Commit | Line | Data |
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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 */ | |
10 | ||
11 | #include "blk.h" | |
12 | ||
6728cb0e | 13 | unsigned long blk_max_low_pfn; |
86db1e29 | 14 | EXPORT_SYMBOL(blk_max_low_pfn); |
6728cb0e JA |
15 | |
16 | unsigned long blk_max_pfn; | |
86db1e29 JA |
17 | |
18 | /** | |
19 | * blk_queue_prep_rq - set a prepare_request function for queue | |
20 | * @q: queue | |
21 | * @pfn: prepare_request function | |
22 | * | |
23 | * It's possible for a queue to register a prepare_request callback which | |
24 | * is invoked before the request is handed to the request_fn. The goal of | |
25 | * the function is to prepare a request for I/O, it can be used to build a | |
26 | * cdb from the request data for instance. | |
27 | * | |
28 | */ | |
29 | void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn) | |
30 | { | |
31 | q->prep_rq_fn = pfn; | |
32 | } | |
86db1e29 JA |
33 | EXPORT_SYMBOL(blk_queue_prep_rq); |
34 | ||
fb2dce86 DW |
35 | /** |
36 | * blk_queue_set_discard - set a discard_sectors function for queue | |
37 | * @q: queue | |
38 | * @dfn: prepare_discard function | |
39 | * | |
40 | * It's possible for a queue to register a discard callback which is used | |
41 | * to transform a discard request into the appropriate type for the | |
42 | * hardware. If none is registered, then discard requests are failed | |
43 | * with %EOPNOTSUPP. | |
44 | * | |
45 | */ | |
46 | void blk_queue_set_discard(struct request_queue *q, prepare_discard_fn *dfn) | |
47 | { | |
48 | q->prepare_discard_fn = dfn; | |
49 | } | |
50 | EXPORT_SYMBOL(blk_queue_set_discard); | |
51 | ||
86db1e29 JA |
52 | /** |
53 | * blk_queue_merge_bvec - set a merge_bvec function for queue | |
54 | * @q: queue | |
55 | * @mbfn: merge_bvec_fn | |
56 | * | |
57 | * Usually queues have static limitations on the max sectors or segments that | |
58 | * we can put in a request. Stacking drivers may have some settings that | |
59 | * are dynamic, and thus we have to query the queue whether it is ok to | |
60 | * add a new bio_vec to a bio at a given offset or not. If the block device | |
61 | * has such limitations, it needs to register a merge_bvec_fn to control | |
62 | * the size of bio's sent to it. Note that a block device *must* allow a | |
63 | * single page to be added to an empty bio. The block device driver may want | |
64 | * to use the bio_split() function to deal with these bio's. By default | |
65 | * no merge_bvec_fn is defined for a queue, and only the fixed limits are | |
66 | * honored. | |
67 | */ | |
68 | void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn) | |
69 | { | |
70 | q->merge_bvec_fn = mbfn; | |
71 | } | |
86db1e29 JA |
72 | EXPORT_SYMBOL(blk_queue_merge_bvec); |
73 | ||
74 | void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn) | |
75 | { | |
76 | q->softirq_done_fn = fn; | |
77 | } | |
86db1e29 JA |
78 | EXPORT_SYMBOL(blk_queue_softirq_done); |
79 | ||
242f9dcb JA |
80 | void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout) |
81 | { | |
82 | q->rq_timeout = timeout; | |
83 | } | |
84 | EXPORT_SYMBOL_GPL(blk_queue_rq_timeout); | |
85 | ||
86 | void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn) | |
87 | { | |
88 | q->rq_timed_out_fn = fn; | |
89 | } | |
90 | EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out); | |
91 | ||
ef9e3fac KU |
92 | void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn) |
93 | { | |
94 | q->lld_busy_fn = fn; | |
95 | } | |
96 | EXPORT_SYMBOL_GPL(blk_queue_lld_busy); | |
97 | ||
e475bba2 MP |
98 | /** |
99 | * blk_set_default_limits - reset limits to default values | |
f740f5ca | 100 | * @lim: the queue_limits structure to reset |
e475bba2 MP |
101 | * |
102 | * Description: | |
103 | * Returns a queue_limit struct to its default state. Can be used by | |
104 | * stacking drivers like DM that stage table swaps and reuse an | |
105 | * existing device queue. | |
106 | */ | |
107 | void blk_set_default_limits(struct queue_limits *lim) | |
108 | { | |
109 | lim->max_phys_segments = MAX_PHYS_SEGMENTS; | |
110 | lim->max_hw_segments = MAX_HW_SEGMENTS; | |
111 | lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK; | |
112 | lim->max_segment_size = MAX_SEGMENT_SIZE; | |
113 | lim->max_sectors = lim->max_hw_sectors = SAFE_MAX_SECTORS; | |
114 | lim->logical_block_size = lim->physical_block_size = lim->io_min = 512; | |
3a02c8e8 | 115 | lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT); |
e475bba2 MP |
116 | lim->alignment_offset = 0; |
117 | lim->io_opt = 0; | |
118 | lim->misaligned = 0; | |
119 | lim->no_cluster = 0; | |
120 | } | |
121 | EXPORT_SYMBOL(blk_set_default_limits); | |
122 | ||
86db1e29 JA |
123 | /** |
124 | * blk_queue_make_request - define an alternate make_request function for a device | |
125 | * @q: the request queue for the device to be affected | |
126 | * @mfn: the alternate make_request function | |
127 | * | |
128 | * Description: | |
129 | * The normal way for &struct bios to be passed to a device | |
130 | * driver is for them to be collected into requests on a request | |
131 | * queue, and then to allow the device driver to select requests | |
132 | * off that queue when it is ready. This works well for many block | |
133 | * devices. However some block devices (typically virtual devices | |
134 | * such as md or lvm) do not benefit from the processing on the | |
135 | * request queue, and are served best by having the requests passed | |
136 | * directly to them. This can be achieved by providing a function | |
137 | * to blk_queue_make_request(). | |
138 | * | |
139 | * Caveat: | |
140 | * The driver that does this *must* be able to deal appropriately | |
141 | * with buffers in "highmemory". This can be accomplished by either calling | |
142 | * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling | |
143 | * blk_queue_bounce() to create a buffer in normal memory. | |
144 | **/ | |
6728cb0e | 145 | void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn) |
86db1e29 JA |
146 | { |
147 | /* | |
148 | * set defaults | |
149 | */ | |
150 | q->nr_requests = BLKDEV_MAX_RQ; | |
0e435ac2 | 151 | |
86db1e29 | 152 | q->make_request_fn = mfn; |
86db1e29 JA |
153 | blk_queue_dma_alignment(q, 511); |
154 | blk_queue_congestion_threshold(q); | |
155 | q->nr_batching = BLK_BATCH_REQ; | |
156 | ||
157 | q->unplug_thresh = 4; /* hmm */ | |
158 | q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */ | |
159 | if (q->unplug_delay == 0) | |
160 | q->unplug_delay = 1; | |
161 | ||
86db1e29 JA |
162 | q->unplug_timer.function = blk_unplug_timeout; |
163 | q->unplug_timer.data = (unsigned long)q; | |
164 | ||
e475bba2 MP |
165 | blk_set_default_limits(&q->limits); |
166 | ||
a4e7d464 JA |
167 | /* |
168 | * If the caller didn't supply a lock, fall back to our embedded | |
169 | * per-queue locks | |
170 | */ | |
171 | if (!q->queue_lock) | |
172 | q->queue_lock = &q->__queue_lock; | |
173 | ||
86db1e29 JA |
174 | /* |
175 | * by default assume old behaviour and bounce for any highmem page | |
176 | */ | |
177 | blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH); | |
178 | } | |
86db1e29 JA |
179 | EXPORT_SYMBOL(blk_queue_make_request); |
180 | ||
181 | /** | |
182 | * blk_queue_bounce_limit - set bounce buffer limit for queue | |
cd0aca2d TH |
183 | * @q: the request queue for the device |
184 | * @dma_mask: the maximum address the device can handle | |
86db1e29 JA |
185 | * |
186 | * Description: | |
187 | * Different hardware can have different requirements as to what pages | |
188 | * it can do I/O directly to. A low level driver can call | |
189 | * blk_queue_bounce_limit to have lower memory pages allocated as bounce | |
cd0aca2d | 190 | * buffers for doing I/O to pages residing above @dma_mask. |
86db1e29 | 191 | **/ |
cd0aca2d | 192 | void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask) |
86db1e29 | 193 | { |
cd0aca2d | 194 | unsigned long b_pfn = dma_mask >> PAGE_SHIFT; |
86db1e29 JA |
195 | int dma = 0; |
196 | ||
197 | q->bounce_gfp = GFP_NOIO; | |
198 | #if BITS_PER_LONG == 64 | |
cd0aca2d TH |
199 | /* |
200 | * Assume anything <= 4GB can be handled by IOMMU. Actually | |
201 | * some IOMMUs can handle everything, but I don't know of a | |
202 | * way to test this here. | |
203 | */ | |
204 | if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT)) | |
86db1e29 | 205 | dma = 1; |
025146e1 | 206 | q->limits.bounce_pfn = max_low_pfn; |
86db1e29 | 207 | #else |
6728cb0e | 208 | if (b_pfn < blk_max_low_pfn) |
86db1e29 | 209 | dma = 1; |
025146e1 | 210 | q->limits.bounce_pfn = b_pfn; |
86db1e29 JA |
211 | #endif |
212 | if (dma) { | |
213 | init_emergency_isa_pool(); | |
214 | q->bounce_gfp = GFP_NOIO | GFP_DMA; | |
025146e1 | 215 | q->limits.bounce_pfn = b_pfn; |
86db1e29 JA |
216 | } |
217 | } | |
86db1e29 JA |
218 | EXPORT_SYMBOL(blk_queue_bounce_limit); |
219 | ||
220 | /** | |
221 | * blk_queue_max_sectors - set max sectors for a request for this queue | |
222 | * @q: the request queue for the device | |
223 | * @max_sectors: max sectors in the usual 512b unit | |
224 | * | |
225 | * Description: | |
226 | * Enables a low level driver to set an upper limit on the size of | |
227 | * received requests. | |
228 | **/ | |
229 | void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors) | |
230 | { | |
231 | if ((max_sectors << 9) < PAGE_CACHE_SIZE) { | |
232 | max_sectors = 1 << (PAGE_CACHE_SHIFT - 9); | |
24c03d47 HH |
233 | printk(KERN_INFO "%s: set to minimum %d\n", |
234 | __func__, max_sectors); | |
86db1e29 JA |
235 | } |
236 | ||
237 | if (BLK_DEF_MAX_SECTORS > max_sectors) | |
025146e1 | 238 | q->limits.max_hw_sectors = q->limits.max_sectors = max_sectors; |
86db1e29 | 239 | else { |
025146e1 MP |
240 | q->limits.max_sectors = BLK_DEF_MAX_SECTORS; |
241 | q->limits.max_hw_sectors = max_sectors; | |
86db1e29 JA |
242 | } |
243 | } | |
86db1e29 JA |
244 | EXPORT_SYMBOL(blk_queue_max_sectors); |
245 | ||
ae03bf63 MP |
246 | void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_sectors) |
247 | { | |
248 | if (BLK_DEF_MAX_SECTORS > max_sectors) | |
025146e1 | 249 | q->limits.max_hw_sectors = BLK_DEF_MAX_SECTORS; |
ae03bf63 | 250 | else |
025146e1 | 251 | q->limits.max_hw_sectors = max_sectors; |
ae03bf63 MP |
252 | } |
253 | EXPORT_SYMBOL(blk_queue_max_hw_sectors); | |
254 | ||
86db1e29 JA |
255 | /** |
256 | * blk_queue_max_phys_segments - set max phys segments for a request for this queue | |
257 | * @q: the request queue for the device | |
258 | * @max_segments: max number of segments | |
259 | * | |
260 | * Description: | |
261 | * Enables a low level driver to set an upper limit on the number of | |
262 | * physical data segments in a request. This would be the largest sized | |
263 | * scatter list the driver could handle. | |
264 | **/ | |
265 | void blk_queue_max_phys_segments(struct request_queue *q, | |
266 | unsigned short max_segments) | |
267 | { | |
268 | if (!max_segments) { | |
269 | max_segments = 1; | |
24c03d47 HH |
270 | printk(KERN_INFO "%s: set to minimum %d\n", |
271 | __func__, max_segments); | |
86db1e29 JA |
272 | } |
273 | ||
025146e1 | 274 | q->limits.max_phys_segments = max_segments; |
86db1e29 | 275 | } |
86db1e29 JA |
276 | EXPORT_SYMBOL(blk_queue_max_phys_segments); |
277 | ||
278 | /** | |
279 | * blk_queue_max_hw_segments - set max hw segments for a request for this queue | |
280 | * @q: the request queue for the device | |
281 | * @max_segments: max number of segments | |
282 | * | |
283 | * Description: | |
284 | * Enables a low level driver to set an upper limit on the number of | |
285 | * hw data segments in a request. This would be the largest number of | |
710027a4 | 286 | * address/length pairs the host adapter can actually give at once |
86db1e29 JA |
287 | * to the device. |
288 | **/ | |
289 | void blk_queue_max_hw_segments(struct request_queue *q, | |
290 | unsigned short max_segments) | |
291 | { | |
292 | if (!max_segments) { | |
293 | max_segments = 1; | |
24c03d47 HH |
294 | printk(KERN_INFO "%s: set to minimum %d\n", |
295 | __func__, max_segments); | |
86db1e29 JA |
296 | } |
297 | ||
025146e1 | 298 | q->limits.max_hw_segments = max_segments; |
86db1e29 | 299 | } |
86db1e29 JA |
300 | EXPORT_SYMBOL(blk_queue_max_hw_segments); |
301 | ||
302 | /** | |
303 | * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg | |
304 | * @q: the request queue for the device | |
305 | * @max_size: max size of segment in bytes | |
306 | * | |
307 | * Description: | |
308 | * Enables a low level driver to set an upper limit on the size of a | |
309 | * coalesced segment | |
310 | **/ | |
311 | void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size) | |
312 | { | |
313 | if (max_size < PAGE_CACHE_SIZE) { | |
314 | max_size = PAGE_CACHE_SIZE; | |
24c03d47 HH |
315 | printk(KERN_INFO "%s: set to minimum %d\n", |
316 | __func__, max_size); | |
86db1e29 JA |
317 | } |
318 | ||
025146e1 | 319 | q->limits.max_segment_size = max_size; |
86db1e29 | 320 | } |
86db1e29 JA |
321 | EXPORT_SYMBOL(blk_queue_max_segment_size); |
322 | ||
323 | /** | |
e1defc4f | 324 | * blk_queue_logical_block_size - set logical block size for the queue |
86db1e29 | 325 | * @q: the request queue for the device |
e1defc4f | 326 | * @size: the logical block size, in bytes |
86db1e29 JA |
327 | * |
328 | * Description: | |
e1defc4f MP |
329 | * This should be set to the lowest possible block size that the |
330 | * storage device can address. The default of 512 covers most | |
331 | * hardware. | |
86db1e29 | 332 | **/ |
e1defc4f | 333 | void blk_queue_logical_block_size(struct request_queue *q, unsigned short size) |
86db1e29 | 334 | { |
025146e1 | 335 | q->limits.logical_block_size = size; |
c72758f3 MP |
336 | |
337 | if (q->limits.physical_block_size < size) | |
338 | q->limits.physical_block_size = size; | |
339 | ||
340 | if (q->limits.io_min < q->limits.physical_block_size) | |
341 | q->limits.io_min = q->limits.physical_block_size; | |
86db1e29 | 342 | } |
e1defc4f | 343 | EXPORT_SYMBOL(blk_queue_logical_block_size); |
86db1e29 | 344 | |
c72758f3 MP |
345 | /** |
346 | * blk_queue_physical_block_size - set physical block size for the queue | |
347 | * @q: the request queue for the device | |
348 | * @size: the physical block size, in bytes | |
349 | * | |
350 | * Description: | |
351 | * This should be set to the lowest possible sector size that the | |
352 | * hardware can operate on without reverting to read-modify-write | |
353 | * operations. | |
354 | */ | |
355 | void blk_queue_physical_block_size(struct request_queue *q, unsigned short size) | |
356 | { | |
357 | q->limits.physical_block_size = size; | |
358 | ||
359 | if (q->limits.physical_block_size < q->limits.logical_block_size) | |
360 | q->limits.physical_block_size = q->limits.logical_block_size; | |
361 | ||
362 | if (q->limits.io_min < q->limits.physical_block_size) | |
363 | q->limits.io_min = q->limits.physical_block_size; | |
364 | } | |
365 | EXPORT_SYMBOL(blk_queue_physical_block_size); | |
366 | ||
367 | /** | |
368 | * blk_queue_alignment_offset - set physical block alignment offset | |
369 | * @q: the request queue for the device | |
8ebf9756 | 370 | * @offset: alignment offset in bytes |
c72758f3 MP |
371 | * |
372 | * Description: | |
373 | * Some devices are naturally misaligned to compensate for things like | |
374 | * the legacy DOS partition table 63-sector offset. Low-level drivers | |
375 | * should call this function for devices whose first sector is not | |
376 | * naturally aligned. | |
377 | */ | |
378 | void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset) | |
379 | { | |
380 | q->limits.alignment_offset = | |
381 | offset & (q->limits.physical_block_size - 1); | |
382 | q->limits.misaligned = 0; | |
383 | } | |
384 | EXPORT_SYMBOL(blk_queue_alignment_offset); | |
385 | ||
386 | /** | |
387 | * blk_queue_io_min - set minimum request size for the queue | |
388 | * @q: the request queue for the device | |
8ebf9756 | 389 | * @min: smallest I/O size in bytes |
c72758f3 MP |
390 | * |
391 | * Description: | |
392 | * Some devices have an internal block size bigger than the reported | |
393 | * hardware sector size. This function can be used to signal the | |
394 | * smallest I/O the device can perform without incurring a performance | |
395 | * penalty. | |
396 | */ | |
397 | void blk_queue_io_min(struct request_queue *q, unsigned int min) | |
398 | { | |
399 | q->limits.io_min = min; | |
400 | ||
401 | if (q->limits.io_min < q->limits.logical_block_size) | |
402 | q->limits.io_min = q->limits.logical_block_size; | |
403 | ||
404 | if (q->limits.io_min < q->limits.physical_block_size) | |
405 | q->limits.io_min = q->limits.physical_block_size; | |
406 | } | |
407 | EXPORT_SYMBOL(blk_queue_io_min); | |
408 | ||
409 | /** | |
410 | * blk_queue_io_opt - set optimal request size for the queue | |
411 | * @q: the request queue for the device | |
8ebf9756 | 412 | * @opt: optimal request size in bytes |
c72758f3 MP |
413 | * |
414 | * Description: | |
415 | * Drivers can call this function to set the preferred I/O request | |
416 | * size for devices that report such a value. | |
417 | */ | |
418 | void blk_queue_io_opt(struct request_queue *q, unsigned int opt) | |
419 | { | |
420 | q->limits.io_opt = opt; | |
421 | } | |
422 | EXPORT_SYMBOL(blk_queue_io_opt); | |
423 | ||
86db1e29 JA |
424 | /* |
425 | * Returns the minimum that is _not_ zero, unless both are zero. | |
426 | */ | |
427 | #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) | |
428 | ||
429 | /** | |
430 | * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers | |
431 | * @t: the stacking driver (top) | |
432 | * @b: the underlying device (bottom) | |
433 | **/ | |
434 | void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) | |
435 | { | |
436 | /* zero is "infinity" */ | |
025146e1 MP |
437 | t->limits.max_sectors = min_not_zero(queue_max_sectors(t), |
438 | queue_max_sectors(b)); | |
439 | ||
440 | t->limits.max_hw_sectors = min_not_zero(queue_max_hw_sectors(t), | |
441 | queue_max_hw_sectors(b)); | |
442 | ||
443 | t->limits.seg_boundary_mask = min_not_zero(queue_segment_boundary(t), | |
444 | queue_segment_boundary(b)); | |
445 | ||
446 | t->limits.max_phys_segments = min_not_zero(queue_max_phys_segments(t), | |
447 | queue_max_phys_segments(b)); | |
448 | ||
449 | t->limits.max_hw_segments = min_not_zero(queue_max_hw_segments(t), | |
450 | queue_max_hw_segments(b)); | |
451 | ||
452 | t->limits.max_segment_size = min_not_zero(queue_max_segment_size(t), | |
453 | queue_max_segment_size(b)); | |
454 | ||
455 | t->limits.logical_block_size = max(queue_logical_block_size(t), | |
456 | queue_logical_block_size(b)); | |
457 | ||
e7e72bf6 NB |
458 | if (!t->queue_lock) |
459 | WARN_ON_ONCE(1); | |
460 | else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) { | |
461 | unsigned long flags; | |
462 | spin_lock_irqsave(t->queue_lock, flags); | |
75ad23bc | 463 | queue_flag_clear(QUEUE_FLAG_CLUSTER, t); |
e7e72bf6 NB |
464 | spin_unlock_irqrestore(t->queue_lock, flags); |
465 | } | |
86db1e29 | 466 | } |
86db1e29 JA |
467 | EXPORT_SYMBOL(blk_queue_stack_limits); |
468 | ||
c72758f3 MP |
469 | /** |
470 | * blk_stack_limits - adjust queue_limits for stacked devices | |
471 | * @t: the stacking driver limits (top) | |
77634f33 | 472 | * @b: the underlying queue limits (bottom) |
c72758f3 MP |
473 | * @offset: offset to beginning of data within component device |
474 | * | |
475 | * Description: | |
476 | * Merges two queue_limit structs. Returns 0 if alignment didn't | |
477 | * change. Returns -1 if adding the bottom device caused | |
478 | * misalignment. | |
479 | */ | |
480 | int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, | |
481 | sector_t offset) | |
482 | { | |
483 | t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); | |
484 | t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); | |
77634f33 | 485 | t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); |
c72758f3 MP |
486 | |
487 | t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, | |
488 | b->seg_boundary_mask); | |
489 | ||
490 | t->max_phys_segments = min_not_zero(t->max_phys_segments, | |
491 | b->max_phys_segments); | |
492 | ||
493 | t->max_hw_segments = min_not_zero(t->max_hw_segments, | |
494 | b->max_hw_segments); | |
495 | ||
496 | t->max_segment_size = min_not_zero(t->max_segment_size, | |
497 | b->max_segment_size); | |
498 | ||
499 | t->logical_block_size = max(t->logical_block_size, | |
500 | b->logical_block_size); | |
501 | ||
502 | t->physical_block_size = max(t->physical_block_size, | |
503 | b->physical_block_size); | |
504 | ||
505 | t->io_min = max(t->io_min, b->io_min); | |
506 | t->no_cluster |= b->no_cluster; | |
507 | ||
508 | /* Bottom device offset aligned? */ | |
509 | if (offset && | |
510 | (offset & (b->physical_block_size - 1)) != b->alignment_offset) { | |
511 | t->misaligned = 1; | |
512 | return -1; | |
513 | } | |
514 | ||
515 | /* If top has no alignment offset, inherit from bottom */ | |
516 | if (!t->alignment_offset) | |
517 | t->alignment_offset = | |
518 | b->alignment_offset & (b->physical_block_size - 1); | |
519 | ||
520 | /* Top device aligned on logical block boundary? */ | |
521 | if (t->alignment_offset & (t->logical_block_size - 1)) { | |
522 | t->misaligned = 1; | |
523 | return -1; | |
524 | } | |
525 | ||
526 | return 0; | |
527 | } | |
5d85d324 | 528 | EXPORT_SYMBOL(blk_stack_limits); |
c72758f3 MP |
529 | |
530 | /** | |
531 | * disk_stack_limits - adjust queue limits for stacked drivers | |
77634f33 | 532 | * @disk: MD/DM gendisk (top) |
c72758f3 MP |
533 | * @bdev: the underlying block device (bottom) |
534 | * @offset: offset to beginning of data within component device | |
535 | * | |
536 | * Description: | |
537 | * Merges the limits for two queues. Returns 0 if alignment | |
538 | * didn't change. Returns -1 if adding the bottom device caused | |
539 | * misalignment. | |
540 | */ | |
541 | void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, | |
542 | sector_t offset) | |
543 | { | |
544 | struct request_queue *t = disk->queue; | |
545 | struct request_queue *b = bdev_get_queue(bdev); | |
546 | ||
547 | offset += get_start_sect(bdev) << 9; | |
548 | ||
549 | if (blk_stack_limits(&t->limits, &b->limits, offset) < 0) { | |
550 | char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE]; | |
551 | ||
552 | disk_name(disk, 0, top); | |
553 | bdevname(bdev, bottom); | |
554 | ||
555 | printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n", | |
556 | top, bottom); | |
557 | } | |
558 | ||
559 | if (!t->queue_lock) | |
560 | WARN_ON_ONCE(1); | |
561 | else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) { | |
562 | unsigned long flags; | |
563 | ||
564 | spin_lock_irqsave(t->queue_lock, flags); | |
565 | if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) | |
566 | queue_flag_clear(QUEUE_FLAG_CLUSTER, t); | |
567 | spin_unlock_irqrestore(t->queue_lock, flags); | |
568 | } | |
569 | } | |
570 | EXPORT_SYMBOL(disk_stack_limits); | |
571 | ||
e3790c7d TH |
572 | /** |
573 | * blk_queue_dma_pad - set pad mask | |
574 | * @q: the request queue for the device | |
575 | * @mask: pad mask | |
576 | * | |
27f8221a | 577 | * Set dma pad mask. |
e3790c7d | 578 | * |
27f8221a FT |
579 | * Appending pad buffer to a request modifies the last entry of a |
580 | * scatter list such that it includes the pad buffer. | |
e3790c7d TH |
581 | **/ |
582 | void blk_queue_dma_pad(struct request_queue *q, unsigned int mask) | |
583 | { | |
584 | q->dma_pad_mask = mask; | |
585 | } | |
586 | EXPORT_SYMBOL(blk_queue_dma_pad); | |
587 | ||
27f8221a FT |
588 | /** |
589 | * blk_queue_update_dma_pad - update pad mask | |
590 | * @q: the request queue for the device | |
591 | * @mask: pad mask | |
592 | * | |
593 | * Update dma pad mask. | |
594 | * | |
595 | * Appending pad buffer to a request modifies the last entry of a | |
596 | * scatter list such that it includes the pad buffer. | |
597 | **/ | |
598 | void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask) | |
599 | { | |
600 | if (mask > q->dma_pad_mask) | |
601 | q->dma_pad_mask = mask; | |
602 | } | |
603 | EXPORT_SYMBOL(blk_queue_update_dma_pad); | |
604 | ||
86db1e29 JA |
605 | /** |
606 | * blk_queue_dma_drain - Set up a drain buffer for excess dma. | |
86db1e29 | 607 | * @q: the request queue for the device |
2fb98e84 | 608 | * @dma_drain_needed: fn which returns non-zero if drain is necessary |
86db1e29 JA |
609 | * @buf: physically contiguous buffer |
610 | * @size: size of the buffer in bytes | |
611 | * | |
612 | * Some devices have excess DMA problems and can't simply discard (or | |
613 | * zero fill) the unwanted piece of the transfer. They have to have a | |
614 | * real area of memory to transfer it into. The use case for this is | |
615 | * ATAPI devices in DMA mode. If the packet command causes a transfer | |
616 | * bigger than the transfer size some HBAs will lock up if there | |
617 | * aren't DMA elements to contain the excess transfer. What this API | |
618 | * does is adjust the queue so that the buf is always appended | |
619 | * silently to the scatterlist. | |
620 | * | |
621 | * Note: This routine adjusts max_hw_segments to make room for | |
622 | * appending the drain buffer. If you call | |
623 | * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after | |
624 | * calling this routine, you must set the limit to one fewer than your | |
625 | * device can support otherwise there won't be room for the drain | |
626 | * buffer. | |
627 | */ | |
448da4d2 | 628 | int blk_queue_dma_drain(struct request_queue *q, |
2fb98e84 TH |
629 | dma_drain_needed_fn *dma_drain_needed, |
630 | void *buf, unsigned int size) | |
86db1e29 | 631 | { |
ae03bf63 | 632 | if (queue_max_hw_segments(q) < 2 || queue_max_phys_segments(q) < 2) |
86db1e29 JA |
633 | return -EINVAL; |
634 | /* make room for appending the drain */ | |
ae03bf63 MP |
635 | blk_queue_max_hw_segments(q, queue_max_hw_segments(q) - 1); |
636 | blk_queue_max_phys_segments(q, queue_max_phys_segments(q) - 1); | |
2fb98e84 | 637 | q->dma_drain_needed = dma_drain_needed; |
86db1e29 JA |
638 | q->dma_drain_buffer = buf; |
639 | q->dma_drain_size = size; | |
640 | ||
641 | return 0; | |
642 | } | |
86db1e29 JA |
643 | EXPORT_SYMBOL_GPL(blk_queue_dma_drain); |
644 | ||
645 | /** | |
646 | * blk_queue_segment_boundary - set boundary rules for segment merging | |
647 | * @q: the request queue for the device | |
648 | * @mask: the memory boundary mask | |
649 | **/ | |
650 | void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask) | |
651 | { | |
652 | if (mask < PAGE_CACHE_SIZE - 1) { | |
653 | mask = PAGE_CACHE_SIZE - 1; | |
24c03d47 HH |
654 | printk(KERN_INFO "%s: set to minimum %lx\n", |
655 | __func__, mask); | |
86db1e29 JA |
656 | } |
657 | ||
025146e1 | 658 | q->limits.seg_boundary_mask = mask; |
86db1e29 | 659 | } |
86db1e29 JA |
660 | EXPORT_SYMBOL(blk_queue_segment_boundary); |
661 | ||
662 | /** | |
663 | * blk_queue_dma_alignment - set dma length and memory alignment | |
664 | * @q: the request queue for the device | |
665 | * @mask: alignment mask | |
666 | * | |
667 | * description: | |
710027a4 | 668 | * set required memory and length alignment for direct dma transactions. |
8feb4d20 | 669 | * this is used when building direct io requests for the queue. |
86db1e29 JA |
670 | * |
671 | **/ | |
672 | void blk_queue_dma_alignment(struct request_queue *q, int mask) | |
673 | { | |
674 | q->dma_alignment = mask; | |
675 | } | |
86db1e29 JA |
676 | EXPORT_SYMBOL(blk_queue_dma_alignment); |
677 | ||
678 | /** | |
679 | * blk_queue_update_dma_alignment - update dma length and memory alignment | |
680 | * @q: the request queue for the device | |
681 | * @mask: alignment mask | |
682 | * | |
683 | * description: | |
710027a4 | 684 | * update required memory and length alignment for direct dma transactions. |
86db1e29 JA |
685 | * If the requested alignment is larger than the current alignment, then |
686 | * the current queue alignment is updated to the new value, otherwise it | |
687 | * is left alone. The design of this is to allow multiple objects | |
688 | * (driver, device, transport etc) to set their respective | |
689 | * alignments without having them interfere. | |
690 | * | |
691 | **/ | |
692 | void blk_queue_update_dma_alignment(struct request_queue *q, int mask) | |
693 | { | |
694 | BUG_ON(mask > PAGE_SIZE); | |
695 | ||
696 | if (mask > q->dma_alignment) | |
697 | q->dma_alignment = mask; | |
698 | } | |
86db1e29 JA |
699 | EXPORT_SYMBOL(blk_queue_update_dma_alignment); |
700 | ||
aeb3d3a8 | 701 | static int __init blk_settings_init(void) |
86db1e29 JA |
702 | { |
703 | blk_max_low_pfn = max_low_pfn - 1; | |
704 | blk_max_pfn = max_pfn - 1; | |
705 | return 0; | |
706 | } | |
707 | subsys_initcall(blk_settings_init); |