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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 | ||
86db1e29 JA |
98 | /** |
99 | * blk_queue_make_request - define an alternate make_request function for a device | |
100 | * @q: the request queue for the device to be affected | |
101 | * @mfn: the alternate make_request function | |
102 | * | |
103 | * Description: | |
104 | * The normal way for &struct bios to be passed to a device | |
105 | * driver is for them to be collected into requests on a request | |
106 | * queue, and then to allow the device driver to select requests | |
107 | * off that queue when it is ready. This works well for many block | |
108 | * devices. However some block devices (typically virtual devices | |
109 | * such as md or lvm) do not benefit from the processing on the | |
110 | * request queue, and are served best by having the requests passed | |
111 | * directly to them. This can be achieved by providing a function | |
112 | * to blk_queue_make_request(). | |
113 | * | |
114 | * Caveat: | |
115 | * The driver that does this *must* be able to deal appropriately | |
116 | * with buffers in "highmemory". This can be accomplished by either calling | |
117 | * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling | |
118 | * blk_queue_bounce() to create a buffer in normal memory. | |
119 | **/ | |
6728cb0e | 120 | void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn) |
86db1e29 JA |
121 | { |
122 | /* | |
123 | * set defaults | |
124 | */ | |
125 | q->nr_requests = BLKDEV_MAX_RQ; | |
126 | blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); | |
127 | blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); | |
0e435ac2 MB |
128 | blk_queue_segment_boundary(q, BLK_SEG_BOUNDARY_MASK); |
129 | blk_queue_max_segment_size(q, MAX_SEGMENT_SIZE); | |
130 | ||
86db1e29 | 131 | q->make_request_fn = mfn; |
6728cb0e JA |
132 | q->backing_dev_info.ra_pages = |
133 | (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; | |
86db1e29 JA |
134 | q->backing_dev_info.state = 0; |
135 | q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY; | |
136 | blk_queue_max_sectors(q, SAFE_MAX_SECTORS); | |
e1defc4f | 137 | blk_queue_logical_block_size(q, 512); |
86db1e29 JA |
138 | blk_queue_dma_alignment(q, 511); |
139 | blk_queue_congestion_threshold(q); | |
140 | q->nr_batching = BLK_BATCH_REQ; | |
141 | ||
142 | q->unplug_thresh = 4; /* hmm */ | |
143 | q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */ | |
144 | if (q->unplug_delay == 0) | |
145 | q->unplug_delay = 1; | |
146 | ||
86db1e29 JA |
147 | q->unplug_timer.function = blk_unplug_timeout; |
148 | q->unplug_timer.data = (unsigned long)q; | |
149 | ||
150 | /* | |
151 | * by default assume old behaviour and bounce for any highmem page | |
152 | */ | |
153 | blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH); | |
154 | } | |
86db1e29 JA |
155 | EXPORT_SYMBOL(blk_queue_make_request); |
156 | ||
157 | /** | |
158 | * blk_queue_bounce_limit - set bounce buffer limit for queue | |
cd0aca2d TH |
159 | * @q: the request queue for the device |
160 | * @dma_mask: the maximum address the device can handle | |
86db1e29 JA |
161 | * |
162 | * Description: | |
163 | * Different hardware can have different requirements as to what pages | |
164 | * it can do I/O directly to. A low level driver can call | |
165 | * blk_queue_bounce_limit to have lower memory pages allocated as bounce | |
cd0aca2d | 166 | * buffers for doing I/O to pages residing above @dma_mask. |
86db1e29 | 167 | **/ |
cd0aca2d | 168 | void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask) |
86db1e29 | 169 | { |
cd0aca2d | 170 | unsigned long b_pfn = dma_mask >> PAGE_SHIFT; |
86db1e29 JA |
171 | int dma = 0; |
172 | ||
173 | q->bounce_gfp = GFP_NOIO; | |
174 | #if BITS_PER_LONG == 64 | |
cd0aca2d TH |
175 | /* |
176 | * Assume anything <= 4GB can be handled by IOMMU. Actually | |
177 | * some IOMMUs can handle everything, but I don't know of a | |
178 | * way to test this here. | |
179 | */ | |
180 | if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT)) | |
86db1e29 | 181 | dma = 1; |
025146e1 | 182 | q->limits.bounce_pfn = max_low_pfn; |
86db1e29 | 183 | #else |
6728cb0e | 184 | if (b_pfn < blk_max_low_pfn) |
86db1e29 | 185 | dma = 1; |
025146e1 | 186 | q->limits.bounce_pfn = b_pfn; |
86db1e29 JA |
187 | #endif |
188 | if (dma) { | |
189 | init_emergency_isa_pool(); | |
190 | q->bounce_gfp = GFP_NOIO | GFP_DMA; | |
025146e1 | 191 | q->limits.bounce_pfn = b_pfn; |
86db1e29 JA |
192 | } |
193 | } | |
86db1e29 JA |
194 | EXPORT_SYMBOL(blk_queue_bounce_limit); |
195 | ||
196 | /** | |
197 | * blk_queue_max_sectors - set max sectors for a request for this queue | |
198 | * @q: the request queue for the device | |
199 | * @max_sectors: max sectors in the usual 512b unit | |
200 | * | |
201 | * Description: | |
202 | * Enables a low level driver to set an upper limit on the size of | |
203 | * received requests. | |
204 | **/ | |
205 | void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors) | |
206 | { | |
207 | if ((max_sectors << 9) < PAGE_CACHE_SIZE) { | |
208 | max_sectors = 1 << (PAGE_CACHE_SHIFT - 9); | |
24c03d47 HH |
209 | printk(KERN_INFO "%s: set to minimum %d\n", |
210 | __func__, max_sectors); | |
86db1e29 JA |
211 | } |
212 | ||
213 | if (BLK_DEF_MAX_SECTORS > max_sectors) | |
025146e1 | 214 | q->limits.max_hw_sectors = q->limits.max_sectors = max_sectors; |
86db1e29 | 215 | else { |
025146e1 MP |
216 | q->limits.max_sectors = BLK_DEF_MAX_SECTORS; |
217 | q->limits.max_hw_sectors = max_sectors; | |
86db1e29 JA |
218 | } |
219 | } | |
86db1e29 JA |
220 | EXPORT_SYMBOL(blk_queue_max_sectors); |
221 | ||
ae03bf63 MP |
222 | void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_sectors) |
223 | { | |
224 | if (BLK_DEF_MAX_SECTORS > max_sectors) | |
025146e1 | 225 | q->limits.max_hw_sectors = BLK_DEF_MAX_SECTORS; |
ae03bf63 | 226 | else |
025146e1 | 227 | q->limits.max_hw_sectors = max_sectors; |
ae03bf63 MP |
228 | } |
229 | EXPORT_SYMBOL(blk_queue_max_hw_sectors); | |
230 | ||
86db1e29 JA |
231 | /** |
232 | * blk_queue_max_phys_segments - set max phys segments for a request for this queue | |
233 | * @q: the request queue for the device | |
234 | * @max_segments: max number of segments | |
235 | * | |
236 | * Description: | |
237 | * Enables a low level driver to set an upper limit on the number of | |
238 | * physical data segments in a request. This would be the largest sized | |
239 | * scatter list the driver could handle. | |
240 | **/ | |
241 | void blk_queue_max_phys_segments(struct request_queue *q, | |
242 | unsigned short max_segments) | |
243 | { | |
244 | if (!max_segments) { | |
245 | max_segments = 1; | |
24c03d47 HH |
246 | printk(KERN_INFO "%s: set to minimum %d\n", |
247 | __func__, max_segments); | |
86db1e29 JA |
248 | } |
249 | ||
025146e1 | 250 | q->limits.max_phys_segments = max_segments; |
86db1e29 | 251 | } |
86db1e29 JA |
252 | EXPORT_SYMBOL(blk_queue_max_phys_segments); |
253 | ||
254 | /** | |
255 | * blk_queue_max_hw_segments - set max hw segments for a request for this queue | |
256 | * @q: the request queue for the device | |
257 | * @max_segments: max number of segments | |
258 | * | |
259 | * Description: | |
260 | * Enables a low level driver to set an upper limit on the number of | |
261 | * hw data segments in a request. This would be the largest number of | |
710027a4 | 262 | * address/length pairs the host adapter can actually give at once |
86db1e29 JA |
263 | * to the device. |
264 | **/ | |
265 | void blk_queue_max_hw_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_hw_segments = max_segments; |
86db1e29 | 275 | } |
86db1e29 JA |
276 | EXPORT_SYMBOL(blk_queue_max_hw_segments); |
277 | ||
278 | /** | |
279 | * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg | |
280 | * @q: the request queue for the device | |
281 | * @max_size: max size of segment in bytes | |
282 | * | |
283 | * Description: | |
284 | * Enables a low level driver to set an upper limit on the size of a | |
285 | * coalesced segment | |
286 | **/ | |
287 | void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size) | |
288 | { | |
289 | if (max_size < PAGE_CACHE_SIZE) { | |
290 | max_size = PAGE_CACHE_SIZE; | |
24c03d47 HH |
291 | printk(KERN_INFO "%s: set to minimum %d\n", |
292 | __func__, max_size); | |
86db1e29 JA |
293 | } |
294 | ||
025146e1 | 295 | q->limits.max_segment_size = max_size; |
86db1e29 | 296 | } |
86db1e29 JA |
297 | EXPORT_SYMBOL(blk_queue_max_segment_size); |
298 | ||
299 | /** | |
e1defc4f | 300 | * blk_queue_logical_block_size - set logical block size for the queue |
86db1e29 | 301 | * @q: the request queue for the device |
e1defc4f | 302 | * @size: the logical block size, in bytes |
86db1e29 JA |
303 | * |
304 | * Description: | |
e1defc4f MP |
305 | * This should be set to the lowest possible block size that the |
306 | * storage device can address. The default of 512 covers most | |
307 | * hardware. | |
86db1e29 | 308 | **/ |
e1defc4f | 309 | void blk_queue_logical_block_size(struct request_queue *q, unsigned short size) |
86db1e29 | 310 | { |
025146e1 | 311 | q->limits.logical_block_size = size; |
c72758f3 MP |
312 | |
313 | if (q->limits.physical_block_size < size) | |
314 | q->limits.physical_block_size = size; | |
315 | ||
316 | if (q->limits.io_min < q->limits.physical_block_size) | |
317 | q->limits.io_min = q->limits.physical_block_size; | |
86db1e29 | 318 | } |
e1defc4f | 319 | EXPORT_SYMBOL(blk_queue_logical_block_size); |
86db1e29 | 320 | |
c72758f3 MP |
321 | /** |
322 | * blk_queue_physical_block_size - set physical block size for the queue | |
323 | * @q: the request queue for the device | |
324 | * @size: the physical block size, in bytes | |
325 | * | |
326 | * Description: | |
327 | * This should be set to the lowest possible sector size that the | |
328 | * hardware can operate on without reverting to read-modify-write | |
329 | * operations. | |
330 | */ | |
331 | void blk_queue_physical_block_size(struct request_queue *q, unsigned short size) | |
332 | { | |
333 | q->limits.physical_block_size = size; | |
334 | ||
335 | if (q->limits.physical_block_size < q->limits.logical_block_size) | |
336 | q->limits.physical_block_size = q->limits.logical_block_size; | |
337 | ||
338 | if (q->limits.io_min < q->limits.physical_block_size) | |
339 | q->limits.io_min = q->limits.physical_block_size; | |
340 | } | |
341 | EXPORT_SYMBOL(blk_queue_physical_block_size); | |
342 | ||
343 | /** | |
344 | * blk_queue_alignment_offset - set physical block alignment offset | |
345 | * @q: the request queue for the device | |
346 | * @alignment: alignment offset in bytes | |
347 | * | |
348 | * Description: | |
349 | * Some devices are naturally misaligned to compensate for things like | |
350 | * the legacy DOS partition table 63-sector offset. Low-level drivers | |
351 | * should call this function for devices whose first sector is not | |
352 | * naturally aligned. | |
353 | */ | |
354 | void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset) | |
355 | { | |
356 | q->limits.alignment_offset = | |
357 | offset & (q->limits.physical_block_size - 1); | |
358 | q->limits.misaligned = 0; | |
359 | } | |
360 | EXPORT_SYMBOL(blk_queue_alignment_offset); | |
361 | ||
362 | /** | |
363 | * blk_queue_io_min - set minimum request size for the queue | |
364 | * @q: the request queue for the device | |
365 | * @io_min: smallest I/O size in bytes | |
366 | * | |
367 | * Description: | |
368 | * Some devices have an internal block size bigger than the reported | |
369 | * hardware sector size. This function can be used to signal the | |
370 | * smallest I/O the device can perform without incurring a performance | |
371 | * penalty. | |
372 | */ | |
373 | void blk_queue_io_min(struct request_queue *q, unsigned int min) | |
374 | { | |
375 | q->limits.io_min = min; | |
376 | ||
377 | if (q->limits.io_min < q->limits.logical_block_size) | |
378 | q->limits.io_min = q->limits.logical_block_size; | |
379 | ||
380 | if (q->limits.io_min < q->limits.physical_block_size) | |
381 | q->limits.io_min = q->limits.physical_block_size; | |
382 | } | |
383 | EXPORT_SYMBOL(blk_queue_io_min); | |
384 | ||
385 | /** | |
386 | * blk_queue_io_opt - set optimal request size for the queue | |
387 | * @q: the request queue for the device | |
388 | * @io_opt: optimal request size in bytes | |
389 | * | |
390 | * Description: | |
391 | * Drivers can call this function to set the preferred I/O request | |
392 | * size for devices that report such a value. | |
393 | */ | |
394 | void blk_queue_io_opt(struct request_queue *q, unsigned int opt) | |
395 | { | |
396 | q->limits.io_opt = opt; | |
397 | } | |
398 | EXPORT_SYMBOL(blk_queue_io_opt); | |
399 | ||
86db1e29 JA |
400 | /* |
401 | * Returns the minimum that is _not_ zero, unless both are zero. | |
402 | */ | |
403 | #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) | |
404 | ||
405 | /** | |
406 | * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers | |
407 | * @t: the stacking driver (top) | |
408 | * @b: the underlying device (bottom) | |
409 | **/ | |
410 | void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) | |
411 | { | |
412 | /* zero is "infinity" */ | |
025146e1 MP |
413 | t->limits.max_sectors = min_not_zero(queue_max_sectors(t), |
414 | queue_max_sectors(b)); | |
415 | ||
416 | t->limits.max_hw_sectors = min_not_zero(queue_max_hw_sectors(t), | |
417 | queue_max_hw_sectors(b)); | |
418 | ||
419 | t->limits.seg_boundary_mask = min_not_zero(queue_segment_boundary(t), | |
420 | queue_segment_boundary(b)); | |
421 | ||
422 | t->limits.max_phys_segments = min_not_zero(queue_max_phys_segments(t), | |
423 | queue_max_phys_segments(b)); | |
424 | ||
425 | t->limits.max_hw_segments = min_not_zero(queue_max_hw_segments(t), | |
426 | queue_max_hw_segments(b)); | |
427 | ||
428 | t->limits.max_segment_size = min_not_zero(queue_max_segment_size(t), | |
429 | queue_max_segment_size(b)); | |
430 | ||
431 | t->limits.logical_block_size = max(queue_logical_block_size(t), | |
432 | queue_logical_block_size(b)); | |
433 | ||
e7e72bf6 NB |
434 | if (!t->queue_lock) |
435 | WARN_ON_ONCE(1); | |
436 | else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) { | |
437 | unsigned long flags; | |
438 | spin_lock_irqsave(t->queue_lock, flags); | |
75ad23bc | 439 | queue_flag_clear(QUEUE_FLAG_CLUSTER, t); |
e7e72bf6 NB |
440 | spin_unlock_irqrestore(t->queue_lock, flags); |
441 | } | |
86db1e29 | 442 | } |
86db1e29 JA |
443 | EXPORT_SYMBOL(blk_queue_stack_limits); |
444 | ||
c72758f3 MP |
445 | /** |
446 | * blk_stack_limits - adjust queue_limits for stacked devices | |
447 | * @t: the stacking driver limits (top) | |
448 | * @bdev: the underlying queue limits (bottom) | |
449 | * @offset: offset to beginning of data within component device | |
450 | * | |
451 | * Description: | |
452 | * Merges two queue_limit structs. Returns 0 if alignment didn't | |
453 | * change. Returns -1 if adding the bottom device caused | |
454 | * misalignment. | |
455 | */ | |
456 | int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, | |
457 | sector_t offset) | |
458 | { | |
459 | t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); | |
460 | t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); | |
461 | ||
462 | t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, | |
463 | b->seg_boundary_mask); | |
464 | ||
465 | t->max_phys_segments = min_not_zero(t->max_phys_segments, | |
466 | b->max_phys_segments); | |
467 | ||
468 | t->max_hw_segments = min_not_zero(t->max_hw_segments, | |
469 | b->max_hw_segments); | |
470 | ||
471 | t->max_segment_size = min_not_zero(t->max_segment_size, | |
472 | b->max_segment_size); | |
473 | ||
474 | t->logical_block_size = max(t->logical_block_size, | |
475 | b->logical_block_size); | |
476 | ||
477 | t->physical_block_size = max(t->physical_block_size, | |
478 | b->physical_block_size); | |
479 | ||
480 | t->io_min = max(t->io_min, b->io_min); | |
481 | t->no_cluster |= b->no_cluster; | |
482 | ||
483 | /* Bottom device offset aligned? */ | |
484 | if (offset && | |
485 | (offset & (b->physical_block_size - 1)) != b->alignment_offset) { | |
486 | t->misaligned = 1; | |
487 | return -1; | |
488 | } | |
489 | ||
490 | /* If top has no alignment offset, inherit from bottom */ | |
491 | if (!t->alignment_offset) | |
492 | t->alignment_offset = | |
493 | b->alignment_offset & (b->physical_block_size - 1); | |
494 | ||
495 | /* Top device aligned on logical block boundary? */ | |
496 | if (t->alignment_offset & (t->logical_block_size - 1)) { | |
497 | t->misaligned = 1; | |
498 | return -1; | |
499 | } | |
500 | ||
501 | return 0; | |
502 | } | |
503 | ||
504 | /** | |
505 | * disk_stack_limits - adjust queue limits for stacked drivers | |
506 | * @t: MD/DM gendisk (top) | |
507 | * @bdev: the underlying block device (bottom) | |
508 | * @offset: offset to beginning of data within component device | |
509 | * | |
510 | * Description: | |
511 | * Merges the limits for two queues. Returns 0 if alignment | |
512 | * didn't change. Returns -1 if adding the bottom device caused | |
513 | * misalignment. | |
514 | */ | |
515 | void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, | |
516 | sector_t offset) | |
517 | { | |
518 | struct request_queue *t = disk->queue; | |
519 | struct request_queue *b = bdev_get_queue(bdev); | |
520 | ||
521 | offset += get_start_sect(bdev) << 9; | |
522 | ||
523 | if (blk_stack_limits(&t->limits, &b->limits, offset) < 0) { | |
524 | char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE]; | |
525 | ||
526 | disk_name(disk, 0, top); | |
527 | bdevname(bdev, bottom); | |
528 | ||
529 | printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n", | |
530 | top, bottom); | |
531 | } | |
532 | ||
533 | if (!t->queue_lock) | |
534 | WARN_ON_ONCE(1); | |
535 | else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) { | |
536 | unsigned long flags; | |
537 | ||
538 | spin_lock_irqsave(t->queue_lock, flags); | |
539 | if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) | |
540 | queue_flag_clear(QUEUE_FLAG_CLUSTER, t); | |
541 | spin_unlock_irqrestore(t->queue_lock, flags); | |
542 | } | |
543 | } | |
544 | EXPORT_SYMBOL(disk_stack_limits); | |
545 | ||
e3790c7d TH |
546 | /** |
547 | * blk_queue_dma_pad - set pad mask | |
548 | * @q: the request queue for the device | |
549 | * @mask: pad mask | |
550 | * | |
27f8221a | 551 | * Set dma pad mask. |
e3790c7d | 552 | * |
27f8221a FT |
553 | * Appending pad buffer to a request modifies the last entry of a |
554 | * scatter list such that it includes the pad buffer. | |
e3790c7d TH |
555 | **/ |
556 | void blk_queue_dma_pad(struct request_queue *q, unsigned int mask) | |
557 | { | |
558 | q->dma_pad_mask = mask; | |
559 | } | |
560 | EXPORT_SYMBOL(blk_queue_dma_pad); | |
561 | ||
27f8221a FT |
562 | /** |
563 | * blk_queue_update_dma_pad - update pad mask | |
564 | * @q: the request queue for the device | |
565 | * @mask: pad mask | |
566 | * | |
567 | * Update dma pad mask. | |
568 | * | |
569 | * Appending pad buffer to a request modifies the last entry of a | |
570 | * scatter list such that it includes the pad buffer. | |
571 | **/ | |
572 | void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask) | |
573 | { | |
574 | if (mask > q->dma_pad_mask) | |
575 | q->dma_pad_mask = mask; | |
576 | } | |
577 | EXPORT_SYMBOL(blk_queue_update_dma_pad); | |
578 | ||
86db1e29 JA |
579 | /** |
580 | * blk_queue_dma_drain - Set up a drain buffer for excess dma. | |
86db1e29 | 581 | * @q: the request queue for the device |
2fb98e84 | 582 | * @dma_drain_needed: fn which returns non-zero if drain is necessary |
86db1e29 JA |
583 | * @buf: physically contiguous buffer |
584 | * @size: size of the buffer in bytes | |
585 | * | |
586 | * Some devices have excess DMA problems and can't simply discard (or | |
587 | * zero fill) the unwanted piece of the transfer. They have to have a | |
588 | * real area of memory to transfer it into. The use case for this is | |
589 | * ATAPI devices in DMA mode. If the packet command causes a transfer | |
590 | * bigger than the transfer size some HBAs will lock up if there | |
591 | * aren't DMA elements to contain the excess transfer. What this API | |
592 | * does is adjust the queue so that the buf is always appended | |
593 | * silently to the scatterlist. | |
594 | * | |
595 | * Note: This routine adjusts max_hw_segments to make room for | |
596 | * appending the drain buffer. If you call | |
597 | * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after | |
598 | * calling this routine, you must set the limit to one fewer than your | |
599 | * device can support otherwise there won't be room for the drain | |
600 | * buffer. | |
601 | */ | |
448da4d2 | 602 | int blk_queue_dma_drain(struct request_queue *q, |
2fb98e84 TH |
603 | dma_drain_needed_fn *dma_drain_needed, |
604 | void *buf, unsigned int size) | |
86db1e29 | 605 | { |
ae03bf63 | 606 | if (queue_max_hw_segments(q) < 2 || queue_max_phys_segments(q) < 2) |
86db1e29 JA |
607 | return -EINVAL; |
608 | /* make room for appending the drain */ | |
ae03bf63 MP |
609 | blk_queue_max_hw_segments(q, queue_max_hw_segments(q) - 1); |
610 | blk_queue_max_phys_segments(q, queue_max_phys_segments(q) - 1); | |
2fb98e84 | 611 | q->dma_drain_needed = dma_drain_needed; |
86db1e29 JA |
612 | q->dma_drain_buffer = buf; |
613 | q->dma_drain_size = size; | |
614 | ||
615 | return 0; | |
616 | } | |
86db1e29 JA |
617 | EXPORT_SYMBOL_GPL(blk_queue_dma_drain); |
618 | ||
619 | /** | |
620 | * blk_queue_segment_boundary - set boundary rules for segment merging | |
621 | * @q: the request queue for the device | |
622 | * @mask: the memory boundary mask | |
623 | **/ | |
624 | void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask) | |
625 | { | |
626 | if (mask < PAGE_CACHE_SIZE - 1) { | |
627 | mask = PAGE_CACHE_SIZE - 1; | |
24c03d47 HH |
628 | printk(KERN_INFO "%s: set to minimum %lx\n", |
629 | __func__, mask); | |
86db1e29 JA |
630 | } |
631 | ||
025146e1 | 632 | q->limits.seg_boundary_mask = mask; |
86db1e29 | 633 | } |
86db1e29 JA |
634 | EXPORT_SYMBOL(blk_queue_segment_boundary); |
635 | ||
636 | /** | |
637 | * blk_queue_dma_alignment - set dma length and memory alignment | |
638 | * @q: the request queue for the device | |
639 | * @mask: alignment mask | |
640 | * | |
641 | * description: | |
710027a4 | 642 | * set required memory and length alignment for direct dma transactions. |
8feb4d20 | 643 | * this is used when building direct io requests for the queue. |
86db1e29 JA |
644 | * |
645 | **/ | |
646 | void blk_queue_dma_alignment(struct request_queue *q, int mask) | |
647 | { | |
648 | q->dma_alignment = mask; | |
649 | } | |
86db1e29 JA |
650 | EXPORT_SYMBOL(blk_queue_dma_alignment); |
651 | ||
652 | /** | |
653 | * blk_queue_update_dma_alignment - update dma length and memory alignment | |
654 | * @q: the request queue for the device | |
655 | * @mask: alignment mask | |
656 | * | |
657 | * description: | |
710027a4 | 658 | * update required memory and length alignment for direct dma transactions. |
86db1e29 JA |
659 | * If the requested alignment is larger than the current alignment, then |
660 | * the current queue alignment is updated to the new value, otherwise it | |
661 | * is left alone. The design of this is to allow multiple objects | |
662 | * (driver, device, transport etc) to set their respective | |
663 | * alignments without having them interfere. | |
664 | * | |
665 | **/ | |
666 | void blk_queue_update_dma_alignment(struct request_queue *q, int mask) | |
667 | { | |
668 | BUG_ON(mask > PAGE_SIZE); | |
669 | ||
670 | if (mask > q->dma_alignment) | |
671 | q->dma_alignment = mask; | |
672 | } | |
86db1e29 JA |
673 | EXPORT_SYMBOL(blk_queue_update_dma_alignment); |
674 | ||
aeb3d3a8 | 675 | static int __init blk_settings_init(void) |
86db1e29 JA |
676 | { |
677 | blk_max_low_pfn = max_low_pfn - 1; | |
678 | blk_max_pfn = max_pfn - 1; | |
679 | return 0; | |
680 | } | |
681 | subsys_initcall(blk_settings_init); |