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