This should be set to the lowest possible block size that the | |
337 | * storage device can address. The default of 512 covers most | |
338 | * hardware. | |
339 | **/ | |
340 | void blk_queue_logical_block_size(struct request_queue *q, unsigned short size) | |
341 | { | |
342 | q->limits.logical_block_size = size; | |
343 | ||
344 | if (q->limits.physical_block_size < size) | |
345 | q->limits.physical_block_size = size; | |
346 | ||
347 | if (q->limits.io_min < q->limits.physical_block_size) | |
348 | q->limits.io_min = q->limits.physical_block_size; | |
349 | } | |
350 | EXPORT_SYMBOL(blk_queue_logical_block_size); | |
351 | ||
352 | /** | |
353 | * blk_queue_physical_block_size - set physical block size for the queue | |
354 | * @q: the request queue for the device | |
355 | * @size: the physical block size, in bytes | |
356 | * | |
357 | * Description: | |
358 | * This should be set to the lowest possible sector size that the | |
359 | * hardware can operate on without reverting to read-modify-write | |
360 | * operations. | |
361 | */ | |
362 | void blk_queue_physical_block_size(struct request_queue *q, unsigned int size) | |
363 | { | |
364 | q->limits.physical_block_size = size; | |
365 | ||
366 | if (q->limits.physical_block_size < q->limits.logical_block_size) | |
367 | q->limits.physical_block_size = q->limits.logical_block_size; | |
368 | ||
369 | if (q->limits.io_min < q->limits.physical_block_size) | |
370 | q->limits.io_min = q->limits.physical_block_size; | |
371 | } | |
372 | EXPORT_SYMBOL(blk_queue_physical_block_size); | |
373 | ||
374 | /** | |
375 | * blk_queue_alignment_offset - set physical block alignment offset | |
376 | * @q: the request queue for the device | |
377 | * @offset: alignment offset in bytes | |
378 | * | |
379 | * Description: | |
380 | * Some devices are naturally misaligned to compensate for things like | |
381 | * the legacy DOS partition table 63-sector offset. Low-level drivers | |
382 | * should call this function for devices whose first sector is not | |
383 | * naturally aligned. | |
384 | */ | |
385 | void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset) | |
386 | { | |
387 | q->limits.alignment_offset = | |
388 | offset & (q->limits.physical_block_size - 1); | |
389 | q->limits.misaligned = 0; | |
390 | } | |
391 | EXPORT_SYMBOL(blk_queue_alignment_offset); | |
392 | ||
393 | /** | |
394 | * blk_limits_io_min - set minimum request size for a device | |
395 | * @limits: the queue limits | |
396 | * @min: smallest I/O size in bytes | |
397 | * | |
398 | * Description: | |
399 | * Some devices have an internal block size bigger than the reported | |
400 | * hardware sector size. This function can be used to signal the | |
401 | * smallest I/O the device can perform without incurring a performance | |
402 | * penalty. | |
403 | */ | |
404 | void blk_limits_io_min(struct queue_limits *limits, unsigned int min) | |
405 | { | |
406 | limits->io_min = min; | |
407 | ||
408 | if (limits->io_min < limits->logical_block_size) | |
409 | limits->io_min = limits->logical_block_size; | |
410 | ||
411 | if (limits->io_min < limits->physical_block_size) | |
412 | limits->io_min = limits->physical_block_size; | |
413 | } | |
414 | EXPORT_SYMBOL(blk_limits_io_min); | |
415 | ||
416 | /** | |
417 | * blk_queue_io_min - set minimum request size for the queue | |
418 | * @q: the request queue for the device | |
419 | * @min: smallest I/O size in bytes | |
420 | * | |
421 | * Description: | |
422 | * Storage devices may report a granularity or preferred minimum I/O | |
423 | * size which is the smallest request the device can perform without | |
424 | * incurring a performance penalty. For disk drives this is often the | |
425 | * physical block size. For RAID arrays it is often the stripe chunk | |
426 | * size. A properly aligned multiple of minimum_io_size is the | |
427 | * preferred request size for workloads where a high number of I/O | |
428 | * operations is desired. | |
429 | */ | |
430 | void blk_queue_io_min(struct request_queue *q, unsigned int min) | |
431 | { | |
432 | blk_limits_io_min(&q->limits, min); | |
433 | } | |
434 | EXPORT_SYMBOL(blk_queue_io_min); | |
435 | ||
436 | /** | |
437 | * blk_limits_io_opt - set optimal request size for a device | |
438 | * @limits: the queue limits | |
439 | * @opt: smallest I/O size in bytes | |
440 | * | |
441 | * Description: | |
442 | * Storage devices may report an optimal I/O size, which is the | |
443 | * device's preferred unit for sustained I/O. This is rarely reported | |
444 | * for disk drives. For RAID arrays it is usually the stripe width or | |
445 | * the internal track size. A properly aligned multiple of | |
446 | * optimal_io_size is the preferred request size for workloads where | |
447 | * sustained throughput is desired. | |
448 | */ | |
449 | void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt) | |
450 | { | |
451 | limits->io_opt = opt; | |
452 | } | |
453 | EXPORT_SYMBOL(blk_limits_io_opt); | |
454 | ||
455 | /** | |
456 | * blk_queue_io_opt - set optimal request size for the queue | |
457 | * @q: the request queue for the device | |
458 | * @opt: optimal request size in bytes | |
459 | * | |
460 | * Description: | |
461 | * Storage devices may report an optimal I/O size, which is the | |
462 | * device's preferred unit for sustained I/O. This is rarely reported | |
463 | * for disk drives. For RAID arrays it is usually the stripe width or | |
464 | * the internal track size. A properly aligned multiple of | |
465 | * optimal_io_size is the preferred request size for workloads where | |
466 | * sustained throughput is desired. | |
467 | */ | |
468 | void blk_queue_io_opt(struct request_queue *q, unsigned int opt) | |
469 | { | |
470 | blk_limits_io_opt(&q->limits, opt); | |
471 | } | |
472 | EXPORT_SYMBOL(blk_queue_io_opt); | |
473 | ||
474 | /** | |
475 | * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers | |
476 | * @t: the stacking driver (top) | |
477 | * @b: the underlying device (bottom) | |
478 | **/ | |
479 | void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) | |
480 | { | |
481 | blk_stack_limits(&t->limits, &b->limits, 0); | |
482 | } | |
483 | EXPORT_SYMBOL(blk_queue_stack_limits); | |
484 | ||
485 | /** | |
486 | * blk_stack_limits - adjust queue_limits for stacked devices | |
487 | * @t: the stacking driver limits (top device) | |
488 | * @b: the underlying queue limits (bottom, component device) | |
489 | * @start: first data sector within component device | |
490 | * | |
491 | * Description: | |
492 | * This function is used by stacking drivers like MD and DM to ensure | |
493 | * that all component devices have compatible block sizes and | |
494 | * alignments. The stacking driver must provide a queue_limits | |
495 | * struct (top) and then iteratively call the stacking function for | |
496 | * all component (bottom) devices. The stacking function will | |
497 | * attempt to combine the values and ensure proper alignment. | |
498 | * | |
499 | * Returns 0 if the top and bottom queue_limits are compatible. The | |
500 | * top device's block sizes and alignment offsets may be adjusted to | |
501 | * ensure alignment with the bottom device. If no compatible sizes | |
502 | * and alignments exist, -1 is returned and the resulting top | |
503 | * queue_limits will have the misaligned flag set to indicate that | |
504 | * the alignment_offset is undefined. | |
505 | */ | |
506 | int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, | |
507 | sector_t start) | |
508 | { | |
509 | unsigned int top, bottom, alignment, ret = 0; | |
510 | ||
511 | t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); | |
512 | t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); | |
513 | t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); | |
514 | ||
515 | t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, | |
516 | b->seg_boundary_mask); | |
517 | ||
518 | t->max_segments = min_not_zero(t->max_segments, b->max_segments); | |
519 | t->max_integrity_segments = min_not_zero(t->max_integrity_segments, | |
520 | b->max_integrity_segments); | |
521 | ||
522 | t->max_segment_size = min_not_zero(t->max_segment_size, | |
523 | b->max_segment_size); | |
524 | ||
525 | t->misaligned |= b->misaligned; | |
526 | ||
527 | 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 | if (t->alignment_offset != alignment) { | |
533 | ||
534 | top = max(t->physical_block_size, t->io_min) | |
535 | + t->alignment_offset; | |
536 | bottom = max(b->physical_block_size, b->io_min) + alignment; | |
537 | ||
538 | /* Verify that top and bottom intervals line up */ | |
539 | if (max(top, bottom) & (min(top, bottom) - 1)) { | |
540 | t->misaligned = 1; | |
541 | ret = -1; | |
542 | } | |
543 | } | |
544 | ||
545 | t->logical_block_size = max(t->logical_block_size, | |
546 | b->logical_block_size); | |
547 | ||
548 | t->physical_block_size = max(t->physical_block_size, | |
549 | b->physical_block_size); | |
550 | ||
551 | t->io_min = max(t->io_min, b->io_min); | |
552 | t->io_opt = lcm(t->io_opt, b->io_opt); | |
553 | ||
554 | t->cluster &= b->cluster; | |
555 | t->discard_zeroes_data &= b->discard_zeroes_data; | |
556 | ||
557 | /* Physical block size a multiple of the logical block size? */ | |
558 | if (t->physical_block_size & (t->logical_block_size - 1)) { | |
559 | t->physical_block_size = t->logical_block_size; | |
560 | t->misaligned = 1; | |
561 | ret = -1; | |
562 | } | |
563 | ||
564 | /* Minimum I/O a multiple of the physical block size? */ | |
565 | if (t->io_min & (t->physical_block_size - 1)) { | |
566 | t->io_min = t->physical_block_size; | |
567 | t->misaligned = 1; | |
568 | ret = -1; | |
569 | } | |
570 | ||
571 | /* Optimal I/O a multiple of the physical block size? */ | |
572 | if (t->io_opt & (t->physical_block_size - 1)) { | |
573 | t->io_opt = 0; | |
574 | t->misaligned = 1; | |
575 | ret = -1; | |
576 | } | |
577 | ||
578 | /* Find lowest common alignment_offset */ | |
579 | t->alignment_offset = lcm(t->alignment_offset, alignment) | |
580 | & (max(t->physical_block_size, t->io_min) - 1); | |
581 | ||
582 | /* Verify that new alignment_offset is on a logical block boundary */ | |
583 | if (t->alignment_offset & (t->logical_block_size - 1)) { | |
584 | t->misaligned = 1; | |
585 | ret = -1; | |
586 | } | |
587 | ||
588 | /* Discard alignment and granularity */ | |
589 | if (b->discard_granularity) { | |
590 | alignment = queue_limit_discard_alignment(b, start); | |
591 | ||
592 | if (t->discard_granularity != 0 && | |
593 | t->discard_alignment != alignment) { | |
594 | top = t->discard_granularity + t->discard_alignment; | |
595 | bottom = b->discard_granularity + alignment; | |
596 | ||
597 | /* Verify that top and bottom intervals line up */ | |
598 | if (max(top, bottom) & (min(top, bottom) - 1)) | |
599 | t->discard_misaligned = 1; | |
600 | } | |
601 | ||
602 | t->max_discard_sectors = min_not_zero(t->max_discard_sectors, | |
603 | b->max_discard_sectors); | |
604 | t->discard_granularity = max(t->discard_granularity, | |
605 | b->discard_granularity); | |
606 | t->discard_alignment = lcm(t->discard_alignment, alignment) & | |
607 | (t->discard_granularity - 1); | |
608 | } | |
609 | ||
610 | return ret; | |
611 | } | |
612 | EXPORT_SYMBOL(blk_stack_limits); | |
613 | ||
614 | /** | |
615 | * bdev_stack_limits - adjust queue limits for stacked drivers | |
616 | * @t: the stacking driver limits (top device) | |
617 | * @bdev: the component block_device (bottom) | |
618 | * @start: first data sector within component device | |
619 | * | |
620 | * Description: | |
621 | * Merges queue limits for a top device and a block_device. Returns | |
622 | * 0 if alignment didn't change. Returns -1 if adding the bottom | |
623 | * device caused misalignment. | |
624 | */ | |
625 | int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev, | |
626 | sector_t start) | |
627 | { | |
628 | struct request_queue *bq = bdev_get_queue(bdev); | |
629 | ||
630 | start += get_start_sect(bdev); | |
631 | ||
632 | return blk_stack_limits(t, &bq->limits, start); | |
633 | } | |
634 | EXPORT_SYMBOL(bdev_stack_limits); | |
635 | ||
636 | /** | |
637 | * disk_stack_limits - adjust queue limits for stacked drivers | |
638 | * @disk: MD/DM gendisk (top) | |
639 | * @bdev: the underlying block device (bottom) | |
640 | * @offset: offset to beginning of data within component device | |
641 | * | |
642 | * Description: | |
643 | * Merges the limits for a top level gendisk and a bottom level | |
644 | * block_device. | |
645 | */ | |
646 | void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, | |
647 | sector_t offset) | |
648 | { | |
649 | struct request_queue *t = disk->queue; | |
650 | ||
651 | if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) { | |
652 | char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE]; | |
653 | ||
654 | disk_name(disk, 0, top); | |
655 | bdevname(bdev, bottom); | |
656 | ||
657 | printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n", | |
658 | top, bottom); | |
659 | } | |
660 | } | |
661 | EXPORT_SYMBOL(disk_stack_limits); | |
662 | ||
663 | /** | |
664 | * blk_queue_dma_pad - set pad mask | |
665 | * @q: the request queue for the device | |
666 | * @mask: pad mask | |
667 | * | |
668 | * Set dma pad mask. | |
669 | * | |
670 | * Appending pad buffer to a request modifies the last entry of a | |
671 | * scatter list such that it includes the pad buffer. | |
672 | **/ | |
673 | void blk_queue_dma_pad(struct request_queue *q, unsigned int mask) | |
674 | { | |
675 | q->dma_pad_mask = mask; | |
676 | } | |
677 | EXPORT_SYMBOL(blk_queue_dma_pad); | |
678 | ||
679 | /** | |
680 | * blk_queue_update_dma_pad - update pad mask | |
681 | * @q: the request queue for the device | |
682 | * @mask: pad mask | |
683 | * | |
684 | * Update dma pad mask. | |
685 | * | |
686 | * Appending pad buffer to a request modifies the last entry of a | |
687 | * scatter list such that it includes the pad buffer. | |
688 | **/ | |
689 | void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask) | |
690 | { | |
691 | if (mask > q->dma_pad_mask) | |
692 | q->dma_pad_mask = mask; | |
693 | } | |
694 | EXPORT_SYMBOL(blk_queue_update_dma_pad); | |
695 | ||
696 | /** | |
697 | * blk_queue_dma_drain - Set up a drain buffer for excess dma. | |
698 | * @q: the request queue for the device | |
699 | * @dma_drain_needed: fn which returns non-zero if drain is necessary | |
700 | * @buf: physically contiguous buffer | |
701 | * @size: size of the buffer in bytes | |
702 | * | |
703 | * Some devices have excess DMA problems and can't simply discard (or | |
704 | * zero fill) the unwanted piece of the transfer. They have to have a | |
705 | * real area of memory to transfer it into. The use case for this is | |
706 | * ATAPI devices in DMA mode. If the packet command causes a transfer | |
707 | * bigger than the transfer size some HBAs will lock up if there | |
708 | * aren't DMA elements to contain the excess transfer. What this API | |
709 | * does is adjust the queue so that the buf is always appended | |
710 | * silently to the scatterlist. | |
711 | * | |
712 | * Note: This routine adjusts max_hw_segments to make room for appending | |
713 | * the drain buffer. If you call blk_queue_max_segments() after calling | |
714 | * this routine, you must set the limit to one fewer than your device | |
715 | * can support otherwise there won't be room for the drain buffer. | |
716 | */ | |
717 | int blk_queue_dma_drain(struct request_queue *q, | |
718 | dma_drain_needed_fn *dma_drain_needed, | |
719 | void *buf, unsigned int size) | |
720 | { | |
721 | if (queue_max_segments(q) < 2) | |
722 | return -EINVAL; | |
723 | /* make room for appending the drain */ | |
724 | blk_queue_max_segments(q, queue_max_segments(q) - 1); | |
725 | q->dma_drain_needed = dma_drain_needed; | |
726 | q->dma_drain_buffer = buf; | |
727 | q->dma_drain_size = size; | |
728 | ||
729 | return 0; | |
730 | } | |
731 | EXPORT_SYMBOL_GPL(blk_queue_dma_drain); | |
732 | ||
733 | /** | |
734 | * blk_queue_segment_boundary - set boundary rules for segment merging | |
735 | * @q: the request queue for the device | |
736 | * @mask: the memory boundary mask | |
737 | **/ | |
738 | void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask) | |
739 | { | |
740 | if (mask < PAGE_CACHE_SIZE - 1) { | |
741 | mask = PAGE_CACHE_SIZE - 1; | |
742 | printk(KERN_INFO "%s: set to minimum %lx\n", | |
743 | __func__, mask); | |
744 | } | |
745 | ||
746 | q->limits.seg_boundary_mask = mask; | |
747 | } | |
748 | EXPORT_SYMBOL(blk_queue_segment_boundary); | |
749 | ||
750 | /** | |
751 | * blk_queue_dma_alignment - set dma length and memory alignment | |
752 | * @q: the request queue for the device | |
753 | * @mask: alignment mask | |
754 | * | |
755 | * description: | |
756 | * set required memory and length alignment for direct dma transactions. | |
757 | * this is used when building direct io requests for the queue. | |
758 | * | |
759 | **/ | |
760 | void blk_queue_dma_alignment(struct request_queue *q, int mask) | |
761 | { | |
762 | q->dma_alignment = mask; | |
763 | } | |
764 | EXPORT_SYMBOL(blk_queue_dma_alignment); | |
765 | ||
766 | /** | |
767 | * blk_queue_update_dma_alignment - update dma length and memory alignment | |
768 | * @q: the request queue for the device | |
769 | * @mask: alignment mask | |
770 | * | |
771 | * description: | |
772 | * update required memory and length alignment for direct dma transactions. | |
773 | * If the requested alignment is larger than the current alignment, then | |
774 | * the current queue alignment is updated to the new value, otherwise it | |
775 | * is left alone. The design of this is to allow multiple objects | |
776 | * (driver, device, transport etc) to set their respective | |
777 | * alignments without having them interfere. | |
778 | * | |
779 | **/ | |
780 | void blk_queue_update_dma_alignment(struct request_queue *q, int mask) | |
781 | { | |
782 | BUG_ON(mask > PAGE_SIZE); | |
783 | ||
784 | if (mask > q->dma_alignment) | |
785 | q->dma_alignment = mask; | |
786 | } | |
787 | EXPORT_SYMBOL(blk_queue_update_dma_alignment); | |
788 | ||
789 | /** | |
790 | * blk_queue_flush - configure queue's cache flush capability | |
791 | * @q: the request queue for the device | |
792 | * @flush: 0, REQ_FLUSH or REQ_FLUSH | REQ_FUA | |
793 | * | |
794 | * Tell block layer cache flush capability of @q. If it supports | |
795 | * flushing, REQ_FLUSH should be set. If it supports bypassing | |
796 | * write cache for individual writes, REQ_FUA should be set. | |
797 | */ | |
798 | void blk_queue_flush(struct request_queue *q, unsigned int flush) | |
799 | { | |
800 | WARN_ON_ONCE(flush & ~(REQ_FLUSH | REQ_FUA)); | |
801 | ||
802 | if (WARN_ON_ONCE(!(flush & REQ_FLUSH) && (flush & REQ_FUA))) | |
803 | flush &= ~REQ_FUA; | |
804 | ||
805 | q->flush_flags = flush & (REQ_FLUSH | REQ_FUA); | |
806 | } | |
807 | EXPORT_SYMBOL_GPL(blk_queue_flush); | |
808 | ||
809 | void blk_queue_flush_queueable(struct request_queue *q, bool queueable) | |
810 | { | |
811 | q->flush_not_queueable = !queueable; | |
812 | } | |
813 | EXPORT_SYMBOL_GPL(blk_queue_flush_queueable); | |
814 | ||
815 | static int __init blk_settings_init(void) | |
816 | { | |
817 | blk_max_low_pfn = max_low_pfn - 1; | |
818 | blk_max_pfn = max_pfn - 1; | |
819 | return 0; | |
820 | } | |
821 | subsys_initcall(blk_settings_init); |