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 | ||
cda22646 MK |
10 | #include <trace/events/block.h> |
11 | ||
d6d48196 JA |
12 | #include "blk.h" |
13 | ||
54efd50b KO |
14 | static struct bio *blk_bio_discard_split(struct request_queue *q, |
15 | struct bio *bio, | |
bdced438 ML |
16 | struct bio_set *bs, |
17 | unsigned *nsegs) | |
54efd50b KO |
18 | { |
19 | unsigned int max_discard_sectors, granularity; | |
20 | int alignment; | |
21 | sector_t tmp; | |
22 | unsigned split_sectors; | |
23 | ||
bdced438 ML |
24 | *nsegs = 1; |
25 | ||
54efd50b KO |
26 | /* Zero-sector (unknown) and one-sector granularities are the same. */ |
27 | granularity = max(q->limits.discard_granularity >> 9, 1U); | |
28 | ||
29 | max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); | |
30 | max_discard_sectors -= max_discard_sectors % granularity; | |
31 | ||
32 | if (unlikely(!max_discard_sectors)) { | |
33 | /* XXX: warn */ | |
34 | return NULL; | |
35 | } | |
36 | ||
37 | if (bio_sectors(bio) <= max_discard_sectors) | |
38 | return NULL; | |
39 | ||
40 | split_sectors = max_discard_sectors; | |
41 | ||
42 | /* | |
43 | * If the next starting sector would be misaligned, stop the discard at | |
44 | * the previous aligned sector. | |
45 | */ | |
46 | alignment = (q->limits.discard_alignment >> 9) % granularity; | |
47 | ||
48 | tmp = bio->bi_iter.bi_sector + split_sectors - alignment; | |
49 | tmp = sector_div(tmp, granularity); | |
50 | ||
51 | if (split_sectors > tmp) | |
52 | split_sectors -= tmp; | |
53 | ||
54 | return bio_split(bio, split_sectors, GFP_NOIO, bs); | |
55 | } | |
56 | ||
57 | static struct bio *blk_bio_write_same_split(struct request_queue *q, | |
58 | struct bio *bio, | |
bdced438 ML |
59 | struct bio_set *bs, |
60 | unsigned *nsegs) | |
54efd50b | 61 | { |
bdced438 ML |
62 | *nsegs = 1; |
63 | ||
54efd50b KO |
64 | if (!q->limits.max_write_same_sectors) |
65 | return NULL; | |
66 | ||
67 | if (bio_sectors(bio) <= q->limits.max_write_same_sectors) | |
68 | return NULL; | |
69 | ||
70 | return bio_split(bio, q->limits.max_write_same_sectors, GFP_NOIO, bs); | |
71 | } | |
72 | ||
73 | static struct bio *blk_bio_segment_split(struct request_queue *q, | |
74 | struct bio *bio, | |
bdced438 ML |
75 | struct bio_set *bs, |
76 | unsigned *segs) | |
54efd50b | 77 | { |
5014c311 | 78 | struct bio_vec bv, bvprv, *bvprvp = NULL; |
54efd50b | 79 | struct bvec_iter iter; |
8ae12666 | 80 | unsigned seg_size = 0, nsegs = 0, sectors = 0; |
02e70742 ML |
81 | unsigned front_seg_size = bio->bi_seg_front_size; |
82 | bool do_split = true; | |
83 | struct bio *new = NULL; | |
54efd50b | 84 | |
54efd50b | 85 | bio_for_each_segment(bv, bio, iter) { |
54efd50b KO |
86 | /* |
87 | * If the queue doesn't support SG gaps and adding this | |
88 | * offset would create a gap, disallow it. | |
89 | */ | |
5014c311 | 90 | if (bvprvp && bvec_gap_to_prev(q, bvprvp, bv.bv_offset)) |
54efd50b KO |
91 | goto split; |
92 | ||
e36f6204 KB |
93 | if (sectors + (bv.bv_len >> 9) > |
94 | blk_max_size_offset(q, bio->bi_iter.bi_sector)) { | |
95 | /* | |
96 | * Consider this a new segment if we're splitting in | |
97 | * the middle of this vector. | |
98 | */ | |
99 | if (nsegs < queue_max_segments(q) && | |
100 | sectors < blk_max_size_offset(q, | |
101 | bio->bi_iter.bi_sector)) { | |
102 | nsegs++; | |
103 | sectors = blk_max_size_offset(q, | |
104 | bio->bi_iter.bi_sector); | |
105 | } | |
106 | goto split; | |
107 | } | |
108 | ||
5014c311 | 109 | if (bvprvp && blk_queue_cluster(q)) { |
54efd50b KO |
110 | if (seg_size + bv.bv_len > queue_max_segment_size(q)) |
111 | goto new_segment; | |
5014c311 | 112 | if (!BIOVEC_PHYS_MERGEABLE(bvprvp, &bv)) |
54efd50b | 113 | goto new_segment; |
5014c311 | 114 | if (!BIOVEC_SEG_BOUNDARY(q, bvprvp, &bv)) |
54efd50b KO |
115 | goto new_segment; |
116 | ||
117 | seg_size += bv.bv_len; | |
118 | bvprv = bv; | |
578270bf | 119 | bvprvp = &bvprv; |
52cc6eea | 120 | sectors += bv.bv_len >> 9; |
a88d32af ML |
121 | |
122 | if (nsegs == 1 && seg_size > front_seg_size) | |
123 | front_seg_size = seg_size; | |
54efd50b KO |
124 | continue; |
125 | } | |
126 | new_segment: | |
127 | if (nsegs == queue_max_segments(q)) | |
128 | goto split; | |
129 | ||
130 | nsegs++; | |
131 | bvprv = bv; | |
578270bf | 132 | bvprvp = &bvprv; |
54efd50b | 133 | seg_size = bv.bv_len; |
52cc6eea | 134 | sectors += bv.bv_len >> 9; |
02e70742 ML |
135 | |
136 | if (nsegs == 1 && seg_size > front_seg_size) | |
137 | front_seg_size = seg_size; | |
54efd50b KO |
138 | } |
139 | ||
02e70742 | 140 | do_split = false; |
54efd50b | 141 | split: |
bdced438 | 142 | *segs = nsegs; |
02e70742 ML |
143 | |
144 | if (do_split) { | |
145 | new = bio_split(bio, sectors, GFP_NOIO, bs); | |
146 | if (new) | |
147 | bio = new; | |
148 | } | |
149 | ||
150 | bio->bi_seg_front_size = front_seg_size; | |
151 | if (seg_size > bio->bi_seg_back_size) | |
152 | bio->bi_seg_back_size = seg_size; | |
153 | ||
154 | return do_split ? new : NULL; | |
54efd50b KO |
155 | } |
156 | ||
157 | void blk_queue_split(struct request_queue *q, struct bio **bio, | |
158 | struct bio_set *bs) | |
159 | { | |
bdced438 ML |
160 | struct bio *split, *res; |
161 | unsigned nsegs; | |
54efd50b KO |
162 | |
163 | if ((*bio)->bi_rw & REQ_DISCARD) | |
bdced438 | 164 | split = blk_bio_discard_split(q, *bio, bs, &nsegs); |
54efd50b | 165 | else if ((*bio)->bi_rw & REQ_WRITE_SAME) |
bdced438 | 166 | split = blk_bio_write_same_split(q, *bio, bs, &nsegs); |
54efd50b | 167 | else |
bdced438 ML |
168 | split = blk_bio_segment_split(q, *bio, q->bio_split, &nsegs); |
169 | ||
170 | /* physical segments can be figured out during splitting */ | |
171 | res = split ? split : *bio; | |
172 | res->bi_phys_segments = nsegs; | |
173 | bio_set_flag(res, BIO_SEG_VALID); | |
54efd50b KO |
174 | |
175 | if (split) { | |
6ac45aeb ML |
176 | /* there isn't chance to merge the splitted bio */ |
177 | split->bi_rw |= REQ_NOMERGE; | |
178 | ||
54efd50b | 179 | bio_chain(split, *bio); |
cda22646 | 180 | trace_block_split(q, split, (*bio)->bi_iter.bi_sector); |
54efd50b KO |
181 | generic_make_request(*bio); |
182 | *bio = split; | |
183 | } | |
184 | } | |
185 | EXPORT_SYMBOL(blk_queue_split); | |
186 | ||
1e428079 | 187 | static unsigned int __blk_recalc_rq_segments(struct request_queue *q, |
07388549 ML |
188 | struct bio *bio, |
189 | bool no_sg_merge) | |
d6d48196 | 190 | { |
7988613b | 191 | struct bio_vec bv, bvprv = { NULL }; |
54efd50b | 192 | int cluster, prev = 0; |
1e428079 | 193 | unsigned int seg_size, nr_phys_segs; |
59247eae | 194 | struct bio *fbio, *bbio; |
7988613b | 195 | struct bvec_iter iter; |
d6d48196 | 196 | |
1e428079 JA |
197 | if (!bio) |
198 | return 0; | |
d6d48196 | 199 | |
5cb8850c KO |
200 | /* |
201 | * This should probably be returning 0, but blk_add_request_payload() | |
202 | * (Christoph!!!!) | |
203 | */ | |
204 | if (bio->bi_rw & REQ_DISCARD) | |
205 | return 1; | |
206 | ||
207 | if (bio->bi_rw & REQ_WRITE_SAME) | |
208 | return 1; | |
209 | ||
1e428079 | 210 | fbio = bio; |
e692cb66 | 211 | cluster = blk_queue_cluster(q); |
5df97b91 | 212 | seg_size = 0; |
2c8919de | 213 | nr_phys_segs = 0; |
1e428079 | 214 | for_each_bio(bio) { |
7988613b | 215 | bio_for_each_segment(bv, bio, iter) { |
05f1dd53 JA |
216 | /* |
217 | * If SG merging is disabled, each bio vector is | |
218 | * a segment | |
219 | */ | |
220 | if (no_sg_merge) | |
221 | goto new_segment; | |
222 | ||
54efd50b | 223 | if (prev && cluster) { |
7988613b | 224 | if (seg_size + bv.bv_len |
ae03bf63 | 225 | > queue_max_segment_size(q)) |
1e428079 | 226 | goto new_segment; |
7988613b | 227 | if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv)) |
1e428079 | 228 | goto new_segment; |
7988613b | 229 | if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv)) |
1e428079 | 230 | goto new_segment; |
d6d48196 | 231 | |
7988613b | 232 | seg_size += bv.bv_len; |
1e428079 JA |
233 | bvprv = bv; |
234 | continue; | |
235 | } | |
d6d48196 | 236 | new_segment: |
1e428079 JA |
237 | if (nr_phys_segs == 1 && seg_size > |
238 | fbio->bi_seg_front_size) | |
239 | fbio->bi_seg_front_size = seg_size; | |
86771427 | 240 | |
1e428079 JA |
241 | nr_phys_segs++; |
242 | bvprv = bv; | |
54efd50b | 243 | prev = 1; |
7988613b | 244 | seg_size = bv.bv_len; |
1e428079 | 245 | } |
59247eae | 246 | bbio = bio; |
d6d48196 JA |
247 | } |
248 | ||
59247eae JA |
249 | if (nr_phys_segs == 1 && seg_size > fbio->bi_seg_front_size) |
250 | fbio->bi_seg_front_size = seg_size; | |
251 | if (seg_size > bbio->bi_seg_back_size) | |
252 | bbio->bi_seg_back_size = seg_size; | |
1e428079 JA |
253 | |
254 | return nr_phys_segs; | |
255 | } | |
256 | ||
257 | void blk_recalc_rq_segments(struct request *rq) | |
258 | { | |
07388549 ML |
259 | bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE, |
260 | &rq->q->queue_flags); | |
261 | ||
262 | rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio, | |
263 | no_sg_merge); | |
d6d48196 JA |
264 | } |
265 | ||
266 | void blk_recount_segments(struct request_queue *q, struct bio *bio) | |
267 | { | |
7f60dcaa ML |
268 | unsigned short seg_cnt; |
269 | ||
270 | /* estimate segment number by bi_vcnt for non-cloned bio */ | |
271 | if (bio_flagged(bio, BIO_CLONED)) | |
272 | seg_cnt = bio_segments(bio); | |
273 | else | |
274 | seg_cnt = bio->bi_vcnt; | |
764f612c | 275 | |
7f60dcaa ML |
276 | if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) && |
277 | (seg_cnt < queue_max_segments(q))) | |
278 | bio->bi_phys_segments = seg_cnt; | |
05f1dd53 JA |
279 | else { |
280 | struct bio *nxt = bio->bi_next; | |
281 | ||
282 | bio->bi_next = NULL; | |
7f60dcaa | 283 | bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, false); |
05f1dd53 JA |
284 | bio->bi_next = nxt; |
285 | } | |
1e428079 | 286 | |
b7c44ed9 | 287 | bio_set_flag(bio, BIO_SEG_VALID); |
d6d48196 JA |
288 | } |
289 | EXPORT_SYMBOL(blk_recount_segments); | |
290 | ||
291 | static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, | |
292 | struct bio *nxt) | |
293 | { | |
2b8221e1 | 294 | struct bio_vec end_bv = { NULL }, nxt_bv; |
f619d254 KO |
295 | struct bvec_iter iter; |
296 | ||
e692cb66 | 297 | if (!blk_queue_cluster(q)) |
d6d48196 JA |
298 | return 0; |
299 | ||
86771427 | 300 | if (bio->bi_seg_back_size + nxt->bi_seg_front_size > |
ae03bf63 | 301 | queue_max_segment_size(q)) |
d6d48196 JA |
302 | return 0; |
303 | ||
e17fc0a1 DW |
304 | if (!bio_has_data(bio)) |
305 | return 1; | |
306 | ||
f619d254 KO |
307 | bio_for_each_segment(end_bv, bio, iter) |
308 | if (end_bv.bv_len == iter.bi_size) | |
309 | break; | |
310 | ||
311 | nxt_bv = bio_iovec(nxt); | |
312 | ||
313 | if (!BIOVEC_PHYS_MERGEABLE(&end_bv, &nxt_bv)) | |
e17fc0a1 DW |
314 | return 0; |
315 | ||
d6d48196 | 316 | /* |
e17fc0a1 | 317 | * bio and nxt are contiguous in memory; check if the queue allows |
d6d48196 JA |
318 | * these two to be merged into one |
319 | */ | |
f619d254 | 320 | if (BIOVEC_SEG_BOUNDARY(q, &end_bv, &nxt_bv)) |
d6d48196 JA |
321 | return 1; |
322 | ||
323 | return 0; | |
324 | } | |
325 | ||
7988613b | 326 | static inline void |
963ab9e5 | 327 | __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec, |
7988613b | 328 | struct scatterlist *sglist, struct bio_vec *bvprv, |
963ab9e5 AH |
329 | struct scatterlist **sg, int *nsegs, int *cluster) |
330 | { | |
331 | ||
332 | int nbytes = bvec->bv_len; | |
333 | ||
7988613b | 334 | if (*sg && *cluster) { |
963ab9e5 AH |
335 | if ((*sg)->length + nbytes > queue_max_segment_size(q)) |
336 | goto new_segment; | |
337 | ||
7988613b | 338 | if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) |
963ab9e5 | 339 | goto new_segment; |
7988613b | 340 | if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) |
963ab9e5 AH |
341 | goto new_segment; |
342 | ||
343 | (*sg)->length += nbytes; | |
344 | } else { | |
345 | new_segment: | |
346 | if (!*sg) | |
347 | *sg = sglist; | |
348 | else { | |
349 | /* | |
350 | * If the driver previously mapped a shorter | |
351 | * list, we could see a termination bit | |
352 | * prematurely unless it fully inits the sg | |
353 | * table on each mapping. We KNOW that there | |
354 | * must be more entries here or the driver | |
355 | * would be buggy, so force clear the | |
356 | * termination bit to avoid doing a full | |
357 | * sg_init_table() in drivers for each command. | |
358 | */ | |
c8164d89 | 359 | sg_unmark_end(*sg); |
963ab9e5 AH |
360 | *sg = sg_next(*sg); |
361 | } | |
362 | ||
363 | sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset); | |
364 | (*nsegs)++; | |
365 | } | |
7988613b | 366 | *bvprv = *bvec; |
963ab9e5 AH |
367 | } |
368 | ||
5cb8850c KO |
369 | static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, |
370 | struct scatterlist *sglist, | |
371 | struct scatterlist **sg) | |
d6d48196 | 372 | { |
2b8221e1 | 373 | struct bio_vec bvec, bvprv = { NULL }; |
5cb8850c | 374 | struct bvec_iter iter; |
d6d48196 JA |
375 | int nsegs, cluster; |
376 | ||
377 | nsegs = 0; | |
e692cb66 | 378 | cluster = blk_queue_cluster(q); |
d6d48196 | 379 | |
5cb8850c KO |
380 | if (bio->bi_rw & REQ_DISCARD) { |
381 | /* | |
382 | * This is a hack - drivers should be neither modifying the | |
383 | * biovec, nor relying on bi_vcnt - but because of | |
384 | * blk_add_request_payload(), a discard bio may or may not have | |
385 | * a payload we need to set up here (thank you Christoph) and | |
386 | * bi_vcnt is really the only way of telling if we need to. | |
387 | */ | |
388 | ||
389 | if (bio->bi_vcnt) | |
390 | goto single_segment; | |
391 | ||
392 | return 0; | |
393 | } | |
394 | ||
395 | if (bio->bi_rw & REQ_WRITE_SAME) { | |
396 | single_segment: | |
397 | *sg = sglist; | |
398 | bvec = bio_iovec(bio); | |
399 | sg_set_page(*sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset); | |
400 | return 1; | |
401 | } | |
402 | ||
403 | for_each_bio(bio) | |
404 | bio_for_each_segment(bvec, bio, iter) | |
405 | __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, | |
406 | &nsegs, &cluster); | |
d6d48196 | 407 | |
5cb8850c KO |
408 | return nsegs; |
409 | } | |
410 | ||
411 | /* | |
412 | * map a request to scatterlist, return number of sg entries setup. Caller | |
413 | * must make sure sg can hold rq->nr_phys_segments entries | |
414 | */ | |
415 | int blk_rq_map_sg(struct request_queue *q, struct request *rq, | |
416 | struct scatterlist *sglist) | |
417 | { | |
418 | struct scatterlist *sg = NULL; | |
419 | int nsegs = 0; | |
420 | ||
421 | if (rq->bio) | |
422 | nsegs = __blk_bios_map_sg(q, rq->bio, sglist, &sg); | |
f18573ab FT |
423 | |
424 | if (unlikely(rq->cmd_flags & REQ_COPY_USER) && | |
2e46e8b2 TH |
425 | (blk_rq_bytes(rq) & q->dma_pad_mask)) { |
426 | unsigned int pad_len = | |
427 | (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; | |
f18573ab FT |
428 | |
429 | sg->length += pad_len; | |
430 | rq->extra_len += pad_len; | |
431 | } | |
432 | ||
2fb98e84 | 433 | if (q->dma_drain_size && q->dma_drain_needed(rq)) { |
7b6d91da | 434 | if (rq->cmd_flags & REQ_WRITE) |
db0a2e00 TH |
435 | memset(q->dma_drain_buffer, 0, q->dma_drain_size); |
436 | ||
da81ed16 | 437 | sg_unmark_end(sg); |
d6d48196 JA |
438 | sg = sg_next(sg); |
439 | sg_set_page(sg, virt_to_page(q->dma_drain_buffer), | |
440 | q->dma_drain_size, | |
441 | ((unsigned long)q->dma_drain_buffer) & | |
442 | (PAGE_SIZE - 1)); | |
443 | nsegs++; | |
7a85f889 | 444 | rq->extra_len += q->dma_drain_size; |
d6d48196 JA |
445 | } |
446 | ||
447 | if (sg) | |
448 | sg_mark_end(sg); | |
449 | ||
12e57f59 ML |
450 | /* |
451 | * Something must have been wrong if the figured number of | |
452 | * segment is bigger than number of req's physical segments | |
453 | */ | |
454 | WARN_ON(nsegs > rq->nr_phys_segments); | |
455 | ||
d6d48196 JA |
456 | return nsegs; |
457 | } | |
d6d48196 JA |
458 | EXPORT_SYMBOL(blk_rq_map_sg); |
459 | ||
d6d48196 JA |
460 | static inline int ll_new_hw_segment(struct request_queue *q, |
461 | struct request *req, | |
462 | struct bio *bio) | |
463 | { | |
d6d48196 JA |
464 | int nr_phys_segs = bio_phys_segments(q, bio); |
465 | ||
13f05c8d MP |
466 | if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) |
467 | goto no_merge; | |
468 | ||
4eaf99be | 469 | if (blk_integrity_merge_bio(q, req, bio) == false) |
13f05c8d | 470 | goto no_merge; |
d6d48196 JA |
471 | |
472 | /* | |
473 | * This will form the start of a new hw segment. Bump both | |
474 | * counters. | |
475 | */ | |
d6d48196 JA |
476 | req->nr_phys_segments += nr_phys_segs; |
477 | return 1; | |
13f05c8d MP |
478 | |
479 | no_merge: | |
480 | req->cmd_flags |= REQ_NOMERGE; | |
481 | if (req == q->last_merge) | |
482 | q->last_merge = NULL; | |
483 | return 0; | |
d6d48196 JA |
484 | } |
485 | ||
486 | int ll_back_merge_fn(struct request_queue *q, struct request *req, | |
487 | struct bio *bio) | |
488 | { | |
5e7c4274 JA |
489 | if (req_gap_back_merge(req, bio)) |
490 | return 0; | |
7f39add3 SG |
491 | if (blk_integrity_rq(req) && |
492 | integrity_req_gap_back_merge(req, bio)) | |
493 | return 0; | |
f31dc1cd MP |
494 | if (blk_rq_sectors(req) + bio_sectors(bio) > |
495 | blk_rq_get_max_sectors(req)) { | |
d6d48196 JA |
496 | req->cmd_flags |= REQ_NOMERGE; |
497 | if (req == q->last_merge) | |
498 | q->last_merge = NULL; | |
499 | return 0; | |
500 | } | |
2cdf79ca | 501 | if (!bio_flagged(req->biotail, BIO_SEG_VALID)) |
d6d48196 | 502 | blk_recount_segments(q, req->biotail); |
2cdf79ca | 503 | if (!bio_flagged(bio, BIO_SEG_VALID)) |
d6d48196 | 504 | blk_recount_segments(q, bio); |
d6d48196 JA |
505 | |
506 | return ll_new_hw_segment(q, req, bio); | |
507 | } | |
508 | ||
6728cb0e | 509 | int ll_front_merge_fn(struct request_queue *q, struct request *req, |
d6d48196 JA |
510 | struct bio *bio) |
511 | { | |
5e7c4274 JA |
512 | |
513 | if (req_gap_front_merge(req, bio)) | |
514 | return 0; | |
7f39add3 SG |
515 | if (blk_integrity_rq(req) && |
516 | integrity_req_gap_front_merge(req, bio)) | |
517 | return 0; | |
f31dc1cd MP |
518 | if (blk_rq_sectors(req) + bio_sectors(bio) > |
519 | blk_rq_get_max_sectors(req)) { | |
d6d48196 JA |
520 | req->cmd_flags |= REQ_NOMERGE; |
521 | if (req == q->last_merge) | |
522 | q->last_merge = NULL; | |
523 | return 0; | |
524 | } | |
2cdf79ca | 525 | if (!bio_flagged(bio, BIO_SEG_VALID)) |
d6d48196 | 526 | blk_recount_segments(q, bio); |
2cdf79ca | 527 | if (!bio_flagged(req->bio, BIO_SEG_VALID)) |
d6d48196 | 528 | blk_recount_segments(q, req->bio); |
d6d48196 JA |
529 | |
530 | return ll_new_hw_segment(q, req, bio); | |
531 | } | |
532 | ||
e7e24500 JA |
533 | /* |
534 | * blk-mq uses req->special to carry normal driver per-request payload, it | |
535 | * does not indicate a prepared command that we cannot merge with. | |
536 | */ | |
537 | static bool req_no_special_merge(struct request *req) | |
538 | { | |
539 | struct request_queue *q = req->q; | |
540 | ||
541 | return !q->mq_ops && req->special; | |
542 | } | |
543 | ||
d6d48196 JA |
544 | static int ll_merge_requests_fn(struct request_queue *q, struct request *req, |
545 | struct request *next) | |
546 | { | |
547 | int total_phys_segments; | |
86771427 FT |
548 | unsigned int seg_size = |
549 | req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size; | |
d6d48196 JA |
550 | |
551 | /* | |
552 | * First check if the either of the requests are re-queued | |
553 | * requests. Can't merge them if they are. | |
554 | */ | |
e7e24500 | 555 | if (req_no_special_merge(req) || req_no_special_merge(next)) |
d6d48196 JA |
556 | return 0; |
557 | ||
5e7c4274 | 558 | if (req_gap_back_merge(req, next->bio)) |
854fbb9c KB |
559 | return 0; |
560 | ||
d6d48196 JA |
561 | /* |
562 | * Will it become too large? | |
563 | */ | |
f31dc1cd MP |
564 | if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > |
565 | blk_rq_get_max_sectors(req)) | |
d6d48196 JA |
566 | return 0; |
567 | ||
568 | total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; | |
86771427 FT |
569 | if (blk_phys_contig_segment(q, req->biotail, next->bio)) { |
570 | if (req->nr_phys_segments == 1) | |
571 | req->bio->bi_seg_front_size = seg_size; | |
572 | if (next->nr_phys_segments == 1) | |
573 | next->biotail->bi_seg_back_size = seg_size; | |
d6d48196 | 574 | total_phys_segments--; |
86771427 | 575 | } |
d6d48196 | 576 | |
8a78362c | 577 | if (total_phys_segments > queue_max_segments(q)) |
d6d48196 JA |
578 | return 0; |
579 | ||
4eaf99be | 580 | if (blk_integrity_merge_rq(q, req, next) == false) |
13f05c8d MP |
581 | return 0; |
582 | ||
d6d48196 JA |
583 | /* Merge is OK... */ |
584 | req->nr_phys_segments = total_phys_segments; | |
d6d48196 JA |
585 | return 1; |
586 | } | |
587 | ||
80a761fd TH |
588 | /** |
589 | * blk_rq_set_mixed_merge - mark a request as mixed merge | |
590 | * @rq: request to mark as mixed merge | |
591 | * | |
592 | * Description: | |
593 | * @rq is about to be mixed merged. Make sure the attributes | |
594 | * which can be mixed are set in each bio and mark @rq as mixed | |
595 | * merged. | |
596 | */ | |
597 | void blk_rq_set_mixed_merge(struct request *rq) | |
598 | { | |
599 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
600 | struct bio *bio; | |
601 | ||
602 | if (rq->cmd_flags & REQ_MIXED_MERGE) | |
603 | return; | |
604 | ||
605 | /* | |
606 | * @rq will no longer represent mixable attributes for all the | |
607 | * contained bios. It will just track those of the first one. | |
608 | * Distributes the attributs to each bio. | |
609 | */ | |
610 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
611 | WARN_ON_ONCE((bio->bi_rw & REQ_FAILFAST_MASK) && | |
612 | (bio->bi_rw & REQ_FAILFAST_MASK) != ff); | |
613 | bio->bi_rw |= ff; | |
614 | } | |
615 | rq->cmd_flags |= REQ_MIXED_MERGE; | |
616 | } | |
617 | ||
26308eab JM |
618 | static void blk_account_io_merge(struct request *req) |
619 | { | |
620 | if (blk_do_io_stat(req)) { | |
621 | struct hd_struct *part; | |
622 | int cpu; | |
623 | ||
624 | cpu = part_stat_lock(); | |
09e099d4 | 625 | part = req->part; |
26308eab JM |
626 | |
627 | part_round_stats(cpu, part); | |
316d315b | 628 | part_dec_in_flight(part, rq_data_dir(req)); |
26308eab | 629 | |
6c23a968 | 630 | hd_struct_put(part); |
26308eab JM |
631 | part_stat_unlock(); |
632 | } | |
633 | } | |
634 | ||
d6d48196 JA |
635 | /* |
636 | * Has to be called with the request spinlock acquired | |
637 | */ | |
638 | static int attempt_merge(struct request_queue *q, struct request *req, | |
639 | struct request *next) | |
640 | { | |
641 | if (!rq_mergeable(req) || !rq_mergeable(next)) | |
642 | return 0; | |
643 | ||
f31dc1cd MP |
644 | if (!blk_check_merge_flags(req->cmd_flags, next->cmd_flags)) |
645 | return 0; | |
646 | ||
d6d48196 JA |
647 | /* |
648 | * not contiguous | |
649 | */ | |
83096ebf | 650 | if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next)) |
d6d48196 JA |
651 | return 0; |
652 | ||
653 | if (rq_data_dir(req) != rq_data_dir(next) | |
654 | || req->rq_disk != next->rq_disk | |
e7e24500 | 655 | || req_no_special_merge(next)) |
d6d48196 JA |
656 | return 0; |
657 | ||
4363ac7c MP |
658 | if (req->cmd_flags & REQ_WRITE_SAME && |
659 | !blk_write_same_mergeable(req->bio, next->bio)) | |
660 | return 0; | |
661 | ||
d6d48196 JA |
662 | /* |
663 | * If we are allowed to merge, then append bio list | |
664 | * from next to rq and release next. merge_requests_fn | |
665 | * will have updated segment counts, update sector | |
666 | * counts here. | |
667 | */ | |
668 | if (!ll_merge_requests_fn(q, req, next)) | |
669 | return 0; | |
670 | ||
80a761fd TH |
671 | /* |
672 | * If failfast settings disagree or any of the two is already | |
673 | * a mixed merge, mark both as mixed before proceeding. This | |
674 | * makes sure that all involved bios have mixable attributes | |
675 | * set properly. | |
676 | */ | |
677 | if ((req->cmd_flags | next->cmd_flags) & REQ_MIXED_MERGE || | |
678 | (req->cmd_flags & REQ_FAILFAST_MASK) != | |
679 | (next->cmd_flags & REQ_FAILFAST_MASK)) { | |
680 | blk_rq_set_mixed_merge(req); | |
681 | blk_rq_set_mixed_merge(next); | |
682 | } | |
683 | ||
d6d48196 JA |
684 | /* |
685 | * At this point we have either done a back merge | |
686 | * or front merge. We need the smaller start_time of | |
687 | * the merged requests to be the current request | |
688 | * for accounting purposes. | |
689 | */ | |
690 | if (time_after(req->start_time, next->start_time)) | |
691 | req->start_time = next->start_time; | |
692 | ||
693 | req->biotail->bi_next = next->bio; | |
694 | req->biotail = next->biotail; | |
695 | ||
a2dec7b3 | 696 | req->__data_len += blk_rq_bytes(next); |
d6d48196 JA |
697 | |
698 | elv_merge_requests(q, req, next); | |
699 | ||
42dad764 JM |
700 | /* |
701 | * 'next' is going away, so update stats accordingly | |
702 | */ | |
703 | blk_account_io_merge(next); | |
d6d48196 JA |
704 | |
705 | req->ioprio = ioprio_best(req->ioprio, next->ioprio); | |
ab780f1e JA |
706 | if (blk_rq_cpu_valid(next)) |
707 | req->cpu = next->cpu; | |
d6d48196 | 708 | |
1cd96c24 BH |
709 | /* owner-ship of bio passed from next to req */ |
710 | next->bio = NULL; | |
d6d48196 JA |
711 | __blk_put_request(q, next); |
712 | return 1; | |
713 | } | |
714 | ||
715 | int attempt_back_merge(struct request_queue *q, struct request *rq) | |
716 | { | |
717 | struct request *next = elv_latter_request(q, rq); | |
718 | ||
719 | if (next) | |
720 | return attempt_merge(q, rq, next); | |
721 | ||
722 | return 0; | |
723 | } | |
724 | ||
725 | int attempt_front_merge(struct request_queue *q, struct request *rq) | |
726 | { | |
727 | struct request *prev = elv_former_request(q, rq); | |
728 | ||
729 | if (prev) | |
730 | return attempt_merge(q, prev, rq); | |
731 | ||
732 | return 0; | |
733 | } | |
5e84ea3a JA |
734 | |
735 | int blk_attempt_req_merge(struct request_queue *q, struct request *rq, | |
736 | struct request *next) | |
737 | { | |
738 | return attempt_merge(q, rq, next); | |
739 | } | |
050c8ea8 TH |
740 | |
741 | bool blk_rq_merge_ok(struct request *rq, struct bio *bio) | |
742 | { | |
e2a60da7 | 743 | if (!rq_mergeable(rq) || !bio_mergeable(bio)) |
050c8ea8 TH |
744 | return false; |
745 | ||
f31dc1cd MP |
746 | if (!blk_check_merge_flags(rq->cmd_flags, bio->bi_rw)) |
747 | return false; | |
748 | ||
050c8ea8 TH |
749 | /* different data direction or already started, don't merge */ |
750 | if (bio_data_dir(bio) != rq_data_dir(rq)) | |
751 | return false; | |
752 | ||
753 | /* must be same device and not a special request */ | |
e7e24500 | 754 | if (rq->rq_disk != bio->bi_bdev->bd_disk || req_no_special_merge(rq)) |
050c8ea8 TH |
755 | return false; |
756 | ||
757 | /* only merge integrity protected bio into ditto rq */ | |
4eaf99be | 758 | if (blk_integrity_merge_bio(rq->q, rq, bio) == false) |
050c8ea8 TH |
759 | return false; |
760 | ||
4363ac7c MP |
761 | /* must be using the same buffer */ |
762 | if (rq->cmd_flags & REQ_WRITE_SAME && | |
763 | !blk_write_same_mergeable(rq->bio, bio)) | |
764 | return false; | |
765 | ||
050c8ea8 TH |
766 | return true; |
767 | } | |
768 | ||
769 | int blk_try_merge(struct request *rq, struct bio *bio) | |
770 | { | |
4f024f37 | 771 | if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector) |
050c8ea8 | 772 | return ELEVATOR_BACK_MERGE; |
4f024f37 | 773 | else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector) |
050c8ea8 TH |
774 | return ELEVATOR_FRONT_MERGE; |
775 | return ELEVATOR_NO_MERGE; | |
776 | } |