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