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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); | |
128 | q->make_request_fn = mfn; | |
6728cb0e JA |
129 | q->backing_dev_info.ra_pages = |
130 | (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; | |
86db1e29 JA |
131 | q->backing_dev_info.state = 0; |
132 | q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY; | |
133 | blk_queue_max_sectors(q, SAFE_MAX_SECTORS); | |
134 | blk_queue_hardsect_size(q, 512); | |
135 | blk_queue_dma_alignment(q, 511); | |
136 | blk_queue_congestion_threshold(q); | |
137 | q->nr_batching = BLK_BATCH_REQ; | |
138 | ||
139 | q->unplug_thresh = 4; /* hmm */ | |
140 | q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */ | |
141 | if (q->unplug_delay == 0) | |
142 | q->unplug_delay = 1; | |
143 | ||
86db1e29 JA |
144 | q->unplug_timer.function = blk_unplug_timeout; |
145 | q->unplug_timer.data = (unsigned long)q; | |
146 | ||
147 | /* | |
148 | * by default assume old behaviour and bounce for any highmem page | |
149 | */ | |
150 | blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH); | |
151 | } | |
86db1e29 JA |
152 | EXPORT_SYMBOL(blk_queue_make_request); |
153 | ||
154 | /** | |
155 | * blk_queue_bounce_limit - set bounce buffer limit for queue | |
156 | * @q: the request queue for the device | |
157 | * @dma_addr: bus address limit | |
158 | * | |
159 | * Description: | |
160 | * Different hardware can have different requirements as to what pages | |
161 | * it can do I/O directly to. A low level driver can call | |
162 | * blk_queue_bounce_limit to have lower memory pages allocated as bounce | |
710027a4 | 163 | * buffers for doing I/O to pages residing above @dma_addr. |
86db1e29 JA |
164 | **/ |
165 | void blk_queue_bounce_limit(struct request_queue *q, u64 dma_addr) | |
166 | { | |
6728cb0e | 167 | unsigned long b_pfn = dma_addr >> PAGE_SHIFT; |
86db1e29 JA |
168 | int dma = 0; |
169 | ||
170 | q->bounce_gfp = GFP_NOIO; | |
171 | #if BITS_PER_LONG == 64 | |
172 | /* Assume anything <= 4GB can be handled by IOMMU. | |
173 | Actually some IOMMUs can handle everything, but I don't | |
174 | know of a way to test this here. */ | |
00d61e3e | 175 | if (b_pfn < (min_t(u64, 0x100000000UL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT)) |
86db1e29 JA |
176 | dma = 1; |
177 | q->bounce_pfn = max_low_pfn; | |
178 | #else | |
6728cb0e | 179 | if (b_pfn < blk_max_low_pfn) |
86db1e29 | 180 | dma = 1; |
6728cb0e | 181 | q->bounce_pfn = b_pfn; |
86db1e29 JA |
182 | #endif |
183 | if (dma) { | |
184 | init_emergency_isa_pool(); | |
185 | q->bounce_gfp = GFP_NOIO | GFP_DMA; | |
6728cb0e | 186 | q->bounce_pfn = b_pfn; |
86db1e29 JA |
187 | } |
188 | } | |
86db1e29 JA |
189 | EXPORT_SYMBOL(blk_queue_bounce_limit); |
190 | ||
191 | /** | |
192 | * blk_queue_max_sectors - set max sectors for a request for this queue | |
193 | * @q: the request queue for the device | |
194 | * @max_sectors: max sectors in the usual 512b unit | |
195 | * | |
196 | * Description: | |
197 | * Enables a low level driver to set an upper limit on the size of | |
198 | * received requests. | |
199 | **/ | |
200 | void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors) | |
201 | { | |
202 | if ((max_sectors << 9) < PAGE_CACHE_SIZE) { | |
203 | max_sectors = 1 << (PAGE_CACHE_SHIFT - 9); | |
24c03d47 HH |
204 | printk(KERN_INFO "%s: set to minimum %d\n", |
205 | __func__, max_sectors); | |
86db1e29 JA |
206 | } |
207 | ||
208 | if (BLK_DEF_MAX_SECTORS > max_sectors) | |
209 | q->max_hw_sectors = q->max_sectors = max_sectors; | |
210 | else { | |
211 | q->max_sectors = BLK_DEF_MAX_SECTORS; | |
212 | q->max_hw_sectors = max_sectors; | |
213 | } | |
214 | } | |
86db1e29 JA |
215 | EXPORT_SYMBOL(blk_queue_max_sectors); |
216 | ||
217 | /** | |
218 | * blk_queue_max_phys_segments - set max phys segments for a request for this queue | |
219 | * @q: the request queue for the device | |
220 | * @max_segments: max number of segments | |
221 | * | |
222 | * Description: | |
223 | * Enables a low level driver to set an upper limit on the number of | |
224 | * physical data segments in a request. This would be the largest sized | |
225 | * scatter list the driver could handle. | |
226 | **/ | |
227 | void blk_queue_max_phys_segments(struct request_queue *q, | |
228 | unsigned short max_segments) | |
229 | { | |
230 | if (!max_segments) { | |
231 | max_segments = 1; | |
24c03d47 HH |
232 | printk(KERN_INFO "%s: set to minimum %d\n", |
233 | __func__, max_segments); | |
86db1e29 JA |
234 | } |
235 | ||
236 | q->max_phys_segments = max_segments; | |
237 | } | |
86db1e29 JA |
238 | EXPORT_SYMBOL(blk_queue_max_phys_segments); |
239 | ||
240 | /** | |
241 | * blk_queue_max_hw_segments - set max hw segments for a request for this queue | |
242 | * @q: the request queue for the device | |
243 | * @max_segments: max number of segments | |
244 | * | |
245 | * Description: | |
246 | * Enables a low level driver to set an upper limit on the number of | |
247 | * hw data segments in a request. This would be the largest number of | |
710027a4 | 248 | * address/length pairs the host adapter can actually give at once |
86db1e29 JA |
249 | * to the device. |
250 | **/ | |
251 | void blk_queue_max_hw_segments(struct request_queue *q, | |
252 | unsigned short max_segments) | |
253 | { | |
254 | if (!max_segments) { | |
255 | max_segments = 1; | |
24c03d47 HH |
256 | printk(KERN_INFO "%s: set to minimum %d\n", |
257 | __func__, max_segments); | |
86db1e29 JA |
258 | } |
259 | ||
260 | q->max_hw_segments = max_segments; | |
261 | } | |
86db1e29 JA |
262 | EXPORT_SYMBOL(blk_queue_max_hw_segments); |
263 | ||
264 | /** | |
265 | * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg | |
266 | * @q: the request queue for the device | |
267 | * @max_size: max size of segment in bytes | |
268 | * | |
269 | * Description: | |
270 | * Enables a low level driver to set an upper limit on the size of a | |
271 | * coalesced segment | |
272 | **/ | |
273 | void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size) | |
274 | { | |
275 | if (max_size < PAGE_CACHE_SIZE) { | |
276 | max_size = PAGE_CACHE_SIZE; | |
24c03d47 HH |
277 | printk(KERN_INFO "%s: set to minimum %d\n", |
278 | __func__, max_size); | |
86db1e29 JA |
279 | } |
280 | ||
281 | q->max_segment_size = max_size; | |
282 | } | |
86db1e29 JA |
283 | EXPORT_SYMBOL(blk_queue_max_segment_size); |
284 | ||
285 | /** | |
286 | * blk_queue_hardsect_size - set hardware sector size for the queue | |
287 | * @q: the request queue for the device | |
288 | * @size: the hardware sector size, in bytes | |
289 | * | |
290 | * Description: | |
291 | * This should typically be set to the lowest possible sector size | |
292 | * that the hardware can operate on (possible without reverting to | |
293 | * even internal read-modify-write operations). Usually the default | |
294 | * of 512 covers most hardware. | |
295 | **/ | |
296 | void blk_queue_hardsect_size(struct request_queue *q, unsigned short size) | |
297 | { | |
298 | q->hardsect_size = size; | |
299 | } | |
86db1e29 JA |
300 | EXPORT_SYMBOL(blk_queue_hardsect_size); |
301 | ||
302 | /* | |
303 | * Returns the minimum that is _not_ zero, unless both are zero. | |
304 | */ | |
305 | #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) | |
306 | ||
307 | /** | |
308 | * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers | |
309 | * @t: the stacking driver (top) | |
310 | * @b: the underlying device (bottom) | |
311 | **/ | |
312 | void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) | |
313 | { | |
314 | /* zero is "infinity" */ | |
6728cb0e JA |
315 | t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); |
316 | t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); | |
86db1e29 | 317 | |
6728cb0e JA |
318 | t->max_phys_segments = min(t->max_phys_segments, b->max_phys_segments); |
319 | t->max_hw_segments = min(t->max_hw_segments, b->max_hw_segments); | |
320 | t->max_segment_size = min(t->max_segment_size, b->max_segment_size); | |
321 | t->hardsect_size = max(t->hardsect_size, b->hardsect_size); | |
e7e72bf6 NB |
322 | if (!t->queue_lock) |
323 | WARN_ON_ONCE(1); | |
324 | else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) { | |
325 | unsigned long flags; | |
326 | spin_lock_irqsave(t->queue_lock, flags); | |
75ad23bc | 327 | queue_flag_clear(QUEUE_FLAG_CLUSTER, t); |
e7e72bf6 NB |
328 | spin_unlock_irqrestore(t->queue_lock, flags); |
329 | } | |
86db1e29 | 330 | } |
86db1e29 JA |
331 | EXPORT_SYMBOL(blk_queue_stack_limits); |
332 | ||
e3790c7d TH |
333 | /** |
334 | * blk_queue_dma_pad - set pad mask | |
335 | * @q: the request queue for the device | |
336 | * @mask: pad mask | |
337 | * | |
27f8221a | 338 | * Set dma pad mask. |
e3790c7d | 339 | * |
27f8221a FT |
340 | * Appending pad buffer to a request modifies the last entry of a |
341 | * scatter list such that it includes the pad buffer. | |
e3790c7d TH |
342 | **/ |
343 | void blk_queue_dma_pad(struct request_queue *q, unsigned int mask) | |
344 | { | |
345 | q->dma_pad_mask = mask; | |
346 | } | |
347 | EXPORT_SYMBOL(blk_queue_dma_pad); | |
348 | ||
27f8221a FT |
349 | /** |
350 | * blk_queue_update_dma_pad - update pad mask | |
351 | * @q: the request queue for the device | |
352 | * @mask: pad mask | |
353 | * | |
354 | * Update dma pad mask. | |
355 | * | |
356 | * Appending pad buffer to a request modifies the last entry of a | |
357 | * scatter list such that it includes the pad buffer. | |
358 | **/ | |
359 | void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask) | |
360 | { | |
361 | if (mask > q->dma_pad_mask) | |
362 | q->dma_pad_mask = mask; | |
363 | } | |
364 | EXPORT_SYMBOL(blk_queue_update_dma_pad); | |
365 | ||
86db1e29 JA |
366 | /** |
367 | * blk_queue_dma_drain - Set up a drain buffer for excess dma. | |
86db1e29 | 368 | * @q: the request queue for the device |
2fb98e84 | 369 | * @dma_drain_needed: fn which returns non-zero if drain is necessary |
86db1e29 JA |
370 | * @buf: physically contiguous buffer |
371 | * @size: size of the buffer in bytes | |
372 | * | |
373 | * Some devices have excess DMA problems and can't simply discard (or | |
374 | * zero fill) the unwanted piece of the transfer. They have to have a | |
375 | * real area of memory to transfer it into. The use case for this is | |
376 | * ATAPI devices in DMA mode. If the packet command causes a transfer | |
377 | * bigger than the transfer size some HBAs will lock up if there | |
378 | * aren't DMA elements to contain the excess transfer. What this API | |
379 | * does is adjust the queue so that the buf is always appended | |
380 | * silently to the scatterlist. | |
381 | * | |
382 | * Note: This routine adjusts max_hw_segments to make room for | |
383 | * appending the drain buffer. If you call | |
384 | * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after | |
385 | * calling this routine, you must set the limit to one fewer than your | |
386 | * device can support otherwise there won't be room for the drain | |
387 | * buffer. | |
388 | */ | |
448da4d2 | 389 | int blk_queue_dma_drain(struct request_queue *q, |
2fb98e84 TH |
390 | dma_drain_needed_fn *dma_drain_needed, |
391 | void *buf, unsigned int size) | |
86db1e29 JA |
392 | { |
393 | if (q->max_hw_segments < 2 || q->max_phys_segments < 2) | |
394 | return -EINVAL; | |
395 | /* make room for appending the drain */ | |
396 | --q->max_hw_segments; | |
397 | --q->max_phys_segments; | |
2fb98e84 | 398 | q->dma_drain_needed = dma_drain_needed; |
86db1e29 JA |
399 | q->dma_drain_buffer = buf; |
400 | q->dma_drain_size = size; | |
401 | ||
402 | return 0; | |
403 | } | |
86db1e29 JA |
404 | EXPORT_SYMBOL_GPL(blk_queue_dma_drain); |
405 | ||
406 | /** | |
407 | * blk_queue_segment_boundary - set boundary rules for segment merging | |
408 | * @q: the request queue for the device | |
409 | * @mask: the memory boundary mask | |
410 | **/ | |
411 | void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask) | |
412 | { | |
413 | if (mask < PAGE_CACHE_SIZE - 1) { | |
414 | mask = PAGE_CACHE_SIZE - 1; | |
24c03d47 HH |
415 | printk(KERN_INFO "%s: set to minimum %lx\n", |
416 | __func__, mask); | |
86db1e29 JA |
417 | } |
418 | ||
419 | q->seg_boundary_mask = mask; | |
420 | } | |
86db1e29 JA |
421 | EXPORT_SYMBOL(blk_queue_segment_boundary); |
422 | ||
423 | /** | |
424 | * blk_queue_dma_alignment - set dma length and memory alignment | |
425 | * @q: the request queue for the device | |
426 | * @mask: alignment mask | |
427 | * | |
428 | * description: | |
710027a4 | 429 | * set required memory and length alignment for direct dma transactions. |
86db1e29 JA |
430 | * this is used when buiding direct io requests for the queue. |
431 | * | |
432 | **/ | |
433 | void blk_queue_dma_alignment(struct request_queue *q, int mask) | |
434 | { | |
435 | q->dma_alignment = mask; | |
436 | } | |
86db1e29 JA |
437 | EXPORT_SYMBOL(blk_queue_dma_alignment); |
438 | ||
439 | /** | |
440 | * blk_queue_update_dma_alignment - update dma length and memory alignment | |
441 | * @q: the request queue for the device | |
442 | * @mask: alignment mask | |
443 | * | |
444 | * description: | |
710027a4 | 445 | * update required memory and length alignment for direct dma transactions. |
86db1e29 JA |
446 | * If the requested alignment is larger than the current alignment, then |
447 | * the current queue alignment is updated to the new value, otherwise it | |
448 | * is left alone. The design of this is to allow multiple objects | |
449 | * (driver, device, transport etc) to set their respective | |
450 | * alignments without having them interfere. | |
451 | * | |
452 | **/ | |
453 | void blk_queue_update_dma_alignment(struct request_queue *q, int mask) | |
454 | { | |
455 | BUG_ON(mask > PAGE_SIZE); | |
456 | ||
457 | if (mask > q->dma_alignment) | |
458 | q->dma_alignment = mask; | |
459 | } | |
86db1e29 JA |
460 | EXPORT_SYMBOL(blk_queue_update_dma_alignment); |
461 | ||
aeb3d3a8 | 462 | static int __init blk_settings_init(void) |
86db1e29 JA |
463 | { |
464 | blk_max_low_pfn = max_low_pfn - 1; | |
465 | blk_max_pfn = max_pfn - 1; | |
466 | return 0; | |
467 | } | |
468 | subsys_initcall(blk_settings_init); |