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1 | /* | |
2 | * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public Licens | |
14 | * along with this program; if not, write to the Free Software | |
15 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- | |
16 | * | |
17 | */ | |
18 | #include <linux/mm.h> | |
19 | #include <linux/swap.h> | |
20 | #include <linux/bio.h> | |
21 | #include <linux/blkdev.h> | |
22 | #include <linux/iocontext.h> | |
23 | #include <linux/slab.h> | |
24 | #include <linux/init.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/export.h> | |
27 | #include <linux/mempool.h> | |
28 | #include <linux/workqueue.h> | |
29 | #include <linux/cgroup.h> | |
30 | #include <scsi/sg.h> /* for struct sg_iovec */ | |
31 | ||
32 | #include <trace/events/block.h> | |
33 | ||
34 | /* | |
35 | * Test patch to inline a certain number of bi_io_vec's inside the bio | |
36 | * itself, to shrink a bio data allocation from two mempool calls to one | |
37 | */ | |
38 | #define BIO_INLINE_VECS 4 | |
39 | ||
40 | static mempool_t *bio_split_pool __read_mostly; | |
41 | ||
42 | /* | |
43 | * if you change this list, also change bvec_alloc or things will | |
44 | * break badly! cannot be bigger than what you can fit into an | |
45 | * unsigned short | |
46 | */ | |
47 | #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) } | |
48 | static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = { | |
49 | BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES), | |
50 | }; | |
51 | #undef BV | |
52 | ||
53 | /* | |
54 | * fs_bio_set is the bio_set containing bio and iovec memory pools used by | |
55 | * IO code that does not need private memory pools. | |
56 | */ | |
57 | struct bio_set *fs_bio_set; | |
58 | ||
59 | /* | |
60 | * Our slab pool management | |
61 | */ | |
62 | struct bio_slab { | |
63 | struct kmem_cache *slab; | |
64 | unsigned int slab_ref; | |
65 | unsigned int slab_size; | |
66 | char name[8]; | |
67 | }; | |
68 | static DEFINE_MUTEX(bio_slab_lock); | |
69 | static struct bio_slab *bio_slabs; | |
70 | static unsigned int bio_slab_nr, bio_slab_max; | |
71 | ||
72 | static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size) | |
73 | { | |
74 | unsigned int sz = sizeof(struct bio) + extra_size; | |
75 | struct kmem_cache *slab = NULL; | |
76 | struct bio_slab *bslab, *new_bio_slabs; | |
77 | unsigned int i, entry = -1; | |
78 | ||
79 | mutex_lock(&bio_slab_lock); | |
80 | ||
81 | i = 0; | |
82 | while (i < bio_slab_nr) { | |
83 | bslab = &bio_slabs[i]; | |
84 | ||
85 | if (!bslab->slab && entry == -1) | |
86 | entry = i; | |
87 | else if (bslab->slab_size == sz) { | |
88 | slab = bslab->slab; | |
89 | bslab->slab_ref++; | |
90 | break; | |
91 | } | |
92 | i++; | |
93 | } | |
94 | ||
95 | if (slab) | |
96 | goto out_unlock; | |
97 | ||
98 | if (bio_slab_nr == bio_slab_max && entry == -1) { | |
99 | bio_slab_max <<= 1; | |
100 | new_bio_slabs = krealloc(bio_slabs, | |
101 | bio_slab_max * sizeof(struct bio_slab), | |
102 | GFP_KERNEL); | |
103 | if (!new_bio_slabs) | |
104 | goto out_unlock; | |
105 | bio_slabs = new_bio_slabs; | |
106 | } | |
107 | if (entry == -1) | |
108 | entry = bio_slab_nr++; | |
109 | ||
110 | bslab = &bio_slabs[entry]; | |
111 | ||
112 | snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry); | |
113 | slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL); | |
114 | if (!slab) | |
115 | goto out_unlock; | |
116 | ||
117 | printk(KERN_INFO "bio: create slab <%s> at %d\n", bslab->name, entry); | |
118 | bslab->slab = slab; | |
119 | bslab->slab_ref = 1; | |
120 | bslab->slab_size = sz; | |
121 | out_unlock: | |
122 | mutex_unlock(&bio_slab_lock); | |
123 | return slab; | |
124 | } | |
125 | ||
126 | static void bio_put_slab(struct bio_set *bs) | |
127 | { | |
128 | struct bio_slab *bslab = NULL; | |
129 | unsigned int i; | |
130 | ||
131 | mutex_lock(&bio_slab_lock); | |
132 | ||
133 | for (i = 0; i < bio_slab_nr; i++) { | |
134 | if (bs->bio_slab == bio_slabs[i].slab) { | |
135 | bslab = &bio_slabs[i]; | |
136 | break; | |
137 | } | |
138 | } | |
139 | ||
140 | if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n")) | |
141 | goto out; | |
142 | ||
143 | WARN_ON(!bslab->slab_ref); | |
144 | ||
145 | if (--bslab->slab_ref) | |
146 | goto out; | |
147 | ||
148 | kmem_cache_destroy(bslab->slab); | |
149 | bslab->slab = NULL; | |
150 | ||
151 | out: | |
152 | mutex_unlock(&bio_slab_lock); | |
153 | } | |
154 | ||
155 | unsigned int bvec_nr_vecs(unsigned short idx) | |
156 | { | |
157 | return bvec_slabs[idx].nr_vecs; | |
158 | } | |
159 | ||
160 | void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx) | |
161 | { | |
162 | BIO_BUG_ON(idx >= BIOVEC_NR_POOLS); | |
163 | ||
164 | if (idx == BIOVEC_MAX_IDX) | |
165 | mempool_free(bv, bs->bvec_pool); | |
166 | else { | |
167 | struct biovec_slab *bvs = bvec_slabs + idx; | |
168 | ||
169 | kmem_cache_free(bvs->slab, bv); | |
170 | } | |
171 | } | |
172 | ||
173 | struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, | |
174 | struct bio_set *bs) | |
175 | { | |
176 | struct bio_vec *bvl; | |
177 | ||
178 | /* | |
179 | * see comment near bvec_array define! | |
180 | */ | |
181 | switch (nr) { | |
182 | case 1: | |
183 | *idx = 0; | |
184 | break; | |
185 | case 2 ... 4: | |
186 | *idx = 1; | |
187 | break; | |
188 | case 5 ... 16: | |
189 | *idx = 2; | |
190 | break; | |
191 | case 17 ... 64: | |
192 | *idx = 3; | |
193 | break; | |
194 | case 65 ... 128: | |
195 | *idx = 4; | |
196 | break; | |
197 | case 129 ... BIO_MAX_PAGES: | |
198 | *idx = 5; | |
199 | break; | |
200 | default: | |
201 | return NULL; | |
202 | } | |
203 | ||
204 | /* | |
205 | * idx now points to the pool we want to allocate from. only the | |
206 | * 1-vec entry pool is mempool backed. | |
207 | */ | |
208 | if (*idx == BIOVEC_MAX_IDX) { | |
209 | fallback: | |
210 | bvl = mempool_alloc(bs->bvec_pool, gfp_mask); | |
211 | } else { | |
212 | struct biovec_slab *bvs = bvec_slabs + *idx; | |
213 | gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO); | |
214 | ||
215 | /* | |
216 | * Make this allocation restricted and don't dump info on | |
217 | * allocation failures, since we'll fallback to the mempool | |
218 | * in case of failure. | |
219 | */ | |
220 | __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; | |
221 | ||
222 | /* | |
223 | * Try a slab allocation. If this fails and __GFP_WAIT | |
224 | * is set, retry with the 1-entry mempool | |
225 | */ | |
226 | bvl = kmem_cache_alloc(bvs->slab, __gfp_mask); | |
227 | if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) { | |
228 | *idx = BIOVEC_MAX_IDX; | |
229 | goto fallback; | |
230 | } | |
231 | } | |
232 | ||
233 | return bvl; | |
234 | } | |
235 | ||
236 | void bio_free(struct bio *bio, struct bio_set *bs) | |
237 | { | |
238 | void *p; | |
239 | ||
240 | if (bio_has_allocated_vec(bio)) | |
241 | bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio)); | |
242 | ||
243 | if (bio_integrity(bio)) | |
244 | bio_integrity_free(bio); | |
245 | ||
246 | /* | |
247 | * If we have front padding, adjust the bio pointer before freeing | |
248 | */ | |
249 | p = bio; | |
250 | if (bs->front_pad) | |
251 | p -= bs->front_pad; | |
252 | ||
253 | mempool_free(p, bs->bio_pool); | |
254 | } | |
255 | EXPORT_SYMBOL(bio_free); | |
256 | ||
257 | void bio_init(struct bio *bio) | |
258 | { | |
259 | memset(bio, 0, sizeof(*bio)); | |
260 | bio->bi_flags = 1 << BIO_UPTODATE; | |
261 | atomic_set(&bio->bi_cnt, 1); | |
262 | } | |
263 | EXPORT_SYMBOL(bio_init); | |
264 | ||
265 | /** | |
266 | * bio_reset - reinitialize a bio | |
267 | * @bio: bio to reset | |
268 | * | |
269 | * Description: | |
270 | * After calling bio_reset(), @bio will be in the same state as a freshly | |
271 | * allocated bio returned bio bio_alloc_bioset() - the only fields that are | |
272 | * preserved are the ones that are initialized by bio_alloc_bioset(). See | |
273 | * comment in struct bio. | |
274 | */ | |
275 | void bio_reset(struct bio *bio) | |
276 | { | |
277 | unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS); | |
278 | ||
279 | if (bio_integrity(bio)) | |
280 | bio_integrity_free(bio); | |
281 | ||
282 | bio_disassociate_task(bio); | |
283 | ||
284 | memset(bio, 0, BIO_RESET_BYTES); | |
285 | bio->bi_flags = flags|(1 << BIO_UPTODATE); | |
286 | } | |
287 | EXPORT_SYMBOL(bio_reset); | |
288 | ||
289 | /** | |
290 | * bio_alloc_bioset - allocate a bio for I/O | |
291 | * @gfp_mask: the GFP_ mask given to the slab allocator | |
292 | * @nr_iovecs: number of iovecs to pre-allocate | |
293 | * @bs: the bio_set to allocate from. | |
294 | * | |
295 | * Description: | |
296 | * bio_alloc_bioset will try its own mempool to satisfy the allocation. | |
297 | * If %__GFP_WAIT is set then we will block on the internal pool waiting | |
298 | * for a &struct bio to become free. | |
299 | **/ | |
300 | struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) | |
301 | { | |
302 | unsigned long idx = BIO_POOL_NONE; | |
303 | struct bio_vec *bvl = NULL; | |
304 | struct bio *bio; | |
305 | void *p; | |
306 | ||
307 | p = mempool_alloc(bs->bio_pool, gfp_mask); | |
308 | if (unlikely(!p)) | |
309 | return NULL; | |
310 | bio = p + bs->front_pad; | |
311 | ||
312 | bio_init(bio); | |
313 | bio->bi_pool = bs; | |
314 | ||
315 | if (unlikely(!nr_iovecs)) | |
316 | goto out_set; | |
317 | ||
318 | if (nr_iovecs <= BIO_INLINE_VECS) { | |
319 | bvl = bio->bi_inline_vecs; | |
320 | nr_iovecs = BIO_INLINE_VECS; | |
321 | } else { | |
322 | bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs); | |
323 | if (unlikely(!bvl)) | |
324 | goto err_free; | |
325 | ||
326 | nr_iovecs = bvec_nr_vecs(idx); | |
327 | } | |
328 | out_set: | |
329 | bio->bi_flags |= idx << BIO_POOL_OFFSET; | |
330 | bio->bi_max_vecs = nr_iovecs; | |
331 | bio->bi_io_vec = bvl; | |
332 | return bio; | |
333 | ||
334 | err_free: | |
335 | mempool_free(p, bs->bio_pool); | |
336 | return NULL; | |
337 | } | |
338 | EXPORT_SYMBOL(bio_alloc_bioset); | |
339 | ||
340 | /** | |
341 | * bio_alloc - allocate a new bio, memory pool backed | |
342 | * @gfp_mask: allocation mask to use | |
343 | * @nr_iovecs: number of iovecs | |
344 | * | |
345 | * bio_alloc will allocate a bio and associated bio_vec array that can hold | |
346 | * at least @nr_iovecs entries. Allocations will be done from the | |
347 | * fs_bio_set. Also see @bio_alloc_bioset and @bio_kmalloc. | |
348 | * | |
349 | * If %__GFP_WAIT is set, then bio_alloc will always be able to allocate | |
350 | * a bio. This is due to the mempool guarantees. To make this work, callers | |
351 | * must never allocate more than 1 bio at a time from this pool. Callers | |
352 | * that need to allocate more than 1 bio must always submit the previously | |
353 | * allocated bio for IO before attempting to allocate a new one. Failure to | |
354 | * do so can cause livelocks under memory pressure. | |
355 | * | |
356 | * RETURNS: | |
357 | * Pointer to new bio on success, NULL on failure. | |
358 | */ | |
359 | struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs) | |
360 | { | |
361 | return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set); | |
362 | } | |
363 | EXPORT_SYMBOL(bio_alloc); | |
364 | ||
365 | static void bio_kmalloc_destructor(struct bio *bio) | |
366 | { | |
367 | if (bio_integrity(bio)) | |
368 | bio_integrity_free(bio); | |
369 | kfree(bio); | |
370 | } | |
371 | ||
372 | /** | |
373 | * bio_kmalloc - allocate a bio for I/O using kmalloc() | |
374 | * @gfp_mask: the GFP_ mask given to the slab allocator | |
375 | * @nr_iovecs: number of iovecs to pre-allocate | |
376 | * | |
377 | * Description: | |
378 | * Allocate a new bio with @nr_iovecs bvecs. If @gfp_mask contains | |
379 | * %__GFP_WAIT, the allocation is guaranteed to succeed. | |
380 | * | |
381 | **/ | |
382 | struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs) | |
383 | { | |
384 | struct bio *bio; | |
385 | ||
386 | if (nr_iovecs > UIO_MAXIOV) | |
387 | return NULL; | |
388 | ||
389 | bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec), | |
390 | gfp_mask); | |
391 | if (unlikely(!bio)) | |
392 | return NULL; | |
393 | ||
394 | bio_init(bio); | |
395 | bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET; | |
396 | bio->bi_max_vecs = nr_iovecs; | |
397 | bio->bi_io_vec = bio->bi_inline_vecs; | |
398 | bio->bi_destructor = bio_kmalloc_destructor; | |
399 | ||
400 | return bio; | |
401 | } | |
402 | EXPORT_SYMBOL(bio_kmalloc); | |
403 | ||
404 | void zero_fill_bio(struct bio *bio) | |
405 | { | |
406 | unsigned long flags; | |
407 | struct bio_vec *bv; | |
408 | int i; | |
409 | ||
410 | bio_for_each_segment(bv, bio, i) { | |
411 | char *data = bvec_kmap_irq(bv, &flags); | |
412 | memset(data, 0, bv->bv_len); | |
413 | flush_dcache_page(bv->bv_page); | |
414 | bvec_kunmap_irq(data, &flags); | |
415 | } | |
416 | } | |
417 | EXPORT_SYMBOL(zero_fill_bio); | |
418 | ||
419 | /** | |
420 | * bio_put - release a reference to a bio | |
421 | * @bio: bio to release reference to | |
422 | * | |
423 | * Description: | |
424 | * Put a reference to a &struct bio, either one you have gotten with | |
425 | * bio_alloc, bio_get or bio_clone. The last put of a bio will free it. | |
426 | **/ | |
427 | void bio_put(struct bio *bio) | |
428 | { | |
429 | BIO_BUG_ON(!atomic_read(&bio->bi_cnt)); | |
430 | ||
431 | /* | |
432 | * last put frees it | |
433 | */ | |
434 | if (atomic_dec_and_test(&bio->bi_cnt)) { | |
435 | bio_disassociate_task(bio); | |
436 | bio->bi_next = NULL; | |
437 | ||
438 | /* | |
439 | * This if statement is temporary - bi_pool is replacing | |
440 | * bi_destructor, but bi_destructor will be taken out in another | |
441 | * patch. | |
442 | */ | |
443 | if (bio->bi_pool) | |
444 | bio_free(bio, bio->bi_pool); | |
445 | else | |
446 | bio->bi_destructor(bio); | |
447 | } | |
448 | } | |
449 | EXPORT_SYMBOL(bio_put); | |
450 | ||
451 | inline int bio_phys_segments(struct request_queue *q, struct bio *bio) | |
452 | { | |
453 | if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
454 | blk_recount_segments(q, bio); | |
455 | ||
456 | return bio->bi_phys_segments; | |
457 | } | |
458 | EXPORT_SYMBOL(bio_phys_segments); | |
459 | ||
460 | /** | |
461 | * __bio_clone - clone a bio | |
462 | * @bio: destination bio | |
463 | * @bio_src: bio to clone | |
464 | * | |
465 | * Clone a &bio. Caller will own the returned bio, but not | |
466 | * the actual data it points to. Reference count of returned | |
467 | * bio will be one. | |
468 | */ | |
469 | void __bio_clone(struct bio *bio, struct bio *bio_src) | |
470 | { | |
471 | memcpy(bio->bi_io_vec, bio_src->bi_io_vec, | |
472 | bio_src->bi_max_vecs * sizeof(struct bio_vec)); | |
473 | ||
474 | /* | |
475 | * most users will be overriding ->bi_bdev with a new target, | |
476 | * so we don't set nor calculate new physical/hw segment counts here | |
477 | */ | |
478 | bio->bi_sector = bio_src->bi_sector; | |
479 | bio->bi_bdev = bio_src->bi_bdev; | |
480 | bio->bi_flags |= 1 << BIO_CLONED; | |
481 | bio->bi_rw = bio_src->bi_rw; | |
482 | bio->bi_vcnt = bio_src->bi_vcnt; | |
483 | bio->bi_size = bio_src->bi_size; | |
484 | bio->bi_idx = bio_src->bi_idx; | |
485 | } | |
486 | EXPORT_SYMBOL(__bio_clone); | |
487 | ||
488 | /** | |
489 | * bio_clone - clone a bio | |
490 | * @bio: bio to clone | |
491 | * @gfp_mask: allocation priority | |
492 | * | |
493 | * Like __bio_clone, only also allocates the returned bio | |
494 | */ | |
495 | struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask) | |
496 | { | |
497 | struct bio *b = bio_alloc(gfp_mask, bio->bi_max_vecs); | |
498 | ||
499 | if (!b) | |
500 | return NULL; | |
501 | ||
502 | __bio_clone(b, bio); | |
503 | ||
504 | if (bio_integrity(bio)) { | |
505 | int ret; | |
506 | ||
507 | ret = bio_integrity_clone(b, bio, gfp_mask); | |
508 | ||
509 | if (ret < 0) { | |
510 | bio_put(b); | |
511 | return NULL; | |
512 | } | |
513 | } | |
514 | ||
515 | return b; | |
516 | } | |
517 | EXPORT_SYMBOL(bio_clone); | |
518 | ||
519 | /** | |
520 | * bio_get_nr_vecs - return approx number of vecs | |
521 | * @bdev: I/O target | |
522 | * | |
523 | * Return the approximate number of pages we can send to this target. | |
524 | * There's no guarantee that you will be able to fit this number of pages | |
525 | * into a bio, it does not account for dynamic restrictions that vary | |
526 | * on offset. | |
527 | */ | |
528 | int bio_get_nr_vecs(struct block_device *bdev) | |
529 | { | |
530 | struct request_queue *q = bdev_get_queue(bdev); | |
531 | int nr_pages; | |
532 | ||
533 | nr_pages = min_t(unsigned, | |
534 | queue_max_segments(q), | |
535 | queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1); | |
536 | ||
537 | return min_t(unsigned, nr_pages, BIO_MAX_PAGES); | |
538 | ||
539 | } | |
540 | EXPORT_SYMBOL(bio_get_nr_vecs); | |
541 | ||
542 | static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page | |
543 | *page, unsigned int len, unsigned int offset, | |
544 | unsigned short max_sectors) | |
545 | { | |
546 | int retried_segments = 0; | |
547 | struct bio_vec *bvec; | |
548 | ||
549 | /* | |
550 | * cloned bio must not modify vec list | |
551 | */ | |
552 | if (unlikely(bio_flagged(bio, BIO_CLONED))) | |
553 | return 0; | |
554 | ||
555 | if (((bio->bi_size + len) >> 9) > max_sectors) | |
556 | return 0; | |
557 | ||
558 | /* | |
559 | * For filesystems with a blocksize smaller than the pagesize | |
560 | * we will often be called with the same page as last time and | |
561 | * a consecutive offset. Optimize this special case. | |
562 | */ | |
563 | if (bio->bi_vcnt > 0) { | |
564 | struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1]; | |
565 | ||
566 | if (page == prev->bv_page && | |
567 | offset == prev->bv_offset + prev->bv_len) { | |
568 | unsigned int prev_bv_len = prev->bv_len; | |
569 | prev->bv_len += len; | |
570 | ||
571 | if (q->merge_bvec_fn) { | |
572 | struct bvec_merge_data bvm = { | |
573 | /* prev_bvec is already charged in | |
574 | bi_size, discharge it in order to | |
575 | simulate merging updated prev_bvec | |
576 | as new bvec. */ | |
577 | .bi_bdev = bio->bi_bdev, | |
578 | .bi_sector = bio->bi_sector, | |
579 | .bi_size = bio->bi_size - prev_bv_len, | |
580 | .bi_rw = bio->bi_rw, | |
581 | }; | |
582 | ||
583 | if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) { | |
584 | prev->bv_len -= len; | |
585 | return 0; | |
586 | } | |
587 | } | |
588 | ||
589 | goto done; | |
590 | } | |
591 | } | |
592 | ||
593 | if (bio->bi_vcnt >= bio->bi_max_vecs) | |
594 | return 0; | |
595 | ||
596 | /* | |
597 | * we might lose a segment or two here, but rather that than | |
598 | * make this too complex. | |
599 | */ | |
600 | ||
601 | while (bio->bi_phys_segments >= queue_max_segments(q)) { | |
602 | ||
603 | if (retried_segments) | |
604 | return 0; | |
605 | ||
606 | retried_segments = 1; | |
607 | blk_recount_segments(q, bio); | |
608 | } | |
609 | ||
610 | /* | |
611 | * setup the new entry, we might clear it again later if we | |
612 | * cannot add the page | |
613 | */ | |
614 | bvec = &bio->bi_io_vec[bio->bi_vcnt]; | |
615 | bvec->bv_page = page; | |
616 | bvec->bv_len = len; | |
617 | bvec->bv_offset = offset; | |
618 | ||
619 | /* | |
620 | * if queue has other restrictions (eg varying max sector size | |
621 | * depending on offset), it can specify a merge_bvec_fn in the | |
622 | * queue to get further control | |
623 | */ | |
624 | if (q->merge_bvec_fn) { | |
625 | struct bvec_merge_data bvm = { | |
626 | .bi_bdev = bio->bi_bdev, | |
627 | .bi_sector = bio->bi_sector, | |
628 | .bi_size = bio->bi_size, | |
629 | .bi_rw = bio->bi_rw, | |
630 | }; | |
631 | ||
632 | /* | |
633 | * merge_bvec_fn() returns number of bytes it can accept | |
634 | * at this offset | |
635 | */ | |
636 | if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) { | |
637 | bvec->bv_page = NULL; | |
638 | bvec->bv_len = 0; | |
639 | bvec->bv_offset = 0; | |
640 | return 0; | |
641 | } | |
642 | } | |
643 | ||
644 | /* If we may be able to merge these biovecs, force a recount */ | |
645 | if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec))) | |
646 | bio->bi_flags &= ~(1 << BIO_SEG_VALID); | |
647 | ||
648 | bio->bi_vcnt++; | |
649 | bio->bi_phys_segments++; | |
650 | done: | |
651 | bio->bi_size += len; | |
652 | return len; | |
653 | } | |
654 | ||
655 | /** | |
656 | * bio_add_pc_page - attempt to add page to bio | |
657 | * @q: the target queue | |
658 | * @bio: destination bio | |
659 | * @page: page to add | |
660 | * @len: vec entry length | |
661 | * @offset: vec entry offset | |
662 | * | |
663 | * Attempt to add a page to the bio_vec maplist. This can fail for a | |
664 | * number of reasons, such as the bio being full or target block device | |
665 | * limitations. The target block device must allow bio's up to PAGE_SIZE, | |
666 | * so it is always possible to add a single page to an empty bio. | |
667 | * | |
668 | * This should only be used by REQ_PC bios. | |
669 | */ | |
670 | int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page, | |
671 | unsigned int len, unsigned int offset) | |
672 | { | |
673 | return __bio_add_page(q, bio, page, len, offset, | |
674 | queue_max_hw_sectors(q)); | |
675 | } | |
676 | EXPORT_SYMBOL(bio_add_pc_page); | |
677 | ||
678 | /** | |
679 | * bio_add_page - attempt to add page to bio | |
680 | * @bio: destination bio | |
681 | * @page: page to add | |
682 | * @len: vec entry length | |
683 | * @offset: vec entry offset | |
684 | * | |
685 | * Attempt to add a page to the bio_vec maplist. This can fail for a | |
686 | * number of reasons, such as the bio being full or target block device | |
687 | * limitations. The target block device must allow bio's up to PAGE_SIZE, | |
688 | * so it is always possible to add a single page to an empty bio. | |
689 | */ | |
690 | int bio_add_page(struct bio *bio, struct page *page, unsigned int len, | |
691 | unsigned int offset) | |
692 | { | |
693 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); | |
694 | return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q)); | |
695 | } | |
696 | EXPORT_SYMBOL(bio_add_page); | |
697 | ||
698 | struct bio_map_data { | |
699 | struct bio_vec *iovecs; | |
700 | struct sg_iovec *sgvecs; | |
701 | int nr_sgvecs; | |
702 | int is_our_pages; | |
703 | }; | |
704 | ||
705 | static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio, | |
706 | struct sg_iovec *iov, int iov_count, | |
707 | int is_our_pages) | |
708 | { | |
709 | memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt); | |
710 | memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count); | |
711 | bmd->nr_sgvecs = iov_count; | |
712 | bmd->is_our_pages = is_our_pages; | |
713 | bio->bi_private = bmd; | |
714 | } | |
715 | ||
716 | static void bio_free_map_data(struct bio_map_data *bmd) | |
717 | { | |
718 | kfree(bmd->iovecs); | |
719 | kfree(bmd->sgvecs); | |
720 | kfree(bmd); | |
721 | } | |
722 | ||
723 | static struct bio_map_data *bio_alloc_map_data(int nr_segs, | |
724 | unsigned int iov_count, | |
725 | gfp_t gfp_mask) | |
726 | { | |
727 | struct bio_map_data *bmd; | |
728 | ||
729 | if (iov_count > UIO_MAXIOV) | |
730 | return NULL; | |
731 | ||
732 | bmd = kmalloc(sizeof(*bmd), gfp_mask); | |
733 | if (!bmd) | |
734 | return NULL; | |
735 | ||
736 | bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask); | |
737 | if (!bmd->iovecs) { | |
738 | kfree(bmd); | |
739 | return NULL; | |
740 | } | |
741 | ||
742 | bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask); | |
743 | if (bmd->sgvecs) | |
744 | return bmd; | |
745 | ||
746 | kfree(bmd->iovecs); | |
747 | kfree(bmd); | |
748 | return NULL; | |
749 | } | |
750 | ||
751 | static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs, | |
752 | struct sg_iovec *iov, int iov_count, | |
753 | int to_user, int from_user, int do_free_page) | |
754 | { | |
755 | int ret = 0, i; | |
756 | struct bio_vec *bvec; | |
757 | int iov_idx = 0; | |
758 | unsigned int iov_off = 0; | |
759 | ||
760 | __bio_for_each_segment(bvec, bio, i, 0) { | |
761 | char *bv_addr = page_address(bvec->bv_page); | |
762 | unsigned int bv_len = iovecs[i].bv_len; | |
763 | ||
764 | while (bv_len && iov_idx < iov_count) { | |
765 | unsigned int bytes; | |
766 | char __user *iov_addr; | |
767 | ||
768 | bytes = min_t(unsigned int, | |
769 | iov[iov_idx].iov_len - iov_off, bv_len); | |
770 | iov_addr = iov[iov_idx].iov_base + iov_off; | |
771 | ||
772 | if (!ret) { | |
773 | if (to_user) | |
774 | ret = copy_to_user(iov_addr, bv_addr, | |
775 | bytes); | |
776 | ||
777 | if (from_user) | |
778 | ret = copy_from_user(bv_addr, iov_addr, | |
779 | bytes); | |
780 | ||
781 | if (ret) | |
782 | ret = -EFAULT; | |
783 | } | |
784 | ||
785 | bv_len -= bytes; | |
786 | bv_addr += bytes; | |
787 | iov_addr += bytes; | |
788 | iov_off += bytes; | |
789 | ||
790 | if (iov[iov_idx].iov_len == iov_off) { | |
791 | iov_idx++; | |
792 | iov_off = 0; | |
793 | } | |
794 | } | |
795 | ||
796 | if (do_free_page) | |
797 | __free_page(bvec->bv_page); | |
798 | } | |
799 | ||
800 | return ret; | |
801 | } | |
802 | ||
803 | /** | |
804 | * bio_uncopy_user - finish previously mapped bio | |
805 | * @bio: bio being terminated | |
806 | * | |
807 | * Free pages allocated from bio_copy_user() and write back data | |
808 | * to user space in case of a read. | |
809 | */ | |
810 | int bio_uncopy_user(struct bio *bio) | |
811 | { | |
812 | struct bio_map_data *bmd = bio->bi_private; | |
813 | int ret = 0; | |
814 | ||
815 | if (!bio_flagged(bio, BIO_NULL_MAPPED)) | |
816 | ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs, | |
817 | bmd->nr_sgvecs, bio_data_dir(bio) == READ, | |
818 | 0, bmd->is_our_pages); | |
819 | bio_free_map_data(bmd); | |
820 | bio_put(bio); | |
821 | return ret; | |
822 | } | |
823 | EXPORT_SYMBOL(bio_uncopy_user); | |
824 | ||
825 | /** | |
826 | * bio_copy_user_iov - copy user data to bio | |
827 | * @q: destination block queue | |
828 | * @map_data: pointer to the rq_map_data holding pages (if necessary) | |
829 | * @iov: the iovec. | |
830 | * @iov_count: number of elements in the iovec | |
831 | * @write_to_vm: bool indicating writing to pages or not | |
832 | * @gfp_mask: memory allocation flags | |
833 | * | |
834 | * Prepares and returns a bio for indirect user io, bouncing data | |
835 | * to/from kernel pages as necessary. Must be paired with | |
836 | * call bio_uncopy_user() on io completion. | |
837 | */ | |
838 | struct bio *bio_copy_user_iov(struct request_queue *q, | |
839 | struct rq_map_data *map_data, | |
840 | struct sg_iovec *iov, int iov_count, | |
841 | int write_to_vm, gfp_t gfp_mask) | |
842 | { | |
843 | struct bio_map_data *bmd; | |
844 | struct bio_vec *bvec; | |
845 | struct page *page; | |
846 | struct bio *bio; | |
847 | int i, ret; | |
848 | int nr_pages = 0; | |
849 | unsigned int len = 0; | |
850 | unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0; | |
851 | ||
852 | for (i = 0; i < iov_count; i++) { | |
853 | unsigned long uaddr; | |
854 | unsigned long end; | |
855 | unsigned long start; | |
856 | ||
857 | uaddr = (unsigned long)iov[i].iov_base; | |
858 | end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
859 | start = uaddr >> PAGE_SHIFT; | |
860 | ||
861 | /* | |
862 | * Overflow, abort | |
863 | */ | |
864 | if (end < start) | |
865 | return ERR_PTR(-EINVAL); | |
866 | ||
867 | nr_pages += end - start; | |
868 | len += iov[i].iov_len; | |
869 | } | |
870 | ||
871 | if (offset) | |
872 | nr_pages++; | |
873 | ||
874 | bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask); | |
875 | if (!bmd) | |
876 | return ERR_PTR(-ENOMEM); | |
877 | ||
878 | ret = -ENOMEM; | |
879 | bio = bio_kmalloc(gfp_mask, nr_pages); | |
880 | if (!bio) | |
881 | goto out_bmd; | |
882 | ||
883 | if (!write_to_vm) | |
884 | bio->bi_rw |= REQ_WRITE; | |
885 | ||
886 | ret = 0; | |
887 | ||
888 | if (map_data) { | |
889 | nr_pages = 1 << map_data->page_order; | |
890 | i = map_data->offset / PAGE_SIZE; | |
891 | } | |
892 | while (len) { | |
893 | unsigned int bytes = PAGE_SIZE; | |
894 | ||
895 | bytes -= offset; | |
896 | ||
897 | if (bytes > len) | |
898 | bytes = len; | |
899 | ||
900 | if (map_data) { | |
901 | if (i == map_data->nr_entries * nr_pages) { | |
902 | ret = -ENOMEM; | |
903 | break; | |
904 | } | |
905 | ||
906 | page = map_data->pages[i / nr_pages]; | |
907 | page += (i % nr_pages); | |
908 | ||
909 | i++; | |
910 | } else { | |
911 | page = alloc_page(q->bounce_gfp | gfp_mask); | |
912 | if (!page) { | |
913 | ret = -ENOMEM; | |
914 | break; | |
915 | } | |
916 | } | |
917 | ||
918 | if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) | |
919 | break; | |
920 | ||
921 | len -= bytes; | |
922 | offset = 0; | |
923 | } | |
924 | ||
925 | if (ret) | |
926 | goto cleanup; | |
927 | ||
928 | /* | |
929 | * success | |
930 | */ | |
931 | if ((!write_to_vm && (!map_data || !map_data->null_mapped)) || | |
932 | (map_data && map_data->from_user)) { | |
933 | ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0); | |
934 | if (ret) | |
935 | goto cleanup; | |
936 | } | |
937 | ||
938 | bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1); | |
939 | return bio; | |
940 | cleanup: | |
941 | if (!map_data) | |
942 | bio_for_each_segment(bvec, bio, i) | |
943 | __free_page(bvec->bv_page); | |
944 | ||
945 | bio_put(bio); | |
946 | out_bmd: | |
947 | bio_free_map_data(bmd); | |
948 | return ERR_PTR(ret); | |
949 | } | |
950 | ||
951 | /** | |
952 | * bio_copy_user - copy user data to bio | |
953 | * @q: destination block queue | |
954 | * @map_data: pointer to the rq_map_data holding pages (if necessary) | |
955 | * @uaddr: start of user address | |
956 | * @len: length in bytes | |
957 | * @write_to_vm: bool indicating writing to pages or not | |
958 | * @gfp_mask: memory allocation flags | |
959 | * | |
960 | * Prepares and returns a bio for indirect user io, bouncing data | |
961 | * to/from kernel pages as necessary. Must be paired with | |
962 | * call bio_uncopy_user() on io completion. | |
963 | */ | |
964 | struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data, | |
965 | unsigned long uaddr, unsigned int len, | |
966 | int write_to_vm, gfp_t gfp_mask) | |
967 | { | |
968 | struct sg_iovec iov; | |
969 | ||
970 | iov.iov_base = (void __user *)uaddr; | |
971 | iov.iov_len = len; | |
972 | ||
973 | return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask); | |
974 | } | |
975 | EXPORT_SYMBOL(bio_copy_user); | |
976 | ||
977 | static struct bio *__bio_map_user_iov(struct request_queue *q, | |
978 | struct block_device *bdev, | |
979 | struct sg_iovec *iov, int iov_count, | |
980 | int write_to_vm, gfp_t gfp_mask) | |
981 | { | |
982 | int i, j; | |
983 | int nr_pages = 0; | |
984 | struct page **pages; | |
985 | struct bio *bio; | |
986 | int cur_page = 0; | |
987 | int ret, offset; | |
988 | ||
989 | for (i = 0; i < iov_count; i++) { | |
990 | unsigned long uaddr = (unsigned long)iov[i].iov_base; | |
991 | unsigned long len = iov[i].iov_len; | |
992 | unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
993 | unsigned long start = uaddr >> PAGE_SHIFT; | |
994 | ||
995 | /* | |
996 | * Overflow, abort | |
997 | */ | |
998 | if (end < start) | |
999 | return ERR_PTR(-EINVAL); | |
1000 | ||
1001 | nr_pages += end - start; | |
1002 | /* | |
1003 | * buffer must be aligned to at least hardsector size for now | |
1004 | */ | |
1005 | if (uaddr & queue_dma_alignment(q)) | |
1006 | return ERR_PTR(-EINVAL); | |
1007 | } | |
1008 | ||
1009 | if (!nr_pages) | |
1010 | return ERR_PTR(-EINVAL); | |
1011 | ||
1012 | bio = bio_kmalloc(gfp_mask, nr_pages); | |
1013 | if (!bio) | |
1014 | return ERR_PTR(-ENOMEM); | |
1015 | ||
1016 | ret = -ENOMEM; | |
1017 | pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask); | |
1018 | if (!pages) | |
1019 | goto out; | |
1020 | ||
1021 | for (i = 0; i < iov_count; i++) { | |
1022 | unsigned long uaddr = (unsigned long)iov[i].iov_base; | |
1023 | unsigned long len = iov[i].iov_len; | |
1024 | unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1025 | unsigned long start = uaddr >> PAGE_SHIFT; | |
1026 | const int local_nr_pages = end - start; | |
1027 | const int page_limit = cur_page + local_nr_pages; | |
1028 | ||
1029 | ret = get_user_pages_fast(uaddr, local_nr_pages, | |
1030 | write_to_vm, &pages[cur_page]); | |
1031 | if (ret < local_nr_pages) { | |
1032 | ret = -EFAULT; | |
1033 | goto out_unmap; | |
1034 | } | |
1035 | ||
1036 | offset = uaddr & ~PAGE_MASK; | |
1037 | for (j = cur_page; j < page_limit; j++) { | |
1038 | unsigned int bytes = PAGE_SIZE - offset; | |
1039 | ||
1040 | if (len <= 0) | |
1041 | break; | |
1042 | ||
1043 | if (bytes > len) | |
1044 | bytes = len; | |
1045 | ||
1046 | /* | |
1047 | * sorry... | |
1048 | */ | |
1049 | if (bio_add_pc_page(q, bio, pages[j], bytes, offset) < | |
1050 | bytes) | |
1051 | break; | |
1052 | ||
1053 | len -= bytes; | |
1054 | offset = 0; | |
1055 | } | |
1056 | ||
1057 | cur_page = j; | |
1058 | /* | |
1059 | * release the pages we didn't map into the bio, if any | |
1060 | */ | |
1061 | while (j < page_limit) | |
1062 | page_cache_release(pages[j++]); | |
1063 | } | |
1064 | ||
1065 | kfree(pages); | |
1066 | ||
1067 | /* | |
1068 | * set data direction, and check if mapped pages need bouncing | |
1069 | */ | |
1070 | if (!write_to_vm) | |
1071 | bio->bi_rw |= REQ_WRITE; | |
1072 | ||
1073 | bio->bi_bdev = bdev; | |
1074 | bio->bi_flags |= (1 << BIO_USER_MAPPED); | |
1075 | return bio; | |
1076 | ||
1077 | out_unmap: | |
1078 | for (i = 0; i < nr_pages; i++) { | |
1079 | if(!pages[i]) | |
1080 | break; | |
1081 | page_cache_release(pages[i]); | |
1082 | } | |
1083 | out: | |
1084 | kfree(pages); | |
1085 | bio_put(bio); | |
1086 | return ERR_PTR(ret); | |
1087 | } | |
1088 | ||
1089 | /** | |
1090 | * bio_map_user - map user address into bio | |
1091 | * @q: the struct request_queue for the bio | |
1092 | * @bdev: destination block device | |
1093 | * @uaddr: start of user address | |
1094 | * @len: length in bytes | |
1095 | * @write_to_vm: bool indicating writing to pages or not | |
1096 | * @gfp_mask: memory allocation flags | |
1097 | * | |
1098 | * Map the user space address into a bio suitable for io to a block | |
1099 | * device. Returns an error pointer in case of error. | |
1100 | */ | |
1101 | struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev, | |
1102 | unsigned long uaddr, unsigned int len, int write_to_vm, | |
1103 | gfp_t gfp_mask) | |
1104 | { | |
1105 | struct sg_iovec iov; | |
1106 | ||
1107 | iov.iov_base = (void __user *)uaddr; | |
1108 | iov.iov_len = len; | |
1109 | ||
1110 | return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask); | |
1111 | } | |
1112 | EXPORT_SYMBOL(bio_map_user); | |
1113 | ||
1114 | /** | |
1115 | * bio_map_user_iov - map user sg_iovec table into bio | |
1116 | * @q: the struct request_queue for the bio | |
1117 | * @bdev: destination block device | |
1118 | * @iov: the iovec. | |
1119 | * @iov_count: number of elements in the iovec | |
1120 | * @write_to_vm: bool indicating writing to pages or not | |
1121 | * @gfp_mask: memory allocation flags | |
1122 | * | |
1123 | * Map the user space address into a bio suitable for io to a block | |
1124 | * device. Returns an error pointer in case of error. | |
1125 | */ | |
1126 | struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev, | |
1127 | struct sg_iovec *iov, int iov_count, | |
1128 | int write_to_vm, gfp_t gfp_mask) | |
1129 | { | |
1130 | struct bio *bio; | |
1131 | ||
1132 | bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm, | |
1133 | gfp_mask); | |
1134 | if (IS_ERR(bio)) | |
1135 | return bio; | |
1136 | ||
1137 | /* | |
1138 | * subtle -- if __bio_map_user() ended up bouncing a bio, | |
1139 | * it would normally disappear when its bi_end_io is run. | |
1140 | * however, we need it for the unmap, so grab an extra | |
1141 | * reference to it | |
1142 | */ | |
1143 | bio_get(bio); | |
1144 | ||
1145 | return bio; | |
1146 | } | |
1147 | ||
1148 | static void __bio_unmap_user(struct bio *bio) | |
1149 | { | |
1150 | struct bio_vec *bvec; | |
1151 | int i; | |
1152 | ||
1153 | /* | |
1154 | * make sure we dirty pages we wrote to | |
1155 | */ | |
1156 | __bio_for_each_segment(bvec, bio, i, 0) { | |
1157 | if (bio_data_dir(bio) == READ) | |
1158 | set_page_dirty_lock(bvec->bv_page); | |
1159 | ||
1160 | page_cache_release(bvec->bv_page); | |
1161 | } | |
1162 | ||
1163 | bio_put(bio); | |
1164 | } | |
1165 | ||
1166 | /** | |
1167 | * bio_unmap_user - unmap a bio | |
1168 | * @bio: the bio being unmapped | |
1169 | * | |
1170 | * Unmap a bio previously mapped by bio_map_user(). Must be called with | |
1171 | * a process context. | |
1172 | * | |
1173 | * bio_unmap_user() may sleep. | |
1174 | */ | |
1175 | void bio_unmap_user(struct bio *bio) | |
1176 | { | |
1177 | __bio_unmap_user(bio); | |
1178 | bio_put(bio); | |
1179 | } | |
1180 | EXPORT_SYMBOL(bio_unmap_user); | |
1181 | ||
1182 | static void bio_map_kern_endio(struct bio *bio, int err) | |
1183 | { | |
1184 | bio_put(bio); | |
1185 | } | |
1186 | ||
1187 | static struct bio *__bio_map_kern(struct request_queue *q, void *data, | |
1188 | unsigned int len, gfp_t gfp_mask) | |
1189 | { | |
1190 | unsigned long kaddr = (unsigned long)data; | |
1191 | unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1192 | unsigned long start = kaddr >> PAGE_SHIFT; | |
1193 | const int nr_pages = end - start; | |
1194 | int offset, i; | |
1195 | struct bio *bio; | |
1196 | ||
1197 | bio = bio_kmalloc(gfp_mask, nr_pages); | |
1198 | if (!bio) | |
1199 | return ERR_PTR(-ENOMEM); | |
1200 | ||
1201 | offset = offset_in_page(kaddr); | |
1202 | for (i = 0; i < nr_pages; i++) { | |
1203 | unsigned int bytes = PAGE_SIZE - offset; | |
1204 | ||
1205 | if (len <= 0) | |
1206 | break; | |
1207 | ||
1208 | if (bytes > len) | |
1209 | bytes = len; | |
1210 | ||
1211 | if (bio_add_pc_page(q, bio, virt_to_page(data), bytes, | |
1212 | offset) < bytes) | |
1213 | break; | |
1214 | ||
1215 | data += bytes; | |
1216 | len -= bytes; | |
1217 | offset = 0; | |
1218 | } | |
1219 | ||
1220 | bio->bi_end_io = bio_map_kern_endio; | |
1221 | return bio; | |
1222 | } | |
1223 | ||
1224 | /** | |
1225 | * bio_map_kern - map kernel address into bio | |
1226 | * @q: the struct request_queue for the bio | |
1227 | * @data: pointer to buffer to map | |
1228 | * @len: length in bytes | |
1229 | * @gfp_mask: allocation flags for bio allocation | |
1230 | * | |
1231 | * Map the kernel address into a bio suitable for io to a block | |
1232 | * device. Returns an error pointer in case of error. | |
1233 | */ | |
1234 | struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, | |
1235 | gfp_t gfp_mask) | |
1236 | { | |
1237 | struct bio *bio; | |
1238 | ||
1239 | bio = __bio_map_kern(q, data, len, gfp_mask); | |
1240 | if (IS_ERR(bio)) | |
1241 | return bio; | |
1242 | ||
1243 | if (bio->bi_size == len) | |
1244 | return bio; | |
1245 | ||
1246 | /* | |
1247 | * Don't support partial mappings. | |
1248 | */ | |
1249 | bio_put(bio); | |
1250 | return ERR_PTR(-EINVAL); | |
1251 | } | |
1252 | EXPORT_SYMBOL(bio_map_kern); | |
1253 | ||
1254 | static void bio_copy_kern_endio(struct bio *bio, int err) | |
1255 | { | |
1256 | struct bio_vec *bvec; | |
1257 | const int read = bio_data_dir(bio) == READ; | |
1258 | struct bio_map_data *bmd = bio->bi_private; | |
1259 | int i; | |
1260 | char *p = bmd->sgvecs[0].iov_base; | |
1261 | ||
1262 | __bio_for_each_segment(bvec, bio, i, 0) { | |
1263 | char *addr = page_address(bvec->bv_page); | |
1264 | int len = bmd->iovecs[i].bv_len; | |
1265 | ||
1266 | if (read) | |
1267 | memcpy(p, addr, len); | |
1268 | ||
1269 | __free_page(bvec->bv_page); | |
1270 | p += len; | |
1271 | } | |
1272 | ||
1273 | bio_free_map_data(bmd); | |
1274 | bio_put(bio); | |
1275 | } | |
1276 | ||
1277 | /** | |
1278 | * bio_copy_kern - copy kernel address into bio | |
1279 | * @q: the struct request_queue for the bio | |
1280 | * @data: pointer to buffer to copy | |
1281 | * @len: length in bytes | |
1282 | * @gfp_mask: allocation flags for bio and page allocation | |
1283 | * @reading: data direction is READ | |
1284 | * | |
1285 | * copy the kernel address into a bio suitable for io to a block | |
1286 | * device. Returns an error pointer in case of error. | |
1287 | */ | |
1288 | struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, | |
1289 | gfp_t gfp_mask, int reading) | |
1290 | { | |
1291 | struct bio *bio; | |
1292 | struct bio_vec *bvec; | |
1293 | int i; | |
1294 | ||
1295 | bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask); | |
1296 | if (IS_ERR(bio)) | |
1297 | return bio; | |
1298 | ||
1299 | if (!reading) { | |
1300 | void *p = data; | |
1301 | ||
1302 | bio_for_each_segment(bvec, bio, i) { | |
1303 | char *addr = page_address(bvec->bv_page); | |
1304 | ||
1305 | memcpy(addr, p, bvec->bv_len); | |
1306 | p += bvec->bv_len; | |
1307 | } | |
1308 | } | |
1309 | ||
1310 | bio->bi_end_io = bio_copy_kern_endio; | |
1311 | ||
1312 | return bio; | |
1313 | } | |
1314 | EXPORT_SYMBOL(bio_copy_kern); | |
1315 | ||
1316 | /* | |
1317 | * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions | |
1318 | * for performing direct-IO in BIOs. | |
1319 | * | |
1320 | * The problem is that we cannot run set_page_dirty() from interrupt context | |
1321 | * because the required locks are not interrupt-safe. So what we can do is to | |
1322 | * mark the pages dirty _before_ performing IO. And in interrupt context, | |
1323 | * check that the pages are still dirty. If so, fine. If not, redirty them | |
1324 | * in process context. | |
1325 | * | |
1326 | * We special-case compound pages here: normally this means reads into hugetlb | |
1327 | * pages. The logic in here doesn't really work right for compound pages | |
1328 | * because the VM does not uniformly chase down the head page in all cases. | |
1329 | * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't | |
1330 | * handle them at all. So we skip compound pages here at an early stage. | |
1331 | * | |
1332 | * Note that this code is very hard to test under normal circumstances because | |
1333 | * direct-io pins the pages with get_user_pages(). This makes | |
1334 | * is_page_cache_freeable return false, and the VM will not clean the pages. | |
1335 | * But other code (eg, flusher threads) could clean the pages if they are mapped | |
1336 | * pagecache. | |
1337 | * | |
1338 | * Simply disabling the call to bio_set_pages_dirty() is a good way to test the | |
1339 | * deferred bio dirtying paths. | |
1340 | */ | |
1341 | ||
1342 | /* | |
1343 | * bio_set_pages_dirty() will mark all the bio's pages as dirty. | |
1344 | */ | |
1345 | void bio_set_pages_dirty(struct bio *bio) | |
1346 | { | |
1347 | struct bio_vec *bvec = bio->bi_io_vec; | |
1348 | int i; | |
1349 | ||
1350 | for (i = 0; i < bio->bi_vcnt; i++) { | |
1351 | struct page *page = bvec[i].bv_page; | |
1352 | ||
1353 | if (page && !PageCompound(page)) | |
1354 | set_page_dirty_lock(page); | |
1355 | } | |
1356 | } | |
1357 | ||
1358 | static void bio_release_pages(struct bio *bio) | |
1359 | { | |
1360 | struct bio_vec *bvec = bio->bi_io_vec; | |
1361 | int i; | |
1362 | ||
1363 | for (i = 0; i < bio->bi_vcnt; i++) { | |
1364 | struct page *page = bvec[i].bv_page; | |
1365 | ||
1366 | if (page) | |
1367 | put_page(page); | |
1368 | } | |
1369 | } | |
1370 | ||
1371 | /* | |
1372 | * bio_check_pages_dirty() will check that all the BIO's pages are still dirty. | |
1373 | * If they are, then fine. If, however, some pages are clean then they must | |
1374 | * have been written out during the direct-IO read. So we take another ref on | |
1375 | * the BIO and the offending pages and re-dirty the pages in process context. | |
1376 | * | |
1377 | * It is expected that bio_check_pages_dirty() will wholly own the BIO from | |
1378 | * here on. It will run one page_cache_release() against each page and will | |
1379 | * run one bio_put() against the BIO. | |
1380 | */ | |
1381 | ||
1382 | static void bio_dirty_fn(struct work_struct *work); | |
1383 | ||
1384 | static DECLARE_WORK(bio_dirty_work, bio_dirty_fn); | |
1385 | static DEFINE_SPINLOCK(bio_dirty_lock); | |
1386 | static struct bio *bio_dirty_list; | |
1387 | ||
1388 | /* | |
1389 | * This runs in process context | |
1390 | */ | |
1391 | static void bio_dirty_fn(struct work_struct *work) | |
1392 | { | |
1393 | unsigned long flags; | |
1394 | struct bio *bio; | |
1395 | ||
1396 | spin_lock_irqsave(&bio_dirty_lock, flags); | |
1397 | bio = bio_dirty_list; | |
1398 | bio_dirty_list = NULL; | |
1399 | spin_unlock_irqrestore(&bio_dirty_lock, flags); | |
1400 | ||
1401 | while (bio) { | |
1402 | struct bio *next = bio->bi_private; | |
1403 | ||
1404 | bio_set_pages_dirty(bio); | |
1405 | bio_release_pages(bio); | |
1406 | bio_put(bio); | |
1407 | bio = next; | |
1408 | } | |
1409 | } | |
1410 | ||
1411 | void bio_check_pages_dirty(struct bio *bio) | |
1412 | { | |
1413 | struct bio_vec *bvec = bio->bi_io_vec; | |
1414 | int nr_clean_pages = 0; | |
1415 | int i; | |
1416 | ||
1417 | for (i = 0; i < bio->bi_vcnt; i++) { | |
1418 | struct page *page = bvec[i].bv_page; | |
1419 | ||
1420 | if (PageDirty(page) || PageCompound(page)) { | |
1421 | page_cache_release(page); | |
1422 | bvec[i].bv_page = NULL; | |
1423 | } else { | |
1424 | nr_clean_pages++; | |
1425 | } | |
1426 | } | |
1427 | ||
1428 | if (nr_clean_pages) { | |
1429 | unsigned long flags; | |
1430 | ||
1431 | spin_lock_irqsave(&bio_dirty_lock, flags); | |
1432 | bio->bi_private = bio_dirty_list; | |
1433 | bio_dirty_list = bio; | |
1434 | spin_unlock_irqrestore(&bio_dirty_lock, flags); | |
1435 | schedule_work(&bio_dirty_work); | |
1436 | } else { | |
1437 | bio_put(bio); | |
1438 | } | |
1439 | } | |
1440 | ||
1441 | #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE | |
1442 | void bio_flush_dcache_pages(struct bio *bi) | |
1443 | { | |
1444 | int i; | |
1445 | struct bio_vec *bvec; | |
1446 | ||
1447 | bio_for_each_segment(bvec, bi, i) | |
1448 | flush_dcache_page(bvec->bv_page); | |
1449 | } | |
1450 | EXPORT_SYMBOL(bio_flush_dcache_pages); | |
1451 | #endif | |
1452 | ||
1453 | /** | |
1454 | * bio_endio - end I/O on a bio | |
1455 | * @bio: bio | |
1456 | * @error: error, if any | |
1457 | * | |
1458 | * Description: | |
1459 | * bio_endio() will end I/O on the whole bio. bio_endio() is the | |
1460 | * preferred way to end I/O on a bio, it takes care of clearing | |
1461 | * BIO_UPTODATE on error. @error is 0 on success, and and one of the | |
1462 | * established -Exxxx (-EIO, for instance) error values in case | |
1463 | * something went wrong. No one should call bi_end_io() directly on a | |
1464 | * bio unless they own it and thus know that it has an end_io | |
1465 | * function. | |
1466 | **/ | |
1467 | void bio_endio(struct bio *bio, int error) | |
1468 | { | |
1469 | if (error) | |
1470 | clear_bit(BIO_UPTODATE, &bio->bi_flags); | |
1471 | else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
1472 | error = -EIO; | |
1473 | ||
1474 | if (bio->bi_end_io) | |
1475 | bio->bi_end_io(bio, error); | |
1476 | } | |
1477 | EXPORT_SYMBOL(bio_endio); | |
1478 | ||
1479 | void bio_pair_release(struct bio_pair *bp) | |
1480 | { | |
1481 | if (atomic_dec_and_test(&bp->cnt)) { | |
1482 | struct bio *master = bp->bio1.bi_private; | |
1483 | ||
1484 | bio_endio(master, bp->error); | |
1485 | mempool_free(bp, bp->bio2.bi_private); | |
1486 | } | |
1487 | } | |
1488 | EXPORT_SYMBOL(bio_pair_release); | |
1489 | ||
1490 | static void bio_pair_end_1(struct bio *bi, int err) | |
1491 | { | |
1492 | struct bio_pair *bp = container_of(bi, struct bio_pair, bio1); | |
1493 | ||
1494 | if (err) | |
1495 | bp->error = err; | |
1496 | ||
1497 | bio_pair_release(bp); | |
1498 | } | |
1499 | ||
1500 | static void bio_pair_end_2(struct bio *bi, int err) | |
1501 | { | |
1502 | struct bio_pair *bp = container_of(bi, struct bio_pair, bio2); | |
1503 | ||
1504 | if (err) | |
1505 | bp->error = err; | |
1506 | ||
1507 | bio_pair_release(bp); | |
1508 | } | |
1509 | ||
1510 | /* | |
1511 | * split a bio - only worry about a bio with a single page in its iovec | |
1512 | */ | |
1513 | struct bio_pair *bio_split(struct bio *bi, int first_sectors) | |
1514 | { | |
1515 | struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO); | |
1516 | ||
1517 | if (!bp) | |
1518 | return bp; | |
1519 | ||
1520 | trace_block_split(bdev_get_queue(bi->bi_bdev), bi, | |
1521 | bi->bi_sector + first_sectors); | |
1522 | ||
1523 | BUG_ON(bi->bi_vcnt != 1); | |
1524 | BUG_ON(bi->bi_idx != 0); | |
1525 | atomic_set(&bp->cnt, 3); | |
1526 | bp->error = 0; | |
1527 | bp->bio1 = *bi; | |
1528 | bp->bio2 = *bi; | |
1529 | bp->bio2.bi_sector += first_sectors; | |
1530 | bp->bio2.bi_size -= first_sectors << 9; | |
1531 | bp->bio1.bi_size = first_sectors << 9; | |
1532 | ||
1533 | bp->bv1 = bi->bi_io_vec[0]; | |
1534 | bp->bv2 = bi->bi_io_vec[0]; | |
1535 | bp->bv2.bv_offset += first_sectors << 9; | |
1536 | bp->bv2.bv_len -= first_sectors << 9; | |
1537 | bp->bv1.bv_len = first_sectors << 9; | |
1538 | ||
1539 | bp->bio1.bi_io_vec = &bp->bv1; | |
1540 | bp->bio2.bi_io_vec = &bp->bv2; | |
1541 | ||
1542 | bp->bio1.bi_max_vecs = 1; | |
1543 | bp->bio2.bi_max_vecs = 1; | |
1544 | ||
1545 | bp->bio1.bi_end_io = bio_pair_end_1; | |
1546 | bp->bio2.bi_end_io = bio_pair_end_2; | |
1547 | ||
1548 | bp->bio1.bi_private = bi; | |
1549 | bp->bio2.bi_private = bio_split_pool; | |
1550 | ||
1551 | if (bio_integrity(bi)) | |
1552 | bio_integrity_split(bi, bp, first_sectors); | |
1553 | ||
1554 | return bp; | |
1555 | } | |
1556 | EXPORT_SYMBOL(bio_split); | |
1557 | ||
1558 | /** | |
1559 | * bio_sector_offset - Find hardware sector offset in bio | |
1560 | * @bio: bio to inspect | |
1561 | * @index: bio_vec index | |
1562 | * @offset: offset in bv_page | |
1563 | * | |
1564 | * Return the number of hardware sectors between beginning of bio | |
1565 | * and an end point indicated by a bio_vec index and an offset | |
1566 | * within that vector's page. | |
1567 | */ | |
1568 | sector_t bio_sector_offset(struct bio *bio, unsigned short index, | |
1569 | unsigned int offset) | |
1570 | { | |
1571 | unsigned int sector_sz; | |
1572 | struct bio_vec *bv; | |
1573 | sector_t sectors; | |
1574 | int i; | |
1575 | ||
1576 | sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue); | |
1577 | sectors = 0; | |
1578 | ||
1579 | if (index >= bio->bi_idx) | |
1580 | index = bio->bi_vcnt - 1; | |
1581 | ||
1582 | __bio_for_each_segment(bv, bio, i, 0) { | |
1583 | if (i == index) { | |
1584 | if (offset > bv->bv_offset) | |
1585 | sectors += (offset - bv->bv_offset) / sector_sz; | |
1586 | break; | |
1587 | } | |
1588 | ||
1589 | sectors += bv->bv_len / sector_sz; | |
1590 | } | |
1591 | ||
1592 | return sectors; | |
1593 | } | |
1594 | EXPORT_SYMBOL(bio_sector_offset); | |
1595 | ||
1596 | /* | |
1597 | * create memory pools for biovec's in a bio_set. | |
1598 | * use the global biovec slabs created for general use. | |
1599 | */ | |
1600 | static int biovec_create_pools(struct bio_set *bs, int pool_entries) | |
1601 | { | |
1602 | struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX; | |
1603 | ||
1604 | bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab); | |
1605 | if (!bs->bvec_pool) | |
1606 | return -ENOMEM; | |
1607 | ||
1608 | return 0; | |
1609 | } | |
1610 | ||
1611 | static void biovec_free_pools(struct bio_set *bs) | |
1612 | { | |
1613 | mempool_destroy(bs->bvec_pool); | |
1614 | } | |
1615 | ||
1616 | void bioset_free(struct bio_set *bs) | |
1617 | { | |
1618 | if (bs->bio_pool) | |
1619 | mempool_destroy(bs->bio_pool); | |
1620 | ||
1621 | bioset_integrity_free(bs); | |
1622 | biovec_free_pools(bs); | |
1623 | bio_put_slab(bs); | |
1624 | ||
1625 | kfree(bs); | |
1626 | } | |
1627 | EXPORT_SYMBOL(bioset_free); | |
1628 | ||
1629 | /** | |
1630 | * bioset_create - Create a bio_set | |
1631 | * @pool_size: Number of bio and bio_vecs to cache in the mempool | |
1632 | * @front_pad: Number of bytes to allocate in front of the returned bio | |
1633 | * | |
1634 | * Description: | |
1635 | * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller | |
1636 | * to ask for a number of bytes to be allocated in front of the bio. | |
1637 | * Front pad allocation is useful for embedding the bio inside | |
1638 | * another structure, to avoid allocating extra data to go with the bio. | |
1639 | * Note that the bio must be embedded at the END of that structure always, | |
1640 | * or things will break badly. | |
1641 | */ | |
1642 | struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) | |
1643 | { | |
1644 | unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); | |
1645 | struct bio_set *bs; | |
1646 | ||
1647 | bs = kzalloc(sizeof(*bs), GFP_KERNEL); | |
1648 | if (!bs) | |
1649 | return NULL; | |
1650 | ||
1651 | bs->front_pad = front_pad; | |
1652 | ||
1653 | bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad); | |
1654 | if (!bs->bio_slab) { | |
1655 | kfree(bs); | |
1656 | return NULL; | |
1657 | } | |
1658 | ||
1659 | bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab); | |
1660 | if (!bs->bio_pool) | |
1661 | goto bad; | |
1662 | ||
1663 | if (!biovec_create_pools(bs, pool_size)) | |
1664 | return bs; | |
1665 | ||
1666 | bad: | |
1667 | bioset_free(bs); | |
1668 | return NULL; | |
1669 | } | |
1670 | EXPORT_SYMBOL(bioset_create); | |
1671 | ||
1672 | #ifdef CONFIG_BLK_CGROUP | |
1673 | /** | |
1674 | * bio_associate_current - associate a bio with %current | |
1675 | * @bio: target bio | |
1676 | * | |
1677 | * Associate @bio with %current if it hasn't been associated yet. Block | |
1678 | * layer will treat @bio as if it were issued by %current no matter which | |
1679 | * task actually issues it. | |
1680 | * | |
1681 | * This function takes an extra reference of @task's io_context and blkcg | |
1682 | * which will be put when @bio is released. The caller must own @bio, | |
1683 | * ensure %current->io_context exists, and is responsible for synchronizing | |
1684 | * calls to this function. | |
1685 | */ | |
1686 | int bio_associate_current(struct bio *bio) | |
1687 | { | |
1688 | struct io_context *ioc; | |
1689 | struct cgroup_subsys_state *css; | |
1690 | ||
1691 | if (bio->bi_ioc) | |
1692 | return -EBUSY; | |
1693 | ||
1694 | ioc = current->io_context; | |
1695 | if (!ioc) | |
1696 | return -ENOENT; | |
1697 | ||
1698 | /* acquire active ref on @ioc and associate */ | |
1699 | get_io_context_active(ioc); | |
1700 | bio->bi_ioc = ioc; | |
1701 | ||
1702 | /* associate blkcg if exists */ | |
1703 | rcu_read_lock(); | |
1704 | css = task_subsys_state(current, blkio_subsys_id); | |
1705 | if (css && css_tryget(css)) | |
1706 | bio->bi_css = css; | |
1707 | rcu_read_unlock(); | |
1708 | ||
1709 | return 0; | |
1710 | } | |
1711 | ||
1712 | /** | |
1713 | * bio_disassociate_task - undo bio_associate_current() | |
1714 | * @bio: target bio | |
1715 | */ | |
1716 | void bio_disassociate_task(struct bio *bio) | |
1717 | { | |
1718 | if (bio->bi_ioc) { | |
1719 | put_io_context(bio->bi_ioc); | |
1720 | bio->bi_ioc = NULL; | |
1721 | } | |
1722 | if (bio->bi_css) { | |
1723 | css_put(bio->bi_css); | |
1724 | bio->bi_css = NULL; | |
1725 | } | |
1726 | } | |
1727 | ||
1728 | #endif /* CONFIG_BLK_CGROUP */ | |
1729 | ||
1730 | static void __init biovec_init_slabs(void) | |
1731 | { | |
1732 | int i; | |
1733 | ||
1734 | for (i = 0; i < BIOVEC_NR_POOLS; i++) { | |
1735 | int size; | |
1736 | struct biovec_slab *bvs = bvec_slabs + i; | |
1737 | ||
1738 | if (bvs->nr_vecs <= BIO_INLINE_VECS) { | |
1739 | bvs->slab = NULL; | |
1740 | continue; | |
1741 | } | |
1742 | ||
1743 | size = bvs->nr_vecs * sizeof(struct bio_vec); | |
1744 | bvs->slab = kmem_cache_create(bvs->name, size, 0, | |
1745 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); | |
1746 | } | |
1747 | } | |
1748 | ||
1749 | static int __init init_bio(void) | |
1750 | { | |
1751 | bio_slab_max = 2; | |
1752 | bio_slab_nr = 0; | |
1753 | bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL); | |
1754 | if (!bio_slabs) | |
1755 | panic("bio: can't allocate bios\n"); | |
1756 | ||
1757 | bio_integrity_init(); | |
1758 | biovec_init_slabs(); | |
1759 | ||
1760 | fs_bio_set = bioset_create(BIO_POOL_SIZE, 0); | |
1761 | if (!fs_bio_set) | |
1762 | panic("bio: can't allocate bios\n"); | |
1763 | ||
1764 | if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE)) | |
1765 | panic("bio: can't create integrity pool\n"); | |
1766 | ||
1767 | bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES, | |
1768 | sizeof(struct bio_pair)); | |
1769 | if (!bio_split_pool) | |
1770 | panic("bio: can't create split pool\n"); | |
1771 | ||
1772 | return 0; | |
1773 | } | |
1774 | subsys_initcall(init_bio); |