Commit | Line | Data |
---|---|---|
d6d48196 JA |
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 | ||
54efd50b KO |
12 | static struct bio *blk_bio_discard_split(struct request_queue *q, |
13 | struct bio *bio, | |
14 | struct bio_set *bs) | |
15 | { | |
16 | unsigned int max_discard_sectors, granularity; | |
17 | int alignment; | |
18 | sector_t tmp; | |
19 | unsigned split_sectors; | |
20 | ||
21 | /* Zero-sector (unknown) and one-sector granularities are the same. */ | |
22 | granularity = max(q->limits.discard_granularity >> 9, 1U); | |
23 | ||
24 | max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); | |
25 | max_discard_sectors -= max_discard_sectors % granularity; | |
26 | ||
27 | if (unlikely(!max_discard_sectors)) { | |
28 | /* XXX: warn */ | |
29 | return NULL; | |
30 | } | |
31 | ||
32 | if (bio_sectors(bio) <= max_discard_sectors) | |
33 | return NULL; | |
34 | ||
35 | split_sectors = max_discard_sectors; | |
36 | ||
37 | /* | |
38 | * If the next starting sector would be misaligned, stop the discard at | |
39 | * the previous aligned sector. | |
40 | */ | |
41 | alignment = (q->limits.discard_alignment >> 9) % granularity; | |
42 | ||
43 | tmp = bio->bi_iter.bi_sector + split_sectors - alignment; | |
44 | tmp = sector_div(tmp, granularity); | |
45 | ||
46 | if (split_sectors > tmp) | |
47 | split_sectors -= tmp; | |
48 | ||
49 | return bio_split(bio, split_sectors, GFP_NOIO, bs); | |
50 | } | |
51 | ||
52 | static struct bio *blk_bio_write_same_split(struct request_queue *q, | |
53 | struct bio *bio, | |
54 | struct bio_set *bs) | |
55 | { | |
56 | if (!q->limits.max_write_same_sectors) | |
57 | return NULL; | |
58 | ||
59 | if (bio_sectors(bio) <= q->limits.max_write_same_sectors) | |
60 | return NULL; | |
61 | ||
62 | return bio_split(bio, q->limits.max_write_same_sectors, GFP_NOIO, bs); | |
63 | } | |
64 | ||
65 | static struct bio *blk_bio_segment_split(struct request_queue *q, | |
66 | struct bio *bio, | |
67 | struct bio_set *bs) | |
68 | { | |
69 | struct bio *split; | |
5014c311 | 70 | struct bio_vec bv, bvprv, *bvprvp = NULL; |
54efd50b | 71 | struct bvec_iter iter; |
8ae12666 | 72 | unsigned seg_size = 0, nsegs = 0, sectors = 0; |
54efd50b | 73 | |
54efd50b | 74 | bio_for_each_segment(bv, bio, iter) { |
8ae12666 | 75 | sectors += bv.bv_len >> 9; |
54efd50b | 76 | |
8ae12666 | 77 | if (sectors > queue_max_sectors(q)) |
54efd50b KO |
78 | goto split; |
79 | ||
80 | /* | |
81 | * If the queue doesn't support SG gaps and adding this | |
82 | * offset would create a gap, disallow it. | |
83 | */ | |
5014c311 | 84 | if (bvprvp && bvec_gap_to_prev(q, bvprvp, bv.bv_offset)) |
54efd50b KO |
85 | goto split; |
86 | ||
5014c311 | 87 | if (bvprvp && blk_queue_cluster(q)) { |
54efd50b KO |
88 | if (seg_size + bv.bv_len > queue_max_segment_size(q)) |
89 | goto new_segment; | |
5014c311 | 90 | if (!BIOVEC_PHYS_MERGEABLE(bvprvp, &bv)) |
54efd50b | 91 | goto new_segment; |
5014c311 | 92 | if (!BIOVEC_SEG_BOUNDARY(q, bvprvp, &bv)) |
54efd50b KO |
93 | goto new_segment; |
94 | ||
95 | seg_size += bv.bv_len; | |
96 | bvprv = bv; | |
5014c311 | 97 | bvprvp = &bv; |
54efd50b KO |
98 | continue; |
99 | } | |
100 | new_segment: | |
101 | if (nsegs == queue_max_segments(q)) | |
102 | goto split; | |
103 | ||
104 | nsegs++; | |
105 | bvprv = bv; | |
5014c311 | 106 | bvprvp = &bv; |
54efd50b KO |
107 | seg_size = bv.bv_len; |
108 | } | |
109 | ||
110 | return NULL; | |
111 | split: | |
112 | split = bio_clone_bioset(bio, GFP_NOIO, bs); | |
113 | ||
114 | split->bi_iter.bi_size -= iter.bi_size; | |
115 | bio->bi_iter = iter; | |
116 | ||
117 | if (bio_integrity(bio)) { | |
118 | bio_integrity_advance(bio, split->bi_iter.bi_size); | |
119 | bio_integrity_trim(split, 0, bio_sectors(split)); | |
120 | } | |
121 | ||
122 | return split; | |
123 | } | |
124 | ||
125 | void blk_queue_split(struct request_queue *q, struct bio **bio, | |
126 | struct bio_set *bs) | |
127 | { | |
128 | struct bio *split; | |
129 | ||
130 | if ((*bio)->bi_rw & REQ_DISCARD) | |
131 | split = blk_bio_discard_split(q, *bio, bs); | |
132 | else if ((*bio)->bi_rw & REQ_WRITE_SAME) | |
133 | split = blk_bio_write_same_split(q, *bio, bs); | |
134 | else | |
135 | split = blk_bio_segment_split(q, *bio, q->bio_split); | |
136 | ||
137 | if (split) { | |
138 | bio_chain(split, *bio); | |
139 | generic_make_request(*bio); | |
140 | *bio = split; | |
141 | } | |
142 | } | |
143 | EXPORT_SYMBOL(blk_queue_split); | |
144 | ||
1e428079 | 145 | static unsigned int __blk_recalc_rq_segments(struct request_queue *q, |
07388549 ML |
146 | struct bio *bio, |
147 | bool no_sg_merge) | |
d6d48196 | 148 | { |
7988613b | 149 | struct bio_vec bv, bvprv = { NULL }; |
54efd50b | 150 | int cluster, prev = 0; |
1e428079 | 151 | unsigned int seg_size, nr_phys_segs; |
59247eae | 152 | struct bio *fbio, *bbio; |
7988613b | 153 | struct bvec_iter iter; |
d6d48196 | 154 | |
1e428079 JA |
155 | if (!bio) |
156 | return 0; | |
d6d48196 | 157 | |
5cb8850c KO |
158 | /* |
159 | * This should probably be returning 0, but blk_add_request_payload() | |
160 | * (Christoph!!!!) | |
161 | */ | |
162 | if (bio->bi_rw & REQ_DISCARD) | |
163 | return 1; | |
164 | ||
165 | if (bio->bi_rw & REQ_WRITE_SAME) | |
166 | return 1; | |
167 | ||
1e428079 | 168 | fbio = bio; |
e692cb66 | 169 | cluster = blk_queue_cluster(q); |
5df97b91 | 170 | seg_size = 0; |
2c8919de | 171 | nr_phys_segs = 0; |
1e428079 | 172 | for_each_bio(bio) { |
7988613b | 173 | bio_for_each_segment(bv, bio, iter) { |
05f1dd53 JA |
174 | /* |
175 | * If SG merging is disabled, each bio vector is | |
176 | * a segment | |
177 | */ | |
178 | if (no_sg_merge) | |
179 | goto new_segment; | |
180 | ||
54efd50b | 181 | if (prev && cluster) { |
7988613b | 182 | if (seg_size + bv.bv_len |
ae03bf63 | 183 | > queue_max_segment_size(q)) |
1e428079 | 184 | goto new_segment; |
7988613b | 185 | if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv)) |
1e428079 | 186 | goto new_segment; |
7988613b | 187 | if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv)) |
1e428079 | 188 | goto new_segment; |
d6d48196 | 189 | |
7988613b | 190 | seg_size += bv.bv_len; |
1e428079 JA |
191 | bvprv = bv; |
192 | continue; | |
193 | } | |
d6d48196 | 194 | new_segment: |
1e428079 JA |
195 | if (nr_phys_segs == 1 && seg_size > |
196 | fbio->bi_seg_front_size) | |
197 | fbio->bi_seg_front_size = seg_size; | |
86771427 | 198 | |
1e428079 JA |
199 | nr_phys_segs++; |
200 | bvprv = bv; | |
54efd50b | 201 | prev = 1; |
7988613b | 202 | seg_size = bv.bv_len; |
1e428079 | 203 | } |
59247eae | 204 | bbio = bio; |
d6d48196 JA |
205 | } |
206 | ||
59247eae JA |
207 | if (nr_phys_segs == 1 && seg_size > fbio->bi_seg_front_size) |
208 | fbio->bi_seg_front_size = seg_size; | |
209 | if (seg_size > bbio->bi_seg_back_size) | |
210 | bbio->bi_seg_back_size = seg_size; | |
1e428079 JA |
211 | |
212 | return nr_phys_segs; | |
213 | } | |
214 | ||
215 | void blk_recalc_rq_segments(struct request *rq) | |
216 | { | |
07388549 ML |
217 | bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE, |
218 | &rq->q->queue_flags); | |
219 | ||
220 | rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio, | |
221 | no_sg_merge); | |
d6d48196 JA |
222 | } |
223 | ||
224 | void blk_recount_segments(struct request_queue *q, struct bio *bio) | |
225 | { | |
7f60dcaa ML |
226 | unsigned short seg_cnt; |
227 | ||
228 | /* estimate segment number by bi_vcnt for non-cloned bio */ | |
229 | if (bio_flagged(bio, BIO_CLONED)) | |
230 | seg_cnt = bio_segments(bio); | |
231 | else | |
232 | seg_cnt = bio->bi_vcnt; | |
764f612c | 233 | |
7f60dcaa ML |
234 | if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) && |
235 | (seg_cnt < queue_max_segments(q))) | |
236 | bio->bi_phys_segments = seg_cnt; | |
05f1dd53 JA |
237 | else { |
238 | struct bio *nxt = bio->bi_next; | |
239 | ||
240 | bio->bi_next = NULL; | |
7f60dcaa | 241 | bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, false); |
05f1dd53 JA |
242 | bio->bi_next = nxt; |
243 | } | |
1e428079 | 244 | |
b7c44ed9 | 245 | bio_set_flag(bio, BIO_SEG_VALID); |
d6d48196 JA |
246 | } |
247 | EXPORT_SYMBOL(blk_recount_segments); | |
248 | ||
249 | static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, | |
250 | struct bio *nxt) | |
251 | { | |
2b8221e1 | 252 | struct bio_vec end_bv = { NULL }, nxt_bv; |
f619d254 KO |
253 | struct bvec_iter iter; |
254 | ||
e692cb66 | 255 | if (!blk_queue_cluster(q)) |
d6d48196 JA |
256 | return 0; |
257 | ||
86771427 | 258 | if (bio->bi_seg_back_size + nxt->bi_seg_front_size > |
ae03bf63 | 259 | queue_max_segment_size(q)) |
d6d48196 JA |
260 | return 0; |
261 | ||
e17fc0a1 DW |
262 | if (!bio_has_data(bio)) |
263 | return 1; | |
264 | ||
f619d254 KO |
265 | bio_for_each_segment(end_bv, bio, iter) |
266 | if (end_bv.bv_len == iter.bi_size) | |
267 | break; | |
268 | ||
269 | nxt_bv = bio_iovec(nxt); | |
270 | ||
271 | if (!BIOVEC_PHYS_MERGEABLE(&end_bv, &nxt_bv)) | |
e17fc0a1 DW |
272 | return 0; |
273 | ||
d6d48196 | 274 | /* |
e17fc0a1 | 275 | * bio and nxt are contiguous in memory; check if the queue allows |
d6d48196 JA |
276 | * these two to be merged into one |
277 | */ | |
f619d254 | 278 | if (BIOVEC_SEG_BOUNDARY(q, &end_bv, &nxt_bv)) |
d6d48196 JA |
279 | return 1; |
280 | ||
281 | return 0; | |
282 | } | |
283 | ||
7988613b | 284 | static inline void |
963ab9e5 | 285 | __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec, |
7988613b | 286 | struct scatterlist *sglist, struct bio_vec *bvprv, |
963ab9e5 AH |
287 | struct scatterlist **sg, int *nsegs, int *cluster) |
288 | { | |
289 | ||
290 | int nbytes = bvec->bv_len; | |
291 | ||
7988613b | 292 | if (*sg && *cluster) { |
963ab9e5 AH |
293 | if ((*sg)->length + nbytes > queue_max_segment_size(q)) |
294 | goto new_segment; | |
295 | ||
7988613b | 296 | if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) |
963ab9e5 | 297 | goto new_segment; |
7988613b | 298 | if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) |
963ab9e5 AH |
299 | goto new_segment; |
300 | ||
301 | (*sg)->length += nbytes; | |
302 | } else { | |
303 | new_segment: | |
304 | if (!*sg) | |
305 | *sg = sglist; | |
306 | else { | |
307 | /* | |
308 | * If the driver previously mapped a shorter | |
309 | * list, we could see a termination bit | |
310 | * prematurely unless it fully inits the sg | |
311 | * table on each mapping. We KNOW that there | |
312 | * must be more entries here or the driver | |
313 | * would be buggy, so force clear the | |
314 | * termination bit to avoid doing a full | |
315 | * sg_init_table() in drivers for each command. | |
316 | */ | |
c8164d89 | 317 | sg_unmark_end(*sg); |
963ab9e5 AH |
318 | *sg = sg_next(*sg); |
319 | } | |
320 | ||
321 | sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset); | |
322 | (*nsegs)++; | |
323 | } | |
7988613b | 324 | *bvprv = *bvec; |
963ab9e5 AH |
325 | } |
326 | ||
5cb8850c KO |
327 | static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, |
328 | struct scatterlist *sglist, | |
329 | struct scatterlist **sg) | |
d6d48196 | 330 | { |
2b8221e1 | 331 | struct bio_vec bvec, bvprv = { NULL }; |
5cb8850c | 332 | struct bvec_iter iter; |
d6d48196 JA |
333 | int nsegs, cluster; |
334 | ||
335 | nsegs = 0; | |
e692cb66 | 336 | cluster = blk_queue_cluster(q); |
d6d48196 | 337 | |
5cb8850c KO |
338 | if (bio->bi_rw & REQ_DISCARD) { |
339 | /* | |
340 | * This is a hack - drivers should be neither modifying the | |
341 | * biovec, nor relying on bi_vcnt - but because of | |
342 | * blk_add_request_payload(), a discard bio may or may not have | |
343 | * a payload we need to set up here (thank you Christoph) and | |
344 | * bi_vcnt is really the only way of telling if we need to. | |
345 | */ | |
346 | ||
347 | if (bio->bi_vcnt) | |
348 | goto single_segment; | |
349 | ||
350 | return 0; | |
351 | } | |
352 | ||
353 | if (bio->bi_rw & REQ_WRITE_SAME) { | |
354 | single_segment: | |
355 | *sg = sglist; | |
356 | bvec = bio_iovec(bio); | |
357 | sg_set_page(*sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset); | |
358 | return 1; | |
359 | } | |
360 | ||
361 | for_each_bio(bio) | |
362 | bio_for_each_segment(bvec, bio, iter) | |
363 | __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, | |
364 | &nsegs, &cluster); | |
d6d48196 | 365 | |
5cb8850c KO |
366 | return nsegs; |
367 | } | |
368 | ||
369 | /* | |
370 | * map a request to scatterlist, return number of sg entries setup. Caller | |
371 | * must make sure sg can hold rq->nr_phys_segments entries | |
372 | */ | |
373 | int blk_rq_map_sg(struct request_queue *q, struct request *rq, | |
374 | struct scatterlist *sglist) | |
375 | { | |
376 | struct scatterlist *sg = NULL; | |
377 | int nsegs = 0; | |
378 | ||
379 | if (rq->bio) | |
380 | nsegs = __blk_bios_map_sg(q, rq->bio, sglist, &sg); | |
f18573ab FT |
381 | |
382 | if (unlikely(rq->cmd_flags & REQ_COPY_USER) && | |
2e46e8b2 TH |
383 | (blk_rq_bytes(rq) & q->dma_pad_mask)) { |
384 | unsigned int pad_len = | |
385 | (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; | |
f18573ab FT |
386 | |
387 | sg->length += pad_len; | |
388 | rq->extra_len += pad_len; | |
389 | } | |
390 | ||
2fb98e84 | 391 | if (q->dma_drain_size && q->dma_drain_needed(rq)) { |
7b6d91da | 392 | if (rq->cmd_flags & REQ_WRITE) |
db0a2e00 TH |
393 | memset(q->dma_drain_buffer, 0, q->dma_drain_size); |
394 | ||
da81ed16 | 395 | sg_unmark_end(sg); |
d6d48196 JA |
396 | sg = sg_next(sg); |
397 | sg_set_page(sg, virt_to_page(q->dma_drain_buffer), | |
398 | q->dma_drain_size, | |
399 | ((unsigned long)q->dma_drain_buffer) & | |
400 | (PAGE_SIZE - 1)); | |
401 | nsegs++; | |
7a85f889 | 402 | rq->extra_len += q->dma_drain_size; |
d6d48196 JA |
403 | } |
404 | ||
405 | if (sg) | |
406 | sg_mark_end(sg); | |
407 | ||
408 | return nsegs; | |
409 | } | |
d6d48196 JA |
410 | EXPORT_SYMBOL(blk_rq_map_sg); |
411 | ||
d6d48196 JA |
412 | static inline int ll_new_hw_segment(struct request_queue *q, |
413 | struct request *req, | |
414 | struct bio *bio) | |
415 | { | |
d6d48196 JA |
416 | int nr_phys_segs = bio_phys_segments(q, bio); |
417 | ||
13f05c8d MP |
418 | if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) |
419 | goto no_merge; | |
420 | ||
4eaf99be | 421 | if (blk_integrity_merge_bio(q, req, bio) == false) |
13f05c8d | 422 | goto no_merge; |
d6d48196 JA |
423 | |
424 | /* | |
425 | * This will form the start of a new hw segment. Bump both | |
426 | * counters. | |
427 | */ | |
d6d48196 JA |
428 | req->nr_phys_segments += nr_phys_segs; |
429 | return 1; | |
13f05c8d MP |
430 | |
431 | no_merge: | |
432 | req->cmd_flags |= REQ_NOMERGE; | |
433 | if (req == q->last_merge) | |
434 | q->last_merge = NULL; | |
435 | return 0; | |
d6d48196 JA |
436 | } |
437 | ||
438 | int ll_back_merge_fn(struct request_queue *q, struct request *req, | |
439 | struct bio *bio) | |
440 | { | |
f31dc1cd MP |
441 | if (blk_rq_sectors(req) + bio_sectors(bio) > |
442 | blk_rq_get_max_sectors(req)) { | |
d6d48196 JA |
443 | req->cmd_flags |= REQ_NOMERGE; |
444 | if (req == q->last_merge) | |
445 | q->last_merge = NULL; | |
446 | return 0; | |
447 | } | |
2cdf79ca | 448 | if (!bio_flagged(req->biotail, BIO_SEG_VALID)) |
d6d48196 | 449 | blk_recount_segments(q, req->biotail); |
2cdf79ca | 450 | if (!bio_flagged(bio, BIO_SEG_VALID)) |
d6d48196 | 451 | blk_recount_segments(q, bio); |
d6d48196 JA |
452 | |
453 | return ll_new_hw_segment(q, req, bio); | |
454 | } | |
455 | ||
6728cb0e | 456 | int ll_front_merge_fn(struct request_queue *q, struct request *req, |
d6d48196 JA |
457 | struct bio *bio) |
458 | { | |
f31dc1cd MP |
459 | if (blk_rq_sectors(req) + bio_sectors(bio) > |
460 | blk_rq_get_max_sectors(req)) { | |
d6d48196 JA |
461 | req->cmd_flags |= REQ_NOMERGE; |
462 | if (req == q->last_merge) | |
463 | q->last_merge = NULL; | |
464 | return 0; | |
465 | } | |
2cdf79ca | 466 | if (!bio_flagged(bio, BIO_SEG_VALID)) |
d6d48196 | 467 | blk_recount_segments(q, bio); |
2cdf79ca | 468 | if (!bio_flagged(req->bio, BIO_SEG_VALID)) |
d6d48196 | 469 | blk_recount_segments(q, req->bio); |
d6d48196 JA |
470 | |
471 | return ll_new_hw_segment(q, req, bio); | |
472 | } | |
473 | ||
e7e24500 JA |
474 | /* |
475 | * blk-mq uses req->special to carry normal driver per-request payload, it | |
476 | * does not indicate a prepared command that we cannot merge with. | |
477 | */ | |
478 | static bool req_no_special_merge(struct request *req) | |
479 | { | |
480 | struct request_queue *q = req->q; | |
481 | ||
482 | return !q->mq_ops && req->special; | |
483 | } | |
484 | ||
03100aad | 485 | static int req_gap_to_prev(struct request *req, struct bio *next) |
854fbb9c KB |
486 | { |
487 | struct bio *prev = req->biotail; | |
488 | ||
03100aad | 489 | return bvec_gap_to_prev(req->q, &prev->bi_io_vec[prev->bi_vcnt - 1], |
2ca495ac | 490 | next->bi_io_vec[0].bv_offset); |
854fbb9c KB |
491 | } |
492 | ||
d6d48196 JA |
493 | static int ll_merge_requests_fn(struct request_queue *q, struct request *req, |
494 | struct request *next) | |
495 | { | |
496 | int total_phys_segments; | |
86771427 FT |
497 | unsigned int seg_size = |
498 | req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size; | |
d6d48196 JA |
499 | |
500 | /* | |
501 | * First check if the either of the requests are re-queued | |
502 | * requests. Can't merge them if they are. | |
503 | */ | |
e7e24500 | 504 | if (req_no_special_merge(req) || req_no_special_merge(next)) |
d6d48196 JA |
505 | return 0; |
506 | ||
03100aad | 507 | if (req_gap_to_prev(req, next->bio)) |
854fbb9c KB |
508 | return 0; |
509 | ||
d6d48196 JA |
510 | /* |
511 | * Will it become too large? | |
512 | */ | |
f31dc1cd MP |
513 | if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > |
514 | blk_rq_get_max_sectors(req)) | |
d6d48196 JA |
515 | return 0; |
516 | ||
517 | total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; | |
86771427 FT |
518 | if (blk_phys_contig_segment(q, req->biotail, next->bio)) { |
519 | if (req->nr_phys_segments == 1) | |
520 | req->bio->bi_seg_front_size = seg_size; | |
521 | if (next->nr_phys_segments == 1) | |
522 | next->biotail->bi_seg_back_size = seg_size; | |
d6d48196 | 523 | total_phys_segments--; |
86771427 | 524 | } |
d6d48196 | 525 | |
8a78362c | 526 | if (total_phys_segments > queue_max_segments(q)) |
d6d48196 JA |
527 | return 0; |
528 | ||
4eaf99be | 529 | if (blk_integrity_merge_rq(q, req, next) == false) |
13f05c8d MP |
530 | return 0; |
531 | ||
d6d48196 JA |
532 | /* Merge is OK... */ |
533 | req->nr_phys_segments = total_phys_segments; | |
d6d48196 JA |
534 | return 1; |
535 | } | |
536 | ||
80a761fd TH |
537 | /** |
538 | * blk_rq_set_mixed_merge - mark a request as mixed merge | |
539 | * @rq: request to mark as mixed merge | |
540 | * | |
541 | * Description: | |
542 | * @rq is about to be mixed merged. Make sure the attributes | |
543 | * which can be mixed are set in each bio and mark @rq as mixed | |
544 | * merged. | |
545 | */ | |
546 | void blk_rq_set_mixed_merge(struct request *rq) | |
547 | { | |
548 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
549 | struct bio *bio; | |
550 | ||
551 | if (rq->cmd_flags & REQ_MIXED_MERGE) | |
552 | return; | |
553 | ||
554 | /* | |
555 | * @rq will no longer represent mixable attributes for all the | |
556 | * contained bios. It will just track those of the first one. | |
557 | * Distributes the attributs to each bio. | |
558 | */ | |
559 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
560 | WARN_ON_ONCE((bio->bi_rw & REQ_FAILFAST_MASK) && | |
561 | (bio->bi_rw & REQ_FAILFAST_MASK) != ff); | |
562 | bio->bi_rw |= ff; | |
563 | } | |
564 | rq->cmd_flags |= REQ_MIXED_MERGE; | |
565 | } | |
566 | ||
26308eab JM |
567 | static void blk_account_io_merge(struct request *req) |
568 | { | |
569 | if (blk_do_io_stat(req)) { | |
570 | struct hd_struct *part; | |
571 | int cpu; | |
572 | ||
573 | cpu = part_stat_lock(); | |
09e099d4 | 574 | part = req->part; |
26308eab JM |
575 | |
576 | part_round_stats(cpu, part); | |
316d315b | 577 | part_dec_in_flight(part, rq_data_dir(req)); |
26308eab | 578 | |
6c23a968 | 579 | hd_struct_put(part); |
26308eab JM |
580 | part_stat_unlock(); |
581 | } | |
582 | } | |
583 | ||
d6d48196 JA |
584 | /* |
585 | * Has to be called with the request spinlock acquired | |
586 | */ | |
587 | static int attempt_merge(struct request_queue *q, struct request *req, | |
588 | struct request *next) | |
589 | { | |
590 | if (!rq_mergeable(req) || !rq_mergeable(next)) | |
591 | return 0; | |
592 | ||
f31dc1cd MP |
593 | if (!blk_check_merge_flags(req->cmd_flags, next->cmd_flags)) |
594 | return 0; | |
595 | ||
d6d48196 JA |
596 | /* |
597 | * not contiguous | |
598 | */ | |
83096ebf | 599 | if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next)) |
d6d48196 JA |
600 | return 0; |
601 | ||
602 | if (rq_data_dir(req) != rq_data_dir(next) | |
603 | || req->rq_disk != next->rq_disk | |
e7e24500 | 604 | || req_no_special_merge(next)) |
d6d48196 JA |
605 | return 0; |
606 | ||
4363ac7c MP |
607 | if (req->cmd_flags & REQ_WRITE_SAME && |
608 | !blk_write_same_mergeable(req->bio, next->bio)) | |
609 | return 0; | |
610 | ||
d6d48196 JA |
611 | /* |
612 | * If we are allowed to merge, then append bio list | |
613 | * from next to rq and release next. merge_requests_fn | |
614 | * will have updated segment counts, update sector | |
615 | * counts here. | |
616 | */ | |
617 | if (!ll_merge_requests_fn(q, req, next)) | |
618 | return 0; | |
619 | ||
80a761fd TH |
620 | /* |
621 | * If failfast settings disagree or any of the two is already | |
622 | * a mixed merge, mark both as mixed before proceeding. This | |
623 | * makes sure that all involved bios have mixable attributes | |
624 | * set properly. | |
625 | */ | |
626 | if ((req->cmd_flags | next->cmd_flags) & REQ_MIXED_MERGE || | |
627 | (req->cmd_flags & REQ_FAILFAST_MASK) != | |
628 | (next->cmd_flags & REQ_FAILFAST_MASK)) { | |
629 | blk_rq_set_mixed_merge(req); | |
630 | blk_rq_set_mixed_merge(next); | |
631 | } | |
632 | ||
d6d48196 JA |
633 | /* |
634 | * At this point we have either done a back merge | |
635 | * or front merge. We need the smaller start_time of | |
636 | * the merged requests to be the current request | |
637 | * for accounting purposes. | |
638 | */ | |
639 | if (time_after(req->start_time, next->start_time)) | |
640 | req->start_time = next->start_time; | |
641 | ||
642 | req->biotail->bi_next = next->bio; | |
643 | req->biotail = next->biotail; | |
644 | ||
a2dec7b3 | 645 | req->__data_len += blk_rq_bytes(next); |
d6d48196 JA |
646 | |
647 | elv_merge_requests(q, req, next); | |
648 | ||
42dad764 JM |
649 | /* |
650 | * 'next' is going away, so update stats accordingly | |
651 | */ | |
652 | blk_account_io_merge(next); | |
d6d48196 JA |
653 | |
654 | req->ioprio = ioprio_best(req->ioprio, next->ioprio); | |
ab780f1e JA |
655 | if (blk_rq_cpu_valid(next)) |
656 | req->cpu = next->cpu; | |
d6d48196 | 657 | |
1cd96c24 BH |
658 | /* owner-ship of bio passed from next to req */ |
659 | next->bio = NULL; | |
d6d48196 JA |
660 | __blk_put_request(q, next); |
661 | return 1; | |
662 | } | |
663 | ||
664 | int attempt_back_merge(struct request_queue *q, struct request *rq) | |
665 | { | |
666 | struct request *next = elv_latter_request(q, rq); | |
667 | ||
668 | if (next) | |
669 | return attempt_merge(q, rq, next); | |
670 | ||
671 | return 0; | |
672 | } | |
673 | ||
674 | int attempt_front_merge(struct request_queue *q, struct request *rq) | |
675 | { | |
676 | struct request *prev = elv_former_request(q, rq); | |
677 | ||
678 | if (prev) | |
679 | return attempt_merge(q, prev, rq); | |
680 | ||
681 | return 0; | |
682 | } | |
5e84ea3a JA |
683 | |
684 | int blk_attempt_req_merge(struct request_queue *q, struct request *rq, | |
685 | struct request *next) | |
686 | { | |
687 | return attempt_merge(q, rq, next); | |
688 | } | |
050c8ea8 TH |
689 | |
690 | bool blk_rq_merge_ok(struct request *rq, struct bio *bio) | |
691 | { | |
e2a60da7 | 692 | if (!rq_mergeable(rq) || !bio_mergeable(bio)) |
050c8ea8 TH |
693 | return false; |
694 | ||
f31dc1cd MP |
695 | if (!blk_check_merge_flags(rq->cmd_flags, bio->bi_rw)) |
696 | return false; | |
697 | ||
050c8ea8 TH |
698 | /* different data direction or already started, don't merge */ |
699 | if (bio_data_dir(bio) != rq_data_dir(rq)) | |
700 | return false; | |
701 | ||
702 | /* must be same device and not a special request */ | |
e7e24500 | 703 | if (rq->rq_disk != bio->bi_bdev->bd_disk || req_no_special_merge(rq)) |
050c8ea8 TH |
704 | return false; |
705 | ||
706 | /* only merge integrity protected bio into ditto rq */ | |
4eaf99be | 707 | if (blk_integrity_merge_bio(rq->q, rq, bio) == false) |
050c8ea8 TH |
708 | return false; |
709 | ||
4363ac7c MP |
710 | /* must be using the same buffer */ |
711 | if (rq->cmd_flags & REQ_WRITE_SAME && | |
712 | !blk_write_same_mergeable(rq->bio, bio)) | |
713 | return false; | |
714 | ||
beefa6ba | 715 | /* Only check gaps if the bio carries data */ |
03100aad KB |
716 | if (bio_has_data(bio) && req_gap_to_prev(rq, bio)) |
717 | return false; | |
66cb45aa | 718 | |
050c8ea8 TH |
719 | return true; |
720 | } | |
721 | ||
722 | int blk_try_merge(struct request *rq, struct bio *bio) | |
723 | { | |
4f024f37 | 724 | if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector) |
050c8ea8 | 725 | return ELEVATOR_BACK_MERGE; |
4f024f37 | 726 | else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector) |
050c8ea8 TH |
727 | return ELEVATOR_FRONT_MERGE; |
728 | return ELEVATOR_NO_MERGE; | |
729 | } |