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86db1e29 JA |
1 | /* |
2 | * Functions related to setting various queue properties from drivers | |
3 | */ | |
4 | #include <linux/kernel.h> | |
5 | #include <linux/module.h> | |
6 | #include <linux/init.h> | |
7 | #include <linux/bio.h> | |
8 | #include <linux/blkdev.h> | |
9 | #include <linux/bootmem.h> /* for max_pfn/max_low_pfn */ | |
70dd5bf3 | 10 | #include <linux/gcd.h> |
ad5ebd2f | 11 | #include <linux/jiffies.h> |
86db1e29 JA |
12 | |
13 | #include "blk.h" | |
14 | ||
6728cb0e | 15 | unsigned long blk_max_low_pfn; |
86db1e29 | 16 | EXPORT_SYMBOL(blk_max_low_pfn); |
6728cb0e JA |
17 | |
18 | unsigned long blk_max_pfn; | |
86db1e29 JA |
19 | |
20 | /** | |
21 | * blk_queue_prep_rq - set a prepare_request function for queue | |
22 | * @q: queue | |
23 | * @pfn: prepare_request function | |
24 | * | |
25 | * It's possible for a queue to register a prepare_request callback which | |
26 | * is invoked before the request is handed to the request_fn. The goal of | |
27 | * the function is to prepare a request for I/O, it can be used to build a | |
28 | * cdb from the request data for instance. | |
29 | * | |
30 | */ | |
31 | void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn) | |
32 | { | |
33 | q->prep_rq_fn = pfn; | |
34 | } | |
86db1e29 JA |
35 | EXPORT_SYMBOL(blk_queue_prep_rq); |
36 | ||
37 | /** | |
38 | * blk_queue_merge_bvec - set a merge_bvec function for queue | |
39 | * @q: queue | |
40 | * @mbfn: merge_bvec_fn | |
41 | * | |
42 | * Usually queues have static limitations on the max sectors or segments that | |
43 | * we can put in a request. Stacking drivers may have some settings that | |
44 | * are dynamic, and thus we have to query the queue whether it is ok to | |
45 | * add a new bio_vec to a bio at a given offset or not. If the block device | |
46 | * has such limitations, it needs to register a merge_bvec_fn to control | |
47 | * the size of bio's sent to it. Note that a block device *must* allow a | |
48 | * single page to be added to an empty bio. The block device driver may want | |
49 | * to use the bio_split() function to deal with these bio's. By default | |
50 | * no merge_bvec_fn is defined for a queue, and only the fixed limits are | |
51 | * honored. | |
52 | */ | |
53 | void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn) | |
54 | { | |
55 | q->merge_bvec_fn = mbfn; | |
56 | } | |
86db1e29 JA |
57 | EXPORT_SYMBOL(blk_queue_merge_bvec); |
58 | ||
59 | void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn) | |
60 | { | |
61 | q->softirq_done_fn = fn; | |
62 | } | |
86db1e29 JA |
63 | EXPORT_SYMBOL(blk_queue_softirq_done); |
64 | ||
242f9dcb JA |
65 | void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout) |
66 | { | |
67 | q->rq_timeout = timeout; | |
68 | } | |
69 | EXPORT_SYMBOL_GPL(blk_queue_rq_timeout); | |
70 | ||
71 | void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn) | |
72 | { | |
73 | q->rq_timed_out_fn = fn; | |
74 | } | |
75 | EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out); | |
76 | ||
ef9e3fac KU |
77 | void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn) |
78 | { | |
79 | q->lld_busy_fn = fn; | |
80 | } | |
81 | EXPORT_SYMBOL_GPL(blk_queue_lld_busy); | |
82 | ||
e475bba2 MP |
83 | /** |
84 | * blk_set_default_limits - reset limits to default values | |
f740f5ca | 85 | * @lim: the queue_limits structure to reset |
e475bba2 MP |
86 | * |
87 | * Description: | |
88 | * Returns a queue_limit struct to its default state. Can be used by | |
89 | * stacking drivers like DM that stage table swaps and reuse an | |
90 | * existing device queue. | |
91 | */ | |
92 | void blk_set_default_limits(struct queue_limits *lim) | |
93 | { | |
94 | lim->max_phys_segments = MAX_PHYS_SEGMENTS; | |
95 | lim->max_hw_segments = MAX_HW_SEGMENTS; | |
96 | lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK; | |
97 | lim->max_segment_size = MAX_SEGMENT_SIZE; | |
5dee2477 MP |
98 | lim->max_sectors = BLK_DEF_MAX_SECTORS; |
99 | lim->max_hw_sectors = INT_MAX; | |
86b37281 MP |
100 | lim->max_discard_sectors = 0; |
101 | lim->discard_granularity = 0; | |
102 | lim->discard_alignment = 0; | |
103 | lim->discard_misaligned = 0; | |
e475bba2 | 104 | lim->logical_block_size = lim->physical_block_size = lim->io_min = 512; |
3a02c8e8 | 105 | lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT); |
e475bba2 MP |
106 | lim->alignment_offset = 0; |
107 | lim->io_opt = 0; | |
108 | lim->misaligned = 0; | |
109 | lim->no_cluster = 0; | |
110 | } | |
111 | EXPORT_SYMBOL(blk_set_default_limits); | |
112 | ||
86db1e29 JA |
113 | /** |
114 | * blk_queue_make_request - define an alternate make_request function for a device | |
115 | * @q: the request queue for the device to be affected | |
116 | * @mfn: the alternate make_request function | |
117 | * | |
118 | * Description: | |
119 | * The normal way for &struct bios to be passed to a device | |
120 | * driver is for them to be collected into requests on a request | |
121 | * queue, and then to allow the device driver to select requests | |
122 | * off that queue when it is ready. This works well for many block | |
123 | * devices. However some block devices (typically virtual devices | |
124 | * such as md or lvm) do not benefit from the processing on the | |
125 | * request queue, and are served best by having the requests passed | |
126 | * directly to them. This can be achieved by providing a function | |
127 | * to blk_queue_make_request(). | |
128 | * | |
129 | * Caveat: | |
130 | * The driver that does this *must* be able to deal appropriately | |
131 | * with buffers in "highmemory". This can be accomplished by either calling | |
132 | * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling | |
133 | * blk_queue_bounce() to create a buffer in normal memory. | |
134 | **/ | |
6728cb0e | 135 | void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn) |
86db1e29 JA |
136 | { |
137 | /* | |
138 | * set defaults | |
139 | */ | |
140 | q->nr_requests = BLKDEV_MAX_RQ; | |
0e435ac2 | 141 | |
86db1e29 | 142 | q->make_request_fn = mfn; |
86db1e29 JA |
143 | blk_queue_dma_alignment(q, 511); |
144 | blk_queue_congestion_threshold(q); | |
145 | q->nr_batching = BLK_BATCH_REQ; | |
146 | ||
147 | q->unplug_thresh = 4; /* hmm */ | |
ad5ebd2f | 148 | q->unplug_delay = msecs_to_jiffies(3); /* 3 milliseconds */ |
86db1e29 JA |
149 | if (q->unplug_delay == 0) |
150 | q->unplug_delay = 1; | |
151 | ||
86db1e29 JA |
152 | q->unplug_timer.function = blk_unplug_timeout; |
153 | q->unplug_timer.data = (unsigned long)q; | |
154 | ||
e475bba2 | 155 | blk_set_default_limits(&q->limits); |
80ddf247 | 156 | blk_queue_max_sectors(q, SAFE_MAX_SECTORS); |
e475bba2 | 157 | |
a4e7d464 JA |
158 | /* |
159 | * If the caller didn't supply a lock, fall back to our embedded | |
160 | * per-queue locks | |
161 | */ | |
162 | if (!q->queue_lock) | |
163 | q->queue_lock = &q->__queue_lock; | |
164 | ||
86db1e29 JA |
165 | /* |
166 | * by default assume old behaviour and bounce for any highmem page | |
167 | */ | |
168 | blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH); | |
169 | } | |
86db1e29 JA |
170 | EXPORT_SYMBOL(blk_queue_make_request); |
171 | ||
172 | /** | |
173 | * blk_queue_bounce_limit - set bounce buffer limit for queue | |
cd0aca2d TH |
174 | * @q: the request queue for the device |
175 | * @dma_mask: the maximum address the device can handle | |
86db1e29 JA |
176 | * |
177 | * Description: | |
178 | * Different hardware can have different requirements as to what pages | |
179 | * it can do I/O directly to. A low level driver can call | |
180 | * blk_queue_bounce_limit to have lower memory pages allocated as bounce | |
cd0aca2d | 181 | * buffers for doing I/O to pages residing above @dma_mask. |
86db1e29 | 182 | **/ |
cd0aca2d | 183 | void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask) |
86db1e29 | 184 | { |
cd0aca2d | 185 | unsigned long b_pfn = dma_mask >> PAGE_SHIFT; |
86db1e29 JA |
186 | int dma = 0; |
187 | ||
188 | q->bounce_gfp = GFP_NOIO; | |
189 | #if BITS_PER_LONG == 64 | |
cd0aca2d TH |
190 | /* |
191 | * Assume anything <= 4GB can be handled by IOMMU. Actually | |
192 | * some IOMMUs can handle everything, but I don't know of a | |
193 | * way to test this here. | |
194 | */ | |
195 | if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT)) | |
86db1e29 | 196 | dma = 1; |
025146e1 | 197 | q->limits.bounce_pfn = max_low_pfn; |
86db1e29 | 198 | #else |
6728cb0e | 199 | if (b_pfn < blk_max_low_pfn) |
86db1e29 | 200 | dma = 1; |
025146e1 | 201 | q->limits.bounce_pfn = b_pfn; |
86db1e29 JA |
202 | #endif |
203 | if (dma) { | |
204 | init_emergency_isa_pool(); | |
205 | q->bounce_gfp = GFP_NOIO | GFP_DMA; | |
025146e1 | 206 | q->limits.bounce_pfn = b_pfn; |
86db1e29 JA |
207 | } |
208 | } | |
86db1e29 JA |
209 | EXPORT_SYMBOL(blk_queue_bounce_limit); |
210 | ||
211 | /** | |
212 | * blk_queue_max_sectors - set max sectors for a request for this queue | |
213 | * @q: the request queue for the device | |
214 | * @max_sectors: max sectors in the usual 512b unit | |
215 | * | |
216 | * Description: | |
217 | * Enables a low level driver to set an upper limit on the size of | |
218 | * received requests. | |
219 | **/ | |
220 | void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors) | |
221 | { | |
222 | if ((max_sectors << 9) < PAGE_CACHE_SIZE) { | |
223 | max_sectors = 1 << (PAGE_CACHE_SHIFT - 9); | |
24c03d47 HH |
224 | printk(KERN_INFO "%s: set to minimum %d\n", |
225 | __func__, max_sectors); | |
86db1e29 JA |
226 | } |
227 | ||
228 | if (BLK_DEF_MAX_SECTORS > max_sectors) | |
025146e1 | 229 | q->limits.max_hw_sectors = q->limits.max_sectors = max_sectors; |
86db1e29 | 230 | else { |
025146e1 MP |
231 | q->limits.max_sectors = BLK_DEF_MAX_SECTORS; |
232 | q->limits.max_hw_sectors = max_sectors; | |
86db1e29 JA |
233 | } |
234 | } | |
86db1e29 JA |
235 | EXPORT_SYMBOL(blk_queue_max_sectors); |
236 | ||
ae03bf63 MP |
237 | void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_sectors) |
238 | { | |
239 | if (BLK_DEF_MAX_SECTORS > max_sectors) | |
025146e1 | 240 | q->limits.max_hw_sectors = BLK_DEF_MAX_SECTORS; |
ae03bf63 | 241 | else |
025146e1 | 242 | q->limits.max_hw_sectors = max_sectors; |
ae03bf63 MP |
243 | } |
244 | EXPORT_SYMBOL(blk_queue_max_hw_sectors); | |
245 | ||
67efc925 CH |
246 | /** |
247 | * blk_queue_max_discard_sectors - set max sectors for a single discard | |
248 | * @q: the request queue for the device | |
c7ebf065 | 249 | * @max_discard_sectors: maximum number of sectors to discard |
67efc925 CH |
250 | **/ |
251 | void blk_queue_max_discard_sectors(struct request_queue *q, | |
252 | unsigned int max_discard_sectors) | |
253 | { | |
254 | q->limits.max_discard_sectors = max_discard_sectors; | |
255 | } | |
256 | EXPORT_SYMBOL(blk_queue_max_discard_sectors); | |
257 | ||
86db1e29 JA |
258 | /** |
259 | * blk_queue_max_phys_segments - set max phys segments for a request for this queue | |
260 | * @q: the request queue for the device | |
261 | * @max_segments: max number of segments | |
262 | * | |
263 | * Description: | |
264 | * Enables a low level driver to set an upper limit on the number of | |
265 | * physical data segments in a request. This would be the largest sized | |
266 | * scatter list the driver could handle. | |
267 | **/ | |
268 | void blk_queue_max_phys_segments(struct request_queue *q, | |
269 | unsigned short max_segments) | |
270 | { | |
271 | if (!max_segments) { | |
272 | max_segments = 1; | |
24c03d47 HH |
273 | printk(KERN_INFO "%s: set to minimum %d\n", |
274 | __func__, max_segments); | |
86db1e29 JA |
275 | } |
276 | ||
025146e1 | 277 | q->limits.max_phys_segments = max_segments; |
86db1e29 | 278 | } |
86db1e29 JA |
279 | EXPORT_SYMBOL(blk_queue_max_phys_segments); |
280 | ||
281 | /** | |
282 | * blk_queue_max_hw_segments - set max hw segments for a request for this queue | |
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 | * hw data segments in a request. This would be the largest number of | |
710027a4 | 289 | * address/length pairs the host adapter can actually give at once |
86db1e29 JA |
290 | * to the device. |
291 | **/ | |
292 | void blk_queue_max_hw_segments(struct request_queue *q, | |
293 | unsigned short max_segments) | |
294 | { | |
295 | if (!max_segments) { | |
296 | max_segments = 1; | |
24c03d47 HH |
297 | printk(KERN_INFO "%s: set to minimum %d\n", |
298 | __func__, max_segments); | |
86db1e29 JA |
299 | } |
300 | ||
025146e1 | 301 | q->limits.max_hw_segments = max_segments; |
86db1e29 | 302 | } |
86db1e29 JA |
303 | EXPORT_SYMBOL(blk_queue_max_hw_segments); |
304 | ||
305 | /** | |
306 | * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg | |
307 | * @q: the request queue for the device | |
308 | * @max_size: max size of segment in bytes | |
309 | * | |
310 | * Description: | |
311 | * Enables a low level driver to set an upper limit on the size of a | |
312 | * coalesced segment | |
313 | **/ | |
314 | void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size) | |
315 | { | |
316 | if (max_size < PAGE_CACHE_SIZE) { | |
317 | max_size = PAGE_CACHE_SIZE; | |
24c03d47 HH |
318 | printk(KERN_INFO "%s: set to minimum %d\n", |
319 | __func__, max_size); | |
86db1e29 JA |
320 | } |
321 | ||
025146e1 | 322 | q->limits.max_segment_size = max_size; |
86db1e29 | 323 | } |
86db1e29 JA |
324 | EXPORT_SYMBOL(blk_queue_max_segment_size); |
325 | ||
326 | /** | |
e1defc4f | 327 | * blk_queue_logical_block_size - set logical block size for the queue |
86db1e29 | 328 | * @q: the request queue for the device |
e1defc4f | 329 | * @size: the logical block size, in bytes |
86db1e29 JA |
330 | * |
331 | * Description: | |
e1defc4f MP |
332 | * This should be set to the lowest possible block size that the |
333 | * storage device can address. The default of 512 covers most | |
334 | * hardware. | |
86db1e29 | 335 | **/ |
e1defc4f | 336 | void blk_queue_logical_block_size(struct request_queue *q, unsigned short size) |
86db1e29 | 337 | { |
025146e1 | 338 | q->limits.logical_block_size = size; |
c72758f3 MP |
339 | |
340 | if (q->limits.physical_block_size < size) | |
341 | q->limits.physical_block_size = size; | |
342 | ||
343 | if (q->limits.io_min < q->limits.physical_block_size) | |
344 | q->limits.io_min = q->limits.physical_block_size; | |
86db1e29 | 345 | } |
e1defc4f | 346 | EXPORT_SYMBOL(blk_queue_logical_block_size); |
86db1e29 | 347 | |
c72758f3 MP |
348 | /** |
349 | * blk_queue_physical_block_size - set physical block size for the queue | |
350 | * @q: the request queue for the device | |
351 | * @size: the physical block size, in bytes | |
352 | * | |
353 | * Description: | |
354 | * This should be set to the lowest possible sector size that the | |
355 | * hardware can operate on without reverting to read-modify-write | |
356 | * operations. | |
357 | */ | |
358 | void blk_queue_physical_block_size(struct request_queue *q, unsigned short size) | |
359 | { | |
360 | q->limits.physical_block_size = size; | |
361 | ||
362 | if (q->limits.physical_block_size < q->limits.logical_block_size) | |
363 | q->limits.physical_block_size = q->limits.logical_block_size; | |
364 | ||
365 | if (q->limits.io_min < q->limits.physical_block_size) | |
366 | q->limits.io_min = q->limits.physical_block_size; | |
367 | } | |
368 | EXPORT_SYMBOL(blk_queue_physical_block_size); | |
369 | ||
370 | /** | |
371 | * blk_queue_alignment_offset - set physical block alignment offset | |
372 | * @q: the request queue for the device | |
8ebf9756 | 373 | * @offset: alignment offset in bytes |
c72758f3 MP |
374 | * |
375 | * Description: | |
376 | * Some devices are naturally misaligned to compensate for things like | |
377 | * the legacy DOS partition table 63-sector offset. Low-level drivers | |
378 | * should call this function for devices whose first sector is not | |
379 | * naturally aligned. | |
380 | */ | |
381 | void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset) | |
382 | { | |
383 | q->limits.alignment_offset = | |
384 | offset & (q->limits.physical_block_size - 1); | |
385 | q->limits.misaligned = 0; | |
386 | } | |
387 | EXPORT_SYMBOL(blk_queue_alignment_offset); | |
388 | ||
7c958e32 MP |
389 | /** |
390 | * blk_limits_io_min - set minimum request size for a device | |
391 | * @limits: the queue limits | |
392 | * @min: smallest I/O size in bytes | |
393 | * | |
394 | * Description: | |
395 | * Some devices have an internal block size bigger than the reported | |
396 | * hardware sector size. This function can be used to signal the | |
397 | * smallest I/O the device can perform without incurring a performance | |
398 | * penalty. | |
399 | */ | |
400 | void blk_limits_io_min(struct queue_limits *limits, unsigned int min) | |
401 | { | |
402 | limits->io_min = min; | |
403 | ||
404 | if (limits->io_min < limits->logical_block_size) | |
405 | limits->io_min = limits->logical_block_size; | |
406 | ||
407 | if (limits->io_min < limits->physical_block_size) | |
408 | limits->io_min = limits->physical_block_size; | |
409 | } | |
410 | EXPORT_SYMBOL(blk_limits_io_min); | |
411 | ||
c72758f3 MP |
412 | /** |
413 | * blk_queue_io_min - set minimum request size for the queue | |
414 | * @q: the request queue for the device | |
8ebf9756 | 415 | * @min: smallest I/O size in bytes |
c72758f3 MP |
416 | * |
417 | * Description: | |
7e5f5fb0 MP |
418 | * Storage devices may report a granularity or preferred minimum I/O |
419 | * size which is the smallest request the device can perform without | |
420 | * incurring a performance penalty. For disk drives this is often the | |
421 | * physical block size. For RAID arrays it is often the stripe chunk | |
422 | * size. A properly aligned multiple of minimum_io_size is the | |
423 | * preferred request size for workloads where a high number of I/O | |
424 | * operations is desired. | |
c72758f3 MP |
425 | */ |
426 | void blk_queue_io_min(struct request_queue *q, unsigned int min) | |
427 | { | |
7c958e32 | 428 | blk_limits_io_min(&q->limits, min); |
c72758f3 MP |
429 | } |
430 | EXPORT_SYMBOL(blk_queue_io_min); | |
431 | ||
3c5820c7 MP |
432 | /** |
433 | * blk_limits_io_opt - set optimal request size for a device | |
434 | * @limits: the queue limits | |
435 | * @opt: smallest I/O size in bytes | |
436 | * | |
437 | * Description: | |
438 | * Storage devices may report an optimal I/O size, which is the | |
439 | * device's preferred unit for sustained I/O. This is rarely reported | |
440 | * for disk drives. For RAID arrays it is usually the stripe width or | |
441 | * the internal track size. A properly aligned multiple of | |
442 | * optimal_io_size is the preferred request size for workloads where | |
443 | * sustained throughput is desired. | |
444 | */ | |
445 | void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt) | |
446 | { | |
447 | limits->io_opt = opt; | |
448 | } | |
449 | EXPORT_SYMBOL(blk_limits_io_opt); | |
450 | ||
c72758f3 MP |
451 | /** |
452 | * blk_queue_io_opt - set optimal request size for the queue | |
453 | * @q: the request queue for the device | |
8ebf9756 | 454 | * @opt: optimal request size in bytes |
c72758f3 MP |
455 | * |
456 | * Description: | |
7e5f5fb0 MP |
457 | * Storage devices may report an optimal I/O size, which is the |
458 | * device's preferred unit for sustained I/O. This is rarely reported | |
459 | * for disk drives. For RAID arrays it is usually the stripe width or | |
460 | * the internal track size. A properly aligned multiple of | |
461 | * optimal_io_size is the preferred request size for workloads where | |
462 | * sustained throughput is desired. | |
c72758f3 MP |
463 | */ |
464 | void blk_queue_io_opt(struct request_queue *q, unsigned int opt) | |
465 | { | |
3c5820c7 | 466 | blk_limits_io_opt(&q->limits, opt); |
c72758f3 MP |
467 | } |
468 | EXPORT_SYMBOL(blk_queue_io_opt); | |
469 | ||
86db1e29 JA |
470 | /* |
471 | * Returns the minimum that is _not_ zero, unless both are zero. | |
472 | */ | |
473 | #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) | |
474 | ||
475 | /** | |
476 | * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers | |
477 | * @t: the stacking driver (top) | |
478 | * @b: the underlying device (bottom) | |
479 | **/ | |
480 | void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) | |
481 | { | |
fef24667 | 482 | blk_stack_limits(&t->limits, &b->limits, 0); |
025146e1 | 483 | |
e7e72bf6 NB |
484 | if (!t->queue_lock) |
485 | WARN_ON_ONCE(1); | |
486 | else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) { | |
487 | unsigned long flags; | |
488 | spin_lock_irqsave(t->queue_lock, flags); | |
75ad23bc | 489 | queue_flag_clear(QUEUE_FLAG_CLUSTER, t); |
e7e72bf6 NB |
490 | spin_unlock_irqrestore(t->queue_lock, flags); |
491 | } | |
86db1e29 | 492 | } |
86db1e29 JA |
493 | EXPORT_SYMBOL(blk_queue_stack_limits); |
494 | ||
86b37281 MP |
495 | static unsigned int lcm(unsigned int a, unsigned int b) |
496 | { | |
497 | if (a && b) | |
498 | return (a * b) / gcd(a, b); | |
499 | else if (b) | |
500 | return b; | |
501 | ||
502 | return a; | |
503 | } | |
504 | ||
c72758f3 MP |
505 | /** |
506 | * blk_stack_limits - adjust queue_limits for stacked devices | |
507 | * @t: the stacking driver limits (top) | |
77634f33 | 508 | * @b: the underlying queue limits (bottom) |
c72758f3 MP |
509 | * @offset: offset to beginning of data within component device |
510 | * | |
511 | * Description: | |
512 | * Merges two queue_limit structs. Returns 0 if alignment didn't | |
513 | * change. Returns -1 if adding the bottom device caused | |
514 | * misalignment. | |
515 | */ | |
516 | int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, | |
517 | sector_t offset) | |
518 | { | |
86b37281 MP |
519 | int ret; |
520 | ||
521 | ret = 0; | |
522 | ||
c72758f3 MP |
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); | |
77634f33 | 525 | t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); |
c72758f3 MP |
526 | |
527 | t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, | |
528 | b->seg_boundary_mask); | |
529 | ||
530 | t->max_phys_segments = min_not_zero(t->max_phys_segments, | |
531 | b->max_phys_segments); | |
532 | ||
533 | t->max_hw_segments = min_not_zero(t->max_hw_segments, | |
534 | b->max_hw_segments); | |
535 | ||
536 | t->max_segment_size = min_not_zero(t->max_segment_size, | |
537 | b->max_segment_size); | |
538 | ||
539 | t->logical_block_size = max(t->logical_block_size, | |
540 | b->logical_block_size); | |
541 | ||
542 | t->physical_block_size = max(t->physical_block_size, | |
543 | b->physical_block_size); | |
544 | ||
545 | t->io_min = max(t->io_min, b->io_min); | |
546 | t->no_cluster |= b->no_cluster; | |
547 | ||
548 | /* Bottom device offset aligned? */ | |
549 | if (offset && | |
550 | (offset & (b->physical_block_size - 1)) != b->alignment_offset) { | |
551 | t->misaligned = 1; | |
86b37281 MP |
552 | ret = -1; |
553 | } | |
554 | ||
555 | if (offset && | |
556 | (offset & (b->discard_granularity - 1)) != b->discard_alignment) { | |
557 | t->discard_misaligned = 1; | |
558 | ret = -1; | |
c72758f3 MP |
559 | } |
560 | ||
561 | /* If top has no alignment offset, inherit from bottom */ | |
562 | if (!t->alignment_offset) | |
563 | t->alignment_offset = | |
564 | b->alignment_offset & (b->physical_block_size - 1); | |
565 | ||
86b37281 MP |
566 | if (!t->discard_alignment) |
567 | t->discard_alignment = | |
568 | b->discard_alignment & (b->discard_granularity - 1); | |
569 | ||
c72758f3 MP |
570 | /* Top device aligned on logical block boundary? */ |
571 | if (t->alignment_offset & (t->logical_block_size - 1)) { | |
572 | t->misaligned = 1; | |
86b37281 | 573 | ret = -1; |
c72758f3 MP |
574 | } |
575 | ||
86b37281 MP |
576 | /* Find lcm() of optimal I/O size and granularity */ |
577 | t->io_opt = lcm(t->io_opt, b->io_opt); | |
578 | t->discard_granularity = lcm(t->discard_granularity, | |
579 | b->discard_granularity); | |
70dd5bf3 MP |
580 | |
581 | /* Verify that optimal I/O size is a multiple of io_min */ | |
582 | if (t->io_min && t->io_opt % t->io_min) | |
86b37281 | 583 | ret = -1; |
70dd5bf3 | 584 | |
86b37281 | 585 | return ret; |
c72758f3 | 586 | } |
5d85d324 | 587 | EXPORT_SYMBOL(blk_stack_limits); |
c72758f3 MP |
588 | |
589 | /** | |
590 | * disk_stack_limits - adjust queue limits for stacked drivers | |
77634f33 | 591 | * @disk: MD/DM gendisk (top) |
c72758f3 MP |
592 | * @bdev: the underlying block device (bottom) |
593 | * @offset: offset to beginning of data within component device | |
594 | * | |
595 | * Description: | |
596 | * Merges the limits for two queues. Returns 0 if alignment | |
597 | * didn't change. Returns -1 if adding the bottom device caused | |
598 | * misalignment. | |
599 | */ | |
600 | void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, | |
601 | sector_t offset) | |
602 | { | |
603 | struct request_queue *t = disk->queue; | |
604 | struct request_queue *b = bdev_get_queue(bdev); | |
605 | ||
606 | offset += get_start_sect(bdev) << 9; | |
607 | ||
608 | if (blk_stack_limits(&t->limits, &b->limits, offset) < 0) { | |
609 | char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE]; | |
610 | ||
611 | disk_name(disk, 0, top); | |
612 | bdevname(bdev, bottom); | |
613 | ||
614 | printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n", | |
615 | top, bottom); | |
616 | } | |
617 | ||
618 | if (!t->queue_lock) | |
619 | WARN_ON_ONCE(1); | |
620 | else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) { | |
621 | unsigned long flags; | |
622 | ||
623 | spin_lock_irqsave(t->queue_lock, flags); | |
624 | if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) | |
625 | queue_flag_clear(QUEUE_FLAG_CLUSTER, t); | |
626 | spin_unlock_irqrestore(t->queue_lock, flags); | |
627 | } | |
628 | } | |
629 | EXPORT_SYMBOL(disk_stack_limits); | |
630 | ||
e3790c7d TH |
631 | /** |
632 | * blk_queue_dma_pad - set pad mask | |
633 | * @q: the request queue for the device | |
634 | * @mask: pad mask | |
635 | * | |
27f8221a | 636 | * Set dma pad mask. |
e3790c7d | 637 | * |
27f8221a FT |
638 | * Appending pad buffer to a request modifies the last entry of a |
639 | * scatter list such that it includes the pad buffer. | |
e3790c7d TH |
640 | **/ |
641 | void blk_queue_dma_pad(struct request_queue *q, unsigned int mask) | |
642 | { | |
643 | q->dma_pad_mask = mask; | |
644 | } | |
645 | EXPORT_SYMBOL(blk_queue_dma_pad); | |
646 | ||
27f8221a FT |
647 | /** |
648 | * blk_queue_update_dma_pad - update pad mask | |
649 | * @q: the request queue for the device | |
650 | * @mask: pad mask | |
651 | * | |
652 | * Update dma pad mask. | |
653 | * | |
654 | * Appending pad buffer to a request modifies the last entry of a | |
655 | * scatter list such that it includes the pad buffer. | |
656 | **/ | |
657 | void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask) | |
658 | { | |
659 | if (mask > q->dma_pad_mask) | |
660 | q->dma_pad_mask = mask; | |
661 | } | |
662 | EXPORT_SYMBOL(blk_queue_update_dma_pad); | |
663 | ||
86db1e29 JA |
664 | /** |
665 | * blk_queue_dma_drain - Set up a drain buffer for excess dma. | |
86db1e29 | 666 | * @q: the request queue for the device |
2fb98e84 | 667 | * @dma_drain_needed: fn which returns non-zero if drain is necessary |
86db1e29 JA |
668 | * @buf: physically contiguous buffer |
669 | * @size: size of the buffer in bytes | |
670 | * | |
671 | * Some devices have excess DMA problems and can't simply discard (or | |
672 | * zero fill) the unwanted piece of the transfer. They have to have a | |
673 | * real area of memory to transfer it into. The use case for this is | |
674 | * ATAPI devices in DMA mode. If the packet command causes a transfer | |
675 | * bigger than the transfer size some HBAs will lock up if there | |
676 | * aren't DMA elements to contain the excess transfer. What this API | |
677 | * does is adjust the queue so that the buf is always appended | |
678 | * silently to the scatterlist. | |
679 | * | |
680 | * Note: This routine adjusts max_hw_segments to make room for | |
681 | * appending the drain buffer. If you call | |
682 | * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after | |
683 | * calling this routine, you must set the limit to one fewer than your | |
684 | * device can support otherwise there won't be room for the drain | |
685 | * buffer. | |
686 | */ | |
448da4d2 | 687 | int blk_queue_dma_drain(struct request_queue *q, |
2fb98e84 TH |
688 | dma_drain_needed_fn *dma_drain_needed, |
689 | void *buf, unsigned int size) | |
86db1e29 | 690 | { |
ae03bf63 | 691 | if (queue_max_hw_segments(q) < 2 || queue_max_phys_segments(q) < 2) |
86db1e29 JA |
692 | return -EINVAL; |
693 | /* make room for appending the drain */ | |
ae03bf63 MP |
694 | blk_queue_max_hw_segments(q, queue_max_hw_segments(q) - 1); |
695 | blk_queue_max_phys_segments(q, queue_max_phys_segments(q) - 1); | |
2fb98e84 | 696 | q->dma_drain_needed = dma_drain_needed; |
86db1e29 JA |
697 | q->dma_drain_buffer = buf; |
698 | q->dma_drain_size = size; | |
699 | ||
700 | return 0; | |
701 | } | |
86db1e29 JA |
702 | EXPORT_SYMBOL_GPL(blk_queue_dma_drain); |
703 | ||
704 | /** | |
705 | * blk_queue_segment_boundary - set boundary rules for segment merging | |
706 | * @q: the request queue for the device | |
707 | * @mask: the memory boundary mask | |
708 | **/ | |
709 | void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask) | |
710 | { | |
711 | if (mask < PAGE_CACHE_SIZE - 1) { | |
712 | mask = PAGE_CACHE_SIZE - 1; | |
24c03d47 HH |
713 | printk(KERN_INFO "%s: set to minimum %lx\n", |
714 | __func__, mask); | |
86db1e29 JA |
715 | } |
716 | ||
025146e1 | 717 | q->limits.seg_boundary_mask = mask; |
86db1e29 | 718 | } |
86db1e29 JA |
719 | EXPORT_SYMBOL(blk_queue_segment_boundary); |
720 | ||
721 | /** | |
722 | * blk_queue_dma_alignment - set dma length and memory alignment | |
723 | * @q: the request queue for the device | |
724 | * @mask: alignment mask | |
725 | * | |
726 | * description: | |
710027a4 | 727 | * set required memory and length alignment for direct dma transactions. |
8feb4d20 | 728 | * this is used when building direct io requests for the queue. |
86db1e29 JA |
729 | * |
730 | **/ | |
731 | void blk_queue_dma_alignment(struct request_queue *q, int mask) | |
732 | { | |
733 | q->dma_alignment = mask; | |
734 | } | |
86db1e29 JA |
735 | EXPORT_SYMBOL(blk_queue_dma_alignment); |
736 | ||
737 | /** | |
738 | * blk_queue_update_dma_alignment - update dma length and memory alignment | |
739 | * @q: the request queue for the device | |
740 | * @mask: alignment mask | |
741 | * | |
742 | * description: | |
710027a4 | 743 | * update required memory and length alignment for direct dma transactions. |
86db1e29 JA |
744 | * If the requested alignment is larger than the current alignment, then |
745 | * the current queue alignment is updated to the new value, otherwise it | |
746 | * is left alone. The design of this is to allow multiple objects | |
747 | * (driver, device, transport etc) to set their respective | |
748 | * alignments without having them interfere. | |
749 | * | |
750 | **/ | |
751 | void blk_queue_update_dma_alignment(struct request_queue *q, int mask) | |
752 | { | |
753 | BUG_ON(mask > PAGE_SIZE); | |
754 | ||
755 | if (mask > q->dma_alignment) | |
756 | q->dma_alignment = mask; | |
757 | } | |
86db1e29 JA |
758 | EXPORT_SYMBOL(blk_queue_update_dma_alignment); |
759 | ||
aeb3d3a8 | 760 | static int __init blk_settings_init(void) |
86db1e29 JA |
761 | { |
762 | blk_max_low_pfn = max_low_pfn - 1; | |
763 | blk_max_pfn = max_pfn - 1; | |
764 | return 0; | |
765 | } | |
766 | subsys_initcall(blk_settings_init); |