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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/uio.h> | |
23 | #include <linux/iocontext.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/kernel.h> | |
27 | #include <linux/export.h> | |
28 | #include <linux/mempool.h> | |
29 | #include <linux/workqueue.h> | |
30 | #include <linux/cgroup.h> | |
31 | #include <scsi/sg.h> /* for struct sg_iovec */ | |
32 | ||
33 | #include <trace/events/block.h> | |
34 | ||
35 | /* | |
36 | * Test patch to inline a certain number of bi_io_vec's inside the bio | |
37 | * itself, to shrink a bio data allocation from two mempool calls to one | |
38 | */ | |
39 | #define BIO_INLINE_VECS 4 | |
40 | ||
41 | /* | |
42 | * if you change this list, also change bvec_alloc or things will | |
43 | * break badly! cannot be bigger than what you can fit into an | |
44 | * unsigned short | |
45 | */ | |
46 | #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) } | |
47 | static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = { | |
48 | BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES), | |
49 | }; | |
50 | #undef BV | |
51 | ||
52 | /* | |
53 | * fs_bio_set is the bio_set containing bio and iovec memory pools used by | |
54 | * IO code that does not need private memory pools. | |
55 | */ | |
56 | struct bio_set *fs_bio_set; | |
57 | EXPORT_SYMBOL(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 new_bio_slab_max; | |
78 | unsigned int i, entry = -1; | |
79 | ||
80 | mutex_lock(&bio_slab_lock); | |
81 | ||
82 | i = 0; | |
83 | while (i < bio_slab_nr) { | |
84 | bslab = &bio_slabs[i]; | |
85 | ||
86 | if (!bslab->slab && entry == -1) | |
87 | entry = i; | |
88 | else if (bslab->slab_size == sz) { | |
89 | slab = bslab->slab; | |
90 | bslab->slab_ref++; | |
91 | break; | |
92 | } | |
93 | i++; | |
94 | } | |
95 | ||
96 | if (slab) | |
97 | goto out_unlock; | |
98 | ||
99 | if (bio_slab_nr == bio_slab_max && entry == -1) { | |
100 | new_bio_slab_max = bio_slab_max << 1; | |
101 | new_bio_slabs = krealloc(bio_slabs, | |
102 | new_bio_slab_max * sizeof(struct bio_slab), | |
103 | GFP_KERNEL); | |
104 | if (!new_bio_slabs) | |
105 | goto out_unlock; | |
106 | bio_slab_max = new_bio_slab_max; | |
107 | bio_slabs = new_bio_slabs; | |
108 | } | |
109 | if (entry == -1) | |
110 | entry = bio_slab_nr++; | |
111 | ||
112 | bslab = &bio_slabs[entry]; | |
113 | ||
114 | snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry); | |
115 | slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN, | |
116 | SLAB_HWCACHE_ALIGN, NULL); | |
117 | if (!slab) | |
118 | goto out_unlock; | |
119 | ||
120 | bslab->slab = slab; | |
121 | bslab->slab_ref = 1; | |
122 | bslab->slab_size = sz; | |
123 | out_unlock: | |
124 | mutex_unlock(&bio_slab_lock); | |
125 | return slab; | |
126 | } | |
127 | ||
128 | static void bio_put_slab(struct bio_set *bs) | |
129 | { | |
130 | struct bio_slab *bslab = NULL; | |
131 | unsigned int i; | |
132 | ||
133 | mutex_lock(&bio_slab_lock); | |
134 | ||
135 | for (i = 0; i < bio_slab_nr; i++) { | |
136 | if (bs->bio_slab == bio_slabs[i].slab) { | |
137 | bslab = &bio_slabs[i]; | |
138 | break; | |
139 | } | |
140 | } | |
141 | ||
142 | if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n")) | |
143 | goto out; | |
144 | ||
145 | WARN_ON(!bslab->slab_ref); | |
146 | ||
147 | if (--bslab->slab_ref) | |
148 | goto out; | |
149 | ||
150 | kmem_cache_destroy(bslab->slab); | |
151 | bslab->slab = NULL; | |
152 | ||
153 | out: | |
154 | mutex_unlock(&bio_slab_lock); | |
155 | } | |
156 | ||
157 | unsigned int bvec_nr_vecs(unsigned short idx) | |
158 | { | |
159 | return bvec_slabs[idx].nr_vecs; | |
160 | } | |
161 | ||
162 | void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx) | |
163 | { | |
164 | BIO_BUG_ON(idx >= BIOVEC_NR_POOLS); | |
165 | ||
166 | if (idx == BIOVEC_MAX_IDX) | |
167 | mempool_free(bv, pool); | |
168 | else { | |
169 | struct biovec_slab *bvs = bvec_slabs + idx; | |
170 | ||
171 | kmem_cache_free(bvs->slab, bv); | |
172 | } | |
173 | } | |
174 | ||
175 | struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx, | |
176 | mempool_t *pool) | |
177 | { | |
178 | struct bio_vec *bvl; | |
179 | ||
180 | /* | |
181 | * see comment near bvec_array define! | |
182 | */ | |
183 | switch (nr) { | |
184 | case 1: | |
185 | *idx = 0; | |
186 | break; | |
187 | case 2 ... 4: | |
188 | *idx = 1; | |
189 | break; | |
190 | case 5 ... 16: | |
191 | *idx = 2; | |
192 | break; | |
193 | case 17 ... 64: | |
194 | *idx = 3; | |
195 | break; | |
196 | case 65 ... 128: | |
197 | *idx = 4; | |
198 | break; | |
199 | case 129 ... BIO_MAX_PAGES: | |
200 | *idx = 5; | |
201 | break; | |
202 | default: | |
203 | return NULL; | |
204 | } | |
205 | ||
206 | /* | |
207 | * idx now points to the pool we want to allocate from. only the | |
208 | * 1-vec entry pool is mempool backed. | |
209 | */ | |
210 | if (*idx == BIOVEC_MAX_IDX) { | |
211 | fallback: | |
212 | bvl = mempool_alloc(pool, gfp_mask); | |
213 | } else { | |
214 | struct biovec_slab *bvs = bvec_slabs + *idx; | |
215 | gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO); | |
216 | ||
217 | /* | |
218 | * Make this allocation restricted and don't dump info on | |
219 | * allocation failures, since we'll fallback to the mempool | |
220 | * in case of failure. | |
221 | */ | |
222 | __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; | |
223 | ||
224 | /* | |
225 | * Try a slab allocation. If this fails and __GFP_WAIT | |
226 | * is set, retry with the 1-entry mempool | |
227 | */ | |
228 | bvl = kmem_cache_alloc(bvs->slab, __gfp_mask); | |
229 | if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) { | |
230 | *idx = BIOVEC_MAX_IDX; | |
231 | goto fallback; | |
232 | } | |
233 | } | |
234 | ||
235 | return bvl; | |
236 | } | |
237 | ||
238 | static void __bio_free(struct bio *bio) | |
239 | { | |
240 | bio_disassociate_task(bio); | |
241 | ||
242 | if (bio_integrity(bio)) | |
243 | bio_integrity_free(bio); | |
244 | } | |
245 | ||
246 | static void bio_free(struct bio *bio) | |
247 | { | |
248 | struct bio_set *bs = bio->bi_pool; | |
249 | void *p; | |
250 | ||
251 | __bio_free(bio); | |
252 | ||
253 | if (bs) { | |
254 | if (bio_flagged(bio, BIO_OWNS_VEC)) | |
255 | bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio)); | |
256 | ||
257 | /* | |
258 | * If we have front padding, adjust the bio pointer before freeing | |
259 | */ | |
260 | p = bio; | |
261 | p -= bs->front_pad; | |
262 | ||
263 | mempool_free(p, bs->bio_pool); | |
264 | } else { | |
265 | /* Bio was allocated by bio_kmalloc() */ | |
266 | kfree(bio); | |
267 | } | |
268 | } | |
269 | ||
270 | void bio_init(struct bio *bio) | |
271 | { | |
272 | memset(bio, 0, sizeof(*bio)); | |
273 | bio->bi_flags = 1 << BIO_UPTODATE; | |
274 | atomic_set(&bio->bi_remaining, 1); | |
275 | atomic_set(&bio->bi_cnt, 1); | |
276 | } | |
277 | EXPORT_SYMBOL(bio_init); | |
278 | ||
279 | /** | |
280 | * bio_reset - reinitialize a bio | |
281 | * @bio: bio to reset | |
282 | * | |
283 | * Description: | |
284 | * After calling bio_reset(), @bio will be in the same state as a freshly | |
285 | * allocated bio returned bio bio_alloc_bioset() - the only fields that are | |
286 | * preserved are the ones that are initialized by bio_alloc_bioset(). See | |
287 | * comment in struct bio. | |
288 | */ | |
289 | void bio_reset(struct bio *bio) | |
290 | { | |
291 | unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS); | |
292 | ||
293 | __bio_free(bio); | |
294 | ||
295 | memset(bio, 0, BIO_RESET_BYTES); | |
296 | bio->bi_flags = flags|(1 << BIO_UPTODATE); | |
297 | atomic_set(&bio->bi_remaining, 1); | |
298 | } | |
299 | EXPORT_SYMBOL(bio_reset); | |
300 | ||
301 | static void bio_chain_endio(struct bio *bio, int error) | |
302 | { | |
303 | bio_endio(bio->bi_private, error); | |
304 | bio_put(bio); | |
305 | } | |
306 | ||
307 | /** | |
308 | * bio_chain - chain bio completions | |
309 | * @bio: the target bio | |
310 | * @parent: the @bio's parent bio | |
311 | * | |
312 | * The caller won't have a bi_end_io called when @bio completes - instead, | |
313 | * @parent's bi_end_io won't be called until both @parent and @bio have | |
314 | * completed; the chained bio will also be freed when it completes. | |
315 | * | |
316 | * The caller must not set bi_private or bi_end_io in @bio. | |
317 | */ | |
318 | void bio_chain(struct bio *bio, struct bio *parent) | |
319 | { | |
320 | BUG_ON(bio->bi_private || bio->bi_end_io); | |
321 | ||
322 | bio->bi_private = parent; | |
323 | bio->bi_end_io = bio_chain_endio; | |
324 | atomic_inc(&parent->bi_remaining); | |
325 | } | |
326 | EXPORT_SYMBOL(bio_chain); | |
327 | ||
328 | static void bio_alloc_rescue(struct work_struct *work) | |
329 | { | |
330 | struct bio_set *bs = container_of(work, struct bio_set, rescue_work); | |
331 | struct bio *bio; | |
332 | ||
333 | while (1) { | |
334 | spin_lock(&bs->rescue_lock); | |
335 | bio = bio_list_pop(&bs->rescue_list); | |
336 | spin_unlock(&bs->rescue_lock); | |
337 | ||
338 | if (!bio) | |
339 | break; | |
340 | ||
341 | generic_make_request(bio); | |
342 | } | |
343 | } | |
344 | ||
345 | static void punt_bios_to_rescuer(struct bio_set *bs) | |
346 | { | |
347 | struct bio_list punt, nopunt; | |
348 | struct bio *bio; | |
349 | ||
350 | /* | |
351 | * In order to guarantee forward progress we must punt only bios that | |
352 | * were allocated from this bio_set; otherwise, if there was a bio on | |
353 | * there for a stacking driver higher up in the stack, processing it | |
354 | * could require allocating bios from this bio_set, and doing that from | |
355 | * our own rescuer would be bad. | |
356 | * | |
357 | * Since bio lists are singly linked, pop them all instead of trying to | |
358 | * remove from the middle of the list: | |
359 | */ | |
360 | ||
361 | bio_list_init(&punt); | |
362 | bio_list_init(&nopunt); | |
363 | ||
364 | while ((bio = bio_list_pop(current->bio_list))) | |
365 | bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); | |
366 | ||
367 | *current->bio_list = nopunt; | |
368 | ||
369 | spin_lock(&bs->rescue_lock); | |
370 | bio_list_merge(&bs->rescue_list, &punt); | |
371 | spin_unlock(&bs->rescue_lock); | |
372 | ||
373 | queue_work(bs->rescue_workqueue, &bs->rescue_work); | |
374 | } | |
375 | ||
376 | /** | |
377 | * bio_alloc_bioset - allocate a bio for I/O | |
378 | * @gfp_mask: the GFP_ mask given to the slab allocator | |
379 | * @nr_iovecs: number of iovecs to pre-allocate | |
380 | * @bs: the bio_set to allocate from. | |
381 | * | |
382 | * Description: | |
383 | * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is | |
384 | * backed by the @bs's mempool. | |
385 | * | |
386 | * When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be | |
387 | * able to allocate a bio. This is due to the mempool guarantees. To make this | |
388 | * work, callers must never allocate more than 1 bio at a time from this pool. | |
389 | * Callers that need to allocate more than 1 bio must always submit the | |
390 | * previously allocated bio for IO before attempting to allocate a new one. | |
391 | * Failure to do so can cause deadlocks under memory pressure. | |
392 | * | |
393 | * Note that when running under generic_make_request() (i.e. any block | |
394 | * driver), bios are not submitted until after you return - see the code in | |
395 | * generic_make_request() that converts recursion into iteration, to prevent | |
396 | * stack overflows. | |
397 | * | |
398 | * This would normally mean allocating multiple bios under | |
399 | * generic_make_request() would be susceptible to deadlocks, but we have | |
400 | * deadlock avoidance code that resubmits any blocked bios from a rescuer | |
401 | * thread. | |
402 | * | |
403 | * However, we do not guarantee forward progress for allocations from other | |
404 | * mempools. Doing multiple allocations from the same mempool under | |
405 | * generic_make_request() should be avoided - instead, use bio_set's front_pad | |
406 | * for per bio allocations. | |
407 | * | |
408 | * RETURNS: | |
409 | * Pointer to new bio on success, NULL on failure. | |
410 | */ | |
411 | struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) | |
412 | { | |
413 | gfp_t saved_gfp = gfp_mask; | |
414 | unsigned front_pad; | |
415 | unsigned inline_vecs; | |
416 | unsigned long idx = BIO_POOL_NONE; | |
417 | struct bio_vec *bvl = NULL; | |
418 | struct bio *bio; | |
419 | void *p; | |
420 | ||
421 | if (!bs) { | |
422 | if (nr_iovecs > UIO_MAXIOV) | |
423 | return NULL; | |
424 | ||
425 | p = kmalloc(sizeof(struct bio) + | |
426 | nr_iovecs * sizeof(struct bio_vec), | |
427 | gfp_mask); | |
428 | front_pad = 0; | |
429 | inline_vecs = nr_iovecs; | |
430 | } else { | |
431 | /* should not use nobvec bioset for nr_iovecs > 0 */ | |
432 | if (WARN_ON_ONCE(!bs->bvec_pool && nr_iovecs > 0)) | |
433 | return NULL; | |
434 | /* | |
435 | * generic_make_request() converts recursion to iteration; this | |
436 | * means if we're running beneath it, any bios we allocate and | |
437 | * submit will not be submitted (and thus freed) until after we | |
438 | * return. | |
439 | * | |
440 | * This exposes us to a potential deadlock if we allocate | |
441 | * multiple bios from the same bio_set() while running | |
442 | * underneath generic_make_request(). If we were to allocate | |
443 | * multiple bios (say a stacking block driver that was splitting | |
444 | * bios), we would deadlock if we exhausted the mempool's | |
445 | * reserve. | |
446 | * | |
447 | * We solve this, and guarantee forward progress, with a rescuer | |
448 | * workqueue per bio_set. If we go to allocate and there are | |
449 | * bios on current->bio_list, we first try the allocation | |
450 | * without __GFP_WAIT; if that fails, we punt those bios we | |
451 | * would be blocking to the rescuer workqueue before we retry | |
452 | * with the original gfp_flags. | |
453 | */ | |
454 | ||
455 | if (current->bio_list && !bio_list_empty(current->bio_list)) | |
456 | gfp_mask &= ~__GFP_WAIT; | |
457 | ||
458 | p = mempool_alloc(bs->bio_pool, gfp_mask); | |
459 | if (!p && gfp_mask != saved_gfp) { | |
460 | punt_bios_to_rescuer(bs); | |
461 | gfp_mask = saved_gfp; | |
462 | p = mempool_alloc(bs->bio_pool, gfp_mask); | |
463 | } | |
464 | ||
465 | front_pad = bs->front_pad; | |
466 | inline_vecs = BIO_INLINE_VECS; | |
467 | } | |
468 | ||
469 | if (unlikely(!p)) | |
470 | return NULL; | |
471 | ||
472 | bio = p + front_pad; | |
473 | bio_init(bio); | |
474 | ||
475 | if (nr_iovecs > inline_vecs) { | |
476 | bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool); | |
477 | if (!bvl && gfp_mask != saved_gfp) { | |
478 | punt_bios_to_rescuer(bs); | |
479 | gfp_mask = saved_gfp; | |
480 | bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool); | |
481 | } | |
482 | ||
483 | if (unlikely(!bvl)) | |
484 | goto err_free; | |
485 | ||
486 | bio->bi_flags |= 1 << BIO_OWNS_VEC; | |
487 | } else if (nr_iovecs) { | |
488 | bvl = bio->bi_inline_vecs; | |
489 | } | |
490 | ||
491 | bio->bi_pool = bs; | |
492 | bio->bi_flags |= idx << BIO_POOL_OFFSET; | |
493 | bio->bi_max_vecs = nr_iovecs; | |
494 | bio->bi_io_vec = bvl; | |
495 | return bio; | |
496 | ||
497 | err_free: | |
498 | mempool_free(p, bs->bio_pool); | |
499 | return NULL; | |
500 | } | |
501 | EXPORT_SYMBOL(bio_alloc_bioset); | |
502 | ||
503 | void zero_fill_bio(struct bio *bio) | |
504 | { | |
505 | unsigned long flags; | |
506 | struct bio_vec bv; | |
507 | struct bvec_iter iter; | |
508 | ||
509 | bio_for_each_segment(bv, bio, iter) { | |
510 | char *data = bvec_kmap_irq(&bv, &flags); | |
511 | memset(data, 0, bv.bv_len); | |
512 | flush_dcache_page(bv.bv_page); | |
513 | bvec_kunmap_irq(data, &flags); | |
514 | } | |
515 | } | |
516 | EXPORT_SYMBOL(zero_fill_bio); | |
517 | ||
518 | /** | |
519 | * bio_put - release a reference to a bio | |
520 | * @bio: bio to release reference to | |
521 | * | |
522 | * Description: | |
523 | * Put a reference to a &struct bio, either one you have gotten with | |
524 | * bio_alloc, bio_get or bio_clone. The last put of a bio will free it. | |
525 | **/ | |
526 | void bio_put(struct bio *bio) | |
527 | { | |
528 | BIO_BUG_ON(!atomic_read(&bio->bi_cnt)); | |
529 | ||
530 | /* | |
531 | * last put frees it | |
532 | */ | |
533 | if (atomic_dec_and_test(&bio->bi_cnt)) | |
534 | bio_free(bio); | |
535 | } | |
536 | EXPORT_SYMBOL(bio_put); | |
537 | ||
538 | inline int bio_phys_segments(struct request_queue *q, struct bio *bio) | |
539 | { | |
540 | if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
541 | blk_recount_segments(q, bio); | |
542 | ||
543 | return bio->bi_phys_segments; | |
544 | } | |
545 | EXPORT_SYMBOL(bio_phys_segments); | |
546 | ||
547 | /** | |
548 | * __bio_clone_fast - clone a bio that shares the original bio's biovec | |
549 | * @bio: destination bio | |
550 | * @bio_src: bio to clone | |
551 | * | |
552 | * Clone a &bio. Caller will own the returned bio, but not | |
553 | * the actual data it points to. Reference count of returned | |
554 | * bio will be one. | |
555 | * | |
556 | * Caller must ensure that @bio_src is not freed before @bio. | |
557 | */ | |
558 | void __bio_clone_fast(struct bio *bio, struct bio *bio_src) | |
559 | { | |
560 | BUG_ON(bio->bi_pool && BIO_POOL_IDX(bio) != BIO_POOL_NONE); | |
561 | ||
562 | /* | |
563 | * most users will be overriding ->bi_bdev with a new target, | |
564 | * so we don't set nor calculate new physical/hw segment counts here | |
565 | */ | |
566 | bio->bi_bdev = bio_src->bi_bdev; | |
567 | bio->bi_flags |= 1 << BIO_CLONED; | |
568 | bio->bi_rw = bio_src->bi_rw; | |
569 | bio->bi_iter = bio_src->bi_iter; | |
570 | bio->bi_io_vec = bio_src->bi_io_vec; | |
571 | } | |
572 | EXPORT_SYMBOL(__bio_clone_fast); | |
573 | ||
574 | /** | |
575 | * bio_clone_fast - clone a bio that shares the original bio's biovec | |
576 | * @bio: bio to clone | |
577 | * @gfp_mask: allocation priority | |
578 | * @bs: bio_set to allocate from | |
579 | * | |
580 | * Like __bio_clone_fast, only also allocates the returned bio | |
581 | */ | |
582 | struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs) | |
583 | { | |
584 | struct bio *b; | |
585 | ||
586 | b = bio_alloc_bioset(gfp_mask, 0, bs); | |
587 | if (!b) | |
588 | return NULL; | |
589 | ||
590 | __bio_clone_fast(b, bio); | |
591 | ||
592 | if (bio_integrity(bio)) { | |
593 | int ret; | |
594 | ||
595 | ret = bio_integrity_clone(b, bio, gfp_mask); | |
596 | ||
597 | if (ret < 0) { | |
598 | bio_put(b); | |
599 | return NULL; | |
600 | } | |
601 | } | |
602 | ||
603 | return b; | |
604 | } | |
605 | EXPORT_SYMBOL(bio_clone_fast); | |
606 | ||
607 | /** | |
608 | * bio_clone_bioset - clone a bio | |
609 | * @bio_src: bio to clone | |
610 | * @gfp_mask: allocation priority | |
611 | * @bs: bio_set to allocate from | |
612 | * | |
613 | * Clone bio. Caller will own the returned bio, but not the actual data it | |
614 | * points to. Reference count of returned bio will be one. | |
615 | */ | |
616 | struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, | |
617 | struct bio_set *bs) | |
618 | { | |
619 | struct bvec_iter iter; | |
620 | struct bio_vec bv; | |
621 | struct bio *bio; | |
622 | ||
623 | /* | |
624 | * Pre immutable biovecs, __bio_clone() used to just do a memcpy from | |
625 | * bio_src->bi_io_vec to bio->bi_io_vec. | |
626 | * | |
627 | * We can't do that anymore, because: | |
628 | * | |
629 | * - The point of cloning the biovec is to produce a bio with a biovec | |
630 | * the caller can modify: bi_idx and bi_bvec_done should be 0. | |
631 | * | |
632 | * - The original bio could've had more than BIO_MAX_PAGES biovecs; if | |
633 | * we tried to clone the whole thing bio_alloc_bioset() would fail. | |
634 | * But the clone should succeed as long as the number of biovecs we | |
635 | * actually need to allocate is fewer than BIO_MAX_PAGES. | |
636 | * | |
637 | * - Lastly, bi_vcnt should not be looked at or relied upon by code | |
638 | * that does not own the bio - reason being drivers don't use it for | |
639 | * iterating over the biovec anymore, so expecting it to be kept up | |
640 | * to date (i.e. for clones that share the parent biovec) is just | |
641 | * asking for trouble and would force extra work on | |
642 | * __bio_clone_fast() anyways. | |
643 | */ | |
644 | ||
645 | bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs); | |
646 | if (!bio) | |
647 | return NULL; | |
648 | ||
649 | bio->bi_bdev = bio_src->bi_bdev; | |
650 | bio->bi_rw = bio_src->bi_rw; | |
651 | bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector; | |
652 | bio->bi_iter.bi_size = bio_src->bi_iter.bi_size; | |
653 | ||
654 | if (bio->bi_rw & REQ_DISCARD) | |
655 | goto integrity_clone; | |
656 | ||
657 | if (bio->bi_rw & REQ_WRITE_SAME) { | |
658 | bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0]; | |
659 | goto integrity_clone; | |
660 | } | |
661 | ||
662 | bio_for_each_segment(bv, bio_src, iter) | |
663 | bio->bi_io_vec[bio->bi_vcnt++] = bv; | |
664 | ||
665 | integrity_clone: | |
666 | if (bio_integrity(bio_src)) { | |
667 | int ret; | |
668 | ||
669 | ret = bio_integrity_clone(bio, bio_src, gfp_mask); | |
670 | if (ret < 0) { | |
671 | bio_put(bio); | |
672 | return NULL; | |
673 | } | |
674 | } | |
675 | ||
676 | return bio; | |
677 | } | |
678 | EXPORT_SYMBOL(bio_clone_bioset); | |
679 | ||
680 | /** | |
681 | * bio_get_nr_vecs - return approx number of vecs | |
682 | * @bdev: I/O target | |
683 | * | |
684 | * Return the approximate number of pages we can send to this target. | |
685 | * There's no guarantee that you will be able to fit this number of pages | |
686 | * into a bio, it does not account for dynamic restrictions that vary | |
687 | * on offset. | |
688 | */ | |
689 | int bio_get_nr_vecs(struct block_device *bdev) | |
690 | { | |
691 | struct request_queue *q = bdev_get_queue(bdev); | |
692 | int nr_pages; | |
693 | ||
694 | nr_pages = min_t(unsigned, | |
695 | queue_max_segments(q), | |
696 | queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1); | |
697 | ||
698 | return min_t(unsigned, nr_pages, BIO_MAX_PAGES); | |
699 | ||
700 | } | |
701 | EXPORT_SYMBOL(bio_get_nr_vecs); | |
702 | ||
703 | static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page | |
704 | *page, unsigned int len, unsigned int offset, | |
705 | unsigned int max_sectors) | |
706 | { | |
707 | int retried_segments = 0; | |
708 | struct bio_vec *bvec; | |
709 | ||
710 | /* | |
711 | * cloned bio must not modify vec list | |
712 | */ | |
713 | if (unlikely(bio_flagged(bio, BIO_CLONED))) | |
714 | return 0; | |
715 | ||
716 | if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors) | |
717 | return 0; | |
718 | ||
719 | /* | |
720 | * For filesystems with a blocksize smaller than the pagesize | |
721 | * we will often be called with the same page as last time and | |
722 | * a consecutive offset. Optimize this special case. | |
723 | */ | |
724 | if (bio->bi_vcnt > 0) { | |
725 | struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1]; | |
726 | ||
727 | if (page == prev->bv_page && | |
728 | offset == prev->bv_offset + prev->bv_len) { | |
729 | unsigned int prev_bv_len = prev->bv_len; | |
730 | prev->bv_len += len; | |
731 | ||
732 | if (q->merge_bvec_fn) { | |
733 | struct bvec_merge_data bvm = { | |
734 | /* prev_bvec is already charged in | |
735 | bi_size, discharge it in order to | |
736 | simulate merging updated prev_bvec | |
737 | as new bvec. */ | |
738 | .bi_bdev = bio->bi_bdev, | |
739 | .bi_sector = bio->bi_iter.bi_sector, | |
740 | .bi_size = bio->bi_iter.bi_size - | |
741 | prev_bv_len, | |
742 | .bi_rw = bio->bi_rw, | |
743 | }; | |
744 | ||
745 | if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) { | |
746 | prev->bv_len -= len; | |
747 | return 0; | |
748 | } | |
749 | } | |
750 | ||
751 | goto done; | |
752 | } | |
753 | ||
754 | /* | |
755 | * If the queue doesn't support SG gaps and adding this | |
756 | * offset would create a gap, disallow it. | |
757 | */ | |
758 | if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) && | |
759 | bvec_gap_to_prev(prev, offset)) | |
760 | return 0; | |
761 | } | |
762 | ||
763 | if (bio->bi_vcnt >= bio->bi_max_vecs) | |
764 | return 0; | |
765 | ||
766 | /* | |
767 | * we might lose a segment or two here, but rather that than | |
768 | * make this too complex. | |
769 | */ | |
770 | ||
771 | while (bio->bi_phys_segments >= queue_max_segments(q)) { | |
772 | ||
773 | if (retried_segments) | |
774 | return 0; | |
775 | ||
776 | retried_segments = 1; | |
777 | blk_recount_segments(q, bio); | |
778 | } | |
779 | ||
780 | /* | |
781 | * setup the new entry, we might clear it again later if we | |
782 | * cannot add the page | |
783 | */ | |
784 | bvec = &bio->bi_io_vec[bio->bi_vcnt]; | |
785 | bvec->bv_page = page; | |
786 | bvec->bv_len = len; | |
787 | bvec->bv_offset = offset; | |
788 | ||
789 | /* | |
790 | * if queue has other restrictions (eg varying max sector size | |
791 | * depending on offset), it can specify a merge_bvec_fn in the | |
792 | * queue to get further control | |
793 | */ | |
794 | if (q->merge_bvec_fn) { | |
795 | struct bvec_merge_data bvm = { | |
796 | .bi_bdev = bio->bi_bdev, | |
797 | .bi_sector = bio->bi_iter.bi_sector, | |
798 | .bi_size = bio->bi_iter.bi_size, | |
799 | .bi_rw = bio->bi_rw, | |
800 | }; | |
801 | ||
802 | /* | |
803 | * merge_bvec_fn() returns number of bytes it can accept | |
804 | * at this offset | |
805 | */ | |
806 | if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) { | |
807 | bvec->bv_page = NULL; | |
808 | bvec->bv_len = 0; | |
809 | bvec->bv_offset = 0; | |
810 | return 0; | |
811 | } | |
812 | } | |
813 | ||
814 | /* If we may be able to merge these biovecs, force a recount */ | |
815 | if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec))) | |
816 | bio->bi_flags &= ~(1 << BIO_SEG_VALID); | |
817 | ||
818 | bio->bi_vcnt++; | |
819 | bio->bi_phys_segments++; | |
820 | done: | |
821 | bio->bi_iter.bi_size += len; | |
822 | return len; | |
823 | } | |
824 | ||
825 | /** | |
826 | * bio_add_pc_page - attempt to add page to bio | |
827 | * @q: the target queue | |
828 | * @bio: destination bio | |
829 | * @page: page to add | |
830 | * @len: vec entry length | |
831 | * @offset: vec entry offset | |
832 | * | |
833 | * Attempt to add a page to the bio_vec maplist. This can fail for a | |
834 | * number of reasons, such as the bio being full or target block device | |
835 | * limitations. The target block device must allow bio's up to PAGE_SIZE, | |
836 | * so it is always possible to add a single page to an empty bio. | |
837 | * | |
838 | * This should only be used by REQ_PC bios. | |
839 | */ | |
840 | int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page, | |
841 | unsigned int len, unsigned int offset) | |
842 | { | |
843 | return __bio_add_page(q, bio, page, len, offset, | |
844 | queue_max_hw_sectors(q)); | |
845 | } | |
846 | EXPORT_SYMBOL(bio_add_pc_page); | |
847 | ||
848 | /** | |
849 | * bio_add_page - attempt to add page to bio | |
850 | * @bio: destination bio | |
851 | * @page: page to add | |
852 | * @len: vec entry length | |
853 | * @offset: vec entry offset | |
854 | * | |
855 | * Attempt to add a page to the bio_vec maplist. This can fail for a | |
856 | * number of reasons, such as the bio being full or target block device | |
857 | * limitations. The target block device must allow bio's up to PAGE_SIZE, | |
858 | * so it is always possible to add a single page to an empty bio. | |
859 | */ | |
860 | int bio_add_page(struct bio *bio, struct page *page, unsigned int len, | |
861 | unsigned int offset) | |
862 | { | |
863 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); | |
864 | unsigned int max_sectors; | |
865 | ||
866 | max_sectors = blk_max_size_offset(q, bio->bi_iter.bi_sector); | |
867 | if ((max_sectors < (len >> 9)) && !bio->bi_iter.bi_size) | |
868 | max_sectors = len >> 9; | |
869 | ||
870 | return __bio_add_page(q, bio, page, len, offset, max_sectors); | |
871 | } | |
872 | EXPORT_SYMBOL(bio_add_page); | |
873 | ||
874 | struct submit_bio_ret { | |
875 | struct completion event; | |
876 | int error; | |
877 | }; | |
878 | ||
879 | static void submit_bio_wait_endio(struct bio *bio, int error) | |
880 | { | |
881 | struct submit_bio_ret *ret = bio->bi_private; | |
882 | ||
883 | ret->error = error; | |
884 | complete(&ret->event); | |
885 | } | |
886 | ||
887 | /** | |
888 | * submit_bio_wait - submit a bio, and wait until it completes | |
889 | * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) | |
890 | * @bio: The &struct bio which describes the I/O | |
891 | * | |
892 | * Simple wrapper around submit_bio(). Returns 0 on success, or the error from | |
893 | * bio_endio() on failure. | |
894 | */ | |
895 | int submit_bio_wait(int rw, struct bio *bio) | |
896 | { | |
897 | struct submit_bio_ret ret; | |
898 | ||
899 | rw |= REQ_SYNC; | |
900 | init_completion(&ret.event); | |
901 | bio->bi_private = &ret; | |
902 | bio->bi_end_io = submit_bio_wait_endio; | |
903 | submit_bio(rw, bio); | |
904 | wait_for_completion(&ret.event); | |
905 | ||
906 | return ret.error; | |
907 | } | |
908 | EXPORT_SYMBOL(submit_bio_wait); | |
909 | ||
910 | /** | |
911 | * bio_advance - increment/complete a bio by some number of bytes | |
912 | * @bio: bio to advance | |
913 | * @bytes: number of bytes to complete | |
914 | * | |
915 | * This updates bi_sector, bi_size and bi_idx; if the number of bytes to | |
916 | * complete doesn't align with a bvec boundary, then bv_len and bv_offset will | |
917 | * be updated on the last bvec as well. | |
918 | * | |
919 | * @bio will then represent the remaining, uncompleted portion of the io. | |
920 | */ | |
921 | void bio_advance(struct bio *bio, unsigned bytes) | |
922 | { | |
923 | if (bio_integrity(bio)) | |
924 | bio_integrity_advance(bio, bytes); | |
925 | ||
926 | bio_advance_iter(bio, &bio->bi_iter, bytes); | |
927 | } | |
928 | EXPORT_SYMBOL(bio_advance); | |
929 | ||
930 | /** | |
931 | * bio_alloc_pages - allocates a single page for each bvec in a bio | |
932 | * @bio: bio to allocate pages for | |
933 | * @gfp_mask: flags for allocation | |
934 | * | |
935 | * Allocates pages up to @bio->bi_vcnt. | |
936 | * | |
937 | * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are | |
938 | * freed. | |
939 | */ | |
940 | int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask) | |
941 | { | |
942 | int i; | |
943 | struct bio_vec *bv; | |
944 | ||
945 | bio_for_each_segment_all(bv, bio, i) { | |
946 | bv->bv_page = alloc_page(gfp_mask); | |
947 | if (!bv->bv_page) { | |
948 | while (--bv >= bio->bi_io_vec) | |
949 | __free_page(bv->bv_page); | |
950 | return -ENOMEM; | |
951 | } | |
952 | } | |
953 | ||
954 | return 0; | |
955 | } | |
956 | EXPORT_SYMBOL(bio_alloc_pages); | |
957 | ||
958 | /** | |
959 | * bio_copy_data - copy contents of data buffers from one chain of bios to | |
960 | * another | |
961 | * @src: source bio list | |
962 | * @dst: destination bio list | |
963 | * | |
964 | * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats | |
965 | * @src and @dst as linked lists of bios. | |
966 | * | |
967 | * Stops when it reaches the end of either @src or @dst - that is, copies | |
968 | * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). | |
969 | */ | |
970 | void bio_copy_data(struct bio *dst, struct bio *src) | |
971 | { | |
972 | struct bvec_iter src_iter, dst_iter; | |
973 | struct bio_vec src_bv, dst_bv; | |
974 | void *src_p, *dst_p; | |
975 | unsigned bytes; | |
976 | ||
977 | src_iter = src->bi_iter; | |
978 | dst_iter = dst->bi_iter; | |
979 | ||
980 | while (1) { | |
981 | if (!src_iter.bi_size) { | |
982 | src = src->bi_next; | |
983 | if (!src) | |
984 | break; | |
985 | ||
986 | src_iter = src->bi_iter; | |
987 | } | |
988 | ||
989 | if (!dst_iter.bi_size) { | |
990 | dst = dst->bi_next; | |
991 | if (!dst) | |
992 | break; | |
993 | ||
994 | dst_iter = dst->bi_iter; | |
995 | } | |
996 | ||
997 | src_bv = bio_iter_iovec(src, src_iter); | |
998 | dst_bv = bio_iter_iovec(dst, dst_iter); | |
999 | ||
1000 | bytes = min(src_bv.bv_len, dst_bv.bv_len); | |
1001 | ||
1002 | src_p = kmap_atomic(src_bv.bv_page); | |
1003 | dst_p = kmap_atomic(dst_bv.bv_page); | |
1004 | ||
1005 | memcpy(dst_p + dst_bv.bv_offset, | |
1006 | src_p + src_bv.bv_offset, | |
1007 | bytes); | |
1008 | ||
1009 | kunmap_atomic(dst_p); | |
1010 | kunmap_atomic(src_p); | |
1011 | ||
1012 | bio_advance_iter(src, &src_iter, bytes); | |
1013 | bio_advance_iter(dst, &dst_iter, bytes); | |
1014 | } | |
1015 | } | |
1016 | EXPORT_SYMBOL(bio_copy_data); | |
1017 | ||
1018 | struct bio_map_data { | |
1019 | int nr_sgvecs; | |
1020 | int is_our_pages; | |
1021 | struct sg_iovec sgvecs[]; | |
1022 | }; | |
1023 | ||
1024 | static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio, | |
1025 | const struct sg_iovec *iov, int iov_count, | |
1026 | int is_our_pages) | |
1027 | { | |
1028 | memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count); | |
1029 | bmd->nr_sgvecs = iov_count; | |
1030 | bmd->is_our_pages = is_our_pages; | |
1031 | bio->bi_private = bmd; | |
1032 | } | |
1033 | ||
1034 | static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count, | |
1035 | gfp_t gfp_mask) | |
1036 | { | |
1037 | if (iov_count > UIO_MAXIOV) | |
1038 | return NULL; | |
1039 | ||
1040 | return kmalloc(sizeof(struct bio_map_data) + | |
1041 | sizeof(struct sg_iovec) * iov_count, gfp_mask); | |
1042 | } | |
1043 | ||
1044 | static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_count, | |
1045 | int to_user, int from_user, int do_free_page) | |
1046 | { | |
1047 | int ret = 0, i; | |
1048 | struct bio_vec *bvec; | |
1049 | int iov_idx = 0; | |
1050 | unsigned int iov_off = 0; | |
1051 | ||
1052 | bio_for_each_segment_all(bvec, bio, i) { | |
1053 | char *bv_addr = page_address(bvec->bv_page); | |
1054 | unsigned int bv_len = bvec->bv_len; | |
1055 | ||
1056 | while (bv_len && iov_idx < iov_count) { | |
1057 | unsigned int bytes; | |
1058 | char __user *iov_addr; | |
1059 | ||
1060 | bytes = min_t(unsigned int, | |
1061 | iov[iov_idx].iov_len - iov_off, bv_len); | |
1062 | iov_addr = iov[iov_idx].iov_base + iov_off; | |
1063 | ||
1064 | if (!ret) { | |
1065 | if (to_user) | |
1066 | ret = copy_to_user(iov_addr, bv_addr, | |
1067 | bytes); | |
1068 | ||
1069 | if (from_user) | |
1070 | ret = copy_from_user(bv_addr, iov_addr, | |
1071 | bytes); | |
1072 | ||
1073 | if (ret) | |
1074 | ret = -EFAULT; | |
1075 | } | |
1076 | ||
1077 | bv_len -= bytes; | |
1078 | bv_addr += bytes; | |
1079 | iov_addr += bytes; | |
1080 | iov_off += bytes; | |
1081 | ||
1082 | if (iov[iov_idx].iov_len == iov_off) { | |
1083 | iov_idx++; | |
1084 | iov_off = 0; | |
1085 | } | |
1086 | } | |
1087 | ||
1088 | if (do_free_page) | |
1089 | __free_page(bvec->bv_page); | |
1090 | } | |
1091 | ||
1092 | return ret; | |
1093 | } | |
1094 | ||
1095 | /** | |
1096 | * bio_uncopy_user - finish previously mapped bio | |
1097 | * @bio: bio being terminated | |
1098 | * | |
1099 | * Free pages allocated from bio_copy_user() and write back data | |
1100 | * to user space in case of a read. | |
1101 | */ | |
1102 | int bio_uncopy_user(struct bio *bio) | |
1103 | { | |
1104 | struct bio_map_data *bmd = bio->bi_private; | |
1105 | struct bio_vec *bvec; | |
1106 | int ret = 0, i; | |
1107 | ||
1108 | if (!bio_flagged(bio, BIO_NULL_MAPPED)) { | |
1109 | /* | |
1110 | * if we're in a workqueue, the request is orphaned, so | |
1111 | * don't copy into a random user address space, just free. | |
1112 | */ | |
1113 | if (current->mm) | |
1114 | ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs, | |
1115 | bio_data_dir(bio) == READ, | |
1116 | 0, bmd->is_our_pages); | |
1117 | else if (bmd->is_our_pages) | |
1118 | bio_for_each_segment_all(bvec, bio, i) | |
1119 | __free_page(bvec->bv_page); | |
1120 | } | |
1121 | kfree(bmd); | |
1122 | bio_put(bio); | |
1123 | return ret; | |
1124 | } | |
1125 | EXPORT_SYMBOL(bio_uncopy_user); | |
1126 | ||
1127 | /** | |
1128 | * bio_copy_user_iov - copy user data to bio | |
1129 | * @q: destination block queue | |
1130 | * @map_data: pointer to the rq_map_data holding pages (if necessary) | |
1131 | * @iov: the iovec. | |
1132 | * @iov_count: number of elements in the iovec | |
1133 | * @write_to_vm: bool indicating writing to pages or not | |
1134 | * @gfp_mask: memory allocation flags | |
1135 | * | |
1136 | * Prepares and returns a bio for indirect user io, bouncing data | |
1137 | * to/from kernel pages as necessary. Must be paired with | |
1138 | * call bio_uncopy_user() on io completion. | |
1139 | */ | |
1140 | struct bio *bio_copy_user_iov(struct request_queue *q, | |
1141 | struct rq_map_data *map_data, | |
1142 | const struct sg_iovec *iov, int iov_count, | |
1143 | int write_to_vm, gfp_t gfp_mask) | |
1144 | { | |
1145 | struct bio_map_data *bmd; | |
1146 | struct bio_vec *bvec; | |
1147 | struct page *page; | |
1148 | struct bio *bio; | |
1149 | int i, ret; | |
1150 | int nr_pages = 0; | |
1151 | unsigned int len = 0; | |
1152 | unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0; | |
1153 | ||
1154 | for (i = 0; i < iov_count; i++) { | |
1155 | unsigned long uaddr; | |
1156 | unsigned long end; | |
1157 | unsigned long start; | |
1158 | ||
1159 | uaddr = (unsigned long)iov[i].iov_base; | |
1160 | end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1161 | start = uaddr >> PAGE_SHIFT; | |
1162 | ||
1163 | /* | |
1164 | * Overflow, abort | |
1165 | */ | |
1166 | if (end < start) | |
1167 | return ERR_PTR(-EINVAL); | |
1168 | ||
1169 | nr_pages += end - start; | |
1170 | len += iov[i].iov_len; | |
1171 | } | |
1172 | ||
1173 | if (offset) | |
1174 | nr_pages++; | |
1175 | ||
1176 | bmd = bio_alloc_map_data(iov_count, gfp_mask); | |
1177 | if (!bmd) | |
1178 | return ERR_PTR(-ENOMEM); | |
1179 | ||
1180 | ret = -ENOMEM; | |
1181 | bio = bio_kmalloc(gfp_mask, nr_pages); | |
1182 | if (!bio) | |
1183 | goto out_bmd; | |
1184 | ||
1185 | if (!write_to_vm) | |
1186 | bio->bi_rw |= REQ_WRITE; | |
1187 | ||
1188 | ret = 0; | |
1189 | ||
1190 | if (map_data) { | |
1191 | nr_pages = 1 << map_data->page_order; | |
1192 | i = map_data->offset / PAGE_SIZE; | |
1193 | } | |
1194 | while (len) { | |
1195 | unsigned int bytes = PAGE_SIZE; | |
1196 | ||
1197 | bytes -= offset; | |
1198 | ||
1199 | if (bytes > len) | |
1200 | bytes = len; | |
1201 | ||
1202 | if (map_data) { | |
1203 | if (i == map_data->nr_entries * nr_pages) { | |
1204 | ret = -ENOMEM; | |
1205 | break; | |
1206 | } | |
1207 | ||
1208 | page = map_data->pages[i / nr_pages]; | |
1209 | page += (i % nr_pages); | |
1210 | ||
1211 | i++; | |
1212 | } else { | |
1213 | page = alloc_page(q->bounce_gfp | gfp_mask); | |
1214 | if (!page) { | |
1215 | ret = -ENOMEM; | |
1216 | break; | |
1217 | } | |
1218 | } | |
1219 | ||
1220 | if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) | |
1221 | break; | |
1222 | ||
1223 | len -= bytes; | |
1224 | offset = 0; | |
1225 | } | |
1226 | ||
1227 | if (ret) | |
1228 | goto cleanup; | |
1229 | ||
1230 | /* | |
1231 | * success | |
1232 | */ | |
1233 | if ((!write_to_vm && (!map_data || !map_data->null_mapped)) || | |
1234 | (map_data && map_data->from_user)) { | |
1235 | ret = __bio_copy_iov(bio, iov, iov_count, 0, 1, 0); | |
1236 | if (ret) | |
1237 | goto cleanup; | |
1238 | } | |
1239 | ||
1240 | bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1); | |
1241 | return bio; | |
1242 | cleanup: | |
1243 | if (!map_data) | |
1244 | bio_for_each_segment_all(bvec, bio, i) | |
1245 | __free_page(bvec->bv_page); | |
1246 | ||
1247 | bio_put(bio); | |
1248 | out_bmd: | |
1249 | kfree(bmd); | |
1250 | return ERR_PTR(ret); | |
1251 | } | |
1252 | ||
1253 | /** | |
1254 | * bio_copy_user - copy user data to bio | |
1255 | * @q: destination block queue | |
1256 | * @map_data: pointer to the rq_map_data holding pages (if necessary) | |
1257 | * @uaddr: start of user address | |
1258 | * @len: length in bytes | |
1259 | * @write_to_vm: bool indicating writing to pages or not | |
1260 | * @gfp_mask: memory allocation flags | |
1261 | * | |
1262 | * Prepares and returns a bio for indirect user io, bouncing data | |
1263 | * to/from kernel pages as necessary. Must be paired with | |
1264 | * call bio_uncopy_user() on io completion. | |
1265 | */ | |
1266 | struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data, | |
1267 | unsigned long uaddr, unsigned int len, | |
1268 | int write_to_vm, gfp_t gfp_mask) | |
1269 | { | |
1270 | struct sg_iovec iov; | |
1271 | ||
1272 | iov.iov_base = (void __user *)uaddr; | |
1273 | iov.iov_len = len; | |
1274 | ||
1275 | return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask); | |
1276 | } | |
1277 | EXPORT_SYMBOL(bio_copy_user); | |
1278 | ||
1279 | static struct bio *__bio_map_user_iov(struct request_queue *q, | |
1280 | struct block_device *bdev, | |
1281 | const struct sg_iovec *iov, int iov_count, | |
1282 | int write_to_vm, gfp_t gfp_mask) | |
1283 | { | |
1284 | int i, j; | |
1285 | int nr_pages = 0; | |
1286 | struct page **pages; | |
1287 | struct bio *bio; | |
1288 | int cur_page = 0; | |
1289 | int ret, offset; | |
1290 | ||
1291 | for (i = 0; i < iov_count; i++) { | |
1292 | unsigned long uaddr = (unsigned long)iov[i].iov_base; | |
1293 | unsigned long len = iov[i].iov_len; | |
1294 | unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1295 | unsigned long start = uaddr >> PAGE_SHIFT; | |
1296 | ||
1297 | /* | |
1298 | * Overflow, abort | |
1299 | */ | |
1300 | if (end < start) | |
1301 | return ERR_PTR(-EINVAL); | |
1302 | ||
1303 | nr_pages += end - start; | |
1304 | /* | |
1305 | * buffer must be aligned to at least hardsector size for now | |
1306 | */ | |
1307 | if (uaddr & queue_dma_alignment(q)) | |
1308 | return ERR_PTR(-EINVAL); | |
1309 | } | |
1310 | ||
1311 | if (!nr_pages) | |
1312 | return ERR_PTR(-EINVAL); | |
1313 | ||
1314 | bio = bio_kmalloc(gfp_mask, nr_pages); | |
1315 | if (!bio) | |
1316 | return ERR_PTR(-ENOMEM); | |
1317 | ||
1318 | ret = -ENOMEM; | |
1319 | pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask); | |
1320 | if (!pages) | |
1321 | goto out; | |
1322 | ||
1323 | for (i = 0; i < iov_count; i++) { | |
1324 | unsigned long uaddr = (unsigned long)iov[i].iov_base; | |
1325 | unsigned long len = iov[i].iov_len; | |
1326 | unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1327 | unsigned long start = uaddr >> PAGE_SHIFT; | |
1328 | const int local_nr_pages = end - start; | |
1329 | const int page_limit = cur_page + local_nr_pages; | |
1330 | ||
1331 | ret = get_user_pages_fast(uaddr, local_nr_pages, | |
1332 | write_to_vm, &pages[cur_page]); | |
1333 | if (ret < local_nr_pages) { | |
1334 | ret = -EFAULT; | |
1335 | goto out_unmap; | |
1336 | } | |
1337 | ||
1338 | offset = uaddr & ~PAGE_MASK; | |
1339 | for (j = cur_page; j < page_limit; j++) { | |
1340 | unsigned int bytes = PAGE_SIZE - offset; | |
1341 | ||
1342 | if (len <= 0) | |
1343 | break; | |
1344 | ||
1345 | if (bytes > len) | |
1346 | bytes = len; | |
1347 | ||
1348 | /* | |
1349 | * sorry... | |
1350 | */ | |
1351 | if (bio_add_pc_page(q, bio, pages[j], bytes, offset) < | |
1352 | bytes) | |
1353 | break; | |
1354 | ||
1355 | len -= bytes; | |
1356 | offset = 0; | |
1357 | } | |
1358 | ||
1359 | cur_page = j; | |
1360 | /* | |
1361 | * release the pages we didn't map into the bio, if any | |
1362 | */ | |
1363 | while (j < page_limit) | |
1364 | page_cache_release(pages[j++]); | |
1365 | } | |
1366 | ||
1367 | kfree(pages); | |
1368 | ||
1369 | /* | |
1370 | * set data direction, and check if mapped pages need bouncing | |
1371 | */ | |
1372 | if (!write_to_vm) | |
1373 | bio->bi_rw |= REQ_WRITE; | |
1374 | ||
1375 | bio->bi_bdev = bdev; | |
1376 | bio->bi_flags |= (1 << BIO_USER_MAPPED); | |
1377 | return bio; | |
1378 | ||
1379 | out_unmap: | |
1380 | for (i = 0; i < nr_pages; i++) { | |
1381 | if(!pages[i]) | |
1382 | break; | |
1383 | page_cache_release(pages[i]); | |
1384 | } | |
1385 | out: | |
1386 | kfree(pages); | |
1387 | bio_put(bio); | |
1388 | return ERR_PTR(ret); | |
1389 | } | |
1390 | ||
1391 | /** | |
1392 | * bio_map_user - map user address into bio | |
1393 | * @q: the struct request_queue for the bio | |
1394 | * @bdev: destination block device | |
1395 | * @uaddr: start of user address | |
1396 | * @len: length in bytes | |
1397 | * @write_to_vm: bool indicating writing to pages or not | |
1398 | * @gfp_mask: memory allocation flags | |
1399 | * | |
1400 | * Map the user space address into a bio suitable for io to a block | |
1401 | * device. Returns an error pointer in case of error. | |
1402 | */ | |
1403 | struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev, | |
1404 | unsigned long uaddr, unsigned int len, int write_to_vm, | |
1405 | gfp_t gfp_mask) | |
1406 | { | |
1407 | struct sg_iovec iov; | |
1408 | ||
1409 | iov.iov_base = (void __user *)uaddr; | |
1410 | iov.iov_len = len; | |
1411 | ||
1412 | return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask); | |
1413 | } | |
1414 | EXPORT_SYMBOL(bio_map_user); | |
1415 | ||
1416 | /** | |
1417 | * bio_map_user_iov - map user sg_iovec table into bio | |
1418 | * @q: the struct request_queue for the bio | |
1419 | * @bdev: destination block device | |
1420 | * @iov: the iovec. | |
1421 | * @iov_count: number of elements in the iovec | |
1422 | * @write_to_vm: bool indicating writing to pages or not | |
1423 | * @gfp_mask: memory allocation flags | |
1424 | * | |
1425 | * Map the user space address into a bio suitable for io to a block | |
1426 | * device. Returns an error pointer in case of error. | |
1427 | */ | |
1428 | struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev, | |
1429 | const struct sg_iovec *iov, int iov_count, | |
1430 | int write_to_vm, gfp_t gfp_mask) | |
1431 | { | |
1432 | struct bio *bio; | |
1433 | ||
1434 | bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm, | |
1435 | gfp_mask); | |
1436 | if (IS_ERR(bio)) | |
1437 | return bio; | |
1438 | ||
1439 | /* | |
1440 | * subtle -- if __bio_map_user() ended up bouncing a bio, | |
1441 | * it would normally disappear when its bi_end_io is run. | |
1442 | * however, we need it for the unmap, so grab an extra | |
1443 | * reference to it | |
1444 | */ | |
1445 | bio_get(bio); | |
1446 | ||
1447 | return bio; | |
1448 | } | |
1449 | ||
1450 | static void __bio_unmap_user(struct bio *bio) | |
1451 | { | |
1452 | struct bio_vec *bvec; | |
1453 | int i; | |
1454 | ||
1455 | /* | |
1456 | * make sure we dirty pages we wrote to | |
1457 | */ | |
1458 | bio_for_each_segment_all(bvec, bio, i) { | |
1459 | if (bio_data_dir(bio) == READ) | |
1460 | set_page_dirty_lock(bvec->bv_page); | |
1461 | ||
1462 | page_cache_release(bvec->bv_page); | |
1463 | } | |
1464 | ||
1465 | bio_put(bio); | |
1466 | } | |
1467 | ||
1468 | /** | |
1469 | * bio_unmap_user - unmap a bio | |
1470 | * @bio: the bio being unmapped | |
1471 | * | |
1472 | * Unmap a bio previously mapped by bio_map_user(). Must be called with | |
1473 | * a process context. | |
1474 | * | |
1475 | * bio_unmap_user() may sleep. | |
1476 | */ | |
1477 | void bio_unmap_user(struct bio *bio) | |
1478 | { | |
1479 | __bio_unmap_user(bio); | |
1480 | bio_put(bio); | |
1481 | } | |
1482 | EXPORT_SYMBOL(bio_unmap_user); | |
1483 | ||
1484 | static void bio_map_kern_endio(struct bio *bio, int err) | |
1485 | { | |
1486 | bio_put(bio); | |
1487 | } | |
1488 | ||
1489 | static struct bio *__bio_map_kern(struct request_queue *q, void *data, | |
1490 | unsigned int len, gfp_t gfp_mask) | |
1491 | { | |
1492 | unsigned long kaddr = (unsigned long)data; | |
1493 | unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1494 | unsigned long start = kaddr >> PAGE_SHIFT; | |
1495 | const int nr_pages = end - start; | |
1496 | int offset, i; | |
1497 | struct bio *bio; | |
1498 | ||
1499 | bio = bio_kmalloc(gfp_mask, nr_pages); | |
1500 | if (!bio) | |
1501 | return ERR_PTR(-ENOMEM); | |
1502 | ||
1503 | offset = offset_in_page(kaddr); | |
1504 | for (i = 0; i < nr_pages; i++) { | |
1505 | unsigned int bytes = PAGE_SIZE - offset; | |
1506 | ||
1507 | if (len <= 0) | |
1508 | break; | |
1509 | ||
1510 | if (bytes > len) | |
1511 | bytes = len; | |
1512 | ||
1513 | if (bio_add_pc_page(q, bio, virt_to_page(data), bytes, | |
1514 | offset) < bytes) | |
1515 | break; | |
1516 | ||
1517 | data += bytes; | |
1518 | len -= bytes; | |
1519 | offset = 0; | |
1520 | } | |
1521 | ||
1522 | bio->bi_end_io = bio_map_kern_endio; | |
1523 | return bio; | |
1524 | } | |
1525 | ||
1526 | /** | |
1527 | * bio_map_kern - map kernel address into bio | |
1528 | * @q: the struct request_queue for the bio | |
1529 | * @data: pointer to buffer to map | |
1530 | * @len: length in bytes | |
1531 | * @gfp_mask: allocation flags for bio allocation | |
1532 | * | |
1533 | * Map the kernel address into a bio suitable for io to a block | |
1534 | * device. Returns an error pointer in case of error. | |
1535 | */ | |
1536 | struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, | |
1537 | gfp_t gfp_mask) | |
1538 | { | |
1539 | struct bio *bio; | |
1540 | ||
1541 | bio = __bio_map_kern(q, data, len, gfp_mask); | |
1542 | if (IS_ERR(bio)) | |
1543 | return bio; | |
1544 | ||
1545 | if (bio->bi_iter.bi_size == len) | |
1546 | return bio; | |
1547 | ||
1548 | /* | |
1549 | * Don't support partial mappings. | |
1550 | */ | |
1551 | bio_put(bio); | |
1552 | return ERR_PTR(-EINVAL); | |
1553 | } | |
1554 | EXPORT_SYMBOL(bio_map_kern); | |
1555 | ||
1556 | static void bio_copy_kern_endio(struct bio *bio, int err) | |
1557 | { | |
1558 | struct bio_vec *bvec; | |
1559 | const int read = bio_data_dir(bio) == READ; | |
1560 | struct bio_map_data *bmd = bio->bi_private; | |
1561 | int i; | |
1562 | char *p = bmd->sgvecs[0].iov_base; | |
1563 | ||
1564 | bio_for_each_segment_all(bvec, bio, i) { | |
1565 | char *addr = page_address(bvec->bv_page); | |
1566 | ||
1567 | if (read) | |
1568 | memcpy(p, addr, bvec->bv_len); | |
1569 | ||
1570 | __free_page(bvec->bv_page); | |
1571 | p += bvec->bv_len; | |
1572 | } | |
1573 | ||
1574 | kfree(bmd); | |
1575 | bio_put(bio); | |
1576 | } | |
1577 | ||
1578 | /** | |
1579 | * bio_copy_kern - copy kernel address into bio | |
1580 | * @q: the struct request_queue for the bio | |
1581 | * @data: pointer to buffer to copy | |
1582 | * @len: length in bytes | |
1583 | * @gfp_mask: allocation flags for bio and page allocation | |
1584 | * @reading: data direction is READ | |
1585 | * | |
1586 | * copy the kernel address into a bio suitable for io to a block | |
1587 | * device. Returns an error pointer in case of error. | |
1588 | */ | |
1589 | struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, | |
1590 | gfp_t gfp_mask, int reading) | |
1591 | { | |
1592 | struct bio *bio; | |
1593 | struct bio_vec *bvec; | |
1594 | int i; | |
1595 | ||
1596 | bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask); | |
1597 | if (IS_ERR(bio)) | |
1598 | return bio; | |
1599 | ||
1600 | if (!reading) { | |
1601 | void *p = data; | |
1602 | ||
1603 | bio_for_each_segment_all(bvec, bio, i) { | |
1604 | char *addr = page_address(bvec->bv_page); | |
1605 | ||
1606 | memcpy(addr, p, bvec->bv_len); | |
1607 | p += bvec->bv_len; | |
1608 | } | |
1609 | } | |
1610 | ||
1611 | bio->bi_end_io = bio_copy_kern_endio; | |
1612 | ||
1613 | return bio; | |
1614 | } | |
1615 | EXPORT_SYMBOL(bio_copy_kern); | |
1616 | ||
1617 | /* | |
1618 | * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions | |
1619 | * for performing direct-IO in BIOs. | |
1620 | * | |
1621 | * The problem is that we cannot run set_page_dirty() from interrupt context | |
1622 | * because the required locks are not interrupt-safe. So what we can do is to | |
1623 | * mark the pages dirty _before_ performing IO. And in interrupt context, | |
1624 | * check that the pages are still dirty. If so, fine. If not, redirty them | |
1625 | * in process context. | |
1626 | * | |
1627 | * We special-case compound pages here: normally this means reads into hugetlb | |
1628 | * pages. The logic in here doesn't really work right for compound pages | |
1629 | * because the VM does not uniformly chase down the head page in all cases. | |
1630 | * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't | |
1631 | * handle them at all. So we skip compound pages here at an early stage. | |
1632 | * | |
1633 | * Note that this code is very hard to test under normal circumstances because | |
1634 | * direct-io pins the pages with get_user_pages(). This makes | |
1635 | * is_page_cache_freeable return false, and the VM will not clean the pages. | |
1636 | * But other code (eg, flusher threads) could clean the pages if they are mapped | |
1637 | * pagecache. | |
1638 | * | |
1639 | * Simply disabling the call to bio_set_pages_dirty() is a good way to test the | |
1640 | * deferred bio dirtying paths. | |
1641 | */ | |
1642 | ||
1643 | /* | |
1644 | * bio_set_pages_dirty() will mark all the bio's pages as dirty. | |
1645 | */ | |
1646 | void bio_set_pages_dirty(struct bio *bio) | |
1647 | { | |
1648 | struct bio_vec *bvec; | |
1649 | int i; | |
1650 | ||
1651 | bio_for_each_segment_all(bvec, bio, i) { | |
1652 | struct page *page = bvec->bv_page; | |
1653 | ||
1654 | if (page && !PageCompound(page)) | |
1655 | set_page_dirty_lock(page); | |
1656 | } | |
1657 | } | |
1658 | ||
1659 | static void bio_release_pages(struct bio *bio) | |
1660 | { | |
1661 | struct bio_vec *bvec; | |
1662 | int i; | |
1663 | ||
1664 | bio_for_each_segment_all(bvec, bio, i) { | |
1665 | struct page *page = bvec->bv_page; | |
1666 | ||
1667 | if (page) | |
1668 | put_page(page); | |
1669 | } | |
1670 | } | |
1671 | ||
1672 | /* | |
1673 | * bio_check_pages_dirty() will check that all the BIO's pages are still dirty. | |
1674 | * If they are, then fine. If, however, some pages are clean then they must | |
1675 | * have been written out during the direct-IO read. So we take another ref on | |
1676 | * the BIO and the offending pages and re-dirty the pages in process context. | |
1677 | * | |
1678 | * It is expected that bio_check_pages_dirty() will wholly own the BIO from | |
1679 | * here on. It will run one page_cache_release() against each page and will | |
1680 | * run one bio_put() against the BIO. | |
1681 | */ | |
1682 | ||
1683 | static void bio_dirty_fn(struct work_struct *work); | |
1684 | ||
1685 | static DECLARE_WORK(bio_dirty_work, bio_dirty_fn); | |
1686 | static DEFINE_SPINLOCK(bio_dirty_lock); | |
1687 | static struct bio *bio_dirty_list; | |
1688 | ||
1689 | /* | |
1690 | * This runs in process context | |
1691 | */ | |
1692 | static void bio_dirty_fn(struct work_struct *work) | |
1693 | { | |
1694 | unsigned long flags; | |
1695 | struct bio *bio; | |
1696 | ||
1697 | spin_lock_irqsave(&bio_dirty_lock, flags); | |
1698 | bio = bio_dirty_list; | |
1699 | bio_dirty_list = NULL; | |
1700 | spin_unlock_irqrestore(&bio_dirty_lock, flags); | |
1701 | ||
1702 | while (bio) { | |
1703 | struct bio *next = bio->bi_private; | |
1704 | ||
1705 | bio_set_pages_dirty(bio); | |
1706 | bio_release_pages(bio); | |
1707 | bio_put(bio); | |
1708 | bio = next; | |
1709 | } | |
1710 | } | |
1711 | ||
1712 | void bio_check_pages_dirty(struct bio *bio) | |
1713 | { | |
1714 | struct bio_vec *bvec; | |
1715 | int nr_clean_pages = 0; | |
1716 | int i; | |
1717 | ||
1718 | bio_for_each_segment_all(bvec, bio, i) { | |
1719 | struct page *page = bvec->bv_page; | |
1720 | ||
1721 | if (PageDirty(page) || PageCompound(page)) { | |
1722 | page_cache_release(page); | |
1723 | bvec->bv_page = NULL; | |
1724 | } else { | |
1725 | nr_clean_pages++; | |
1726 | } | |
1727 | } | |
1728 | ||
1729 | if (nr_clean_pages) { | |
1730 | unsigned long flags; | |
1731 | ||
1732 | spin_lock_irqsave(&bio_dirty_lock, flags); | |
1733 | bio->bi_private = bio_dirty_list; | |
1734 | bio_dirty_list = bio; | |
1735 | spin_unlock_irqrestore(&bio_dirty_lock, flags); | |
1736 | schedule_work(&bio_dirty_work); | |
1737 | } else { | |
1738 | bio_put(bio); | |
1739 | } | |
1740 | } | |
1741 | ||
1742 | void generic_start_io_acct(int rw, unsigned long sectors, | |
1743 | struct hd_struct *part) | |
1744 | { | |
1745 | int cpu = part_stat_lock(); | |
1746 | ||
1747 | part_round_stats(cpu, part); | |
1748 | part_stat_inc(cpu, part, ios[rw]); | |
1749 | part_stat_add(cpu, part, sectors[rw], sectors); | |
1750 | part_inc_in_flight(part, rw); | |
1751 | ||
1752 | part_stat_unlock(); | |
1753 | } | |
1754 | EXPORT_SYMBOL(generic_start_io_acct); | |
1755 | ||
1756 | void generic_end_io_acct(int rw, struct hd_struct *part, | |
1757 | unsigned long start_time) | |
1758 | { | |
1759 | unsigned long duration = jiffies - start_time; | |
1760 | int cpu = part_stat_lock(); | |
1761 | ||
1762 | part_stat_add(cpu, part, ticks[rw], duration); | |
1763 | part_round_stats(cpu, part); | |
1764 | part_dec_in_flight(part, rw); | |
1765 | ||
1766 | part_stat_unlock(); | |
1767 | } | |
1768 | EXPORT_SYMBOL(generic_end_io_acct); | |
1769 | ||
1770 | #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE | |
1771 | void bio_flush_dcache_pages(struct bio *bi) | |
1772 | { | |
1773 | struct bio_vec bvec; | |
1774 | struct bvec_iter iter; | |
1775 | ||
1776 | bio_for_each_segment(bvec, bi, iter) | |
1777 | flush_dcache_page(bvec.bv_page); | |
1778 | } | |
1779 | EXPORT_SYMBOL(bio_flush_dcache_pages); | |
1780 | #endif | |
1781 | ||
1782 | /** | |
1783 | * bio_endio - end I/O on a bio | |
1784 | * @bio: bio | |
1785 | * @error: error, if any | |
1786 | * | |
1787 | * Description: | |
1788 | * bio_endio() will end I/O on the whole bio. bio_endio() is the | |
1789 | * preferred way to end I/O on a bio, it takes care of clearing | |
1790 | * BIO_UPTODATE on error. @error is 0 on success, and and one of the | |
1791 | * established -Exxxx (-EIO, for instance) error values in case | |
1792 | * something went wrong. No one should call bi_end_io() directly on a | |
1793 | * bio unless they own it and thus know that it has an end_io | |
1794 | * function. | |
1795 | **/ | |
1796 | void bio_endio(struct bio *bio, int error) | |
1797 | { | |
1798 | while (bio) { | |
1799 | BUG_ON(atomic_read(&bio->bi_remaining) <= 0); | |
1800 | ||
1801 | if (error) | |
1802 | clear_bit(BIO_UPTODATE, &bio->bi_flags); | |
1803 | else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
1804 | error = -EIO; | |
1805 | ||
1806 | if (!atomic_dec_and_test(&bio->bi_remaining)) | |
1807 | return; | |
1808 | ||
1809 | /* | |
1810 | * Need to have a real endio function for chained bios, | |
1811 | * otherwise various corner cases will break (like stacking | |
1812 | * block devices that save/restore bi_end_io) - however, we want | |
1813 | * to avoid unbounded recursion and blowing the stack. Tail call | |
1814 | * optimization would handle this, but compiling with frame | |
1815 | * pointers also disables gcc's sibling call optimization. | |
1816 | */ | |
1817 | if (bio->bi_end_io == bio_chain_endio) { | |
1818 | struct bio *parent = bio->bi_private; | |
1819 | bio_put(bio); | |
1820 | bio = parent; | |
1821 | } else { | |
1822 | if (bio->bi_end_io) | |
1823 | bio->bi_end_io(bio, error); | |
1824 | bio = NULL; | |
1825 | } | |
1826 | } | |
1827 | } | |
1828 | EXPORT_SYMBOL(bio_endio); | |
1829 | ||
1830 | /** | |
1831 | * bio_endio_nodec - end I/O on a bio, without decrementing bi_remaining | |
1832 | * @bio: bio | |
1833 | * @error: error, if any | |
1834 | * | |
1835 | * For code that has saved and restored bi_end_io; thing hard before using this | |
1836 | * function, probably you should've cloned the entire bio. | |
1837 | **/ | |
1838 | void bio_endio_nodec(struct bio *bio, int error) | |
1839 | { | |
1840 | atomic_inc(&bio->bi_remaining); | |
1841 | bio_endio(bio, error); | |
1842 | } | |
1843 | EXPORT_SYMBOL(bio_endio_nodec); | |
1844 | ||
1845 | /** | |
1846 | * bio_split - split a bio | |
1847 | * @bio: bio to split | |
1848 | * @sectors: number of sectors to split from the front of @bio | |
1849 | * @gfp: gfp mask | |
1850 | * @bs: bio set to allocate from | |
1851 | * | |
1852 | * Allocates and returns a new bio which represents @sectors from the start of | |
1853 | * @bio, and updates @bio to represent the remaining sectors. | |
1854 | * | |
1855 | * The newly allocated bio will point to @bio's bi_io_vec; it is the caller's | |
1856 | * responsibility to ensure that @bio is not freed before the split. | |
1857 | */ | |
1858 | struct bio *bio_split(struct bio *bio, int sectors, | |
1859 | gfp_t gfp, struct bio_set *bs) | |
1860 | { | |
1861 | struct bio *split = NULL; | |
1862 | ||
1863 | BUG_ON(sectors <= 0); | |
1864 | BUG_ON(sectors >= bio_sectors(bio)); | |
1865 | ||
1866 | split = bio_clone_fast(bio, gfp, bs); | |
1867 | if (!split) | |
1868 | return NULL; | |
1869 | ||
1870 | split->bi_iter.bi_size = sectors << 9; | |
1871 | ||
1872 | if (bio_integrity(split)) | |
1873 | bio_integrity_trim(split, 0, sectors); | |
1874 | ||
1875 | bio_advance(bio, split->bi_iter.bi_size); | |
1876 | ||
1877 | return split; | |
1878 | } | |
1879 | EXPORT_SYMBOL(bio_split); | |
1880 | ||
1881 | /** | |
1882 | * bio_trim - trim a bio | |
1883 | * @bio: bio to trim | |
1884 | * @offset: number of sectors to trim from the front of @bio | |
1885 | * @size: size we want to trim @bio to, in sectors | |
1886 | */ | |
1887 | void bio_trim(struct bio *bio, int offset, int size) | |
1888 | { | |
1889 | /* 'bio' is a cloned bio which we need to trim to match | |
1890 | * the given offset and size. | |
1891 | */ | |
1892 | ||
1893 | size <<= 9; | |
1894 | if (offset == 0 && size == bio->bi_iter.bi_size) | |
1895 | return; | |
1896 | ||
1897 | clear_bit(BIO_SEG_VALID, &bio->bi_flags); | |
1898 | ||
1899 | bio_advance(bio, offset << 9); | |
1900 | ||
1901 | bio->bi_iter.bi_size = size; | |
1902 | } | |
1903 | EXPORT_SYMBOL_GPL(bio_trim); | |
1904 | ||
1905 | /* | |
1906 | * create memory pools for biovec's in a bio_set. | |
1907 | * use the global biovec slabs created for general use. | |
1908 | */ | |
1909 | mempool_t *biovec_create_pool(int pool_entries) | |
1910 | { | |
1911 | struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX; | |
1912 | ||
1913 | return mempool_create_slab_pool(pool_entries, bp->slab); | |
1914 | } | |
1915 | ||
1916 | void bioset_free(struct bio_set *bs) | |
1917 | { | |
1918 | if (bs->rescue_workqueue) | |
1919 | destroy_workqueue(bs->rescue_workqueue); | |
1920 | ||
1921 | if (bs->bio_pool) | |
1922 | mempool_destroy(bs->bio_pool); | |
1923 | ||
1924 | if (bs->bvec_pool) | |
1925 | mempool_destroy(bs->bvec_pool); | |
1926 | ||
1927 | bioset_integrity_free(bs); | |
1928 | bio_put_slab(bs); | |
1929 | ||
1930 | kfree(bs); | |
1931 | } | |
1932 | EXPORT_SYMBOL(bioset_free); | |
1933 | ||
1934 | static struct bio_set *__bioset_create(unsigned int pool_size, | |
1935 | unsigned int front_pad, | |
1936 | bool create_bvec_pool) | |
1937 | { | |
1938 | unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); | |
1939 | struct bio_set *bs; | |
1940 | ||
1941 | bs = kzalloc(sizeof(*bs), GFP_KERNEL); | |
1942 | if (!bs) | |
1943 | return NULL; | |
1944 | ||
1945 | bs->front_pad = front_pad; | |
1946 | ||
1947 | spin_lock_init(&bs->rescue_lock); | |
1948 | bio_list_init(&bs->rescue_list); | |
1949 | INIT_WORK(&bs->rescue_work, bio_alloc_rescue); | |
1950 | ||
1951 | bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad); | |
1952 | if (!bs->bio_slab) { | |
1953 | kfree(bs); | |
1954 | return NULL; | |
1955 | } | |
1956 | ||
1957 | bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab); | |
1958 | if (!bs->bio_pool) | |
1959 | goto bad; | |
1960 | ||
1961 | if (create_bvec_pool) { | |
1962 | bs->bvec_pool = biovec_create_pool(pool_size); | |
1963 | if (!bs->bvec_pool) | |
1964 | goto bad; | |
1965 | } | |
1966 | ||
1967 | bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0); | |
1968 | if (!bs->rescue_workqueue) | |
1969 | goto bad; | |
1970 | ||
1971 | return bs; | |
1972 | bad: | |
1973 | bioset_free(bs); | |
1974 | return NULL; | |
1975 | } | |
1976 | ||
1977 | /** | |
1978 | * bioset_create - Create a bio_set | |
1979 | * @pool_size: Number of bio and bio_vecs to cache in the mempool | |
1980 | * @front_pad: Number of bytes to allocate in front of the returned bio | |
1981 | * | |
1982 | * Description: | |
1983 | * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller | |
1984 | * to ask for a number of bytes to be allocated in front of the bio. | |
1985 | * Front pad allocation is useful for embedding the bio inside | |
1986 | * another structure, to avoid allocating extra data to go with the bio. | |
1987 | * Note that the bio must be embedded at the END of that structure always, | |
1988 | * or things will break badly. | |
1989 | */ | |
1990 | struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) | |
1991 | { | |
1992 | return __bioset_create(pool_size, front_pad, true); | |
1993 | } | |
1994 | EXPORT_SYMBOL(bioset_create); | |
1995 | ||
1996 | /** | |
1997 | * bioset_create_nobvec - Create a bio_set without bio_vec mempool | |
1998 | * @pool_size: Number of bio to cache in the mempool | |
1999 | * @front_pad: Number of bytes to allocate in front of the returned bio | |
2000 | * | |
2001 | * Description: | |
2002 | * Same functionality as bioset_create() except that mempool is not | |
2003 | * created for bio_vecs. Saving some memory for bio_clone_fast() users. | |
2004 | */ | |
2005 | struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_pad) | |
2006 | { | |
2007 | return __bioset_create(pool_size, front_pad, false); | |
2008 | } | |
2009 | EXPORT_SYMBOL(bioset_create_nobvec); | |
2010 | ||
2011 | #ifdef CONFIG_BLK_CGROUP | |
2012 | /** | |
2013 | * bio_associate_current - associate a bio with %current | |
2014 | * @bio: target bio | |
2015 | * | |
2016 | * Associate @bio with %current if it hasn't been associated yet. Block | |
2017 | * layer will treat @bio as if it were issued by %current no matter which | |
2018 | * task actually issues it. | |
2019 | * | |
2020 | * This function takes an extra reference of @task's io_context and blkcg | |
2021 | * which will be put when @bio is released. The caller must own @bio, | |
2022 | * ensure %current->io_context exists, and is responsible for synchronizing | |
2023 | * calls to this function. | |
2024 | */ | |
2025 | int bio_associate_current(struct bio *bio) | |
2026 | { | |
2027 | struct io_context *ioc; | |
2028 | struct cgroup_subsys_state *css; | |
2029 | ||
2030 | if (bio->bi_ioc) | |
2031 | return -EBUSY; | |
2032 | ||
2033 | ioc = current->io_context; | |
2034 | if (!ioc) | |
2035 | return -ENOENT; | |
2036 | ||
2037 | /* acquire active ref on @ioc and associate */ | |
2038 | get_io_context_active(ioc); | |
2039 | bio->bi_ioc = ioc; | |
2040 | ||
2041 | /* associate blkcg if exists */ | |
2042 | rcu_read_lock(); | |
2043 | css = task_css(current, blkio_cgrp_id); | |
2044 | if (css && css_tryget_online(css)) | |
2045 | bio->bi_css = css; | |
2046 | rcu_read_unlock(); | |
2047 | ||
2048 | return 0; | |
2049 | } | |
2050 | ||
2051 | /** | |
2052 | * bio_disassociate_task - undo bio_associate_current() | |
2053 | * @bio: target bio | |
2054 | */ | |
2055 | void bio_disassociate_task(struct bio *bio) | |
2056 | { | |
2057 | if (bio->bi_ioc) { | |
2058 | put_io_context(bio->bi_ioc); | |
2059 | bio->bi_ioc = NULL; | |
2060 | } | |
2061 | if (bio->bi_css) { | |
2062 | css_put(bio->bi_css); | |
2063 | bio->bi_css = NULL; | |
2064 | } | |
2065 | } | |
2066 | ||
2067 | #endif /* CONFIG_BLK_CGROUP */ | |
2068 | ||
2069 | static void __init biovec_init_slabs(void) | |
2070 | { | |
2071 | int i; | |
2072 | ||
2073 | for (i = 0; i < BIOVEC_NR_POOLS; i++) { | |
2074 | int size; | |
2075 | struct biovec_slab *bvs = bvec_slabs + i; | |
2076 | ||
2077 | if (bvs->nr_vecs <= BIO_INLINE_VECS) { | |
2078 | bvs->slab = NULL; | |
2079 | continue; | |
2080 | } | |
2081 | ||
2082 | size = bvs->nr_vecs * sizeof(struct bio_vec); | |
2083 | bvs->slab = kmem_cache_create(bvs->name, size, 0, | |
2084 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); | |
2085 | } | |
2086 | } | |
2087 | ||
2088 | static int __init init_bio(void) | |
2089 | { | |
2090 | bio_slab_max = 2; | |
2091 | bio_slab_nr = 0; | |
2092 | bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL); | |
2093 | if (!bio_slabs) | |
2094 | panic("bio: can't allocate bios\n"); | |
2095 | ||
2096 | bio_integrity_init(); | |
2097 | biovec_init_slabs(); | |
2098 | ||
2099 | fs_bio_set = bioset_create(BIO_POOL_SIZE, 0); | |
2100 | if (!fs_bio_set) | |
2101 | panic("bio: can't allocate bios\n"); | |
2102 | ||
2103 | if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE)) | |
2104 | panic("bio: can't create integrity pool\n"); | |
2105 | ||
2106 | return 0; | |
2107 | } | |
2108 | subsys_initcall(init_bio); |