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, | |
bdced438 ML |
14 | struct bio_set *bs, |
15 | unsigned *nsegs) | |
54efd50b KO |
16 | { |
17 | unsigned int max_discard_sectors, granularity; | |
18 | int alignment; | |
19 | sector_t tmp; | |
20 | unsigned split_sectors; | |
21 | ||
bdced438 ML |
22 | *nsegs = 1; |
23 | ||
54efd50b KO |
24 | /* Zero-sector (unknown) and one-sector granularities are the same. */ |
25 | granularity = max(q->limits.discard_granularity >> 9, 1U); | |
26 | ||
27 | max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); | |
28 | max_discard_sectors -= max_discard_sectors % granularity; | |
29 | ||
30 | if (unlikely(!max_discard_sectors)) { | |
31 | /* XXX: warn */ | |
32 | return NULL; | |
33 | } | |
34 | ||
35 | if (bio_sectors(bio) <= max_discard_sectors) | |
36 | return NULL; | |
37 | ||
38 | split_sectors = max_discard_sectors; | |
39 | ||
40 | /* | |
41 | * If the next starting sector would be misaligned, stop the discard at | |
42 | * the previous aligned sector. | |
43 | */ | |
44 | alignment = (q->limits.discard_alignment >> 9) % granularity; | |
45 | ||
46 | tmp = bio->bi_iter.bi_sector + split_sectors - alignment; | |
47 | tmp = sector_div(tmp, granularity); | |
48 | ||
49 | if (split_sectors > tmp) | |
50 | split_sectors -= tmp; | |
51 | ||
52 | return bio_split(bio, split_sectors, GFP_NOIO, bs); | |
53 | } | |
54 | ||
55 | static struct bio *blk_bio_write_same_split(struct request_queue *q, | |
56 | struct bio *bio, | |
bdced438 ML |
57 | struct bio_set *bs, |
58 | unsigned *nsegs) | |
54efd50b | 59 | { |
bdced438 ML |
60 | *nsegs = 1; |
61 | ||
54efd50b KO |
62 | if (!q->limits.max_write_same_sectors) |
63 | return NULL; | |
64 | ||
65 | if (bio_sectors(bio) <= q->limits.max_write_same_sectors) | |
66 | return NULL; | |
67 | ||
68 | return bio_split(bio, q->limits.max_write_same_sectors, GFP_NOIO, bs); | |
69 | } | |
70 | ||
71 | static struct bio *blk_bio_segment_split(struct request_queue *q, | |
72 | struct bio *bio, | |
bdced438 ML |
73 | struct bio_set *bs, |
74 | unsigned *segs) | |
54efd50b | 75 | { |
5014c311 | 76 | struct bio_vec bv, bvprv, *bvprvp = NULL; |
54efd50b | 77 | struct bvec_iter iter; |
8ae12666 | 78 | unsigned seg_size = 0, nsegs = 0, sectors = 0; |
02e70742 ML |
79 | unsigned front_seg_size = bio->bi_seg_front_size; |
80 | bool do_split = true; | |
81 | struct bio *new = NULL; | |
54efd50b | 82 | |
54efd50b | 83 | bio_for_each_segment(bv, bio, iter) { |
52cc6eea | 84 | if (sectors + (bv.bv_len >> 9) > queue_max_sectors(q)) |
54efd50b KO |
85 | goto split; |
86 | ||
87 | /* | |
88 | * If the queue doesn't support SG gaps and adding this | |
89 | * offset would create a gap, disallow it. | |
90 | */ | |
5014c311 | 91 | if (bvprvp && bvec_gap_to_prev(q, bvprvp, bv.bv_offset)) |
54efd50b KO |
92 | goto split; |
93 | ||
5014c311 | 94 | if (bvprvp && blk_queue_cluster(q)) { |
54efd50b KO |
95 | if (seg_size + bv.bv_len > queue_max_segment_size(q)) |
96 | goto new_segment; | |
5014c311 | 97 | if (!BIOVEC_PHYS_MERGEABLE(bvprvp, &bv)) |
54efd50b | 98 | goto new_segment; |
5014c311 | 99 | if (!BIOVEC_SEG_BOUNDARY(q, bvprvp, &bv)) |
54efd50b KO |
100 | goto new_segment; |
101 | ||
102 | seg_size += bv.bv_len; | |
103 | bvprv = bv; | |
578270bf | 104 | bvprvp = &bvprv; |
52cc6eea | 105 | sectors += bv.bv_len >> 9; |
54efd50b KO |
106 | continue; |
107 | } | |
108 | new_segment: | |
109 | if (nsegs == queue_max_segments(q)) | |
110 | goto split; | |
111 | ||
112 | nsegs++; | |
113 | bvprv = bv; | |
578270bf | 114 | bvprvp = &bvprv; |
54efd50b | 115 | seg_size = bv.bv_len; |
52cc6eea | 116 | sectors += bv.bv_len >> 9; |
02e70742 ML |
117 | |
118 | if (nsegs == 1 && seg_size > front_seg_size) | |
119 | front_seg_size = seg_size; | |
54efd50b KO |
120 | } |
121 | ||
02e70742 | 122 | do_split = false; |
54efd50b | 123 | split: |
bdced438 | 124 | *segs = nsegs; |
02e70742 ML |
125 | |
126 | if (do_split) { | |
127 | new = bio_split(bio, sectors, GFP_NOIO, bs); | |
128 | if (new) | |
129 | bio = new; | |
130 | } | |
131 | ||
132 | bio->bi_seg_front_size = front_seg_size; | |
133 | if (seg_size > bio->bi_seg_back_size) | |
134 | bio->bi_seg_back_size = seg_size; | |
135 | ||
136 | return do_split ? new : NULL; | |
54efd50b KO |
137 | } |
138 | ||
139 | void blk_queue_split(struct request_queue *q, struct bio **bio, | |
140 | struct bio_set *bs) | |
141 | { | |
bdced438 ML |
142 | struct bio *split, *res; |
143 | unsigned nsegs; | |
54efd50b KO |
144 | |
145 | if ((*bio)->bi_rw & REQ_DISCARD) | |
bdced438 | 146 | split = blk_bio_discard_split(q, *bio, bs, &nsegs); |
54efd50b | 147 | else if ((*bio)->bi_rw & REQ_WRITE_SAME) |
bdced438 | 148 | split = blk_bio_write_same_split(q, *bio, bs, &nsegs); |
54efd50b | 149 | else |
bdced438 ML |
150 | split = blk_bio_segment_split(q, *bio, q->bio_split, &nsegs); |
151 | ||
152 | /* physical segments can be figured out during splitting */ | |
153 | res = split ? split : *bio; | |
154 | res->bi_phys_segments = nsegs; | |
155 | bio_set_flag(res, BIO_SEG_VALID); | |
54efd50b KO |
156 | |
157 | if (split) { | |
6ac45aeb ML |
158 | /* there isn't chance to merge the splitted bio */ |
159 | split->bi_rw |= REQ_NOMERGE; | |
160 | ||
54efd50b KO |
161 | bio_chain(split, *bio); |
162 | generic_make_request(*bio); | |
163 | *bio = split; | |
164 | } | |
165 | } | |
166 | EXPORT_SYMBOL(blk_queue_split); | |
167 | ||
1e428079 | 168 | static unsigned int __blk_recalc_rq_segments(struct request_queue *q, |
07388549 ML |
169 | struct bio *bio, |
170 | bool no_sg_merge) | |
d6d48196 | 171 | { |
7988613b | 172 | struct bio_vec bv, bvprv = { NULL }; |
54efd50b | 173 | int cluster, prev = 0; |
1e428079 | 174 | unsigned int seg_size, nr_phys_segs; |
59247eae | 175 | struct bio *fbio, *bbio; |
7988613b | 176 | struct bvec_iter iter; |
d6d48196 | 177 | |
1e428079 JA |
178 | if (!bio) |
179 | return 0; | |
d6d48196 | 180 | |
5cb8850c KO |
181 | /* |
182 | * This should probably be returning 0, but blk_add_request_payload() | |
183 | * (Christoph!!!!) | |
184 | */ | |
185 | if (bio->bi_rw & REQ_DISCARD) | |
186 | return 1; | |
187 | ||
188 | if (bio->bi_rw & REQ_WRITE_SAME) | |
189 | return 1; | |
190 | ||
1e428079 | 191 | fbio = bio; |
e692cb66 | 192 | cluster = blk_queue_cluster(q); |
5df97b91 | 193 | seg_size = 0; |
2c8919de | 194 | nr_phys_segs = 0; |
1e428079 | 195 | for_each_bio(bio) { |
7988613b | 196 | bio_for_each_segment(bv, bio, iter) { |
05f1dd53 JA |
197 | /* |
198 | * If SG merging is disabled, each bio vector is | |
199 | * a segment | |
200 | */ | |
201 | if (no_sg_merge) | |
202 | goto new_segment; | |
203 | ||
54efd50b | 204 | if (prev && cluster) { |
7988613b | 205 | if (seg_size + bv.bv_len |
ae03bf63 | 206 | > queue_max_segment_size(q)) |
1e428079 | 207 | goto new_segment; |
7988613b | 208 | if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv)) |
1e428079 | 209 | goto new_segment; |
7988613b | 210 | if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv)) |
1e428079 | 211 | goto new_segment; |
d6d48196 | 212 | |
7988613b | 213 | seg_size += bv.bv_len; |
1e428079 JA |
214 | bvprv = bv; |
215 | continue; | |
216 | } | |
d6d48196 | 217 | new_segment: |
1e428079 JA |
218 | if (nr_phys_segs == 1 && seg_size > |
219 | fbio->bi_seg_front_size) | |
220 | fbio->bi_seg_front_size = seg_size; | |
86771427 | 221 | |
1e428079 JA |
222 | nr_phys_segs++; |
223 | bvprv = bv; | |
54efd50b | 224 | prev = 1; |
7988613b | 225 | seg_size = bv.bv_len; |
1e428079 | 226 | } |
59247eae | 227 | bbio = bio; |
d6d48196 JA |
228 | } |
229 | ||
59247eae JA |
230 | if (nr_phys_segs == 1 && seg_size > fbio->bi_seg_front_size) |
231 | fbio->bi_seg_front_size = seg_size; | |
232 | if (seg_size > bbio->bi_seg_back_size) | |
233 | bbio->bi_seg_back_size = seg_size; | |
1e428079 JA |
234 | |
235 | return nr_phys_segs; | |
236 | } | |
237 | ||
238 | void blk_recalc_rq_segments(struct request *rq) | |
239 | { | |
07388549 ML |
240 | bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE, |
241 | &rq->q->queue_flags); | |
242 | ||
243 | rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio, | |
244 | no_sg_merge); | |
d6d48196 JA |
245 | } |
246 | ||
247 | void blk_recount_segments(struct request_queue *q, struct bio *bio) | |
248 | { | |
7f60dcaa ML |
249 | unsigned short seg_cnt; |
250 | ||
251 | /* estimate segment number by bi_vcnt for non-cloned bio */ | |
252 | if (bio_flagged(bio, BIO_CLONED)) | |
253 | seg_cnt = bio_segments(bio); | |
254 | else | |
255 | seg_cnt = bio->bi_vcnt; | |
764f612c | 256 | |
7f60dcaa ML |
257 | if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) && |
258 | (seg_cnt < queue_max_segments(q))) | |
259 | bio->bi_phys_segments = seg_cnt; | |
05f1dd53 JA |
260 | else { |
261 | struct bio *nxt = bio->bi_next; | |
262 | ||
263 | bio->bi_next = NULL; | |
7f60dcaa | 264 | bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, false); |
05f1dd53 JA |
265 | bio->bi_next = nxt; |
266 | } | |
1e428079 | 267 | |
b7c44ed9 | 268 | bio_set_flag(bio, BIO_SEG_VALID); |
d6d48196 JA |
269 | } |
270 | EXPORT_SYMBOL(blk_recount_segments); | |
271 | ||
272 | static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, | |
273 | struct bio *nxt) | |
274 | { | |
2b8221e1 | 275 | struct bio_vec end_bv = { NULL }, nxt_bv; |
f619d254 KO |
276 | struct bvec_iter iter; |
277 | ||
e692cb66 | 278 | if (!blk_queue_cluster(q)) |
d6d48196 JA |
279 | return 0; |
280 | ||
86771427 | 281 | if (bio->bi_seg_back_size + nxt->bi_seg_front_size > |
ae03bf63 | 282 | queue_max_segment_size(q)) |
d6d48196 JA |
283 | return 0; |
284 | ||
e17fc0a1 DW |
285 | if (!bio_has_data(bio)) |
286 | return 1; | |
287 | ||
f619d254 KO |
288 | bio_for_each_segment(end_bv, bio, iter) |
289 | if (end_bv.bv_len == iter.bi_size) | |
290 | break; | |
291 | ||
292 | nxt_bv = bio_iovec(nxt); | |
293 | ||
294 | if (!BIOVEC_PHYS_MERGEABLE(&end_bv, &nxt_bv)) | |
e17fc0a1 DW |
295 | return 0; |
296 | ||
d6d48196 | 297 | /* |
e17fc0a1 | 298 | * bio and nxt are contiguous in memory; check if the queue allows |
d6d48196 JA |
299 | * these two to be merged into one |
300 | */ | |
f619d254 | 301 | if (BIOVEC_SEG_BOUNDARY(q, &end_bv, &nxt_bv)) |
d6d48196 JA |
302 | return 1; |
303 | ||
304 | return 0; | |
305 | } | |
306 | ||
7988613b | 307 | static inline void |
963ab9e5 | 308 | __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec, |
7988613b | 309 | struct scatterlist *sglist, struct bio_vec *bvprv, |
963ab9e5 AH |
310 | struct scatterlist **sg, int *nsegs, int *cluster) |
311 | { | |
312 | ||
313 | int nbytes = bvec->bv_len; | |
314 | ||
7988613b | 315 | if (*sg && *cluster) { |
963ab9e5 AH |
316 | if ((*sg)->length + nbytes > queue_max_segment_size(q)) |
317 | goto new_segment; | |
318 | ||
7988613b | 319 | if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) |
963ab9e5 | 320 | goto new_segment; |
7988613b | 321 | if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) |
963ab9e5 AH |
322 | goto new_segment; |
323 | ||
324 | (*sg)->length += nbytes; | |
325 | } else { | |
326 | new_segment: | |
327 | if (!*sg) | |
328 | *sg = sglist; | |
329 | else { | |
330 | /* | |
331 | * If the driver previously mapped a shorter | |
332 | * list, we could see a termination bit | |
333 | * prematurely unless it fully inits the sg | |
334 | * table on each mapping. We KNOW that there | |
335 | * must be more entries here or the driver | |
336 | * would be buggy, so force clear the | |
337 | * termination bit to avoid doing a full | |
338 | * sg_init_table() in drivers for each command. | |
339 | */ | |
c8164d89 | 340 | sg_unmark_end(*sg); |
963ab9e5 AH |
341 | *sg = sg_next(*sg); |
342 | } | |
343 | ||
344 | sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset); | |
345 | (*nsegs)++; | |
346 | } | |
7988613b | 347 | *bvprv = *bvec; |
963ab9e5 AH |
348 | } |
349 | ||
5cb8850c KO |
350 | static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, |
351 | struct scatterlist *sglist, | |
352 | struct scatterlist **sg) | |
d6d48196 | 353 | { |
2b8221e1 | 354 | struct bio_vec bvec, bvprv = { NULL }; |
5cb8850c | 355 | struct bvec_iter iter; |
d6d48196 JA |
356 | int nsegs, cluster; |
357 | ||
358 | nsegs = 0; | |
e692cb66 | 359 | cluster = blk_queue_cluster(q); |
d6d48196 | 360 | |
5cb8850c KO |
361 | if (bio->bi_rw & REQ_DISCARD) { |
362 | /* | |
363 | * This is a hack - drivers should be neither modifying the | |
364 | * biovec, nor relying on bi_vcnt - but because of | |
365 | * blk_add_request_payload(), a discard bio may or may not have | |
366 | * a payload we need to set up here (thank you Christoph) and | |
367 | * bi_vcnt is really the only way of telling if we need to. | |
368 | */ | |
369 | ||
370 | if (bio->bi_vcnt) | |
371 | goto single_segment; | |
372 | ||
373 | return 0; | |
374 | } | |
375 | ||
376 | if (bio->bi_rw & REQ_WRITE_SAME) { | |
377 | single_segment: | |
378 | *sg = sglist; | |
379 | bvec = bio_iovec(bio); | |
380 | sg_set_page(*sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset); | |
381 | return 1; | |
382 | } | |
383 | ||
384 | for_each_bio(bio) | |
385 | bio_for_each_segment(bvec, bio, iter) | |
386 | __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, | |
387 | &nsegs, &cluster); | |
d6d48196 | 388 | |
5cb8850c KO |
389 | return nsegs; |
390 | } | |
391 | ||
392 | /* | |
393 | * map a request to scatterlist, return number of sg entries setup. Caller | |
394 | * must make sure sg can hold rq->nr_phys_segments entries | |
395 | */ | |
396 | int blk_rq_map_sg(struct request_queue *q, struct request *rq, | |
397 | struct scatterlist *sglist) | |
398 | { | |
399 | struct scatterlist *sg = NULL; | |
400 | int nsegs = 0; | |
401 | ||
402 | if (rq->bio) | |
403 | nsegs = __blk_bios_map_sg(q, rq->bio, sglist, &sg); | |
f18573ab FT |
404 | |
405 | if (unlikely(rq->cmd_flags & REQ_COPY_USER) && | |
2e46e8b2 TH |
406 | (blk_rq_bytes(rq) & q->dma_pad_mask)) { |
407 | unsigned int pad_len = | |
408 | (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; | |
f18573ab FT |
409 | |
410 | sg->length += pad_len; | |
411 | rq->extra_len += pad_len; | |
412 | } | |
413 | ||
2fb98e84 | 414 | if (q->dma_drain_size && q->dma_drain_needed(rq)) { |
7b6d91da | 415 | if (rq->cmd_flags & REQ_WRITE) |
db0a2e00 TH |
416 | memset(q->dma_drain_buffer, 0, q->dma_drain_size); |
417 | ||
da81ed16 | 418 | sg_unmark_end(sg); |
d6d48196 JA |
419 | sg = sg_next(sg); |
420 | sg_set_page(sg, virt_to_page(q->dma_drain_buffer), | |
421 | q->dma_drain_size, | |
422 | ((unsigned long)q->dma_drain_buffer) & | |
423 | (PAGE_SIZE - 1)); | |
424 | nsegs++; | |
7a85f889 | 425 | rq->extra_len += q->dma_drain_size; |
d6d48196 JA |
426 | } |
427 | ||
428 | if (sg) | |
429 | sg_mark_end(sg); | |
430 | ||
12e57f59 ML |
431 | /* |
432 | * Something must have been wrong if the figured number of | |
433 | * segment is bigger than number of req's physical segments | |
434 | */ | |
435 | WARN_ON(nsegs > rq->nr_phys_segments); | |
436 | ||
d6d48196 JA |
437 | return nsegs; |
438 | } | |
d6d48196 JA |
439 | EXPORT_SYMBOL(blk_rq_map_sg); |
440 | ||
d6d48196 JA |
441 | static inline int ll_new_hw_segment(struct request_queue *q, |
442 | struct request *req, | |
443 | struct bio *bio) | |
444 | { | |
d6d48196 JA |
445 | int nr_phys_segs = bio_phys_segments(q, bio); |
446 | ||
13f05c8d MP |
447 | if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) |
448 | goto no_merge; | |
449 | ||
4eaf99be | 450 | if (blk_integrity_merge_bio(q, req, bio) == false) |
13f05c8d | 451 | goto no_merge; |
d6d48196 JA |
452 | |
453 | /* | |
454 | * This will form the start of a new hw segment. Bump both | |
455 | * counters. | |
456 | */ | |
d6d48196 JA |
457 | req->nr_phys_segments += nr_phys_segs; |
458 | return 1; | |
13f05c8d MP |
459 | |
460 | no_merge: | |
461 | req->cmd_flags |= REQ_NOMERGE; | |
462 | if (req == q->last_merge) | |
463 | q->last_merge = NULL; | |
464 | return 0; | |
d6d48196 JA |
465 | } |
466 | ||
467 | int ll_back_merge_fn(struct request_queue *q, struct request *req, | |
468 | struct bio *bio) | |
469 | { | |
5e7c4274 JA |
470 | if (req_gap_back_merge(req, bio)) |
471 | return 0; | |
7f39add3 SG |
472 | if (blk_integrity_rq(req) && |
473 | integrity_req_gap_back_merge(req, bio)) | |
474 | return 0; | |
f31dc1cd MP |
475 | if (blk_rq_sectors(req) + bio_sectors(bio) > |
476 | blk_rq_get_max_sectors(req)) { | |
d6d48196 JA |
477 | req->cmd_flags |= REQ_NOMERGE; |
478 | if (req == q->last_merge) | |
479 | q->last_merge = NULL; | |
480 | return 0; | |
481 | } | |
2cdf79ca | 482 | if (!bio_flagged(req->biotail, BIO_SEG_VALID)) |
d6d48196 | 483 | blk_recount_segments(q, req->biotail); |
2cdf79ca | 484 | if (!bio_flagged(bio, BIO_SEG_VALID)) |
d6d48196 | 485 | blk_recount_segments(q, bio); |
d6d48196 JA |
486 | |
487 | return ll_new_hw_segment(q, req, bio); | |
488 | } | |
489 | ||
6728cb0e | 490 | int ll_front_merge_fn(struct request_queue *q, struct request *req, |
d6d48196 JA |
491 | struct bio *bio) |
492 | { | |
5e7c4274 JA |
493 | |
494 | if (req_gap_front_merge(req, bio)) | |
495 | return 0; | |
7f39add3 SG |
496 | if (blk_integrity_rq(req) && |
497 | integrity_req_gap_front_merge(req, bio)) | |
498 | return 0; | |
f31dc1cd MP |
499 | if (blk_rq_sectors(req) + bio_sectors(bio) > |
500 | blk_rq_get_max_sectors(req)) { | |
d6d48196 JA |
501 | req->cmd_flags |= REQ_NOMERGE; |
502 | if (req == q->last_merge) | |
503 | q->last_merge = NULL; | |
504 | return 0; | |
505 | } | |
2cdf79ca | 506 | if (!bio_flagged(bio, BIO_SEG_VALID)) |
d6d48196 | 507 | blk_recount_segments(q, bio); |
2cdf79ca | 508 | if (!bio_flagged(req->bio, BIO_SEG_VALID)) |
d6d48196 | 509 | blk_recount_segments(q, req->bio); |
d6d48196 JA |
510 | |
511 | return ll_new_hw_segment(q, req, bio); | |
512 | } | |
513 | ||
e7e24500 JA |
514 | /* |
515 | * blk-mq uses req->special to carry normal driver per-request payload, it | |
516 | * does not indicate a prepared command that we cannot merge with. | |
517 | */ | |
518 | static bool req_no_special_merge(struct request *req) | |
519 | { | |
520 | struct request_queue *q = req->q; | |
521 | ||
522 | return !q->mq_ops && req->special; | |
523 | } | |
524 | ||
d6d48196 JA |
525 | static int ll_merge_requests_fn(struct request_queue *q, struct request *req, |
526 | struct request *next) | |
527 | { | |
528 | int total_phys_segments; | |
86771427 FT |
529 | unsigned int seg_size = |
530 | req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size; | |
d6d48196 JA |
531 | |
532 | /* | |
533 | * First check if the either of the requests are re-queued | |
534 | * requests. Can't merge them if they are. | |
535 | */ | |
e7e24500 | 536 | if (req_no_special_merge(req) || req_no_special_merge(next)) |
d6d48196 JA |
537 | return 0; |
538 | ||
5e7c4274 | 539 | if (req_gap_back_merge(req, next->bio)) |
854fbb9c KB |
540 | return 0; |
541 | ||
d6d48196 JA |
542 | /* |
543 | * Will it become too large? | |
544 | */ | |
f31dc1cd MP |
545 | if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > |
546 | blk_rq_get_max_sectors(req)) | |
d6d48196 JA |
547 | return 0; |
548 | ||
549 | total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; | |
86771427 FT |
550 | if (blk_phys_contig_segment(q, req->biotail, next->bio)) { |
551 | if (req->nr_phys_segments == 1) | |
552 | req->bio->bi_seg_front_size = seg_size; | |
553 | if (next->nr_phys_segments == 1) | |
554 | next->biotail->bi_seg_back_size = seg_size; | |
d6d48196 | 555 | total_phys_segments--; |
86771427 | 556 | } |
d6d48196 | 557 | |
8a78362c | 558 | if (total_phys_segments > queue_max_segments(q)) |
d6d48196 JA |
559 | return 0; |
560 | ||
4eaf99be | 561 | if (blk_integrity_merge_rq(q, req, next) == false) |
13f05c8d MP |
562 | return 0; |
563 | ||
d6d48196 JA |
564 | /* Merge is OK... */ |
565 | req->nr_phys_segments = total_phys_segments; | |
d6d48196 JA |
566 | return 1; |
567 | } | |
568 | ||
80a761fd TH |
569 | /** |
570 | * blk_rq_set_mixed_merge - mark a request as mixed merge | |
571 | * @rq: request to mark as mixed merge | |
572 | * | |
573 | * Description: | |
574 | * @rq is about to be mixed merged. Make sure the attributes | |
575 | * which can be mixed are set in each bio and mark @rq as mixed | |
576 | * merged. | |
577 | */ | |
578 | void blk_rq_set_mixed_merge(struct request *rq) | |
579 | { | |
580 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
581 | struct bio *bio; | |
582 | ||
583 | if (rq->cmd_flags & REQ_MIXED_MERGE) | |
584 | return; | |
585 | ||
586 | /* | |
587 | * @rq will no longer represent mixable attributes for all the | |
588 | * contained bios. It will just track those of the first one. | |
589 | * Distributes the attributs to each bio. | |
590 | */ | |
591 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
592 | WARN_ON_ONCE((bio->bi_rw & REQ_FAILFAST_MASK) && | |
593 | (bio->bi_rw & REQ_FAILFAST_MASK) != ff); | |
594 | bio->bi_rw |= ff; | |
595 | } | |
596 | rq->cmd_flags |= REQ_MIXED_MERGE; | |
597 | } | |
598 | ||
26308eab JM |
599 | static void blk_account_io_merge(struct request *req) |
600 | { | |
601 | if (blk_do_io_stat(req)) { | |
602 | struct hd_struct *part; | |
603 | int cpu; | |
604 | ||
605 | cpu = part_stat_lock(); | |
09e099d4 | 606 | part = req->part; |
26308eab JM |
607 | |
608 | part_round_stats(cpu, part); | |
316d315b | 609 | part_dec_in_flight(part, rq_data_dir(req)); |
26308eab | 610 | |
6c23a968 | 611 | hd_struct_put(part); |
26308eab JM |
612 | part_stat_unlock(); |
613 | } | |
614 | } | |
615 | ||
d6d48196 JA |
616 | /* |
617 | * Has to be called with the request spinlock acquired | |
618 | */ | |
619 | static int attempt_merge(struct request_queue *q, struct request *req, | |
620 | struct request *next) | |
621 | { | |
622 | if (!rq_mergeable(req) || !rq_mergeable(next)) | |
623 | return 0; | |
624 | ||
f31dc1cd MP |
625 | if (!blk_check_merge_flags(req->cmd_flags, next->cmd_flags)) |
626 | return 0; | |
627 | ||
d6d48196 JA |
628 | /* |
629 | * not contiguous | |
630 | */ | |
83096ebf | 631 | if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next)) |
d6d48196 JA |
632 | return 0; |
633 | ||
634 | if (rq_data_dir(req) != rq_data_dir(next) | |
635 | || req->rq_disk != next->rq_disk | |
e7e24500 | 636 | || req_no_special_merge(next)) |
d6d48196 JA |
637 | return 0; |
638 | ||
4363ac7c MP |
639 | if (req->cmd_flags & REQ_WRITE_SAME && |
640 | !blk_write_same_mergeable(req->bio, next->bio)) | |
641 | return 0; | |
642 | ||
d6d48196 JA |
643 | /* |
644 | * If we are allowed to merge, then append bio list | |
645 | * from next to rq and release next. merge_requests_fn | |
646 | * will have updated segment counts, update sector | |
647 | * counts here. | |
648 | */ | |
649 | if (!ll_merge_requests_fn(q, req, next)) | |
650 | return 0; | |
651 | ||
80a761fd TH |
652 | /* |
653 | * If failfast settings disagree or any of the two is already | |
654 | * a mixed merge, mark both as mixed before proceeding. This | |
655 | * makes sure that all involved bios have mixable attributes | |
656 | * set properly. | |
657 | */ | |
658 | if ((req->cmd_flags | next->cmd_flags) & REQ_MIXED_MERGE || | |
659 | (req->cmd_flags & REQ_FAILFAST_MASK) != | |
660 | (next->cmd_flags & REQ_FAILFAST_MASK)) { | |
661 | blk_rq_set_mixed_merge(req); | |
662 | blk_rq_set_mixed_merge(next); | |
663 | } | |
664 | ||
d6d48196 JA |
665 | /* |
666 | * At this point we have either done a back merge | |
667 | * or front merge. We need the smaller start_time of | |
668 | * the merged requests to be the current request | |
669 | * for accounting purposes. | |
670 | */ | |
671 | if (time_after(req->start_time, next->start_time)) | |
672 | req->start_time = next->start_time; | |
673 | ||
674 | req->biotail->bi_next = next->bio; | |
675 | req->biotail = next->biotail; | |
676 | ||
a2dec7b3 | 677 | req->__data_len += blk_rq_bytes(next); |
d6d48196 JA |
678 | |
679 | elv_merge_requests(q, req, next); | |
680 | ||
42dad764 JM |
681 | /* |
682 | * 'next' is going away, so update stats accordingly | |
683 | */ | |
684 | blk_account_io_merge(next); | |
d6d48196 JA |
685 | |
686 | req->ioprio = ioprio_best(req->ioprio, next->ioprio); | |
ab780f1e JA |
687 | if (blk_rq_cpu_valid(next)) |
688 | req->cpu = next->cpu; | |
d6d48196 | 689 | |
1cd96c24 BH |
690 | /* owner-ship of bio passed from next to req */ |
691 | next->bio = NULL; | |
d6d48196 JA |
692 | __blk_put_request(q, next); |
693 | return 1; | |
694 | } | |
695 | ||
696 | int attempt_back_merge(struct request_queue *q, struct request *rq) | |
697 | { | |
698 | struct request *next = elv_latter_request(q, rq); | |
699 | ||
700 | if (next) | |
701 | return attempt_merge(q, rq, next); | |
702 | ||
703 | return 0; | |
704 | } | |
705 | ||
706 | int attempt_front_merge(struct request_queue *q, struct request *rq) | |
707 | { | |
708 | struct request *prev = elv_former_request(q, rq); | |
709 | ||
710 | if (prev) | |
711 | return attempt_merge(q, prev, rq); | |
712 | ||
713 | return 0; | |
714 | } | |
5e84ea3a JA |
715 | |
716 | int blk_attempt_req_merge(struct request_queue *q, struct request *rq, | |
717 | struct request *next) | |
718 | { | |
719 | return attempt_merge(q, rq, next); | |
720 | } | |
050c8ea8 TH |
721 | |
722 | bool blk_rq_merge_ok(struct request *rq, struct bio *bio) | |
723 | { | |
e2a60da7 | 724 | if (!rq_mergeable(rq) || !bio_mergeable(bio)) |
050c8ea8 TH |
725 | return false; |
726 | ||
f31dc1cd MP |
727 | if (!blk_check_merge_flags(rq->cmd_flags, bio->bi_rw)) |
728 | return false; | |
729 | ||
050c8ea8 TH |
730 | /* different data direction or already started, don't merge */ |
731 | if (bio_data_dir(bio) != rq_data_dir(rq)) | |
732 | return false; | |
733 | ||
734 | /* must be same device and not a special request */ | |
e7e24500 | 735 | if (rq->rq_disk != bio->bi_bdev->bd_disk || req_no_special_merge(rq)) |
050c8ea8 TH |
736 | return false; |
737 | ||
738 | /* only merge integrity protected bio into ditto rq */ | |
4eaf99be | 739 | if (blk_integrity_merge_bio(rq->q, rq, bio) == false) |
050c8ea8 TH |
740 | return false; |
741 | ||
4363ac7c MP |
742 | /* must be using the same buffer */ |
743 | if (rq->cmd_flags & REQ_WRITE_SAME && | |
744 | !blk_write_same_mergeable(rq->bio, bio)) | |
745 | return false; | |
746 | ||
050c8ea8 TH |
747 | return true; |
748 | } | |
749 | ||
750 | int blk_try_merge(struct request *rq, struct bio *bio) | |
751 | { | |
4f024f37 | 752 | if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector) |
050c8ea8 | 753 | return ELEVATOR_BACK_MERGE; |
4f024f37 | 754 | else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector) |
050c8ea8 TH |
755 | return ELEVATOR_FRONT_MERGE; |
756 | return ELEVATOR_NO_MERGE; | |
757 | } |