Commit d6d48196961729b79509dcaeeb0f0fb4fbb47d29
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db1d08c646
Exists in
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block: ll_rw_blk.c split, add blk-merge.c
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Showing 4 changed files with 495 additions and 481 deletions Side-by-side Diff
block/Makefile
... | ... | @@ -4,7 +4,7 @@ |
4 | 4 | |
5 | 5 | obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \ |
6 | 6 | blk-barrier.o blk-settings.o blk-ioc.o blk-map.o \ |
7 | - blk-exec.o ioctl.o genhd.o scsi_ioctl.o | |
7 | + blk-exec.o blk-merge.o ioctl.o genhd.o scsi_ioctl.o | |
8 | 8 | |
9 | 9 | obj-$(CONFIG_BLK_DEV_BSG) += bsg.o |
10 | 10 | obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o |
block/blk-core.c
... | ... | @@ -29,7 +29,6 @@ |
29 | 29 | #include <linux/cpu.h> |
30 | 30 | #include <linux/blktrace_api.h> |
31 | 31 | #include <linux/fault-inject.h> |
32 | -#include <linux/scatterlist.h> | |
33 | 32 | |
34 | 33 | #include "blk.h" |
35 | 34 | |
36 | 35 | |
... | ... | @@ -181,377 +180,7 @@ |
181 | 180 | |
182 | 181 | EXPORT_SYMBOL(blk_dump_rq_flags); |
183 | 182 | |
184 | -static void blk_recalc_rq_segments(struct request *rq) | |
185 | -{ | |
186 | - int nr_phys_segs; | |
187 | - int nr_hw_segs; | |
188 | - unsigned int phys_size; | |
189 | - unsigned int hw_size; | |
190 | - struct bio_vec *bv, *bvprv = NULL; | |
191 | - int seg_size; | |
192 | - int hw_seg_size; | |
193 | - int cluster; | |
194 | - struct req_iterator iter; | |
195 | - int high, highprv = 1; | |
196 | - struct request_queue *q = rq->q; | |
197 | - | |
198 | - if (!rq->bio) | |
199 | - return; | |
200 | - | |
201 | - cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); | |
202 | - hw_seg_size = seg_size = 0; | |
203 | - phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0; | |
204 | - rq_for_each_segment(bv, rq, iter) { | |
205 | - /* | |
206 | - * the trick here is making sure that a high page is never | |
207 | - * considered part of another segment, since that might | |
208 | - * change with the bounce page. | |
209 | - */ | |
210 | - high = page_to_pfn(bv->bv_page) > q->bounce_pfn; | |
211 | - if (high || highprv) | |
212 | - goto new_hw_segment; | |
213 | - if (cluster) { | |
214 | - if (seg_size + bv->bv_len > q->max_segment_size) | |
215 | - goto new_segment; | |
216 | - if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv)) | |
217 | - goto new_segment; | |
218 | - if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv)) | |
219 | - goto new_segment; | |
220 | - if (BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) | |
221 | - goto new_hw_segment; | |
222 | - | |
223 | - seg_size += bv->bv_len; | |
224 | - hw_seg_size += bv->bv_len; | |
225 | - bvprv = bv; | |
226 | - continue; | |
227 | - } | |
228 | -new_segment: | |
229 | - if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) && | |
230 | - !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) | |
231 | - hw_seg_size += bv->bv_len; | |
232 | - else { | |
233 | -new_hw_segment: | |
234 | - if (nr_hw_segs == 1 && | |
235 | - hw_seg_size > rq->bio->bi_hw_front_size) | |
236 | - rq->bio->bi_hw_front_size = hw_seg_size; | |
237 | - hw_seg_size = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len; | |
238 | - nr_hw_segs++; | |
239 | - } | |
240 | - | |
241 | - nr_phys_segs++; | |
242 | - bvprv = bv; | |
243 | - seg_size = bv->bv_len; | |
244 | - highprv = high; | |
245 | - } | |
246 | - | |
247 | - if (nr_hw_segs == 1 && | |
248 | - hw_seg_size > rq->bio->bi_hw_front_size) | |
249 | - rq->bio->bi_hw_front_size = hw_seg_size; | |
250 | - if (hw_seg_size > rq->biotail->bi_hw_back_size) | |
251 | - rq->biotail->bi_hw_back_size = hw_seg_size; | |
252 | - rq->nr_phys_segments = nr_phys_segs; | |
253 | - rq->nr_hw_segments = nr_hw_segs; | |
254 | -} | |
255 | - | |
256 | -void blk_recount_segments(struct request_queue *q, struct bio *bio) | |
257 | -{ | |
258 | - struct request rq; | |
259 | - struct bio *nxt = bio->bi_next; | |
260 | - rq.q = q; | |
261 | - rq.bio = rq.biotail = bio; | |
262 | - bio->bi_next = NULL; | |
263 | - blk_recalc_rq_segments(&rq); | |
264 | - bio->bi_next = nxt; | |
265 | - bio->bi_phys_segments = rq.nr_phys_segments; | |
266 | - bio->bi_hw_segments = rq.nr_hw_segments; | |
267 | - bio->bi_flags |= (1 << BIO_SEG_VALID); | |
268 | -} | |
269 | -EXPORT_SYMBOL(blk_recount_segments); | |
270 | - | |
271 | -static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, | |
272 | - struct bio *nxt) | |
273 | -{ | |
274 | - if (!(q->queue_flags & (1 << QUEUE_FLAG_CLUSTER))) | |
275 | - return 0; | |
276 | - | |
277 | - if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt))) | |
278 | - return 0; | |
279 | - if (bio->bi_size + nxt->bi_size > q->max_segment_size) | |
280 | - return 0; | |
281 | - | |
282 | - /* | |
283 | - * bio and nxt are contigous in memory, check if the queue allows | |
284 | - * these two to be merged into one | |
285 | - */ | |
286 | - if (BIO_SEG_BOUNDARY(q, bio, nxt)) | |
287 | - return 1; | |
288 | - | |
289 | - return 0; | |
290 | -} | |
291 | - | |
292 | -static int blk_hw_contig_segment(struct request_queue *q, struct bio *bio, | |
293 | - struct bio *nxt) | |
294 | -{ | |
295 | - if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
296 | - blk_recount_segments(q, bio); | |
297 | - if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID))) | |
298 | - blk_recount_segments(q, nxt); | |
299 | - if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) || | |
300 | - BIOVEC_VIRT_OVERSIZE(bio->bi_hw_back_size + nxt->bi_hw_front_size)) | |
301 | - return 0; | |
302 | - if (bio->bi_hw_back_size + nxt->bi_hw_front_size > q->max_segment_size) | |
303 | - return 0; | |
304 | - | |
305 | - return 1; | |
306 | -} | |
307 | - | |
308 | 183 | /* |
309 | - * map a request to scatterlist, return number of sg entries setup. Caller | |
310 | - * must make sure sg can hold rq->nr_phys_segments entries | |
311 | - */ | |
312 | -int blk_rq_map_sg(struct request_queue *q, struct request *rq, | |
313 | - struct scatterlist *sglist) | |
314 | -{ | |
315 | - struct bio_vec *bvec, *bvprv; | |
316 | - struct req_iterator iter; | |
317 | - struct scatterlist *sg; | |
318 | - int nsegs, cluster; | |
319 | - | |
320 | - nsegs = 0; | |
321 | - cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); | |
322 | - | |
323 | - /* | |
324 | - * for each bio in rq | |
325 | - */ | |
326 | - bvprv = NULL; | |
327 | - sg = NULL; | |
328 | - rq_for_each_segment(bvec, rq, iter) { | |
329 | - int nbytes = bvec->bv_len; | |
330 | - | |
331 | - if (bvprv && cluster) { | |
332 | - if (sg->length + nbytes > q->max_segment_size) | |
333 | - goto new_segment; | |
334 | - | |
335 | - if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) | |
336 | - goto new_segment; | |
337 | - if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) | |
338 | - goto new_segment; | |
339 | - | |
340 | - sg->length += nbytes; | |
341 | - } else { | |
342 | -new_segment: | |
343 | - if (!sg) | |
344 | - sg = sglist; | |
345 | - else { | |
346 | - /* | |
347 | - * If the driver previously mapped a shorter | |
348 | - * list, we could see a termination bit | |
349 | - * prematurely unless it fully inits the sg | |
350 | - * table on each mapping. We KNOW that there | |
351 | - * must be more entries here or the driver | |
352 | - * would be buggy, so force clear the | |
353 | - * termination bit to avoid doing a full | |
354 | - * sg_init_table() in drivers for each command. | |
355 | - */ | |
356 | - sg->page_link &= ~0x02; | |
357 | - sg = sg_next(sg); | |
358 | - } | |
359 | - | |
360 | - sg_set_page(sg, bvec->bv_page, nbytes, bvec->bv_offset); | |
361 | - nsegs++; | |
362 | - } | |
363 | - bvprv = bvec; | |
364 | - } /* segments in rq */ | |
365 | - | |
366 | - if (q->dma_drain_size) { | |
367 | - sg->page_link &= ~0x02; | |
368 | - sg = sg_next(sg); | |
369 | - sg_set_page(sg, virt_to_page(q->dma_drain_buffer), | |
370 | - q->dma_drain_size, | |
371 | - ((unsigned long)q->dma_drain_buffer) & | |
372 | - (PAGE_SIZE - 1)); | |
373 | - nsegs++; | |
374 | - } | |
375 | - | |
376 | - if (sg) | |
377 | - sg_mark_end(sg); | |
378 | - | |
379 | - return nsegs; | |
380 | -} | |
381 | - | |
382 | -EXPORT_SYMBOL(blk_rq_map_sg); | |
383 | - | |
384 | -static inline int ll_new_mergeable(struct request_queue *q, | |
385 | - struct request *req, | |
386 | - struct bio *bio) | |
387 | -{ | |
388 | - int nr_phys_segs = bio_phys_segments(q, bio); | |
389 | - | |
390 | - if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { | |
391 | - req->cmd_flags |= REQ_NOMERGE; | |
392 | - if (req == q->last_merge) | |
393 | - q->last_merge = NULL; | |
394 | - return 0; | |
395 | - } | |
396 | - | |
397 | - /* | |
398 | - * A hw segment is just getting larger, bump just the phys | |
399 | - * counter. | |
400 | - */ | |
401 | - req->nr_phys_segments += nr_phys_segs; | |
402 | - return 1; | |
403 | -} | |
404 | - | |
405 | -static inline int ll_new_hw_segment(struct request_queue *q, | |
406 | - struct request *req, | |
407 | - struct bio *bio) | |
408 | -{ | |
409 | - int nr_hw_segs = bio_hw_segments(q, bio); | |
410 | - int nr_phys_segs = bio_phys_segments(q, bio); | |
411 | - | |
412 | - if (req->nr_hw_segments + nr_hw_segs > q->max_hw_segments | |
413 | - || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { | |
414 | - req->cmd_flags |= REQ_NOMERGE; | |
415 | - if (req == q->last_merge) | |
416 | - q->last_merge = NULL; | |
417 | - return 0; | |
418 | - } | |
419 | - | |
420 | - /* | |
421 | - * This will form the start of a new hw segment. Bump both | |
422 | - * counters. | |
423 | - */ | |
424 | - req->nr_hw_segments += nr_hw_segs; | |
425 | - req->nr_phys_segments += nr_phys_segs; | |
426 | - return 1; | |
427 | -} | |
428 | - | |
429 | -int ll_back_merge_fn(struct request_queue *q, struct request *req, | |
430 | - struct bio *bio) | |
431 | -{ | |
432 | - unsigned short max_sectors; | |
433 | - int len; | |
434 | - | |
435 | - if (unlikely(blk_pc_request(req))) | |
436 | - max_sectors = q->max_hw_sectors; | |
437 | - else | |
438 | - max_sectors = q->max_sectors; | |
439 | - | |
440 | - if (req->nr_sectors + bio_sectors(bio) > max_sectors) { | |
441 | - req->cmd_flags |= REQ_NOMERGE; | |
442 | - if (req == q->last_merge) | |
443 | - q->last_merge = NULL; | |
444 | - return 0; | |
445 | - } | |
446 | - if (unlikely(!bio_flagged(req->biotail, BIO_SEG_VALID))) | |
447 | - blk_recount_segments(q, req->biotail); | |
448 | - if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
449 | - blk_recount_segments(q, bio); | |
450 | - len = req->biotail->bi_hw_back_size + bio->bi_hw_front_size; | |
451 | - if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(req->biotail), __BVEC_START(bio)) && | |
452 | - !BIOVEC_VIRT_OVERSIZE(len)) { | |
453 | - int mergeable = ll_new_mergeable(q, req, bio); | |
454 | - | |
455 | - if (mergeable) { | |
456 | - if (req->nr_hw_segments == 1) | |
457 | - req->bio->bi_hw_front_size = len; | |
458 | - if (bio->bi_hw_segments == 1) | |
459 | - bio->bi_hw_back_size = len; | |
460 | - } | |
461 | - return mergeable; | |
462 | - } | |
463 | - | |
464 | - return ll_new_hw_segment(q, req, bio); | |
465 | -} | |
466 | - | |
467 | -static int ll_front_merge_fn(struct request_queue *q, struct request *req, | |
468 | - struct bio *bio) | |
469 | -{ | |
470 | - unsigned short max_sectors; | |
471 | - int len; | |
472 | - | |
473 | - if (unlikely(blk_pc_request(req))) | |
474 | - max_sectors = q->max_hw_sectors; | |
475 | - else | |
476 | - max_sectors = q->max_sectors; | |
477 | - | |
478 | - | |
479 | - if (req->nr_sectors + bio_sectors(bio) > max_sectors) { | |
480 | - req->cmd_flags |= REQ_NOMERGE; | |
481 | - if (req == q->last_merge) | |
482 | - q->last_merge = NULL; | |
483 | - return 0; | |
484 | - } | |
485 | - len = bio->bi_hw_back_size + req->bio->bi_hw_front_size; | |
486 | - if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
487 | - blk_recount_segments(q, bio); | |
488 | - if (unlikely(!bio_flagged(req->bio, BIO_SEG_VALID))) | |
489 | - blk_recount_segments(q, req->bio); | |
490 | - if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(req->bio)) && | |
491 | - !BIOVEC_VIRT_OVERSIZE(len)) { | |
492 | - int mergeable = ll_new_mergeable(q, req, bio); | |
493 | - | |
494 | - if (mergeable) { | |
495 | - if (bio->bi_hw_segments == 1) | |
496 | - bio->bi_hw_front_size = len; | |
497 | - if (req->nr_hw_segments == 1) | |
498 | - req->biotail->bi_hw_back_size = len; | |
499 | - } | |
500 | - return mergeable; | |
501 | - } | |
502 | - | |
503 | - return ll_new_hw_segment(q, req, bio); | |
504 | -} | |
505 | - | |
506 | -static int ll_merge_requests_fn(struct request_queue *q, struct request *req, | |
507 | - struct request *next) | |
508 | -{ | |
509 | - int total_phys_segments; | |
510 | - int total_hw_segments; | |
511 | - | |
512 | - /* | |
513 | - * First check if the either of the requests are re-queued | |
514 | - * requests. Can't merge them if they are. | |
515 | - */ | |
516 | - if (req->special || next->special) | |
517 | - return 0; | |
518 | - | |
519 | - /* | |
520 | - * Will it become too large? | |
521 | - */ | |
522 | - if ((req->nr_sectors + next->nr_sectors) > q->max_sectors) | |
523 | - return 0; | |
524 | - | |
525 | - total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; | |
526 | - if (blk_phys_contig_segment(q, req->biotail, next->bio)) | |
527 | - total_phys_segments--; | |
528 | - | |
529 | - if (total_phys_segments > q->max_phys_segments) | |
530 | - return 0; | |
531 | - | |
532 | - total_hw_segments = req->nr_hw_segments + next->nr_hw_segments; | |
533 | - if (blk_hw_contig_segment(q, req->biotail, next->bio)) { | |
534 | - int len = req->biotail->bi_hw_back_size + next->bio->bi_hw_front_size; | |
535 | - /* | |
536 | - * propagate the combined length to the end of the requests | |
537 | - */ | |
538 | - if (req->nr_hw_segments == 1) | |
539 | - req->bio->bi_hw_front_size = len; | |
540 | - if (next->nr_hw_segments == 1) | |
541 | - next->biotail->bi_hw_back_size = len; | |
542 | - total_hw_segments--; | |
543 | - } | |
544 | - | |
545 | - if (total_hw_segments > q->max_hw_segments) | |
546 | - return 0; | |
547 | - | |
548 | - /* Merge is OK... */ | |
549 | - req->nr_phys_segments = total_phys_segments; | |
550 | - req->nr_hw_segments = total_hw_segments; | |
551 | - return 1; | |
552 | -} | |
553 | - | |
554 | -/* | |
555 | 184 | * "plug" the device if there are no outstanding requests: this will |
556 | 185 | * force the transfer to start only after we have put all the requests |
557 | 186 | * on the list. |
... | ... | @@ -1409,84 +1038,6 @@ |
1409 | 1038 | |
1410 | 1039 | EXPORT_SYMBOL(blk_put_request); |
1411 | 1040 | |
1412 | -/* | |
1413 | - * Has to be called with the request spinlock acquired | |
1414 | - */ | |
1415 | -static int attempt_merge(struct request_queue *q, struct request *req, | |
1416 | - struct request *next) | |
1417 | -{ | |
1418 | - if (!rq_mergeable(req) || !rq_mergeable(next)) | |
1419 | - return 0; | |
1420 | - | |
1421 | - /* | |
1422 | - * not contiguous | |
1423 | - */ | |
1424 | - if (req->sector + req->nr_sectors != next->sector) | |
1425 | - return 0; | |
1426 | - | |
1427 | - if (rq_data_dir(req) != rq_data_dir(next) | |
1428 | - || req->rq_disk != next->rq_disk | |
1429 | - || next->special) | |
1430 | - return 0; | |
1431 | - | |
1432 | - /* | |
1433 | - * If we are allowed to merge, then append bio list | |
1434 | - * from next to rq and release next. merge_requests_fn | |
1435 | - * will have updated segment counts, update sector | |
1436 | - * counts here. | |
1437 | - */ | |
1438 | - if (!ll_merge_requests_fn(q, req, next)) | |
1439 | - return 0; | |
1440 | - | |
1441 | - /* | |
1442 | - * At this point we have either done a back merge | |
1443 | - * or front merge. We need the smaller start_time of | |
1444 | - * the merged requests to be the current request | |
1445 | - * for accounting purposes. | |
1446 | - */ | |
1447 | - if (time_after(req->start_time, next->start_time)) | |
1448 | - req->start_time = next->start_time; | |
1449 | - | |
1450 | - req->biotail->bi_next = next->bio; | |
1451 | - req->biotail = next->biotail; | |
1452 | - | |
1453 | - req->nr_sectors = req->hard_nr_sectors += next->hard_nr_sectors; | |
1454 | - | |
1455 | - elv_merge_requests(q, req, next); | |
1456 | - | |
1457 | - if (req->rq_disk) { | |
1458 | - disk_round_stats(req->rq_disk); | |
1459 | - req->rq_disk->in_flight--; | |
1460 | - } | |
1461 | - | |
1462 | - req->ioprio = ioprio_best(req->ioprio, next->ioprio); | |
1463 | - | |
1464 | - __blk_put_request(q, next); | |
1465 | - return 1; | |
1466 | -} | |
1467 | - | |
1468 | -static inline int attempt_back_merge(struct request_queue *q, | |
1469 | - struct request *rq) | |
1470 | -{ | |
1471 | - struct request *next = elv_latter_request(q, rq); | |
1472 | - | |
1473 | - if (next) | |
1474 | - return attempt_merge(q, rq, next); | |
1475 | - | |
1476 | - return 0; | |
1477 | -} | |
1478 | - | |
1479 | -static inline int attempt_front_merge(struct request_queue *q, | |
1480 | - struct request *rq) | |
1481 | -{ | |
1482 | - struct request *prev = elv_former_request(q, rq); | |
1483 | - | |
1484 | - if (prev) | |
1485 | - return attempt_merge(q, prev, rq); | |
1486 | - | |
1487 | - return 0; | |
1488 | -} | |
1489 | - | |
1490 | 1041 | void init_request_from_bio(struct request *req, struct bio *bio) |
1491 | 1042 | { |
1492 | 1043 | req->cmd_type = REQ_TYPE_FS; |
... | ... | @@ -1937,35 +1488,6 @@ |
1937 | 1488 | } |
1938 | 1489 | |
1939 | 1490 | EXPORT_SYMBOL(submit_bio); |
1940 | - | |
1941 | -static void blk_recalc_rq_sectors(struct request *rq, int nsect) | |
1942 | -{ | |
1943 | - if (blk_fs_request(rq)) { | |
1944 | - rq->hard_sector += nsect; | |
1945 | - rq->hard_nr_sectors -= nsect; | |
1946 | - | |
1947 | - /* | |
1948 | - * Move the I/O submission pointers ahead if required. | |
1949 | - */ | |
1950 | - if ((rq->nr_sectors >= rq->hard_nr_sectors) && | |
1951 | - (rq->sector <= rq->hard_sector)) { | |
1952 | - rq->sector = rq->hard_sector; | |
1953 | - rq->nr_sectors = rq->hard_nr_sectors; | |
1954 | - rq->hard_cur_sectors = bio_cur_sectors(rq->bio); | |
1955 | - rq->current_nr_sectors = rq->hard_cur_sectors; | |
1956 | - rq->buffer = bio_data(rq->bio); | |
1957 | - } | |
1958 | - | |
1959 | - /* | |
1960 | - * if total number of sectors is less than the first segment | |
1961 | - * size, something has gone terribly wrong | |
1962 | - */ | |
1963 | - if (rq->nr_sectors < rq->current_nr_sectors) { | |
1964 | - printk("blk: request botched\n"); | |
1965 | - rq->nr_sectors = rq->current_nr_sectors; | |
1966 | - } | |
1967 | - } | |
1968 | -} | |
1969 | 1491 | |
1970 | 1492 | /** |
1971 | 1493 | * __end_that_request_first - end I/O on a request |
block/blk-merge.c
1 | +/* | |
2 | + * Functions related to segment and merge handling | |
3 | + */ | |
4 | +#include <linux/kernel.h> | |
5 | +#include <linux/module.h> | |
6 | +#include <linux/bio.h> | |
7 | +#include <linux/blkdev.h> | |
8 | +#include <linux/scatterlist.h> | |
9 | + | |
10 | +#include "blk.h" | |
11 | + | |
12 | +void blk_recalc_rq_sectors(struct request *rq, int nsect) | |
13 | +{ | |
14 | + if (blk_fs_request(rq)) { | |
15 | + rq->hard_sector += nsect; | |
16 | + rq->hard_nr_sectors -= nsect; | |
17 | + | |
18 | + /* | |
19 | + * Move the I/O submission pointers ahead if required. | |
20 | + */ | |
21 | + if ((rq->nr_sectors >= rq->hard_nr_sectors) && | |
22 | + (rq->sector <= rq->hard_sector)) { | |
23 | + rq->sector = rq->hard_sector; | |
24 | + rq->nr_sectors = rq->hard_nr_sectors; | |
25 | + rq->hard_cur_sectors = bio_cur_sectors(rq->bio); | |
26 | + rq->current_nr_sectors = rq->hard_cur_sectors; | |
27 | + rq->buffer = bio_data(rq->bio); | |
28 | + } | |
29 | + | |
30 | + /* | |
31 | + * if total number of sectors is less than the first segment | |
32 | + * size, something has gone terribly wrong | |
33 | + */ | |
34 | + if (rq->nr_sectors < rq->current_nr_sectors) { | |
35 | + printk("blk: request botched\n"); | |
36 | + rq->nr_sectors = rq->current_nr_sectors; | |
37 | + } | |
38 | + } | |
39 | +} | |
40 | + | |
41 | +void blk_recalc_rq_segments(struct request *rq) | |
42 | +{ | |
43 | + int nr_phys_segs; | |
44 | + int nr_hw_segs; | |
45 | + unsigned int phys_size; | |
46 | + unsigned int hw_size; | |
47 | + struct bio_vec *bv, *bvprv = NULL; | |
48 | + int seg_size; | |
49 | + int hw_seg_size; | |
50 | + int cluster; | |
51 | + struct req_iterator iter; | |
52 | + int high, highprv = 1; | |
53 | + struct request_queue *q = rq->q; | |
54 | + | |
55 | + if (!rq->bio) | |
56 | + return; | |
57 | + | |
58 | + cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); | |
59 | + hw_seg_size = seg_size = 0; | |
60 | + phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0; | |
61 | + rq_for_each_segment(bv, rq, iter) { | |
62 | + /* | |
63 | + * the trick here is making sure that a high page is never | |
64 | + * considered part of another segment, since that might | |
65 | + * change with the bounce page. | |
66 | + */ | |
67 | + high = page_to_pfn(bv->bv_page) > q->bounce_pfn; | |
68 | + if (high || highprv) | |
69 | + goto new_hw_segment; | |
70 | + if (cluster) { | |
71 | + if (seg_size + bv->bv_len > q->max_segment_size) | |
72 | + goto new_segment; | |
73 | + if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv)) | |
74 | + goto new_segment; | |
75 | + if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv)) | |
76 | + goto new_segment; | |
77 | + if (BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) | |
78 | + goto new_hw_segment; | |
79 | + | |
80 | + seg_size += bv->bv_len; | |
81 | + hw_seg_size += bv->bv_len; | |
82 | + bvprv = bv; | |
83 | + continue; | |
84 | + } | |
85 | +new_segment: | |
86 | + if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) && | |
87 | + !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) | |
88 | + hw_seg_size += bv->bv_len; | |
89 | + else { | |
90 | +new_hw_segment: | |
91 | + if (nr_hw_segs == 1 && | |
92 | + hw_seg_size > rq->bio->bi_hw_front_size) | |
93 | + rq->bio->bi_hw_front_size = hw_seg_size; | |
94 | + hw_seg_size = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len; | |
95 | + nr_hw_segs++; | |
96 | + } | |
97 | + | |
98 | + nr_phys_segs++; | |
99 | + bvprv = bv; | |
100 | + seg_size = bv->bv_len; | |
101 | + highprv = high; | |
102 | + } | |
103 | + | |
104 | + if (nr_hw_segs == 1 && | |
105 | + hw_seg_size > rq->bio->bi_hw_front_size) | |
106 | + rq->bio->bi_hw_front_size = hw_seg_size; | |
107 | + if (hw_seg_size > rq->biotail->bi_hw_back_size) | |
108 | + rq->biotail->bi_hw_back_size = hw_seg_size; | |
109 | + rq->nr_phys_segments = nr_phys_segs; | |
110 | + rq->nr_hw_segments = nr_hw_segs; | |
111 | +} | |
112 | + | |
113 | +void blk_recount_segments(struct request_queue *q, struct bio *bio) | |
114 | +{ | |
115 | + struct request rq; | |
116 | + struct bio *nxt = bio->bi_next; | |
117 | + rq.q = q; | |
118 | + rq.bio = rq.biotail = bio; | |
119 | + bio->bi_next = NULL; | |
120 | + blk_recalc_rq_segments(&rq); | |
121 | + bio->bi_next = nxt; | |
122 | + bio->bi_phys_segments = rq.nr_phys_segments; | |
123 | + bio->bi_hw_segments = rq.nr_hw_segments; | |
124 | + bio->bi_flags |= (1 << BIO_SEG_VALID); | |
125 | +} | |
126 | +EXPORT_SYMBOL(blk_recount_segments); | |
127 | + | |
128 | +static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, | |
129 | + struct bio *nxt) | |
130 | +{ | |
131 | + if (!(q->queue_flags & (1 << QUEUE_FLAG_CLUSTER))) | |
132 | + return 0; | |
133 | + | |
134 | + if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt))) | |
135 | + return 0; | |
136 | + if (bio->bi_size + nxt->bi_size > q->max_segment_size) | |
137 | + return 0; | |
138 | + | |
139 | + /* | |
140 | + * bio and nxt are contigous in memory, check if the queue allows | |
141 | + * these two to be merged into one | |
142 | + */ | |
143 | + if (BIO_SEG_BOUNDARY(q, bio, nxt)) | |
144 | + return 1; | |
145 | + | |
146 | + return 0; | |
147 | +} | |
148 | + | |
149 | +static int blk_hw_contig_segment(struct request_queue *q, struct bio *bio, | |
150 | + struct bio *nxt) | |
151 | +{ | |
152 | + if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
153 | + blk_recount_segments(q, bio); | |
154 | + if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID))) | |
155 | + blk_recount_segments(q, nxt); | |
156 | + if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) || | |
157 | + BIOVEC_VIRT_OVERSIZE(bio->bi_hw_back_size + nxt->bi_hw_front_size)) | |
158 | + return 0; | |
159 | + if (bio->bi_hw_back_size + nxt->bi_hw_front_size > q->max_segment_size) | |
160 | + return 0; | |
161 | + | |
162 | + return 1; | |
163 | +} | |
164 | + | |
165 | +/* | |
166 | + * map a request to scatterlist, return number of sg entries setup. Caller | |
167 | + * must make sure sg can hold rq->nr_phys_segments entries | |
168 | + */ | |
169 | +int blk_rq_map_sg(struct request_queue *q, struct request *rq, | |
170 | + struct scatterlist *sglist) | |
171 | +{ | |
172 | + struct bio_vec *bvec, *bvprv; | |
173 | + struct req_iterator iter; | |
174 | + struct scatterlist *sg; | |
175 | + int nsegs, cluster; | |
176 | + | |
177 | + nsegs = 0; | |
178 | + cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); | |
179 | + | |
180 | + /* | |
181 | + * for each bio in rq | |
182 | + */ | |
183 | + bvprv = NULL; | |
184 | + sg = NULL; | |
185 | + rq_for_each_segment(bvec, rq, iter) { | |
186 | + int nbytes = bvec->bv_len; | |
187 | + | |
188 | + if (bvprv && cluster) { | |
189 | + if (sg->length + nbytes > q->max_segment_size) | |
190 | + goto new_segment; | |
191 | + | |
192 | + if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) | |
193 | + goto new_segment; | |
194 | + if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) | |
195 | + goto new_segment; | |
196 | + | |
197 | + sg->length += nbytes; | |
198 | + } else { | |
199 | +new_segment: | |
200 | + if (!sg) | |
201 | + sg = sglist; | |
202 | + else { | |
203 | + /* | |
204 | + * If the driver previously mapped a shorter | |
205 | + * list, we could see a termination bit | |
206 | + * prematurely unless it fully inits the sg | |
207 | + * table on each mapping. We KNOW that there | |
208 | + * must be more entries here or the driver | |
209 | + * would be buggy, so force clear the | |
210 | + * termination bit to avoid doing a full | |
211 | + * sg_init_table() in drivers for each command. | |
212 | + */ | |
213 | + sg->page_link &= ~0x02; | |
214 | + sg = sg_next(sg); | |
215 | + } | |
216 | + | |
217 | + sg_set_page(sg, bvec->bv_page, nbytes, bvec->bv_offset); | |
218 | + nsegs++; | |
219 | + } | |
220 | + bvprv = bvec; | |
221 | + } /* segments in rq */ | |
222 | + | |
223 | + if (q->dma_drain_size) { | |
224 | + sg->page_link &= ~0x02; | |
225 | + sg = sg_next(sg); | |
226 | + sg_set_page(sg, virt_to_page(q->dma_drain_buffer), | |
227 | + q->dma_drain_size, | |
228 | + ((unsigned long)q->dma_drain_buffer) & | |
229 | + (PAGE_SIZE - 1)); | |
230 | + nsegs++; | |
231 | + } | |
232 | + | |
233 | + if (sg) | |
234 | + sg_mark_end(sg); | |
235 | + | |
236 | + return nsegs; | |
237 | +} | |
238 | + | |
239 | +EXPORT_SYMBOL(blk_rq_map_sg); | |
240 | + | |
241 | +static inline int ll_new_mergeable(struct request_queue *q, | |
242 | + struct request *req, | |
243 | + struct bio *bio) | |
244 | +{ | |
245 | + int nr_phys_segs = bio_phys_segments(q, bio); | |
246 | + | |
247 | + if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { | |
248 | + req->cmd_flags |= REQ_NOMERGE; | |
249 | + if (req == q->last_merge) | |
250 | + q->last_merge = NULL; | |
251 | + return 0; | |
252 | + } | |
253 | + | |
254 | + /* | |
255 | + * A hw segment is just getting larger, bump just the phys | |
256 | + * counter. | |
257 | + */ | |
258 | + req->nr_phys_segments += nr_phys_segs; | |
259 | + return 1; | |
260 | +} | |
261 | + | |
262 | +static inline int ll_new_hw_segment(struct request_queue *q, | |
263 | + struct request *req, | |
264 | + struct bio *bio) | |
265 | +{ | |
266 | + int nr_hw_segs = bio_hw_segments(q, bio); | |
267 | + int nr_phys_segs = bio_phys_segments(q, bio); | |
268 | + | |
269 | + if (req->nr_hw_segments + nr_hw_segs > q->max_hw_segments | |
270 | + || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { | |
271 | + req->cmd_flags |= REQ_NOMERGE; | |
272 | + if (req == q->last_merge) | |
273 | + q->last_merge = NULL; | |
274 | + return 0; | |
275 | + } | |
276 | + | |
277 | + /* | |
278 | + * This will form the start of a new hw segment. Bump both | |
279 | + * counters. | |
280 | + */ | |
281 | + req->nr_hw_segments += nr_hw_segs; | |
282 | + req->nr_phys_segments += nr_phys_segs; | |
283 | + return 1; | |
284 | +} | |
285 | + | |
286 | +int ll_back_merge_fn(struct request_queue *q, struct request *req, | |
287 | + struct bio *bio) | |
288 | +{ | |
289 | + unsigned short max_sectors; | |
290 | + int len; | |
291 | + | |
292 | + if (unlikely(blk_pc_request(req))) | |
293 | + max_sectors = q->max_hw_sectors; | |
294 | + else | |
295 | + max_sectors = q->max_sectors; | |
296 | + | |
297 | + if (req->nr_sectors + bio_sectors(bio) > max_sectors) { | |
298 | + req->cmd_flags |= REQ_NOMERGE; | |
299 | + if (req == q->last_merge) | |
300 | + q->last_merge = NULL; | |
301 | + return 0; | |
302 | + } | |
303 | + if (unlikely(!bio_flagged(req->biotail, BIO_SEG_VALID))) | |
304 | + blk_recount_segments(q, req->biotail); | |
305 | + if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
306 | + blk_recount_segments(q, bio); | |
307 | + len = req->biotail->bi_hw_back_size + bio->bi_hw_front_size; | |
308 | + if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(req->biotail), __BVEC_START(bio)) && | |
309 | + !BIOVEC_VIRT_OVERSIZE(len)) { | |
310 | + int mergeable = ll_new_mergeable(q, req, bio); | |
311 | + | |
312 | + if (mergeable) { | |
313 | + if (req->nr_hw_segments == 1) | |
314 | + req->bio->bi_hw_front_size = len; | |
315 | + if (bio->bi_hw_segments == 1) | |
316 | + bio->bi_hw_back_size = len; | |
317 | + } | |
318 | + return mergeable; | |
319 | + } | |
320 | + | |
321 | + return ll_new_hw_segment(q, req, bio); | |
322 | +} | |
323 | + | |
324 | +int ll_front_merge_fn(struct request_queue *q, struct request *req, | |
325 | + struct bio *bio) | |
326 | +{ | |
327 | + unsigned short max_sectors; | |
328 | + int len; | |
329 | + | |
330 | + if (unlikely(blk_pc_request(req))) | |
331 | + max_sectors = q->max_hw_sectors; | |
332 | + else | |
333 | + max_sectors = q->max_sectors; | |
334 | + | |
335 | + | |
336 | + if (req->nr_sectors + bio_sectors(bio) > max_sectors) { | |
337 | + req->cmd_flags |= REQ_NOMERGE; | |
338 | + if (req == q->last_merge) | |
339 | + q->last_merge = NULL; | |
340 | + return 0; | |
341 | + } | |
342 | + len = bio->bi_hw_back_size + req->bio->bi_hw_front_size; | |
343 | + if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
344 | + blk_recount_segments(q, bio); | |
345 | + if (unlikely(!bio_flagged(req->bio, BIO_SEG_VALID))) | |
346 | + blk_recount_segments(q, req->bio); | |
347 | + if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(req->bio)) && | |
348 | + !BIOVEC_VIRT_OVERSIZE(len)) { | |
349 | + int mergeable = ll_new_mergeable(q, req, bio); | |
350 | + | |
351 | + if (mergeable) { | |
352 | + if (bio->bi_hw_segments == 1) | |
353 | + bio->bi_hw_front_size = len; | |
354 | + if (req->nr_hw_segments == 1) | |
355 | + req->biotail->bi_hw_back_size = len; | |
356 | + } | |
357 | + return mergeable; | |
358 | + } | |
359 | + | |
360 | + return ll_new_hw_segment(q, req, bio); | |
361 | +} | |
362 | + | |
363 | +static int ll_merge_requests_fn(struct request_queue *q, struct request *req, | |
364 | + struct request *next) | |
365 | +{ | |
366 | + int total_phys_segments; | |
367 | + int total_hw_segments; | |
368 | + | |
369 | + /* | |
370 | + * First check if the either of the requests are re-queued | |
371 | + * requests. Can't merge them if they are. | |
372 | + */ | |
373 | + if (req->special || next->special) | |
374 | + return 0; | |
375 | + | |
376 | + /* | |
377 | + * Will it become too large? | |
378 | + */ | |
379 | + if ((req->nr_sectors + next->nr_sectors) > q->max_sectors) | |
380 | + return 0; | |
381 | + | |
382 | + total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; | |
383 | + if (blk_phys_contig_segment(q, req->biotail, next->bio)) | |
384 | + total_phys_segments--; | |
385 | + | |
386 | + if (total_phys_segments > q->max_phys_segments) | |
387 | + return 0; | |
388 | + | |
389 | + total_hw_segments = req->nr_hw_segments + next->nr_hw_segments; | |
390 | + if (blk_hw_contig_segment(q, req->biotail, next->bio)) { | |
391 | + int len = req->biotail->bi_hw_back_size + next->bio->bi_hw_front_size; | |
392 | + /* | |
393 | + * propagate the combined length to the end of the requests | |
394 | + */ | |
395 | + if (req->nr_hw_segments == 1) | |
396 | + req->bio->bi_hw_front_size = len; | |
397 | + if (next->nr_hw_segments == 1) | |
398 | + next->biotail->bi_hw_back_size = len; | |
399 | + total_hw_segments--; | |
400 | + } | |
401 | + | |
402 | + if (total_hw_segments > q->max_hw_segments) | |
403 | + return 0; | |
404 | + | |
405 | + /* Merge is OK... */ | |
406 | + req->nr_phys_segments = total_phys_segments; | |
407 | + req->nr_hw_segments = total_hw_segments; | |
408 | + return 1; | |
409 | +} | |
410 | + | |
411 | +/* | |
412 | + * Has to be called with the request spinlock acquired | |
413 | + */ | |
414 | +static int attempt_merge(struct request_queue *q, struct request *req, | |
415 | + struct request *next) | |
416 | +{ | |
417 | + if (!rq_mergeable(req) || !rq_mergeable(next)) | |
418 | + return 0; | |
419 | + | |
420 | + /* | |
421 | + * not contiguous | |
422 | + */ | |
423 | + if (req->sector + req->nr_sectors != next->sector) | |
424 | + return 0; | |
425 | + | |
426 | + if (rq_data_dir(req) != rq_data_dir(next) | |
427 | + || req->rq_disk != next->rq_disk | |
428 | + || next->special) | |
429 | + return 0; | |
430 | + | |
431 | + /* | |
432 | + * If we are allowed to merge, then append bio list | |
433 | + * from next to rq and release next. merge_requests_fn | |
434 | + * will have updated segment counts, update sector | |
435 | + * counts here. | |
436 | + */ | |
437 | + if (!ll_merge_requests_fn(q, req, next)) | |
438 | + return 0; | |
439 | + | |
440 | + /* | |
441 | + * At this point we have either done a back merge | |
442 | + * or front merge. We need the smaller start_time of | |
443 | + * the merged requests to be the current request | |
444 | + * for accounting purposes. | |
445 | + */ | |
446 | + if (time_after(req->start_time, next->start_time)) | |
447 | + req->start_time = next->start_time; | |
448 | + | |
449 | + req->biotail->bi_next = next->bio; | |
450 | + req->biotail = next->biotail; | |
451 | + | |
452 | + req->nr_sectors = req->hard_nr_sectors += next->hard_nr_sectors; | |
453 | + | |
454 | + elv_merge_requests(q, req, next); | |
455 | + | |
456 | + if (req->rq_disk) { | |
457 | + disk_round_stats(req->rq_disk); | |
458 | + req->rq_disk->in_flight--; | |
459 | + } | |
460 | + | |
461 | + req->ioprio = ioprio_best(req->ioprio, next->ioprio); | |
462 | + | |
463 | + __blk_put_request(q, next); | |
464 | + return 1; | |
465 | +} | |
466 | + | |
467 | +int attempt_back_merge(struct request_queue *q, struct request *rq) | |
468 | +{ | |
469 | + struct request *next = elv_latter_request(q, rq); | |
470 | + | |
471 | + if (next) | |
472 | + return attempt_merge(q, rq, next); | |
473 | + | |
474 | + return 0; | |
475 | +} | |
476 | + | |
477 | +int attempt_front_merge(struct request_queue *q, struct request *rq) | |
478 | +{ | |
479 | + struct request *prev = elv_former_request(q, rq); | |
480 | + | |
481 | + if (prev) | |
482 | + return attempt_merge(q, prev, rq); | |
483 | + | |
484 | + return 0; | |
485 | +} |
block/blk.h
... | ... | @@ -14,14 +14,21 @@ |
14 | 14 | void init_request_from_bio(struct request *req, struct bio *bio); |
15 | 15 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
16 | 16 | struct bio *bio); |
17 | -int ll_back_merge_fn(struct request_queue *q, struct request *req, | |
18 | - struct bio *bio); | |
19 | 17 | void __blk_queue_free_tags(struct request_queue *q); |
20 | 18 | |
21 | 19 | void blk_unplug_work(struct work_struct *work); |
22 | 20 | void blk_unplug_timeout(unsigned long data); |
23 | 21 | |
24 | 22 | struct io_context *current_io_context(gfp_t gfp_flags, int node); |
23 | + | |
24 | +int ll_back_merge_fn(struct request_queue *q, struct request *req, | |
25 | + struct bio *bio); | |
26 | +int ll_front_merge_fn(struct request_queue *q, struct request *req, | |
27 | + struct bio *bio); | |
28 | +int attempt_back_merge(struct request_queue *q, struct request *rq); | |
29 | +int attempt_front_merge(struct request_queue *q, struct request *rq); | |
30 | +void blk_recalc_rq_segments(struct request *rq); | |
31 | +void blk_recalc_rq_sectors(struct request *rq, int nsect); | |
25 | 32 | |
26 | 33 | void blk_queue_congestion_threshold(struct request_queue *q); |
27 | 34 |