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Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
d6d48196 JA |
2 | /* |
3 | * Functions related to segment and merge handling | |
4 | */ | |
5 | #include <linux/kernel.h> | |
6 | #include <linux/module.h> | |
7 | #include <linux/bio.h> | |
8 | #include <linux/blkdev.h> | |
9 | #include <linux/scatterlist.h> | |
10 | ||
cda22646 MK |
11 | #include <trace/events/block.h> |
12 | ||
d6d48196 JA |
13 | #include "blk.h" |
14 | ||
54efd50b KO |
15 | static struct bio *blk_bio_discard_split(struct request_queue *q, |
16 | struct bio *bio, | |
bdced438 ML |
17 | struct bio_set *bs, |
18 | unsigned *nsegs) | |
54efd50b KO |
19 | { |
20 | unsigned int max_discard_sectors, granularity; | |
21 | int alignment; | |
22 | sector_t tmp; | |
23 | unsigned split_sectors; | |
24 | ||
bdced438 ML |
25 | *nsegs = 1; |
26 | ||
54efd50b KO |
27 | /* Zero-sector (unknown) and one-sector granularities are the same. */ |
28 | granularity = max(q->limits.discard_granularity >> 9, 1U); | |
29 | ||
b515257f ML |
30 | max_discard_sectors = min(q->limits.max_discard_sectors, |
31 | bio_allowed_max_sectors(q)); | |
54efd50b KO |
32 | max_discard_sectors -= max_discard_sectors % granularity; |
33 | ||
34 | if (unlikely(!max_discard_sectors)) { | |
35 | /* XXX: warn */ | |
36 | return NULL; | |
37 | } | |
38 | ||
39 | if (bio_sectors(bio) <= max_discard_sectors) | |
40 | return NULL; | |
41 | ||
42 | split_sectors = max_discard_sectors; | |
43 | ||
44 | /* | |
45 | * If the next starting sector would be misaligned, stop the discard at | |
46 | * the previous aligned sector. | |
47 | */ | |
48 | alignment = (q->limits.discard_alignment >> 9) % granularity; | |
49 | ||
50 | tmp = bio->bi_iter.bi_sector + split_sectors - alignment; | |
51 | tmp = sector_div(tmp, granularity); | |
52 | ||
53 | if (split_sectors > tmp) | |
54 | split_sectors -= tmp; | |
55 | ||
56 | return bio_split(bio, split_sectors, GFP_NOIO, bs); | |
57 | } | |
58 | ||
885fa13f CH |
59 | static struct bio *blk_bio_write_zeroes_split(struct request_queue *q, |
60 | struct bio *bio, struct bio_set *bs, unsigned *nsegs) | |
61 | { | |
62 | *nsegs = 1; | |
63 | ||
64 | if (!q->limits.max_write_zeroes_sectors) | |
65 | return NULL; | |
66 | ||
67 | if (bio_sectors(bio) <= q->limits.max_write_zeroes_sectors) | |
68 | return NULL; | |
69 | ||
70 | return bio_split(bio, q->limits.max_write_zeroes_sectors, GFP_NOIO, bs); | |
71 | } | |
72 | ||
54efd50b KO |
73 | static struct bio *blk_bio_write_same_split(struct request_queue *q, |
74 | struct bio *bio, | |
bdced438 ML |
75 | struct bio_set *bs, |
76 | unsigned *nsegs) | |
54efd50b | 77 | { |
bdced438 ML |
78 | *nsegs = 1; |
79 | ||
54efd50b KO |
80 | if (!q->limits.max_write_same_sectors) |
81 | return NULL; | |
82 | ||
83 | if (bio_sectors(bio) <= q->limits.max_write_same_sectors) | |
84 | return NULL; | |
85 | ||
86 | return bio_split(bio, q->limits.max_write_same_sectors, GFP_NOIO, bs); | |
87 | } | |
88 | ||
d0e5fbb0 ML |
89 | static inline unsigned get_max_io_size(struct request_queue *q, |
90 | struct bio *bio) | |
91 | { | |
92 | unsigned sectors = blk_max_size_offset(q, bio->bi_iter.bi_sector); | |
93 | unsigned mask = queue_logical_block_size(q) - 1; | |
94 | ||
95 | /* aligned to logical block size */ | |
96 | sectors &= ~(mask >> 9); | |
97 | ||
98 | return sectors; | |
99 | } | |
100 | ||
54efd50b KO |
101 | static struct bio *blk_bio_segment_split(struct request_queue *q, |
102 | struct bio *bio, | |
bdced438 ML |
103 | struct bio_set *bs, |
104 | unsigned *segs) | |
54efd50b | 105 | { |
5014c311 | 106 | struct bio_vec bv, bvprv, *bvprvp = NULL; |
54efd50b | 107 | struct bvec_iter iter; |
8ae12666 | 108 | unsigned seg_size = 0, nsegs = 0, sectors = 0; |
02e70742 ML |
109 | unsigned front_seg_size = bio->bi_seg_front_size; |
110 | bool do_split = true; | |
111 | struct bio *new = NULL; | |
d0e5fbb0 | 112 | const unsigned max_sectors = get_max_io_size(q, bio); |
54efd50b | 113 | |
54efd50b | 114 | bio_for_each_segment(bv, bio, iter) { |
54efd50b KO |
115 | /* |
116 | * If the queue doesn't support SG gaps and adding this | |
117 | * offset would create a gap, disallow it. | |
118 | */ | |
5014c311 | 119 | if (bvprvp && bvec_gap_to_prev(q, bvprvp, bv.bv_offset)) |
54efd50b KO |
120 | goto split; |
121 | ||
d0e5fbb0 | 122 | if (sectors + (bv.bv_len >> 9) > max_sectors) { |
e36f6204 KB |
123 | /* |
124 | * Consider this a new segment if we're splitting in | |
125 | * the middle of this vector. | |
126 | */ | |
127 | if (nsegs < queue_max_segments(q) && | |
d0e5fbb0 | 128 | sectors < max_sectors) { |
e36f6204 | 129 | nsegs++; |
d0e5fbb0 | 130 | sectors = max_sectors; |
e36f6204 | 131 | } |
d0e5fbb0 ML |
132 | if (sectors) |
133 | goto split; | |
134 | /* Make this single bvec as the 1st segment */ | |
e36f6204 KB |
135 | } |
136 | ||
5014c311 | 137 | if (bvprvp && blk_queue_cluster(q)) { |
54efd50b KO |
138 | if (seg_size + bv.bv_len > queue_max_segment_size(q)) |
139 | goto new_segment; | |
5014c311 | 140 | if (!BIOVEC_PHYS_MERGEABLE(bvprvp, &bv)) |
54efd50b | 141 | goto new_segment; |
5014c311 | 142 | if (!BIOVEC_SEG_BOUNDARY(q, bvprvp, &bv)) |
54efd50b KO |
143 | goto new_segment; |
144 | ||
145 | seg_size += bv.bv_len; | |
146 | bvprv = bv; | |
578270bf | 147 | bvprvp = &bvprv; |
52cc6eea | 148 | sectors += bv.bv_len >> 9; |
a88d32af ML |
149 | |
150 | if (nsegs == 1 && seg_size > front_seg_size) | |
151 | front_seg_size = seg_size; | |
54efd50b KO |
152 | continue; |
153 | } | |
154 | new_segment: | |
155 | if (nsegs == queue_max_segments(q)) | |
156 | goto split; | |
157 | ||
158 | nsegs++; | |
159 | bvprv = bv; | |
578270bf | 160 | bvprvp = &bvprv; |
54efd50b | 161 | seg_size = bv.bv_len; |
52cc6eea | 162 | sectors += bv.bv_len >> 9; |
02e70742 ML |
163 | |
164 | if (nsegs == 1 && seg_size > front_seg_size) | |
165 | front_seg_size = seg_size; | |
54efd50b KO |
166 | } |
167 | ||
02e70742 | 168 | do_split = false; |
54efd50b | 169 | split: |
bdced438 | 170 | *segs = nsegs; |
02e70742 ML |
171 | |
172 | if (do_split) { | |
173 | new = bio_split(bio, sectors, GFP_NOIO, bs); | |
174 | if (new) | |
175 | bio = new; | |
176 | } | |
177 | ||
178 | bio->bi_seg_front_size = front_seg_size; | |
179 | if (seg_size > bio->bi_seg_back_size) | |
180 | bio->bi_seg_back_size = seg_size; | |
181 | ||
182 | return do_split ? new : NULL; | |
54efd50b KO |
183 | } |
184 | ||
af67c31f | 185 | void blk_queue_split(struct request_queue *q, struct bio **bio) |
54efd50b | 186 | { |
bdced438 ML |
187 | struct bio *split, *res; |
188 | unsigned nsegs; | |
54efd50b | 189 | |
7afafc8a AH |
190 | switch (bio_op(*bio)) { |
191 | case REQ_OP_DISCARD: | |
192 | case REQ_OP_SECURE_ERASE: | |
af67c31f | 193 | split = blk_bio_discard_split(q, *bio, q->bio_split, &nsegs); |
7afafc8a | 194 | break; |
a6f0788e | 195 | case REQ_OP_WRITE_ZEROES: |
af67c31f | 196 | split = blk_bio_write_zeroes_split(q, *bio, q->bio_split, &nsegs); |
a6f0788e | 197 | break; |
7afafc8a | 198 | case REQ_OP_WRITE_SAME: |
af67c31f | 199 | split = blk_bio_write_same_split(q, *bio, q->bio_split, &nsegs); |
7afafc8a AH |
200 | break; |
201 | default: | |
bdced438 | 202 | split = blk_bio_segment_split(q, *bio, q->bio_split, &nsegs); |
7afafc8a AH |
203 | break; |
204 | } | |
bdced438 ML |
205 | |
206 | /* physical segments can be figured out during splitting */ | |
207 | res = split ? split : *bio; | |
208 | res->bi_phys_segments = nsegs; | |
209 | bio_set_flag(res, BIO_SEG_VALID); | |
54efd50b KO |
210 | |
211 | if (split) { | |
6ac45aeb | 212 | /* there isn't chance to merge the splitted bio */ |
1eff9d32 | 213 | split->bi_opf |= REQ_NOMERGE; |
6ac45aeb | 214 | |
54efd50b | 215 | bio_chain(split, *bio); |
cda22646 | 216 | trace_block_split(q, split, (*bio)->bi_iter.bi_sector); |
54efd50b KO |
217 | generic_make_request(*bio); |
218 | *bio = split; | |
219 | } | |
220 | } | |
221 | EXPORT_SYMBOL(blk_queue_split); | |
222 | ||
1e428079 | 223 | static unsigned int __blk_recalc_rq_segments(struct request_queue *q, |
07388549 ML |
224 | struct bio *bio, |
225 | bool no_sg_merge) | |
d6d48196 | 226 | { |
7988613b | 227 | struct bio_vec bv, bvprv = { NULL }; |
54efd50b | 228 | int cluster, prev = 0; |
1e428079 | 229 | unsigned int seg_size, nr_phys_segs; |
59247eae | 230 | struct bio *fbio, *bbio; |
7988613b | 231 | struct bvec_iter iter; |
d6d48196 | 232 | |
1e428079 JA |
233 | if (!bio) |
234 | return 0; | |
d6d48196 | 235 | |
a6f0788e CK |
236 | switch (bio_op(bio)) { |
237 | case REQ_OP_DISCARD: | |
238 | case REQ_OP_SECURE_ERASE: | |
a6f0788e | 239 | case REQ_OP_WRITE_ZEROES: |
f9d03f96 CH |
240 | return 0; |
241 | case REQ_OP_WRITE_SAME: | |
5cb8850c | 242 | return 1; |
a6f0788e | 243 | } |
5cb8850c | 244 | |
1e428079 | 245 | fbio = bio; |
e692cb66 | 246 | cluster = blk_queue_cluster(q); |
5df97b91 | 247 | seg_size = 0; |
2c8919de | 248 | nr_phys_segs = 0; |
1e428079 | 249 | for_each_bio(bio) { |
7988613b | 250 | bio_for_each_segment(bv, bio, iter) { |
05f1dd53 JA |
251 | /* |
252 | * If SG merging is disabled, each bio vector is | |
253 | * a segment | |
254 | */ | |
255 | if (no_sg_merge) | |
256 | goto new_segment; | |
257 | ||
54efd50b | 258 | if (prev && cluster) { |
7988613b | 259 | if (seg_size + bv.bv_len |
ae03bf63 | 260 | > queue_max_segment_size(q)) |
1e428079 | 261 | goto new_segment; |
7988613b | 262 | if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv)) |
1e428079 | 263 | goto new_segment; |
7988613b | 264 | if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv)) |
1e428079 | 265 | goto new_segment; |
d6d48196 | 266 | |
7988613b | 267 | seg_size += bv.bv_len; |
1e428079 JA |
268 | bvprv = bv; |
269 | continue; | |
270 | } | |
d6d48196 | 271 | new_segment: |
1e428079 JA |
272 | if (nr_phys_segs == 1 && seg_size > |
273 | fbio->bi_seg_front_size) | |
274 | fbio->bi_seg_front_size = seg_size; | |
86771427 | 275 | |
1e428079 JA |
276 | nr_phys_segs++; |
277 | bvprv = bv; | |
54efd50b | 278 | prev = 1; |
7988613b | 279 | seg_size = bv.bv_len; |
1e428079 | 280 | } |
59247eae | 281 | bbio = bio; |
d6d48196 JA |
282 | } |
283 | ||
59247eae JA |
284 | if (nr_phys_segs == 1 && seg_size > fbio->bi_seg_front_size) |
285 | fbio->bi_seg_front_size = seg_size; | |
286 | if (seg_size > bbio->bi_seg_back_size) | |
287 | bbio->bi_seg_back_size = seg_size; | |
1e428079 JA |
288 | |
289 | return nr_phys_segs; | |
290 | } | |
291 | ||
292 | void blk_recalc_rq_segments(struct request *rq) | |
293 | { | |
07388549 ML |
294 | bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE, |
295 | &rq->q->queue_flags); | |
296 | ||
297 | rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio, | |
298 | no_sg_merge); | |
d6d48196 JA |
299 | } |
300 | ||
301 | void blk_recount_segments(struct request_queue *q, struct bio *bio) | |
302 | { | |
7f60dcaa ML |
303 | unsigned short seg_cnt; |
304 | ||
305 | /* estimate segment number by bi_vcnt for non-cloned bio */ | |
306 | if (bio_flagged(bio, BIO_CLONED)) | |
307 | seg_cnt = bio_segments(bio); | |
308 | else | |
309 | seg_cnt = bio->bi_vcnt; | |
764f612c | 310 | |
7f60dcaa ML |
311 | if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) && |
312 | (seg_cnt < queue_max_segments(q))) | |
313 | bio->bi_phys_segments = seg_cnt; | |
05f1dd53 JA |
314 | else { |
315 | struct bio *nxt = bio->bi_next; | |
316 | ||
317 | bio->bi_next = NULL; | |
7f60dcaa | 318 | bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, false); |
05f1dd53 JA |
319 | bio->bi_next = nxt; |
320 | } | |
1e428079 | 321 | |
b7c44ed9 | 322 | bio_set_flag(bio, BIO_SEG_VALID); |
d6d48196 JA |
323 | } |
324 | EXPORT_SYMBOL(blk_recount_segments); | |
325 | ||
326 | static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, | |
327 | struct bio *nxt) | |
328 | { | |
2b8221e1 | 329 | struct bio_vec end_bv = { NULL }, nxt_bv; |
f619d254 | 330 | |
e692cb66 | 331 | if (!blk_queue_cluster(q)) |
d6d48196 JA |
332 | return 0; |
333 | ||
86771427 | 334 | if (bio->bi_seg_back_size + nxt->bi_seg_front_size > |
ae03bf63 | 335 | queue_max_segment_size(q)) |
d6d48196 JA |
336 | return 0; |
337 | ||
e17fc0a1 DW |
338 | if (!bio_has_data(bio)) |
339 | return 1; | |
340 | ||
e827091c ML |
341 | bio_get_last_bvec(bio, &end_bv); |
342 | bio_get_first_bvec(nxt, &nxt_bv); | |
f619d254 KO |
343 | |
344 | if (!BIOVEC_PHYS_MERGEABLE(&end_bv, &nxt_bv)) | |
e17fc0a1 DW |
345 | return 0; |
346 | ||
d6d48196 | 347 | /* |
e17fc0a1 | 348 | * bio and nxt are contiguous in memory; check if the queue allows |
d6d48196 JA |
349 | * these two to be merged into one |
350 | */ | |
f619d254 | 351 | if (BIOVEC_SEG_BOUNDARY(q, &end_bv, &nxt_bv)) |
d6d48196 JA |
352 | return 1; |
353 | ||
354 | return 0; | |
355 | } | |
356 | ||
7988613b | 357 | static inline void |
963ab9e5 | 358 | __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec, |
7988613b | 359 | struct scatterlist *sglist, struct bio_vec *bvprv, |
963ab9e5 AH |
360 | struct scatterlist **sg, int *nsegs, int *cluster) |
361 | { | |
362 | ||
363 | int nbytes = bvec->bv_len; | |
364 | ||
7988613b | 365 | if (*sg && *cluster) { |
963ab9e5 AH |
366 | if ((*sg)->length + nbytes > queue_max_segment_size(q)) |
367 | goto new_segment; | |
368 | ||
7988613b | 369 | if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) |
963ab9e5 | 370 | goto new_segment; |
7988613b | 371 | if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) |
963ab9e5 AH |
372 | goto new_segment; |
373 | ||
374 | (*sg)->length += nbytes; | |
375 | } else { | |
376 | new_segment: | |
377 | if (!*sg) | |
378 | *sg = sglist; | |
379 | else { | |
380 | /* | |
381 | * If the driver previously mapped a shorter | |
382 | * list, we could see a termination bit | |
383 | * prematurely unless it fully inits the sg | |
384 | * table on each mapping. We KNOW that there | |
385 | * must be more entries here or the driver | |
386 | * would be buggy, so force clear the | |
387 | * termination bit to avoid doing a full | |
388 | * sg_init_table() in drivers for each command. | |
389 | */ | |
c8164d89 | 390 | sg_unmark_end(*sg); |
963ab9e5 AH |
391 | *sg = sg_next(*sg); |
392 | } | |
393 | ||
394 | sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset); | |
395 | (*nsegs)++; | |
396 | } | |
7988613b | 397 | *bvprv = *bvec; |
963ab9e5 AH |
398 | } |
399 | ||
f9d03f96 CH |
400 | static inline int __blk_bvec_map_sg(struct request_queue *q, struct bio_vec bv, |
401 | struct scatterlist *sglist, struct scatterlist **sg) | |
402 | { | |
403 | *sg = sglist; | |
404 | sg_set_page(*sg, bv.bv_page, bv.bv_len, bv.bv_offset); | |
405 | return 1; | |
406 | } | |
407 | ||
5cb8850c KO |
408 | static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, |
409 | struct scatterlist *sglist, | |
410 | struct scatterlist **sg) | |
d6d48196 | 411 | { |
2b8221e1 | 412 | struct bio_vec bvec, bvprv = { NULL }; |
5cb8850c | 413 | struct bvec_iter iter; |
f9d03f96 | 414 | int cluster = blk_queue_cluster(q), nsegs = 0; |
5cb8850c KO |
415 | |
416 | for_each_bio(bio) | |
417 | bio_for_each_segment(bvec, bio, iter) | |
418 | __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, | |
419 | &nsegs, &cluster); | |
d6d48196 | 420 | |
5cb8850c KO |
421 | return nsegs; |
422 | } | |
423 | ||
424 | /* | |
425 | * map a request to scatterlist, return number of sg entries setup. Caller | |
426 | * must make sure sg can hold rq->nr_phys_segments entries | |
427 | */ | |
428 | int blk_rq_map_sg(struct request_queue *q, struct request *rq, | |
429 | struct scatterlist *sglist) | |
430 | { | |
431 | struct scatterlist *sg = NULL; | |
432 | int nsegs = 0; | |
433 | ||
f9d03f96 CH |
434 | if (rq->rq_flags & RQF_SPECIAL_PAYLOAD) |
435 | nsegs = __blk_bvec_map_sg(q, rq->special_vec, sglist, &sg); | |
436 | else if (rq->bio && bio_op(rq->bio) == REQ_OP_WRITE_SAME) | |
437 | nsegs = __blk_bvec_map_sg(q, bio_iovec(rq->bio), sglist, &sg); | |
438 | else if (rq->bio) | |
5cb8850c | 439 | nsegs = __blk_bios_map_sg(q, rq->bio, sglist, &sg); |
f18573ab | 440 | |
e8064021 | 441 | if (unlikely(rq->rq_flags & RQF_COPY_USER) && |
2e46e8b2 TH |
442 | (blk_rq_bytes(rq) & q->dma_pad_mask)) { |
443 | unsigned int pad_len = | |
444 | (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; | |
f18573ab FT |
445 | |
446 | sg->length += pad_len; | |
447 | rq->extra_len += pad_len; | |
448 | } | |
449 | ||
2fb98e84 | 450 | if (q->dma_drain_size && q->dma_drain_needed(rq)) { |
a8ebb056 | 451 | if (op_is_write(req_op(rq))) |
db0a2e00 TH |
452 | memset(q->dma_drain_buffer, 0, q->dma_drain_size); |
453 | ||
da81ed16 | 454 | sg_unmark_end(sg); |
d6d48196 JA |
455 | sg = sg_next(sg); |
456 | sg_set_page(sg, virt_to_page(q->dma_drain_buffer), | |
457 | q->dma_drain_size, | |
458 | ((unsigned long)q->dma_drain_buffer) & | |
459 | (PAGE_SIZE - 1)); | |
460 | nsegs++; | |
7a85f889 | 461 | rq->extra_len += q->dma_drain_size; |
d6d48196 JA |
462 | } |
463 | ||
464 | if (sg) | |
465 | sg_mark_end(sg); | |
466 | ||
12e57f59 ML |
467 | /* |
468 | * Something must have been wrong if the figured number of | |
469 | * segment is bigger than number of req's physical segments | |
470 | */ | |
f9d03f96 | 471 | WARN_ON(nsegs > blk_rq_nr_phys_segments(rq)); |
12e57f59 | 472 | |
d6d48196 JA |
473 | return nsegs; |
474 | } | |
d6d48196 JA |
475 | EXPORT_SYMBOL(blk_rq_map_sg); |
476 | ||
d6d48196 JA |
477 | static inline int ll_new_hw_segment(struct request_queue *q, |
478 | struct request *req, | |
479 | struct bio *bio) | |
480 | { | |
d6d48196 JA |
481 | int nr_phys_segs = bio_phys_segments(q, bio); |
482 | ||
13f05c8d MP |
483 | if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) |
484 | goto no_merge; | |
485 | ||
4eaf99be | 486 | if (blk_integrity_merge_bio(q, req, bio) == false) |
13f05c8d | 487 | goto no_merge; |
d6d48196 JA |
488 | |
489 | /* | |
490 | * This will form the start of a new hw segment. Bump both | |
491 | * counters. | |
492 | */ | |
d6d48196 JA |
493 | req->nr_phys_segments += nr_phys_segs; |
494 | return 1; | |
13f05c8d MP |
495 | |
496 | no_merge: | |
e0c72300 | 497 | req_set_nomerge(q, req); |
13f05c8d | 498 | return 0; |
d6d48196 JA |
499 | } |
500 | ||
501 | int ll_back_merge_fn(struct request_queue *q, struct request *req, | |
502 | struct bio *bio) | |
503 | { | |
5e7c4274 JA |
504 | if (req_gap_back_merge(req, bio)) |
505 | return 0; | |
7f39add3 SG |
506 | if (blk_integrity_rq(req) && |
507 | integrity_req_gap_back_merge(req, bio)) | |
508 | return 0; | |
f31dc1cd | 509 | if (blk_rq_sectors(req) + bio_sectors(bio) > |
17007f39 | 510 | blk_rq_get_max_sectors(req, blk_rq_pos(req))) { |
e0c72300 | 511 | req_set_nomerge(q, req); |
d6d48196 JA |
512 | return 0; |
513 | } | |
2cdf79ca | 514 | if (!bio_flagged(req->biotail, BIO_SEG_VALID)) |
d6d48196 | 515 | blk_recount_segments(q, req->biotail); |
2cdf79ca | 516 | if (!bio_flagged(bio, BIO_SEG_VALID)) |
d6d48196 | 517 | blk_recount_segments(q, bio); |
d6d48196 JA |
518 | |
519 | return ll_new_hw_segment(q, req, bio); | |
520 | } | |
521 | ||
6728cb0e | 522 | int ll_front_merge_fn(struct request_queue *q, struct request *req, |
d6d48196 JA |
523 | struct bio *bio) |
524 | { | |
5e7c4274 JA |
525 | |
526 | if (req_gap_front_merge(req, bio)) | |
527 | return 0; | |
7f39add3 SG |
528 | if (blk_integrity_rq(req) && |
529 | integrity_req_gap_front_merge(req, bio)) | |
530 | return 0; | |
f31dc1cd | 531 | if (blk_rq_sectors(req) + bio_sectors(bio) > |
17007f39 | 532 | blk_rq_get_max_sectors(req, bio->bi_iter.bi_sector)) { |
e0c72300 | 533 | req_set_nomerge(q, req); |
d6d48196 JA |
534 | return 0; |
535 | } | |
2cdf79ca | 536 | if (!bio_flagged(bio, BIO_SEG_VALID)) |
d6d48196 | 537 | blk_recount_segments(q, bio); |
2cdf79ca | 538 | if (!bio_flagged(req->bio, BIO_SEG_VALID)) |
d6d48196 | 539 | blk_recount_segments(q, req->bio); |
d6d48196 JA |
540 | |
541 | return ll_new_hw_segment(q, req, bio); | |
542 | } | |
543 | ||
e7e24500 JA |
544 | /* |
545 | * blk-mq uses req->special to carry normal driver per-request payload, it | |
546 | * does not indicate a prepared command that we cannot merge with. | |
547 | */ | |
548 | static bool req_no_special_merge(struct request *req) | |
549 | { | |
550 | struct request_queue *q = req->q; | |
551 | ||
552 | return !q->mq_ops && req->special; | |
553 | } | |
554 | ||
acf1bbe8 JA |
555 | static bool req_attempt_discard_merge(struct request_queue *q, struct request *req, |
556 | struct request *next) | |
557 | { | |
558 | unsigned short segments = blk_rq_nr_discard_segments(req); | |
559 | ||
560 | if (segments >= queue_max_discard_segments(q)) | |
561 | goto no_merge; | |
562 | if (blk_rq_sectors(req) + bio_sectors(next->bio) > | |
563 | blk_rq_get_max_sectors(req, blk_rq_pos(req))) | |
564 | goto no_merge; | |
565 | ||
566 | req->nr_phys_segments = segments + blk_rq_nr_discard_segments(next); | |
567 | return true; | |
568 | no_merge: | |
569 | req_set_nomerge(q, req); | |
570 | return false; | |
571 | } | |
572 | ||
d6d48196 JA |
573 | static int ll_merge_requests_fn(struct request_queue *q, struct request *req, |
574 | struct request *next) | |
575 | { | |
576 | int total_phys_segments; | |
86771427 FT |
577 | unsigned int seg_size = |
578 | req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size; | |
d6d48196 JA |
579 | |
580 | /* | |
581 | * First check if the either of the requests are re-queued | |
582 | * requests. Can't merge them if they are. | |
583 | */ | |
e7e24500 | 584 | if (req_no_special_merge(req) || req_no_special_merge(next)) |
d6d48196 JA |
585 | return 0; |
586 | ||
5e7c4274 | 587 | if (req_gap_back_merge(req, next->bio)) |
854fbb9c KB |
588 | return 0; |
589 | ||
d6d48196 JA |
590 | /* |
591 | * Will it become too large? | |
592 | */ | |
f31dc1cd | 593 | if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > |
17007f39 | 594 | blk_rq_get_max_sectors(req, blk_rq_pos(req))) |
d6d48196 JA |
595 | return 0; |
596 | ||
597 | total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; | |
86771427 FT |
598 | if (blk_phys_contig_segment(q, req->biotail, next->bio)) { |
599 | if (req->nr_phys_segments == 1) | |
600 | req->bio->bi_seg_front_size = seg_size; | |
601 | if (next->nr_phys_segments == 1) | |
602 | next->biotail->bi_seg_back_size = seg_size; | |
d6d48196 | 603 | total_phys_segments--; |
86771427 | 604 | } |
d6d48196 | 605 | |
8a78362c | 606 | if (total_phys_segments > queue_max_segments(q)) |
d6d48196 JA |
607 | return 0; |
608 | ||
4eaf99be | 609 | if (blk_integrity_merge_rq(q, req, next) == false) |
13f05c8d MP |
610 | return 0; |
611 | ||
d6d48196 JA |
612 | /* Merge is OK... */ |
613 | req->nr_phys_segments = total_phys_segments; | |
d6d48196 JA |
614 | return 1; |
615 | } | |
616 | ||
80a761fd TH |
617 | /** |
618 | * blk_rq_set_mixed_merge - mark a request as mixed merge | |
619 | * @rq: request to mark as mixed merge | |
620 | * | |
621 | * Description: | |
622 | * @rq is about to be mixed merged. Make sure the attributes | |
623 | * which can be mixed are set in each bio and mark @rq as mixed | |
624 | * merged. | |
625 | */ | |
626 | void blk_rq_set_mixed_merge(struct request *rq) | |
627 | { | |
628 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
629 | struct bio *bio; | |
630 | ||
e8064021 | 631 | if (rq->rq_flags & RQF_MIXED_MERGE) |
80a761fd TH |
632 | return; |
633 | ||
634 | /* | |
635 | * @rq will no longer represent mixable attributes for all the | |
636 | * contained bios. It will just track those of the first one. | |
637 | * Distributes the attributs to each bio. | |
638 | */ | |
639 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
1eff9d32 JA |
640 | WARN_ON_ONCE((bio->bi_opf & REQ_FAILFAST_MASK) && |
641 | (bio->bi_opf & REQ_FAILFAST_MASK) != ff); | |
642 | bio->bi_opf |= ff; | |
80a761fd | 643 | } |
e8064021 | 644 | rq->rq_flags |= RQF_MIXED_MERGE; |
80a761fd TH |
645 | } |
646 | ||
26308eab JM |
647 | static void blk_account_io_merge(struct request *req) |
648 | { | |
649 | if (blk_do_io_stat(req)) { | |
650 | struct hd_struct *part; | |
651 | int cpu; | |
652 | ||
653 | cpu = part_stat_lock(); | |
09e099d4 | 654 | part = req->part; |
26308eab | 655 | |
d62e26b3 JA |
656 | part_round_stats(req->q, cpu, part); |
657 | part_dec_in_flight(req->q, part, rq_data_dir(req)); | |
26308eab | 658 | |
6c23a968 | 659 | hd_struct_put(part); |
26308eab JM |
660 | part_stat_unlock(); |
661 | } | |
662 | } | |
9fa72f25 JW |
663 | /* |
664 | * Two cases of handling DISCARD merge: | |
665 | * If max_discard_segments > 1, the driver takes every bio | |
666 | * as a range and send them to controller together. The ranges | |
667 | * needn't to be contiguous. | |
668 | * Otherwise, the bios/requests will be handled as same as | |
669 | * others which should be contiguous. | |
670 | */ | |
671 | static inline bool blk_discard_mergable(struct request *req) | |
672 | { | |
673 | if (req_op(req) == REQ_OP_DISCARD && | |
674 | queue_max_discard_segments(req->q) > 1) | |
675 | return true; | |
676 | return false; | |
677 | } | |
678 | ||
679 | enum elv_merge blk_try_req_merge(struct request *req, struct request *next) | |
680 | { | |
681 | if (blk_discard_mergable(req)) | |
682 | return ELEVATOR_DISCARD_MERGE; | |
683 | else if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next)) | |
684 | return ELEVATOR_BACK_MERGE; | |
685 | ||
686 | return ELEVATOR_NO_MERGE; | |
687 | } | |
26308eab | 688 | |
d6d48196 | 689 | /* |
b973cb7e JA |
690 | * For non-mq, this has to be called with the request spinlock acquired. |
691 | * For mq with scheduling, the appropriate queue wide lock should be held. | |
d6d48196 | 692 | */ |
b973cb7e JA |
693 | static struct request *attempt_merge(struct request_queue *q, |
694 | struct request *req, struct request *next) | |
d6d48196 | 695 | { |
2fff8a92 BVA |
696 | if (!q->mq_ops) |
697 | lockdep_assert_held(q->queue_lock); | |
698 | ||
d6d48196 | 699 | if (!rq_mergeable(req) || !rq_mergeable(next)) |
b973cb7e | 700 | return NULL; |
d6d48196 | 701 | |
288dab8a | 702 | if (req_op(req) != req_op(next)) |
b973cb7e | 703 | return NULL; |
f31dc1cd | 704 | |
d6d48196 JA |
705 | if (rq_data_dir(req) != rq_data_dir(next) |
706 | || req->rq_disk != next->rq_disk | |
e7e24500 | 707 | || req_no_special_merge(next)) |
b973cb7e | 708 | return NULL; |
d6d48196 | 709 | |
8fe0d473 | 710 | if (req_op(req) == REQ_OP_WRITE_SAME && |
4363ac7c | 711 | !blk_write_same_mergeable(req->bio, next->bio)) |
b973cb7e | 712 | return NULL; |
4363ac7c | 713 | |
cb6934f8 JA |
714 | /* |
715 | * Don't allow merge of different write hints, or for a hint with | |
716 | * non-hint IO. | |
717 | */ | |
718 | if (req->write_hint != next->write_hint) | |
719 | return NULL; | |
720 | ||
d6d48196 JA |
721 | /* |
722 | * If we are allowed to merge, then append bio list | |
723 | * from next to rq and release next. merge_requests_fn | |
724 | * will have updated segment counts, update sector | |
acf1bbe8 JA |
725 | * counts here. Handle DISCARDs separately, as they |
726 | * have separate settings. | |
d6d48196 | 727 | */ |
9fa72f25 JW |
728 | |
729 | switch (blk_try_req_merge(req, next)) { | |
730 | case ELEVATOR_DISCARD_MERGE: | |
acf1bbe8 JA |
731 | if (!req_attempt_discard_merge(q, req, next)) |
732 | return NULL; | |
9fa72f25 JW |
733 | break; |
734 | case ELEVATOR_BACK_MERGE: | |
735 | if (!ll_merge_requests_fn(q, req, next)) | |
736 | return NULL; | |
737 | break; | |
738 | default: | |
b973cb7e | 739 | return NULL; |
9fa72f25 | 740 | } |
d6d48196 | 741 | |
80a761fd TH |
742 | /* |
743 | * If failfast settings disagree or any of the two is already | |
744 | * a mixed merge, mark both as mixed before proceeding. This | |
745 | * makes sure that all involved bios have mixable attributes | |
746 | * set properly. | |
747 | */ | |
e8064021 | 748 | if (((req->rq_flags | next->rq_flags) & RQF_MIXED_MERGE) || |
80a761fd TH |
749 | (req->cmd_flags & REQ_FAILFAST_MASK) != |
750 | (next->cmd_flags & REQ_FAILFAST_MASK)) { | |
751 | blk_rq_set_mixed_merge(req); | |
752 | blk_rq_set_mixed_merge(next); | |
753 | } | |
754 | ||
d6d48196 JA |
755 | /* |
756 | * At this point we have either done a back merge | |
757 | * or front merge. We need the smaller start_time of | |
758 | * the merged requests to be the current request | |
759 | * for accounting purposes. | |
760 | */ | |
761 | if (time_after(req->start_time, next->start_time)) | |
762 | req->start_time = next->start_time; | |
763 | ||
764 | req->biotail->bi_next = next->bio; | |
765 | req->biotail = next->biotail; | |
766 | ||
a2dec7b3 | 767 | req->__data_len += blk_rq_bytes(next); |
d6d48196 | 768 | |
5260092b | 769 | if (!blk_discard_mergable(req)) |
acf1bbe8 | 770 | elv_merge_requests(q, req, next); |
d6d48196 | 771 | |
42dad764 JM |
772 | /* |
773 | * 'next' is going away, so update stats accordingly | |
774 | */ | |
775 | blk_account_io_merge(next); | |
d6d48196 JA |
776 | |
777 | req->ioprio = ioprio_best(req->ioprio, next->ioprio); | |
ab780f1e JA |
778 | if (blk_rq_cpu_valid(next)) |
779 | req->cpu = next->cpu; | |
d6d48196 | 780 | |
e4d750c9 JA |
781 | /* |
782 | * ownership of bio passed from next to req, return 'next' for | |
783 | * the caller to free | |
784 | */ | |
1cd96c24 | 785 | next->bio = NULL; |
b973cb7e | 786 | return next; |
d6d48196 JA |
787 | } |
788 | ||
b973cb7e | 789 | struct request *attempt_back_merge(struct request_queue *q, struct request *rq) |
d6d48196 JA |
790 | { |
791 | struct request *next = elv_latter_request(q, rq); | |
792 | ||
793 | if (next) | |
794 | return attempt_merge(q, rq, next); | |
795 | ||
b973cb7e | 796 | return NULL; |
d6d48196 JA |
797 | } |
798 | ||
b973cb7e | 799 | struct request *attempt_front_merge(struct request_queue *q, struct request *rq) |
d6d48196 JA |
800 | { |
801 | struct request *prev = elv_former_request(q, rq); | |
802 | ||
803 | if (prev) | |
804 | return attempt_merge(q, prev, rq); | |
805 | ||
b973cb7e | 806 | return NULL; |
d6d48196 | 807 | } |
5e84ea3a JA |
808 | |
809 | int blk_attempt_req_merge(struct request_queue *q, struct request *rq, | |
810 | struct request *next) | |
811 | { | |
72ef799b | 812 | struct elevator_queue *e = q->elevator; |
e4d750c9 | 813 | struct request *free; |
72ef799b | 814 | |
bd166ef1 | 815 | if (!e->uses_mq && e->type->ops.sq.elevator_allow_rq_merge_fn) |
c51ca6cf | 816 | if (!e->type->ops.sq.elevator_allow_rq_merge_fn(q, rq, next)) |
72ef799b TE |
817 | return 0; |
818 | ||
e4d750c9 JA |
819 | free = attempt_merge(q, rq, next); |
820 | if (free) { | |
821 | __blk_put_request(q, free); | |
822 | return 1; | |
823 | } | |
824 | ||
825 | return 0; | |
5e84ea3a | 826 | } |
050c8ea8 TH |
827 | |
828 | bool blk_rq_merge_ok(struct request *rq, struct bio *bio) | |
829 | { | |
e2a60da7 | 830 | if (!rq_mergeable(rq) || !bio_mergeable(bio)) |
050c8ea8 TH |
831 | return false; |
832 | ||
288dab8a | 833 | if (req_op(rq) != bio_op(bio)) |
f31dc1cd MP |
834 | return false; |
835 | ||
050c8ea8 TH |
836 | /* different data direction or already started, don't merge */ |
837 | if (bio_data_dir(bio) != rq_data_dir(rq)) | |
838 | return false; | |
839 | ||
840 | /* must be same device and not a special request */ | |
74d46992 | 841 | if (rq->rq_disk != bio->bi_disk || req_no_special_merge(rq)) |
050c8ea8 TH |
842 | return false; |
843 | ||
844 | /* only merge integrity protected bio into ditto rq */ | |
4eaf99be | 845 | if (blk_integrity_merge_bio(rq->q, rq, bio) == false) |
050c8ea8 TH |
846 | return false; |
847 | ||
4363ac7c | 848 | /* must be using the same buffer */ |
8fe0d473 | 849 | if (req_op(rq) == REQ_OP_WRITE_SAME && |
4363ac7c MP |
850 | !blk_write_same_mergeable(rq->bio, bio)) |
851 | return false; | |
852 | ||
cb6934f8 JA |
853 | /* |
854 | * Don't allow merge of different write hints, or for a hint with | |
855 | * non-hint IO. | |
856 | */ | |
857 | if (rq->write_hint != bio->bi_write_hint) | |
858 | return false; | |
859 | ||
050c8ea8 TH |
860 | return true; |
861 | } | |
862 | ||
34fe7c05 | 863 | enum elv_merge blk_try_merge(struct request *rq, struct bio *bio) |
050c8ea8 | 864 | { |
9fa72f25 | 865 | if (blk_discard_mergable(rq)) |
1e739730 CH |
866 | return ELEVATOR_DISCARD_MERGE; |
867 | else if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector) | |
050c8ea8 | 868 | return ELEVATOR_BACK_MERGE; |
4f024f37 | 869 | else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector) |
050c8ea8 TH |
870 | return ELEVATOR_FRONT_MERGE; |
871 | return ELEVATOR_NO_MERGE; | |
872 | } |