Branch data Line data Source code
1 : : /*
2 : : * Functions related to setting various queue properties from drivers
3 : : */
4 : : #include <linux/kernel.h>
5 : : #include <linux/module.h>
6 : : #include <linux/init.h>
7 : : #include <linux/bio.h>
8 : : #include <linux/blkdev.h>
9 : : #include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
10 : : #include <linux/gcd.h>
11 : : #include <linux/lcm.h>
12 : : #include <linux/jiffies.h>
13 : : #include <linux/gfp.h>
14 : :
15 : : #include "blk.h"
16 : :
17 : : unsigned long blk_max_low_pfn;
18 : : EXPORT_SYMBOL(blk_max_low_pfn);
19 : :
20 : : unsigned long blk_max_pfn;
21 : :
22 : : /**
23 : : * blk_queue_prep_rq - set a prepare_request function for queue
24 : : * @q: queue
25 : : * @pfn: prepare_request function
26 : : *
27 : : * It's possible for a queue to register a prepare_request callback which
28 : : * is invoked before the request is handed to the request_fn. The goal of
29 : : * the function is to prepare a request for I/O, it can be used to build a
30 : : * cdb from the request data for instance.
31 : : *
32 : : */
33 : 0 : void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
34 : : {
35 : 0 : q->prep_rq_fn = pfn;
36 : 0 : }
37 : : EXPORT_SYMBOL(blk_queue_prep_rq);
38 : :
39 : : /**
40 : : * blk_queue_unprep_rq - set an unprepare_request function for queue
41 : : * @q: queue
42 : : * @ufn: unprepare_request function
43 : : *
44 : : * It's possible for a queue to register an unprepare_request callback
45 : : * which is invoked before the request is finally completed. The goal
46 : : * of the function is to deallocate any data that was allocated in the
47 : : * prepare_request callback.
48 : : *
49 : : */
50 : 0 : void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn)
51 : : {
52 : 0 : q->unprep_rq_fn = ufn;
53 : 0 : }
54 : : EXPORT_SYMBOL(blk_queue_unprep_rq);
55 : :
56 : : /**
57 : : * blk_queue_merge_bvec - set a merge_bvec function for queue
58 : : * @q: queue
59 : : * @mbfn: merge_bvec_fn
60 : : *
61 : : * Usually queues have static limitations on the max sectors or segments that
62 : : * we can put in a request. Stacking drivers may have some settings that
63 : : * are dynamic, and thus we have to query the queue whether it is ok to
64 : : * add a new bio_vec to a bio at a given offset or not. If the block device
65 : : * has such limitations, it needs to register a merge_bvec_fn to control
66 : : * the size of bio's sent to it. Note that a block device *must* allow a
67 : : * single page to be added to an empty bio. The block device driver may want
68 : : * to use the bio_split() function to deal with these bio's. By default
69 : : * no merge_bvec_fn is defined for a queue, and only the fixed limits are
70 : : * honored.
71 : : */
72 : 0 : void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
73 : : {
74 : 0 : q->merge_bvec_fn = mbfn;
75 : 0 : }
76 : : EXPORT_SYMBOL(blk_queue_merge_bvec);
77 : :
78 : 0 : void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
79 : : {
80 : 0 : q->softirq_done_fn = fn;
81 : 0 : }
82 : : EXPORT_SYMBOL(blk_queue_softirq_done);
83 : :
84 : 0 : void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
85 : : {
86 : 0 : q->rq_timeout = timeout;
87 : 0 : }
88 : : EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
89 : :
90 : 0 : void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn)
91 : : {
92 : 0 : q->rq_timed_out_fn = fn;
93 : 0 : }
94 : : EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out);
95 : :
96 : 0 : void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn)
97 : : {
98 : 0 : q->lld_busy_fn = fn;
99 : 0 : }
100 : : EXPORT_SYMBOL_GPL(blk_queue_lld_busy);
101 : :
102 : : /**
103 : : * blk_set_default_limits - reset limits to default values
104 : : * @lim: the queue_limits structure to reset
105 : : *
106 : : * Description:
107 : : * Returns a queue_limit struct to its default state.
108 : : */
109 : 0 : void blk_set_default_limits(struct queue_limits *lim)
110 : : {
111 : 0 : lim->max_segments = BLK_MAX_SEGMENTS;
112 : 0 : lim->max_integrity_segments = 0;
113 : 0 : lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
114 : 0 : lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
115 : 0 : lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
116 : 0 : lim->max_write_same_sectors = 0;
117 : 0 : lim->max_discard_sectors = 0;
118 : 0 : lim->discard_granularity = 0;
119 : 0 : lim->discard_alignment = 0;
120 : 0 : lim->discard_misaligned = 0;
121 : 0 : lim->discard_zeroes_data = 0;
122 : 0 : lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
123 : 0 : lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
124 : 0 : lim->alignment_offset = 0;
125 : 0 : lim->io_opt = 0;
126 : 0 : lim->misaligned = 0;
127 : 0 : lim->cluster = 1;
128 : 0 : }
129 : : EXPORT_SYMBOL(blk_set_default_limits);
130 : :
131 : : /**
132 : : * blk_set_stacking_limits - set default limits for stacking devices
133 : : * @lim: the queue_limits structure to reset
134 : : *
135 : : * Description:
136 : : * Returns a queue_limit struct to its default state. Should be used
137 : : * by stacking drivers like DM that have no internal limits.
138 : : */
139 : 0 : void blk_set_stacking_limits(struct queue_limits *lim)
140 : : {
141 : : blk_set_default_limits(lim);
142 : :
143 : : /* Inherit limits from component devices */
144 : 0 : lim->discard_zeroes_data = 1;
145 : 0 : lim->max_segments = USHRT_MAX;
146 : 0 : lim->max_hw_sectors = UINT_MAX;
147 : 0 : lim->max_segment_size = UINT_MAX;
148 : 0 : lim->max_sectors = UINT_MAX;
149 : 0 : lim->max_write_same_sectors = UINT_MAX;
150 : 0 : }
151 : : EXPORT_SYMBOL(blk_set_stacking_limits);
152 : :
153 : : /**
154 : : * blk_queue_make_request - define an alternate make_request function for a device
155 : : * @q: the request queue for the device to be affected
156 : : * @mfn: the alternate make_request function
157 : : *
158 : : * Description:
159 : : * The normal way for &struct bios to be passed to a device
160 : : * driver is for them to be collected into requests on a request
161 : : * queue, and then to allow the device driver to select requests
162 : : * off that queue when it is ready. This works well for many block
163 : : * devices. However some block devices (typically virtual devices
164 : : * such as md or lvm) do not benefit from the processing on the
165 : : * request queue, and are served best by having the requests passed
166 : : * directly to them. This can be achieved by providing a function
167 : : * to blk_queue_make_request().
168 : : *
169 : : * Caveat:
170 : : * The driver that does this *must* be able to deal appropriately
171 : : * with buffers in "highmemory". This can be accomplished by either calling
172 : : * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
173 : : * blk_queue_bounce() to create a buffer in normal memory.
174 : : **/
175 : 0 : void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
176 : : {
177 : : /*
178 : : * set defaults
179 : : */
180 : 0 : q->nr_requests = BLKDEV_MAX_RQ;
181 : :
182 : 0 : q->make_request_fn = mfn;
183 : : blk_queue_dma_alignment(q, 511);
184 : 0 : blk_queue_congestion_threshold(q);
185 : 0 : q->nr_batching = BLK_BATCH_REQ;
186 : :
187 : : blk_set_default_limits(&q->limits);
188 : :
189 : : /*
190 : : * by default assume old behaviour and bounce for any highmem page
191 : : */
192 : 0 : blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
193 : 0 : }
194 : : EXPORT_SYMBOL(blk_queue_make_request);
195 : :
196 : : /**
197 : : * blk_queue_bounce_limit - set bounce buffer limit for queue
198 : : * @q: the request queue for the device
199 : : * @max_addr: the maximum address the device can handle
200 : : *
201 : : * Description:
202 : : * Different hardware can have different requirements as to what pages
203 : : * it can do I/O directly to. A low level driver can call
204 : : * blk_queue_bounce_limit to have lower memory pages allocated as bounce
205 : : * buffers for doing I/O to pages residing above @max_addr.
206 : : **/
207 : 0 : void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr)
208 : : {
209 : 0 : unsigned long b_pfn = max_addr >> PAGE_SHIFT;
210 : : int dma = 0;
211 : :
212 : 0 : q->bounce_gfp = GFP_NOIO;
213 : : #if BITS_PER_LONG == 64
214 : : /*
215 : : * Assume anything <= 4GB can be handled by IOMMU. Actually
216 : : * some IOMMUs can handle everything, but I don't know of a
217 : : * way to test this here.
218 : : */
219 : : if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
220 : : dma = 1;
221 : : q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
222 : : #else
223 [ # # ][ # # ]: 0 : if (b_pfn < blk_max_low_pfn)
224 : : dma = 1;
225 : 0 : q->limits.bounce_pfn = b_pfn;
226 : : #endif
227 [ # # ][ # # ]: 0 : if (dma) {
228 : 0 : init_emergency_isa_pool();
229 : 0 : q->bounce_gfp = GFP_NOIO | GFP_DMA;
230 : 0 : q->limits.bounce_pfn = b_pfn;
231 : : }
232 : 0 : }
233 : : EXPORT_SYMBOL(blk_queue_bounce_limit);
234 : :
235 : : /**
236 : : * blk_limits_max_hw_sectors - set hard and soft limit of max sectors for request
237 : : * @limits: the queue limits
238 : : * @max_hw_sectors: max hardware sectors in the usual 512b unit
239 : : *
240 : : * Description:
241 : : * Enables a low level driver to set a hard upper limit,
242 : : * max_hw_sectors, on the size of requests. max_hw_sectors is set by
243 : : * the device driver based upon the combined capabilities of I/O
244 : : * controller and storage device.
245 : : *
246 : : * max_sectors is a soft limit imposed by the block layer for
247 : : * filesystem type requests. This value can be overridden on a
248 : : * per-device basis in /sys/block/<device>/queue/max_sectors_kb.
249 : : * The soft limit can not exceed max_hw_sectors.
250 : : **/
251 : 0 : void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_sectors)
252 : : {
253 [ # # ]: 0 : if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) {
254 : : max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
255 : 0 : printk(KERN_INFO "%s: set to minimum %d\n",
256 : : __func__, max_hw_sectors);
257 : : }
258 : :
259 : 0 : limits->max_hw_sectors = max_hw_sectors;
260 : 0 : limits->max_sectors = min_t(unsigned int, max_hw_sectors,
261 : : BLK_DEF_MAX_SECTORS);
262 : 0 : }
263 : : EXPORT_SYMBOL(blk_limits_max_hw_sectors);
264 : :
265 : : /**
266 : : * blk_queue_max_hw_sectors - set max sectors for a request for this queue
267 : : * @q: the request queue for the device
268 : : * @max_hw_sectors: max hardware sectors in the usual 512b unit
269 : : *
270 : : * Description:
271 : : * See description for blk_limits_max_hw_sectors().
272 : : **/
273 : 0 : void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
274 : : {
275 : 0 : blk_limits_max_hw_sectors(&q->limits, max_hw_sectors);
276 : 0 : }
277 : : EXPORT_SYMBOL(blk_queue_max_hw_sectors);
278 : :
279 : : /**
280 : : * blk_queue_max_discard_sectors - set max sectors for a single discard
281 : : * @q: the request queue for the device
282 : : * @max_discard_sectors: maximum number of sectors to discard
283 : : **/
284 : 0 : void blk_queue_max_discard_sectors(struct request_queue *q,
285 : : unsigned int max_discard_sectors)
286 : : {
287 : 0 : q->limits.max_discard_sectors = max_discard_sectors;
288 : 0 : }
289 : : EXPORT_SYMBOL(blk_queue_max_discard_sectors);
290 : :
291 : : /**
292 : : * blk_queue_max_write_same_sectors - set max sectors for a single write same
293 : : * @q: the request queue for the device
294 : : * @max_write_same_sectors: maximum number of sectors to write per command
295 : : **/
296 : 0 : void blk_queue_max_write_same_sectors(struct request_queue *q,
297 : : unsigned int max_write_same_sectors)
298 : : {
299 : 0 : q->limits.max_write_same_sectors = max_write_same_sectors;
300 : 0 : }
301 : : EXPORT_SYMBOL(blk_queue_max_write_same_sectors);
302 : :
303 : : /**
304 : : * blk_queue_max_segments - set max hw segments for a request for this queue
305 : : * @q: the request queue for the device
306 : : * @max_segments: max number of segments
307 : : *
308 : : * Description:
309 : : * Enables a low level driver to set an upper limit on the number of
310 : : * hw data segments in a request.
311 : : **/
312 : 0 : void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
313 : : {
314 [ # # ][ # # ]: 0 : if (!max_segments) {
315 : : max_segments = 1;
316 : 0 : printk(KERN_INFO "%s: set to minimum %d\n",
317 : : __func__, max_segments);
318 : : }
319 : :
320 : 0 : q->limits.max_segments = max_segments;
321 : 0 : }
322 : : EXPORT_SYMBOL(blk_queue_max_segments);
323 : :
324 : : /**
325 : : * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
326 : : * @q: the request queue for the device
327 : : * @max_size: max size of segment in bytes
328 : : *
329 : : * Description:
330 : : * Enables a low level driver to set an upper limit on the size of a
331 : : * coalesced segment
332 : : **/
333 : 0 : void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
334 : : {
335 [ # # ]: 0 : if (max_size < PAGE_CACHE_SIZE) {
336 : : max_size = PAGE_CACHE_SIZE;
337 : 0 : printk(KERN_INFO "%s: set to minimum %d\n",
338 : : __func__, max_size);
339 : : }
340 : :
341 : 0 : q->limits.max_segment_size = max_size;
342 : 0 : }
343 : : EXPORT_SYMBOL(blk_queue_max_segment_size);
344 : :
345 : : /**
346 : : * blk_queue_logical_block_size - set logical block size for the queue
347 : : * @q: the request queue for the device
348 : : * @size: the logical block size, in bytes
349 : : *
350 : : * Description:
351 : : * This should be set to the lowest possible block size that the
352 : : * storage device can address. The default of 512 covers most
353 : : * hardware.
354 : : **/
355 : 0 : void blk_queue_logical_block_size(struct request_queue *q, unsigned short size)
356 : : {
357 : 0 : q->limits.logical_block_size = size;
358 : :
359 [ # # ]: 0 : if (q->limits.physical_block_size < size)
360 : 0 : q->limits.physical_block_size = size;
361 : :
362 [ # # ]: 0 : if (q->limits.io_min < q->limits.physical_block_size)
363 : 0 : q->limits.io_min = q->limits.physical_block_size;
364 : 0 : }
365 : : EXPORT_SYMBOL(blk_queue_logical_block_size);
366 : :
367 : : /**
368 : : * blk_queue_physical_block_size - set physical block size for the queue
369 : : * @q: the request queue for the device
370 : : * @size: the physical block size, in bytes
371 : : *
372 : : * Description:
373 : : * This should be set to the lowest possible sector size that the
374 : : * hardware can operate on without reverting to read-modify-write
375 : : * operations.
376 : : */
377 : 0 : void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
378 : : {
379 : 0 : q->limits.physical_block_size = size;
380 : :
381 [ # # ]: 0 : if (q->limits.physical_block_size < q->limits.logical_block_size)
382 : 0 : q->limits.physical_block_size = q->limits.logical_block_size;
383 : :
384 [ # # ]: 0 : if (q->limits.io_min < q->limits.physical_block_size)
385 : 0 : q->limits.io_min = q->limits.physical_block_size;
386 : 0 : }
387 : : EXPORT_SYMBOL(blk_queue_physical_block_size);
388 : :
389 : : /**
390 : : * blk_queue_alignment_offset - set physical block alignment offset
391 : : * @q: the request queue for the device
392 : : * @offset: alignment offset in bytes
393 : : *
394 : : * Description:
395 : : * Some devices are naturally misaligned to compensate for things like
396 : : * the legacy DOS partition table 63-sector offset. Low-level drivers
397 : : * should call this function for devices whose first sector is not
398 : : * naturally aligned.
399 : : */
400 : 0 : void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
401 : : {
402 : 0 : q->limits.alignment_offset =
403 : 0 : offset & (q->limits.physical_block_size - 1);
404 : 0 : q->limits.misaligned = 0;
405 : 0 : }
406 : : EXPORT_SYMBOL(blk_queue_alignment_offset);
407 : :
408 : : /**
409 : : * blk_limits_io_min - set minimum request size for a device
410 : : * @limits: the queue limits
411 : : * @min: smallest I/O size in bytes
412 : : *
413 : : * Description:
414 : : * Some devices have an internal block size bigger than the reported
415 : : * hardware sector size. This function can be used to signal the
416 : : * smallest I/O the device can perform without incurring a performance
417 : : * penalty.
418 : : */
419 : 0 : void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
420 : : {
421 : 0 : limits->io_min = min;
422 : :
423 [ # # ][ # # ]: 0 : if (limits->io_min < limits->logical_block_size)
424 : 0 : limits->io_min = limits->logical_block_size;
425 : :
426 [ # # ][ # # ]: 0 : if (limits->io_min < limits->physical_block_size)
427 : 0 : limits->io_min = limits->physical_block_size;
428 : 0 : }
429 : : EXPORT_SYMBOL(blk_limits_io_min);
430 : :
431 : : /**
432 : : * blk_queue_io_min - set minimum request size for the queue
433 : : * @q: the request queue for the device
434 : : * @min: smallest I/O size in bytes
435 : : *
436 : : * Description:
437 : : * Storage devices may report a granularity or preferred minimum I/O
438 : : * size which is the smallest request the device can perform without
439 : : * incurring a performance penalty. For disk drives this is often the
440 : : * physical block size. For RAID arrays it is often the stripe chunk
441 : : * size. A properly aligned multiple of minimum_io_size is the
442 : : * preferred request size for workloads where a high number of I/O
443 : : * operations is desired.
444 : : */
445 : 0 : void blk_queue_io_min(struct request_queue *q, unsigned int min)
446 : : {
447 : : blk_limits_io_min(&q->limits, min);
448 : 0 : }
449 : : EXPORT_SYMBOL(blk_queue_io_min);
450 : :
451 : : /**
452 : : * blk_limits_io_opt - set optimal request size for a device
453 : : * @limits: the queue limits
454 : : * @opt: smallest I/O size in bytes
455 : : *
456 : : * Description:
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.
463 : : */
464 : 0 : void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
465 : : {
466 : 0 : limits->io_opt = opt;
467 : 0 : }
468 : : EXPORT_SYMBOL(blk_limits_io_opt);
469 : :
470 : : /**
471 : : * blk_queue_io_opt - set optimal request size for the queue
472 : : * @q: the request queue for the device
473 : : * @opt: optimal request size in bytes
474 : : *
475 : : * Description:
476 : : * Storage devices may report an optimal I/O size, which is the
477 : : * device's preferred unit for sustained I/O. This is rarely reported
478 : : * for disk drives. For RAID arrays it is usually the stripe width or
479 : : * the internal track size. A properly aligned multiple of
480 : : * optimal_io_size is the preferred request size for workloads where
481 : : * sustained throughput is desired.
482 : : */
483 : 0 : void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
484 : : {
485 : : blk_limits_io_opt(&q->limits, opt);
486 : 0 : }
487 : : EXPORT_SYMBOL(blk_queue_io_opt);
488 : :
489 : : /**
490 : : * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
491 : : * @t: the stacking driver (top)
492 : : * @b: the underlying device (bottom)
493 : : **/
494 : 0 : void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
495 : : {
496 : 0 : blk_stack_limits(&t->limits, &b->limits, 0);
497 : 0 : }
498 : : EXPORT_SYMBOL(blk_queue_stack_limits);
499 : :
500 : : /**
501 : : * blk_stack_limits - adjust queue_limits for stacked devices
502 : : * @t: the stacking driver limits (top device)
503 : : * @b: the underlying queue limits (bottom, component device)
504 : : * @start: first data sector within component device
505 : : *
506 : : * Description:
507 : : * This function is used by stacking drivers like MD and DM to ensure
508 : : * that all component devices have compatible block sizes and
509 : : * alignments. The stacking driver must provide a queue_limits
510 : : * struct (top) and then iteratively call the stacking function for
511 : : * all component (bottom) devices. The stacking function will
512 : : * attempt to combine the values and ensure proper alignment.
513 : : *
514 : : * Returns 0 if the top and bottom queue_limits are compatible. The
515 : : * top device's block sizes and alignment offsets may be adjusted to
516 : : * ensure alignment with the bottom device. If no compatible sizes
517 : : * and alignments exist, -1 is returned and the resulting top
518 : : * queue_limits will have the misaligned flag set to indicate that
519 : : * the alignment_offset is undefined.
520 : : */
521 : 0 : int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
522 : : sector_t start)
523 : : {
524 : : unsigned int top, bottom, alignment, ret = 0;
525 : :
526 [ # # ][ # # ]: 0 : t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
527 [ # # ][ # # ]: 0 : t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
528 : 0 : t->max_write_same_sectors = min(t->max_write_same_sectors,
529 : : b->max_write_same_sectors);
530 [ # # ][ # # ]: 0 : t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn);
531 : :
532 [ # # ][ # # ]: 0 : t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
533 : : b->seg_boundary_mask);
534 : :
535 [ # # ][ # # ]: 0 : t->max_segments = min_not_zero(t->max_segments, b->max_segments);
[ # # ]
536 [ # # ][ # # ]: 0 : t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
[ # # ]
537 : : b->max_integrity_segments);
538 : :
539 [ # # ][ # # ]: 0 : t->max_segment_size = min_not_zero(t->max_segment_size,
540 : : b->max_segment_size);
541 : :
542 : 0 : t->misaligned |= b->misaligned;
543 : :
544 : : alignment = queue_limit_alignment_offset(b, start);
545 : :
546 : : /* Bottom device has different alignment. Check that it is
547 : : * compatible with the current top alignment.
548 : : */
549 [ # # ]: 0 : if (t->alignment_offset != alignment) {
550 : :
551 : 0 : top = max(t->physical_block_size, t->io_min)
552 : : + t->alignment_offset;
553 : 0 : bottom = max(b->physical_block_size, b->io_min) + alignment;
554 : :
555 : : /* Verify that top and bottom intervals line up */
556 [ # # ]: 0 : if (max(top, bottom) & (min(top, bottom) - 1)) {
557 : 0 : t->misaligned = 1;
558 : : ret = -1;
559 : : }
560 : : }
561 : :
562 [ # # ]: 0 : t->logical_block_size = max(t->logical_block_size,
563 : : b->logical_block_size);
564 : :
565 : 0 : t->physical_block_size = max(t->physical_block_size,
566 : : b->physical_block_size);
567 : :
568 : 0 : t->io_min = max(t->io_min, b->io_min);
569 : 0 : t->io_opt = lcm(t->io_opt, b->io_opt);
570 : :
571 : 0 : t->cluster &= b->cluster;
572 : 0 : t->discard_zeroes_data &= b->discard_zeroes_data;
573 : :
574 : : /* Physical block size a multiple of the logical block size? */
575 [ # # ]: 0 : if (t->physical_block_size & (t->logical_block_size - 1)) {
576 : 0 : t->physical_block_size = t->logical_block_size;
577 : 0 : t->misaligned = 1;
578 : : ret = -1;
579 : : }
580 : :
581 : : /* Minimum I/O a multiple of the physical block size? */
582 [ # # ]: 0 : if (t->io_min & (t->physical_block_size - 1)) {
583 : 0 : t->io_min = t->physical_block_size;
584 : 0 : t->misaligned = 1;
585 : : ret = -1;
586 : : }
587 : :
588 : : /* Optimal I/O a multiple of the physical block size? */
589 [ # # ]: 0 : if (t->io_opt & (t->physical_block_size - 1)) {
590 : 0 : t->io_opt = 0;
591 : 0 : t->misaligned = 1;
592 : : ret = -1;
593 : : }
594 : :
595 : : /* Find lowest common alignment_offset */
596 : 0 : t->alignment_offset = lcm(t->alignment_offset, alignment)
597 : 0 : & (max(t->physical_block_size, t->io_min) - 1);
598 : :
599 : : /* Verify that new alignment_offset is on a logical block boundary */
600 [ # # ]: 0 : if (t->alignment_offset & (t->logical_block_size - 1)) {
601 : 0 : t->misaligned = 1;
602 : : ret = -1;
603 : : }
604 : :
605 : : /* Discard alignment and granularity */
606 [ # # ]: 0 : if (b->discard_granularity) {
607 : 0 : alignment = queue_limit_discard_alignment(b, start);
608 : :
609 [ # # ][ # # ]: 0 : if (t->discard_granularity != 0 &&
610 : 0 : t->discard_alignment != alignment) {
611 : 0 : top = t->discard_granularity + t->discard_alignment;
612 : 0 : bottom = b->discard_granularity + alignment;
613 : :
614 : : /* Verify that top and bottom intervals line up */
615 [ # # ]: 0 : if ((max(top, bottom) % min(top, bottom)) != 0)
616 : 0 : t->discard_misaligned = 1;
617 : : }
618 : :
619 [ # # ][ # # ]: 0 : t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
620 : : b->max_discard_sectors);
621 : 0 : t->discard_granularity = max(t->discard_granularity,
622 : : b->discard_granularity);
623 : 0 : t->discard_alignment = lcm(t->discard_alignment, alignment) %
624 : : t->discard_granularity;
625 : : }
626 : :
627 : 0 : return ret;
628 : : }
629 : : EXPORT_SYMBOL(blk_stack_limits);
630 : :
631 : : /**
632 : : * bdev_stack_limits - adjust queue limits for stacked drivers
633 : : * @t: the stacking driver limits (top device)
634 : : * @bdev: the component block_device (bottom)
635 : : * @start: first data sector within component device
636 : : *
637 : : * Description:
638 : : * Merges queue limits for a top device and a block_device. Returns
639 : : * 0 if alignment didn't change. Returns -1 if adding the bottom
640 : : * device caused misalignment.
641 : : */
642 : 0 : int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
643 : : sector_t start)
644 : : {
645 : : struct request_queue *bq = bdev_get_queue(bdev);
646 : :
647 : 0 : start += get_start_sect(bdev);
648 : :
649 : 0 : return blk_stack_limits(t, &bq->limits, start);
650 : : }
651 : : EXPORT_SYMBOL(bdev_stack_limits);
652 : :
653 : : /**
654 : : * disk_stack_limits - adjust queue limits for stacked drivers
655 : : * @disk: MD/DM gendisk (top)
656 : : * @bdev: the underlying block device (bottom)
657 : : * @offset: offset to beginning of data within component device
658 : : *
659 : : * Description:
660 : : * Merges the limits for a top level gendisk and a bottom level
661 : : * block_device.
662 : : */
663 : 0 : void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
664 : : sector_t offset)
665 : : {
666 : 0 : struct request_queue *t = disk->queue;
667 : :
668 [ # # ]: 0 : if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {
669 : : char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
670 : :
671 : 0 : disk_name(disk, 0, top);
672 : 0 : bdevname(bdev, bottom);
673 : :
674 : 0 : printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",
675 : : top, bottom);
676 : : }
677 : 0 : }
678 : : EXPORT_SYMBOL(disk_stack_limits);
679 : :
680 : : /**
681 : : * blk_queue_dma_pad - set pad mask
682 : : * @q: the request queue for the device
683 : : * @mask: pad mask
684 : : *
685 : : * Set dma pad mask.
686 : : *
687 : : * Appending pad buffer to a request modifies the last entry of a
688 : : * scatter list such that it includes the pad buffer.
689 : : **/
690 : 0 : void blk_queue_dma_pad(struct request_queue *q, unsigned int mask)
691 : : {
692 : 0 : q->dma_pad_mask = mask;
693 : 0 : }
694 : : EXPORT_SYMBOL(blk_queue_dma_pad);
695 : :
696 : : /**
697 : : * blk_queue_update_dma_pad - update pad mask
698 : : * @q: the request queue for the device
699 : : * @mask: pad mask
700 : : *
701 : : * Update dma pad mask.
702 : : *
703 : : * Appending pad buffer to a request modifies the last entry of a
704 : : * scatter list such that it includes the pad buffer.
705 : : **/
706 : 0 : void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask)
707 : : {
708 [ # # ]: 0 : if (mask > q->dma_pad_mask)
709 : 0 : q->dma_pad_mask = mask;
710 : 0 : }
711 : : EXPORT_SYMBOL(blk_queue_update_dma_pad);
712 : :
713 : : /**
714 : : * blk_queue_dma_drain - Set up a drain buffer for excess dma.
715 : : * @q: the request queue for the device
716 : : * @dma_drain_needed: fn which returns non-zero if drain is necessary
717 : : * @buf: physically contiguous buffer
718 : : * @size: size of the buffer in bytes
719 : : *
720 : : * Some devices have excess DMA problems and can't simply discard (or
721 : : * zero fill) the unwanted piece of the transfer. They have to have a
722 : : * real area of memory to transfer it into. The use case for this is
723 : : * ATAPI devices in DMA mode. If the packet command causes a transfer
724 : : * bigger than the transfer size some HBAs will lock up if there
725 : : * aren't DMA elements to contain the excess transfer. What this API
726 : : * does is adjust the queue so that the buf is always appended
727 : : * silently to the scatterlist.
728 : : *
729 : : * Note: This routine adjusts max_hw_segments to make room for appending
730 : : * the drain buffer. If you call blk_queue_max_segments() after calling
731 : : * this routine, you must set the limit to one fewer than your device
732 : : * can support otherwise there won't be room for the drain buffer.
733 : : */
734 : 0 : int blk_queue_dma_drain(struct request_queue *q,
735 : : dma_drain_needed_fn *dma_drain_needed,
736 : : void *buf, unsigned int size)
737 : : {
738 [ # # ]: 0 : if (queue_max_segments(q) < 2)
739 : : return -EINVAL;
740 : : /* make room for appending the drain */
741 : 0 : blk_queue_max_segments(q, queue_max_segments(q) - 1);
742 : 0 : q->dma_drain_needed = dma_drain_needed;
743 : 0 : q->dma_drain_buffer = buf;
744 : 0 : q->dma_drain_size = size;
745 : :
746 : 0 : return 0;
747 : : }
748 : : EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
749 : :
750 : : /**
751 : : * blk_queue_segment_boundary - set boundary rules for segment merging
752 : : * @q: the request queue for the device
753 : : * @mask: the memory boundary mask
754 : : **/
755 : 0 : void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
756 : : {
757 [ # # ]: 0 : if (mask < PAGE_CACHE_SIZE - 1) {
758 : : mask = PAGE_CACHE_SIZE - 1;
759 : 0 : printk(KERN_INFO "%s: set to minimum %lx\n",
760 : : __func__, mask);
761 : : }
762 : :
763 : 0 : q->limits.seg_boundary_mask = mask;
764 : 0 : }
765 : : EXPORT_SYMBOL(blk_queue_segment_boundary);
766 : :
767 : : /**
768 : : * blk_queue_dma_alignment - set dma length and memory alignment
769 : : * @q: the request queue for the device
770 : : * @mask: alignment mask
771 : : *
772 : : * description:
773 : : * set required memory and length alignment for direct dma transactions.
774 : : * this is used when building direct io requests for the queue.
775 : : *
776 : : **/
777 : 0 : void blk_queue_dma_alignment(struct request_queue *q, int mask)
778 : : {
779 : 0 : q->dma_alignment = mask;
780 : 0 : }
781 : : EXPORT_SYMBOL(blk_queue_dma_alignment);
782 : :
783 : : /**
784 : : * blk_queue_update_dma_alignment - update dma length and memory alignment
785 : : * @q: the request queue for the device
786 : : * @mask: alignment mask
787 : : *
788 : : * description:
789 : : * update required memory and length alignment for direct dma transactions.
790 : : * If the requested alignment is larger than the current alignment, then
791 : : * the current queue alignment is updated to the new value, otherwise it
792 : : * is left alone. The design of this is to allow multiple objects
793 : : * (driver, device, transport etc) to set their respective
794 : : * alignments without having them interfere.
795 : : *
796 : : **/
797 : 0 : void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
798 : : {
799 [ # # ]: 0 : BUG_ON(mask > PAGE_SIZE);
800 : :
801 [ # # ]: 0 : if (mask > q->dma_alignment)
802 : 0 : q->dma_alignment = mask;
803 : 0 : }
804 : : EXPORT_SYMBOL(blk_queue_update_dma_alignment);
805 : :
806 : : /**
807 : : * blk_queue_flush - configure queue's cache flush capability
808 : : * @q: the request queue for the device
809 : : * @flush: 0, REQ_FLUSH or REQ_FLUSH | REQ_FUA
810 : : *
811 : : * Tell block layer cache flush capability of @q. If it supports
812 : : * flushing, REQ_FLUSH should be set. If it supports bypassing
813 : : * write cache for individual writes, REQ_FUA should be set.
814 : : */
815 : 0 : void blk_queue_flush(struct request_queue *q, unsigned int flush)
816 : : {
817 [ # # ][ # # ]: 0 : WARN_ON_ONCE(flush & ~(REQ_FLUSH | REQ_FUA));
[ # # ]
818 : :
819 [ # # ][ # # ]: 0 : if (WARN_ON_ONCE(!(flush & REQ_FLUSH) && (flush & REQ_FUA)))
[ # # ][ # # ]
[ # # ][ # # ]
820 : 0 : flush &= ~REQ_FUA;
821 : :
822 : 0 : q->flush_flags = flush & (REQ_FLUSH | REQ_FUA);
823 : 0 : }
824 : : EXPORT_SYMBOL_GPL(blk_queue_flush);
825 : :
826 : 0 : void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
827 : : {
828 : 0 : q->flush_not_queueable = !queueable;
829 : 0 : }
830 : : EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
831 : :
832 : 0 : static int __init blk_settings_init(void)
833 : : {
834 : 0 : blk_max_low_pfn = max_low_pfn - 1;
835 : 0 : blk_max_pfn = max_pfn - 1;
836 : 0 : return 0;
837 : : }
838 : : subsys_initcall(blk_settings_init);
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