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Source at commit cdde9cf73945d547acd3e96f9508c79e84ad0bf1 created 12 years 9 months ago. By Maarten ter Huurne, MMC: JZ4740: Added support for CPU frequency changing | |
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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, bs); |
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_alloc_bioset - allocate a bio for I/O |
267 | * @gfp_mask: the GFP_ mask given to the slab allocator |
268 | * @nr_iovecs: number of iovecs to pre-allocate |
269 | * @bs: the bio_set to allocate from. |
270 | * |
271 | * Description: |
272 | * bio_alloc_bioset will try its own mempool to satisfy the allocation. |
273 | * If %__GFP_WAIT is set then we will block on the internal pool waiting |
274 | * for a &struct bio to become free. |
275 | * |
276 | * Note that the caller must set ->bi_destructor on successful return |
277 | * of a bio, to do the appropriate freeing of the bio once the reference |
278 | * count drops to zero. |
279 | **/ |
280 | struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) |
281 | { |
282 | unsigned long idx = BIO_POOL_NONE; |
283 | struct bio_vec *bvl = NULL; |
284 | struct bio *bio; |
285 | void *p; |
286 | |
287 | p = mempool_alloc(bs->bio_pool, gfp_mask); |
288 | if (unlikely(!p)) |
289 | return NULL; |
290 | bio = p + bs->front_pad; |
291 | |
292 | bio_init(bio); |
293 | |
294 | if (unlikely(!nr_iovecs)) |
295 | goto out_set; |
296 | |
297 | if (nr_iovecs <= BIO_INLINE_VECS) { |
298 | bvl = bio->bi_inline_vecs; |
299 | nr_iovecs = BIO_INLINE_VECS; |
300 | } else { |
301 | bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs); |
302 | if (unlikely(!bvl)) |
303 | goto err_free; |
304 | |
305 | nr_iovecs = bvec_nr_vecs(idx); |
306 | } |
307 | out_set: |
308 | bio->bi_flags |= idx << BIO_POOL_OFFSET; |
309 | bio->bi_max_vecs = nr_iovecs; |
310 | bio->bi_io_vec = bvl; |
311 | return bio; |
312 | |
313 | err_free: |
314 | mempool_free(p, bs->bio_pool); |
315 | return NULL; |
316 | } |
317 | EXPORT_SYMBOL(bio_alloc_bioset); |
318 | |
319 | static void bio_fs_destructor(struct bio *bio) |
320 | { |
321 | bio_free(bio, fs_bio_set); |
322 | } |
323 | |
324 | /** |
325 | * bio_alloc - allocate a new bio, memory pool backed |
326 | * @gfp_mask: allocation mask to use |
327 | * @nr_iovecs: number of iovecs |
328 | * |
329 | * bio_alloc will allocate a bio and associated bio_vec array that can hold |
330 | * at least @nr_iovecs entries. Allocations will be done from the |
331 | * fs_bio_set. Also see @bio_alloc_bioset and @bio_kmalloc. |
332 | * |
333 | * If %__GFP_WAIT is set, then bio_alloc will always be able to allocate |
334 | * a bio. This is due to the mempool guarantees. To make this work, callers |
335 | * must never allocate more than 1 bio at a time from this pool. Callers |
336 | * that need to allocate more than 1 bio must always submit the previously |
337 | * allocated bio for IO before attempting to allocate a new one. Failure to |
338 | * do so can cause livelocks under memory pressure. |
339 | * |
340 | * RETURNS: |
341 | * Pointer to new bio on success, NULL on failure. |
342 | */ |
343 | struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs) |
344 | { |
345 | struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set); |
346 | |
347 | if (bio) |
348 | bio->bi_destructor = bio_fs_destructor; |
349 | |
350 | return bio; |
351 | } |
352 | EXPORT_SYMBOL(bio_alloc); |
353 | |
354 | static void bio_kmalloc_destructor(struct bio *bio) |
355 | { |
356 | if (bio_integrity(bio)) |
357 | bio_integrity_free(bio, fs_bio_set); |
358 | kfree(bio); |
359 | } |
360 | |
361 | /** |
362 | * bio_kmalloc - allocate a bio for I/O using kmalloc() |
363 | * @gfp_mask: the GFP_ mask given to the slab allocator |
364 | * @nr_iovecs: number of iovecs to pre-allocate |
365 | * |
366 | * Description: |
367 | * Allocate a new bio with @nr_iovecs bvecs. If @gfp_mask contains |
368 | * %__GFP_WAIT, the allocation is guaranteed to succeed. |
369 | * |
370 | **/ |
371 | struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs) |
372 | { |
373 | struct bio *bio; |
374 | |
375 | if (nr_iovecs > UIO_MAXIOV) |
376 | return NULL; |
377 | |
378 | bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec), |
379 | gfp_mask); |
380 | if (unlikely(!bio)) |
381 | return NULL; |
382 | |
383 | bio_init(bio); |
384 | bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET; |
385 | bio->bi_max_vecs = nr_iovecs; |
386 | bio->bi_io_vec = bio->bi_inline_vecs; |
387 | bio->bi_destructor = bio_kmalloc_destructor; |
388 | |
389 | return bio; |
390 | } |
391 | EXPORT_SYMBOL(bio_kmalloc); |
392 | |
393 | void zero_fill_bio(struct bio *bio) |
394 | { |
395 | unsigned long flags; |
396 | struct bio_vec *bv; |
397 | int i; |
398 | |
399 | bio_for_each_segment(bv, bio, i) { |
400 | char *data = bvec_kmap_irq(bv, &flags); |
401 | memset(data, 0, bv->bv_len); |
402 | flush_dcache_page(bv->bv_page); |
403 | bvec_kunmap_irq(data, &flags); |
404 | } |
405 | } |
406 | EXPORT_SYMBOL(zero_fill_bio); |
407 | |
408 | /** |
409 | * bio_put - release a reference to a bio |
410 | * @bio: bio to release reference to |
411 | * |
412 | * Description: |
413 | * Put a reference to a &struct bio, either one you have gotten with |
414 | * bio_alloc, bio_get or bio_clone. The last put of a bio will free it. |
415 | **/ |
416 | void bio_put(struct bio *bio) |
417 | { |
418 | BIO_BUG_ON(!atomic_read(&bio->bi_cnt)); |
419 | |
420 | /* |
421 | * last put frees it |
422 | */ |
423 | if (atomic_dec_and_test(&bio->bi_cnt)) { |
424 | bio_disassociate_task(bio); |
425 | bio->bi_next = NULL; |
426 | bio->bi_destructor(bio); |
427 | } |
428 | } |
429 | EXPORT_SYMBOL(bio_put); |
430 | |
431 | inline int bio_phys_segments(struct request_queue *q, struct bio *bio) |
432 | { |
433 | if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) |
434 | blk_recount_segments(q, bio); |
435 | |
436 | return bio->bi_phys_segments; |
437 | } |
438 | EXPORT_SYMBOL(bio_phys_segments); |
439 | |
440 | /** |
441 | * __bio_clone - clone a bio |
442 | * @bio: destination bio |
443 | * @bio_src: bio to clone |
444 | * |
445 | * Clone a &bio. Caller will own the returned bio, but not |
446 | * the actual data it points to. Reference count of returned |
447 | * bio will be one. |
448 | */ |
449 | void __bio_clone(struct bio *bio, struct bio *bio_src) |
450 | { |
451 | memcpy(bio->bi_io_vec, bio_src->bi_io_vec, |
452 | bio_src->bi_max_vecs * sizeof(struct bio_vec)); |
453 | |
454 | /* |
455 | * most users will be overriding ->bi_bdev with a new target, |
456 | * so we don't set nor calculate new physical/hw segment counts here |
457 | */ |
458 | bio->bi_sector = bio_src->bi_sector; |
459 | bio->bi_bdev = bio_src->bi_bdev; |
460 | bio->bi_flags |= 1 << BIO_CLONED; |
461 | bio->bi_rw = bio_src->bi_rw; |
462 | bio->bi_vcnt = bio_src->bi_vcnt; |
463 | bio->bi_size = bio_src->bi_size; |
464 | bio->bi_idx = bio_src->bi_idx; |
465 | } |
466 | EXPORT_SYMBOL(__bio_clone); |
467 | |
468 | /** |
469 | * bio_clone - clone a bio |
470 | * @bio: bio to clone |
471 | * @gfp_mask: allocation priority |
472 | * |
473 | * Like __bio_clone, only also allocates the returned bio |
474 | */ |
475 | struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask) |
476 | { |
477 | struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set); |
478 | |
479 | if (!b) |
480 | return NULL; |
481 | |
482 | b->bi_destructor = bio_fs_destructor; |
483 | __bio_clone(b, bio); |
484 | |
485 | if (bio_integrity(bio)) { |
486 | int ret; |
487 | |
488 | ret = bio_integrity_clone(b, bio, gfp_mask, fs_bio_set); |
489 | |
490 | if (ret < 0) { |
491 | bio_put(b); |
492 | return NULL; |
493 | } |
494 | } |
495 | |
496 | return b; |
497 | } |
498 | EXPORT_SYMBOL(bio_clone); |
499 | |
500 | /** |
501 | * bio_get_nr_vecs - return approx number of vecs |
502 | * @bdev: I/O target |
503 | * |
504 | * Return the approximate number of pages we can send to this target. |
505 | * There's no guarantee that you will be able to fit this number of pages |
506 | * into a bio, it does not account for dynamic restrictions that vary |
507 | * on offset. |
508 | */ |
509 | int bio_get_nr_vecs(struct block_device *bdev) |
510 | { |
511 | struct request_queue *q = bdev_get_queue(bdev); |
512 | int nr_pages; |
513 | |
514 | nr_pages = min_t(unsigned, |
515 | queue_max_segments(q), |
516 | queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1); |
517 | |
518 | return min_t(unsigned, nr_pages, BIO_MAX_PAGES); |
519 | |
520 | } |
521 | EXPORT_SYMBOL(bio_get_nr_vecs); |
522 | |
523 | static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page |
524 | *page, unsigned int len, unsigned int offset, |
525 | unsigned short max_sectors) |
526 | { |
527 | int retried_segments = 0; |
528 | struct bio_vec *bvec; |
529 | |
530 | /* |
531 | * cloned bio must not modify vec list |
532 | */ |
533 | if (unlikely(bio_flagged(bio, BIO_CLONED))) |
534 | return 0; |
535 | |
536 | if (((bio->bi_size + len) >> 9) > max_sectors) |
537 | return 0; |
538 | |
539 | /* |
540 | * For filesystems with a blocksize smaller than the pagesize |
541 | * we will often be called with the same page as last time and |
542 | * a consecutive offset. Optimize this special case. |
543 | */ |
544 | if (bio->bi_vcnt > 0) { |
545 | struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1]; |
546 | |
547 | if (page == prev->bv_page && |
548 | offset == prev->bv_offset + prev->bv_len) { |
549 | unsigned int prev_bv_len = prev->bv_len; |
550 | prev->bv_len += len; |
551 | |
552 | if (q->merge_bvec_fn) { |
553 | struct bvec_merge_data bvm = { |
554 | /* prev_bvec is already charged in |
555 | bi_size, discharge it in order to |
556 | simulate merging updated prev_bvec |
557 | as new bvec. */ |
558 | .bi_bdev = bio->bi_bdev, |
559 | .bi_sector = bio->bi_sector, |
560 | .bi_size = bio->bi_size - prev_bv_len, |
561 | .bi_rw = bio->bi_rw, |
562 | }; |
563 | |
564 | if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) { |
565 | prev->bv_len -= len; |
566 | return 0; |
567 | } |
568 | } |
569 | |
570 | goto done; |
571 | } |
572 | } |
573 | |
574 | if (bio->bi_vcnt >= bio->bi_max_vecs) |
575 | return 0; |
576 | |
577 | /* |
578 | * we might lose a segment or two here, but rather that than |
579 | * make this too complex. |
580 | */ |
581 | |
582 | while (bio->bi_phys_segments >= queue_max_segments(q)) { |
583 | |
584 | if (retried_segments) |
585 | return 0; |
586 | |
587 | retried_segments = 1; |
588 | blk_recount_segments(q, bio); |
589 | } |
590 | |
591 | /* |
592 | * setup the new entry, we might clear it again later if we |
593 | * cannot add the page |
594 | */ |
595 | bvec = &bio->bi_io_vec[bio->bi_vcnt]; |
596 | bvec->bv_page = page; |
597 | bvec->bv_len = len; |
598 | bvec->bv_offset = offset; |
599 | |
600 | /* |
601 | * if queue has other restrictions (eg varying max sector size |
602 | * depending on offset), it can specify a merge_bvec_fn in the |
603 | * queue to get further control |
604 | */ |
605 | if (q->merge_bvec_fn) { |
606 | struct bvec_merge_data bvm = { |
607 | .bi_bdev = bio->bi_bdev, |
608 | .bi_sector = bio->bi_sector, |
609 | .bi_size = bio->bi_size, |
610 | .bi_rw = bio->bi_rw, |
611 | }; |
612 | |
613 | /* |
614 | * merge_bvec_fn() returns number of bytes it can accept |
615 | * at this offset |
616 | */ |
617 | if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) { |
618 | bvec->bv_page = NULL; |
619 | bvec->bv_len = 0; |
620 | bvec->bv_offset = 0; |
621 | return 0; |
622 | } |
623 | } |
624 | |
625 | /* If we may be able to merge these biovecs, force a recount */ |
626 | if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec))) |
627 | bio->bi_flags &= ~(1 << BIO_SEG_VALID); |
628 | |
629 | bio->bi_vcnt++; |
630 | bio->bi_phys_segments++; |
631 | done: |
632 | bio->bi_size += len; |
633 | return len; |
634 | } |
635 | |
636 | /** |
637 | * bio_add_pc_page - attempt to add page to bio |
638 | * @q: the target queue |
639 | * @bio: destination bio |
640 | * @page: page to add |
641 | * @len: vec entry length |
642 | * @offset: vec entry offset |
643 | * |
644 | * Attempt to add a page to the bio_vec maplist. This can fail for a |
645 | * number of reasons, such as the bio being full or target block device |
646 | * limitations. The target block device must allow bio's up to PAGE_SIZE, |
647 | * so it is always possible to add a single page to an empty bio. |
648 | * |
649 | * This should only be used by REQ_PC bios. |
650 | */ |
651 | int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page, |
652 | unsigned int len, unsigned int offset) |
653 | { |
654 | return __bio_add_page(q, bio, page, len, offset, |
655 | queue_max_hw_sectors(q)); |
656 | } |
657 | EXPORT_SYMBOL(bio_add_pc_page); |
658 | |
659 | /** |
660 | * bio_add_page - attempt to add page to bio |
661 | * @bio: destination bio |
662 | * @page: page to add |
663 | * @len: vec entry length |
664 | * @offset: vec entry offset |
665 | * |
666 | * Attempt to add a page to the bio_vec maplist. This can fail for a |
667 | * number of reasons, such as the bio being full or target block device |
668 | * limitations. The target block device must allow bio's up to PAGE_SIZE, |
669 | * so it is always possible to add a single page to an empty bio. |
670 | */ |
671 | int bio_add_page(struct bio *bio, struct page *page, unsigned int len, |
672 | unsigned int offset) |
673 | { |
674 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
675 | return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q)); |
676 | } |
677 | EXPORT_SYMBOL(bio_add_page); |
678 | |
679 | struct bio_map_data { |
680 | struct bio_vec *iovecs; |
681 | struct sg_iovec *sgvecs; |
682 | int nr_sgvecs; |
683 | int is_our_pages; |
684 | }; |
685 | |
686 | static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio, |
687 | struct sg_iovec *iov, int iov_count, |
688 | int is_our_pages) |
689 | { |
690 | memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt); |
691 | memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count); |
692 | bmd->nr_sgvecs = iov_count; |
693 | bmd->is_our_pages = is_our_pages; |
694 | bio->bi_private = bmd; |
695 | } |
696 | |
697 | static void bio_free_map_data(struct bio_map_data *bmd) |
698 | { |
699 | kfree(bmd->iovecs); |
700 | kfree(bmd->sgvecs); |
701 | kfree(bmd); |
702 | } |
703 | |
704 | static struct bio_map_data *bio_alloc_map_data(int nr_segs, |
705 | unsigned int iov_count, |
706 | gfp_t gfp_mask) |
707 | { |
708 | struct bio_map_data *bmd; |
709 | |
710 | if (iov_count > UIO_MAXIOV) |
711 | return NULL; |
712 | |
713 | bmd = kmalloc(sizeof(*bmd), gfp_mask); |
714 | if (!bmd) |
715 | return NULL; |
716 | |
717 | bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask); |
718 | if (!bmd->iovecs) { |
719 | kfree(bmd); |
720 | return NULL; |
721 | } |
722 | |
723 | bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask); |
724 | if (bmd->sgvecs) |
725 | return bmd; |
726 | |
727 | kfree(bmd->iovecs); |
728 | kfree(bmd); |
729 | return NULL; |
730 | } |
731 | |
732 | static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs, |
733 | struct sg_iovec *iov, int iov_count, |
734 | int to_user, int from_user, int do_free_page) |
735 | { |
736 | int ret = 0, i; |
737 | struct bio_vec *bvec; |
738 | int iov_idx = 0; |
739 | unsigned int iov_off = 0; |
740 | |
741 | __bio_for_each_segment(bvec, bio, i, 0) { |
742 | char *bv_addr = page_address(bvec->bv_page); |
743 | unsigned int bv_len = iovecs[i].bv_len; |
744 | |
745 | while (bv_len && iov_idx < iov_count) { |
746 | unsigned int bytes; |
747 | char __user *iov_addr; |
748 | |
749 | bytes = min_t(unsigned int, |
750 | iov[iov_idx].iov_len - iov_off, bv_len); |
751 | iov_addr = iov[iov_idx].iov_base + iov_off; |
752 | |
753 | if (!ret) { |
754 | if (to_user) |
755 | ret = copy_to_user(iov_addr, bv_addr, |
756 | bytes); |
757 | |
758 | if (from_user) |
759 | ret = copy_from_user(bv_addr, iov_addr, |
760 | bytes); |
761 | |
762 | if (ret) |
763 | ret = -EFAULT; |
764 | } |
765 | |
766 | bv_len -= bytes; |
767 | bv_addr += bytes; |
768 | iov_addr += bytes; |
769 | iov_off += bytes; |
770 | |
771 | if (iov[iov_idx].iov_len == iov_off) { |
772 | iov_idx++; |
773 | iov_off = 0; |
774 | } |
775 | } |
776 | |
777 | if (do_free_page) |
778 | __free_page(bvec->bv_page); |
779 | } |
780 | |
781 | return ret; |
782 | } |
783 | |
784 | /** |
785 | * bio_uncopy_user - finish previously mapped bio |
786 | * @bio: bio being terminated |
787 | * |
788 | * Free pages allocated from bio_copy_user() and write back data |
789 | * to user space in case of a read. |
790 | */ |
791 | int bio_uncopy_user(struct bio *bio) |
792 | { |
793 | struct bio_map_data *bmd = bio->bi_private; |
794 | int ret = 0; |
795 | |
796 | if (!bio_flagged(bio, BIO_NULL_MAPPED)) |
797 | ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs, |
798 | bmd->nr_sgvecs, bio_data_dir(bio) == READ, |
799 | 0, bmd->is_our_pages); |
800 | bio_free_map_data(bmd); |
801 | bio_put(bio); |
802 | return ret; |
803 | } |
804 | EXPORT_SYMBOL(bio_uncopy_user); |
805 | |
806 | /** |
807 | * bio_copy_user_iov - copy user data to bio |
808 | * @q: destination block queue |
809 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
810 | * @iov: the iovec. |
811 | * @iov_count: number of elements in the iovec |
812 | * @write_to_vm: bool indicating writing to pages or not |
813 | * @gfp_mask: memory allocation flags |
814 | * |
815 | * Prepares and returns a bio for indirect user io, bouncing data |
816 | * to/from kernel pages as necessary. Must be paired with |
817 | * call bio_uncopy_user() on io completion. |
818 | */ |
819 | struct bio *bio_copy_user_iov(struct request_queue *q, |
820 | struct rq_map_data *map_data, |
821 | struct sg_iovec *iov, int iov_count, |
822 | int write_to_vm, gfp_t gfp_mask) |
823 | { |
824 | struct bio_map_data *bmd; |
825 | struct bio_vec *bvec; |
826 | struct page *page; |
827 | struct bio *bio; |
828 | int i, ret; |
829 | int nr_pages = 0; |
830 | unsigned int len = 0; |
831 | unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0; |
832 | |
833 | for (i = 0; i < iov_count; i++) { |
834 | unsigned long uaddr; |
835 | unsigned long end; |
836 | unsigned long start; |
837 | |
838 | uaddr = (unsigned long)iov[i].iov_base; |
839 | end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
840 | start = uaddr >> PAGE_SHIFT; |
841 | |
842 | /* |
843 | * Overflow, abort |
844 | */ |
845 | if (end < start) |
846 | return ERR_PTR(-EINVAL); |
847 | |
848 | nr_pages += end - start; |
849 | len += iov[i].iov_len; |
850 | } |
851 | |
852 | if (offset) |
853 | nr_pages++; |
854 | |
855 | bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask); |
856 | if (!bmd) |
857 | return ERR_PTR(-ENOMEM); |
858 | |
859 | ret = -ENOMEM; |
860 | bio = bio_kmalloc(gfp_mask, nr_pages); |
861 | if (!bio) |
862 | goto out_bmd; |
863 | |
864 | if (!write_to_vm) |
865 | bio->bi_rw |= REQ_WRITE; |
866 | |
867 | ret = 0; |
868 | |
869 | if (map_data) { |
870 | nr_pages = 1 << map_data->page_order; |
871 | i = map_data->offset / PAGE_SIZE; |
872 | } |
873 | while (len) { |
874 | unsigned int bytes = PAGE_SIZE; |
875 | |
876 | bytes -= offset; |
877 | |
878 | if (bytes > len) |
879 | bytes = len; |
880 | |
881 | if (map_data) { |
882 | if (i == map_data->nr_entries * nr_pages) { |
883 | ret = -ENOMEM; |
884 | break; |
885 | } |
886 | |
887 | page = map_data->pages[i / nr_pages]; |
888 | page += (i % nr_pages); |
889 | |
890 | i++; |
891 | } else { |
892 | page = alloc_page(q->bounce_gfp | gfp_mask); |
893 | if (!page) { |
894 | ret = -ENOMEM; |
895 | break; |
896 | } |
897 | } |
898 | |
899 | if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) |
900 | break; |
901 | |
902 | len -= bytes; |
903 | offset = 0; |
904 | } |
905 | |
906 | if (ret) |
907 | goto cleanup; |
908 | |
909 | /* |
910 | * success |
911 | */ |
912 | if ((!write_to_vm && (!map_data || !map_data->null_mapped)) || |
913 | (map_data && map_data->from_user)) { |
914 | ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0); |
915 | if (ret) |
916 | goto cleanup; |
917 | } |
918 | |
919 | bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1); |
920 | return bio; |
921 | cleanup: |
922 | if (!map_data) |
923 | bio_for_each_segment(bvec, bio, i) |
924 | __free_page(bvec->bv_page); |
925 | |
926 | bio_put(bio); |
927 | out_bmd: |
928 | bio_free_map_data(bmd); |
929 | return ERR_PTR(ret); |
930 | } |
931 | |
932 | /** |
933 | * bio_copy_user - copy user data to bio |
934 | * @q: destination block queue |
935 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
936 | * @uaddr: start of user address |
937 | * @len: length in bytes |
938 | * @write_to_vm: bool indicating writing to pages or not |
939 | * @gfp_mask: memory allocation flags |
940 | * |
941 | * Prepares and returns a bio for indirect user io, bouncing data |
942 | * to/from kernel pages as necessary. Must be paired with |
943 | * call bio_uncopy_user() on io completion. |
944 | */ |
945 | struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data, |
946 | unsigned long uaddr, unsigned int len, |
947 | int write_to_vm, gfp_t gfp_mask) |
948 | { |
949 | struct sg_iovec iov; |
950 | |
951 | iov.iov_base = (void __user *)uaddr; |
952 | iov.iov_len = len; |
953 | |
954 | return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask); |
955 | } |
956 | EXPORT_SYMBOL(bio_copy_user); |
957 | |
958 | static struct bio *__bio_map_user_iov(struct request_queue *q, |
959 | struct block_device *bdev, |
960 | struct sg_iovec *iov, int iov_count, |
961 | int write_to_vm, gfp_t gfp_mask) |
962 | { |
963 | int i, j; |
964 | int nr_pages = 0; |
965 | struct page **pages; |
966 | struct bio *bio; |
967 | int cur_page = 0; |
968 | int ret, offset; |
969 | |
970 | for (i = 0; i < iov_count; i++) { |
971 | unsigned long uaddr = (unsigned long)iov[i].iov_base; |
972 | unsigned long len = iov[i].iov_len; |
973 | unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
974 | unsigned long start = uaddr >> PAGE_SHIFT; |
975 | |
976 | /* |
977 | * Overflow, abort |
978 | */ |
979 | if (end < start) |
980 | return ERR_PTR(-EINVAL); |
981 | |
982 | nr_pages += end - start; |
983 | /* |
984 | * buffer must be aligned to at least hardsector size for now |
985 | */ |
986 | if (uaddr & queue_dma_alignment(q)) |
987 | return ERR_PTR(-EINVAL); |
988 | } |
989 | |
990 | if (!nr_pages) |
991 | return ERR_PTR(-EINVAL); |
992 | |
993 | bio = bio_kmalloc(gfp_mask, nr_pages); |
994 | if (!bio) |
995 | return ERR_PTR(-ENOMEM); |
996 | |
997 | ret = -ENOMEM; |
998 | pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask); |
999 | if (!pages) |
1000 | goto out; |
1001 | |
1002 | for (i = 0; i < iov_count; i++) { |
1003 | unsigned long uaddr = (unsigned long)iov[i].iov_base; |
1004 | unsigned long len = iov[i].iov_len; |
1005 | unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1006 | unsigned long start = uaddr >> PAGE_SHIFT; |
1007 | const int local_nr_pages = end - start; |
1008 | const int page_limit = cur_page + local_nr_pages; |
1009 | |
1010 | ret = get_user_pages_fast(uaddr, local_nr_pages, |
1011 | write_to_vm, &pages[cur_page]); |
1012 | if (ret < local_nr_pages) { |
1013 | ret = -EFAULT; |
1014 | goto out_unmap; |
1015 | } |
1016 | |
1017 | offset = uaddr & ~PAGE_MASK; |
1018 | for (j = cur_page; j < page_limit; j++) { |
1019 | unsigned int bytes = PAGE_SIZE - offset; |
1020 | |
1021 | if (len <= 0) |
1022 | break; |
1023 | |
1024 | if (bytes > len) |
1025 | bytes = len; |
1026 | |
1027 | /* |
1028 | * sorry... |
1029 | */ |
1030 | if (bio_add_pc_page(q, bio, pages[j], bytes, offset) < |
1031 | bytes) |
1032 | break; |
1033 | |
1034 | len -= bytes; |
1035 | offset = 0; |
1036 | } |
1037 | |
1038 | cur_page = j; |
1039 | /* |
1040 | * release the pages we didn't map into the bio, if any |
1041 | */ |
1042 | while (j < page_limit) |
1043 | page_cache_release(pages[j++]); |
1044 | } |
1045 | |
1046 | kfree(pages); |
1047 | |
1048 | /* |
1049 | * set data direction, and check if mapped pages need bouncing |
1050 | */ |
1051 | if (!write_to_vm) |
1052 | bio->bi_rw |= REQ_WRITE; |
1053 | |
1054 | bio->bi_bdev = bdev; |
1055 | bio->bi_flags |= (1 << BIO_USER_MAPPED); |
1056 | return bio; |
1057 | |
1058 | out_unmap: |
1059 | for (i = 0; i < nr_pages; i++) { |
1060 | if(!pages[i]) |
1061 | break; |
1062 | page_cache_release(pages[i]); |
1063 | } |
1064 | out: |
1065 | kfree(pages); |
1066 | bio_put(bio); |
1067 | return ERR_PTR(ret); |
1068 | } |
1069 | |
1070 | /** |
1071 | * bio_map_user - map user address into bio |
1072 | * @q: the struct request_queue for the bio |
1073 | * @bdev: destination block device |
1074 | * @uaddr: start of user address |
1075 | * @len: length in bytes |
1076 | * @write_to_vm: bool indicating writing to pages or not |
1077 | * @gfp_mask: memory allocation flags |
1078 | * |
1079 | * Map the user space address into a bio suitable for io to a block |
1080 | * device. Returns an error pointer in case of error. |
1081 | */ |
1082 | struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev, |
1083 | unsigned long uaddr, unsigned int len, int write_to_vm, |
1084 | gfp_t gfp_mask) |
1085 | { |
1086 | struct sg_iovec iov; |
1087 | |
1088 | iov.iov_base = (void __user *)uaddr; |
1089 | iov.iov_len = len; |
1090 | |
1091 | return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask); |
1092 | } |
1093 | EXPORT_SYMBOL(bio_map_user); |
1094 | |
1095 | /** |
1096 | * bio_map_user_iov - map user sg_iovec table into bio |
1097 | * @q: the struct request_queue for the bio |
1098 | * @bdev: destination block device |
1099 | * @iov: the iovec. |
1100 | * @iov_count: number of elements in the iovec |
1101 | * @write_to_vm: bool indicating writing to pages or not |
1102 | * @gfp_mask: memory allocation flags |
1103 | * |
1104 | * Map the user space address into a bio suitable for io to a block |
1105 | * device. Returns an error pointer in case of error. |
1106 | */ |
1107 | struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev, |
1108 | struct sg_iovec *iov, int iov_count, |
1109 | int write_to_vm, gfp_t gfp_mask) |
1110 | { |
1111 | struct bio *bio; |
1112 | |
1113 | bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm, |
1114 | gfp_mask); |
1115 | if (IS_ERR(bio)) |
1116 | return bio; |
1117 | |
1118 | /* |
1119 | * subtle -- if __bio_map_user() ended up bouncing a bio, |
1120 | * it would normally disappear when its bi_end_io is run. |
1121 | * however, we need it for the unmap, so grab an extra |
1122 | * reference to it |
1123 | */ |
1124 | bio_get(bio); |
1125 | |
1126 | return bio; |
1127 | } |
1128 | |
1129 | static void __bio_unmap_user(struct bio *bio) |
1130 | { |
1131 | struct bio_vec *bvec; |
1132 | int i; |
1133 | |
1134 | /* |
1135 | * make sure we dirty pages we wrote to |
1136 | */ |
1137 | __bio_for_each_segment(bvec, bio, i, 0) { |
1138 | if (bio_data_dir(bio) == READ) |
1139 | set_page_dirty_lock(bvec->bv_page); |
1140 | |
1141 | page_cache_release(bvec->bv_page); |
1142 | } |
1143 | |
1144 | bio_put(bio); |
1145 | } |
1146 | |
1147 | /** |
1148 | * bio_unmap_user - unmap a bio |
1149 | * @bio: the bio being unmapped |
1150 | * |
1151 | * Unmap a bio previously mapped by bio_map_user(). Must be called with |
1152 | * a process context. |
1153 | * |
1154 | * bio_unmap_user() may sleep. |
1155 | */ |
1156 | void bio_unmap_user(struct bio *bio) |
1157 | { |
1158 | __bio_unmap_user(bio); |
1159 | bio_put(bio); |
1160 | } |
1161 | EXPORT_SYMBOL(bio_unmap_user); |
1162 | |
1163 | static void bio_map_kern_endio(struct bio *bio, int err) |
1164 | { |
1165 | bio_put(bio); |
1166 | } |
1167 | |
1168 | static struct bio *__bio_map_kern(struct request_queue *q, void *data, |
1169 | unsigned int len, gfp_t gfp_mask) |
1170 | { |
1171 | unsigned long kaddr = (unsigned long)data; |
1172 | unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1173 | unsigned long start = kaddr >> PAGE_SHIFT; |
1174 | const int nr_pages = end - start; |
1175 | int offset, i; |
1176 | struct bio *bio; |
1177 | |
1178 | bio = bio_kmalloc(gfp_mask, nr_pages); |
1179 | if (!bio) |
1180 | return ERR_PTR(-ENOMEM); |
1181 | |
1182 | offset = offset_in_page(kaddr); |
1183 | for (i = 0; i < nr_pages; i++) { |
1184 | unsigned int bytes = PAGE_SIZE - offset; |
1185 | |
1186 | if (len <= 0) |
1187 | break; |
1188 | |
1189 | if (bytes > len) |
1190 | bytes = len; |
1191 | |
1192 | if (bio_add_pc_page(q, bio, virt_to_page(data), bytes, |
1193 | offset) < bytes) |
1194 | break; |
1195 | |
1196 | data += bytes; |
1197 | len -= bytes; |
1198 | offset = 0; |
1199 | } |
1200 | |
1201 | bio->bi_end_io = bio_map_kern_endio; |
1202 | return bio; |
1203 | } |
1204 | |
1205 | /** |
1206 | * bio_map_kern - map kernel address into bio |
1207 | * @q: the struct request_queue for the bio |
1208 | * @data: pointer to buffer to map |
1209 | * @len: length in bytes |
1210 | * @gfp_mask: allocation flags for bio allocation |
1211 | * |
1212 | * Map the kernel address into a bio suitable for io to a block |
1213 | * device. Returns an error pointer in case of error. |
1214 | */ |
1215 | struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, |
1216 | gfp_t gfp_mask) |
1217 | { |
1218 | struct bio *bio; |
1219 | |
1220 | bio = __bio_map_kern(q, data, len, gfp_mask); |
1221 | if (IS_ERR(bio)) |
1222 | return bio; |
1223 | |
1224 | if (bio->bi_size == len) |
1225 | return bio; |
1226 | |
1227 | /* |
1228 | * Don't support partial mappings. |
1229 | */ |
1230 | bio_put(bio); |
1231 | return ERR_PTR(-EINVAL); |
1232 | } |
1233 | EXPORT_SYMBOL(bio_map_kern); |
1234 | |
1235 | static void bio_copy_kern_endio(struct bio *bio, int err) |
1236 | { |
1237 | struct bio_vec *bvec; |
1238 | const int read = bio_data_dir(bio) == READ; |
1239 | struct bio_map_data *bmd = bio->bi_private; |
1240 | int i; |
1241 | char *p = bmd->sgvecs[0].iov_base; |
1242 | |
1243 | __bio_for_each_segment(bvec, bio, i, 0) { |
1244 | char *addr = page_address(bvec->bv_page); |
1245 | int len = bmd->iovecs[i].bv_len; |
1246 | |
1247 | if (read) |
1248 | memcpy(p, addr, len); |
1249 | |
1250 | __free_page(bvec->bv_page); |
1251 | p += len; |
1252 | } |
1253 | |
1254 | bio_free_map_data(bmd); |
1255 | bio_put(bio); |
1256 | } |
1257 | |
1258 | /** |
1259 | * bio_copy_kern - copy kernel address into bio |
1260 | * @q: the struct request_queue for the bio |
1261 | * @data: pointer to buffer to copy |
1262 | * @len: length in bytes |
1263 | * @gfp_mask: allocation flags for bio and page allocation |
1264 | * @reading: data direction is READ |
1265 | * |
1266 | * copy the kernel address into a bio suitable for io to a block |
1267 | * device. Returns an error pointer in case of error. |
1268 | */ |
1269 | struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, |
1270 | gfp_t gfp_mask, int reading) |
1271 | { |
1272 | struct bio *bio; |
1273 | struct bio_vec *bvec; |
1274 | int i; |
1275 | |
1276 | bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask); |
1277 | if (IS_ERR(bio)) |
1278 | return bio; |
1279 | |
1280 | if (!reading) { |
1281 | void *p = data; |
1282 | |
1283 | bio_for_each_segment(bvec, bio, i) { |
1284 | char *addr = page_address(bvec->bv_page); |
1285 | |
1286 | memcpy(addr, p, bvec->bv_len); |
1287 | p += bvec->bv_len; |
1288 | } |
1289 | } |
1290 | |
1291 | bio->bi_end_io = bio_copy_kern_endio; |
1292 | |
1293 | return bio; |
1294 | } |
1295 | EXPORT_SYMBOL(bio_copy_kern); |
1296 | |
1297 | /* |
1298 | * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions |
1299 | * for performing direct-IO in BIOs. |
1300 | * |
1301 | * The problem is that we cannot run set_page_dirty() from interrupt context |
1302 | * because the required locks are not interrupt-safe. So what we can do is to |
1303 | * mark the pages dirty _before_ performing IO. And in interrupt context, |
1304 | * check that the pages are still dirty. If so, fine. If not, redirty them |
1305 | * in process context. |
1306 | * |
1307 | * We special-case compound pages here: normally this means reads into hugetlb |
1308 | * pages. The logic in here doesn't really work right for compound pages |
1309 | * because the VM does not uniformly chase down the head page in all cases. |
1310 | * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't |
1311 | * handle them at all. So we skip compound pages here at an early stage. |
1312 | * |
1313 | * Note that this code is very hard to test under normal circumstances because |
1314 | * direct-io pins the pages with get_user_pages(). This makes |
1315 | * is_page_cache_freeable return false, and the VM will not clean the pages. |
1316 | * But other code (eg, flusher threads) could clean the pages if they are mapped |
1317 | * pagecache. |
1318 | * |
1319 | * Simply disabling the call to bio_set_pages_dirty() is a good way to test the |
1320 | * deferred bio dirtying paths. |
1321 | */ |
1322 | |
1323 | /* |
1324 | * bio_set_pages_dirty() will mark all the bio's pages as dirty. |
1325 | */ |
1326 | void bio_set_pages_dirty(struct bio *bio) |
1327 | { |
1328 | struct bio_vec *bvec = bio->bi_io_vec; |
1329 | int i; |
1330 | |
1331 | for (i = 0; i < bio->bi_vcnt; i++) { |
1332 | struct page *page = bvec[i].bv_page; |
1333 | |
1334 | if (page && !PageCompound(page)) |
1335 | set_page_dirty_lock(page); |
1336 | } |
1337 | } |
1338 | |
1339 | static void bio_release_pages(struct bio *bio) |
1340 | { |
1341 | struct bio_vec *bvec = bio->bi_io_vec; |
1342 | int i; |
1343 | |
1344 | for (i = 0; i < bio->bi_vcnt; i++) { |
1345 | struct page *page = bvec[i].bv_page; |
1346 | |
1347 | if (page) |
1348 | put_page(page); |
1349 | } |
1350 | } |
1351 | |
1352 | /* |
1353 | * bio_check_pages_dirty() will check that all the BIO's pages are still dirty. |
1354 | * If they are, then fine. If, however, some pages are clean then they must |
1355 | * have been written out during the direct-IO read. So we take another ref on |
1356 | * the BIO and the offending pages and re-dirty the pages in process context. |
1357 | * |
1358 | * It is expected that bio_check_pages_dirty() will wholly own the BIO from |
1359 | * here on. It will run one page_cache_release() against each page and will |
1360 | * run one bio_put() against the BIO. |
1361 | */ |
1362 | |
1363 | static void bio_dirty_fn(struct work_struct *work); |
1364 | |
1365 | static DECLARE_WORK(bio_dirty_work, bio_dirty_fn); |
1366 | static DEFINE_SPINLOCK(bio_dirty_lock); |
1367 | static struct bio *bio_dirty_list; |
1368 | |
1369 | /* |
1370 | * This runs in process context |
1371 | */ |
1372 | static void bio_dirty_fn(struct work_struct *work) |
1373 | { |
1374 | unsigned long flags; |
1375 | struct bio *bio; |
1376 | |
1377 | spin_lock_irqsave(&bio_dirty_lock, flags); |
1378 | bio = bio_dirty_list; |
1379 | bio_dirty_list = NULL; |
1380 | spin_unlock_irqrestore(&bio_dirty_lock, flags); |
1381 | |
1382 | while (bio) { |
1383 | struct bio *next = bio->bi_private; |
1384 | |
1385 | bio_set_pages_dirty(bio); |
1386 | bio_release_pages(bio); |
1387 | bio_put(bio); |
1388 | bio = next; |
1389 | } |
1390 | } |
1391 | |
1392 | void bio_check_pages_dirty(struct bio *bio) |
1393 | { |
1394 | struct bio_vec *bvec = bio->bi_io_vec; |
1395 | int nr_clean_pages = 0; |
1396 | int i; |
1397 | |
1398 | for (i = 0; i < bio->bi_vcnt; i++) { |
1399 | struct page *page = bvec[i].bv_page; |
1400 | |
1401 | if (PageDirty(page) || PageCompound(page)) { |
1402 | page_cache_release(page); |
1403 | bvec[i].bv_page = NULL; |
1404 | } else { |
1405 | nr_clean_pages++; |
1406 | } |
1407 | } |
1408 | |
1409 | if (nr_clean_pages) { |
1410 | unsigned long flags; |
1411 | |
1412 | spin_lock_irqsave(&bio_dirty_lock, flags); |
1413 | bio->bi_private = bio_dirty_list; |
1414 | bio_dirty_list = bio; |
1415 | spin_unlock_irqrestore(&bio_dirty_lock, flags); |
1416 | schedule_work(&bio_dirty_work); |
1417 | } else { |
1418 | bio_put(bio); |
1419 | } |
1420 | } |
1421 | |
1422 | #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE |
1423 | void bio_flush_dcache_pages(struct bio *bi) |
1424 | { |
1425 | int i; |
1426 | struct bio_vec *bvec; |
1427 | |
1428 | bio_for_each_segment(bvec, bi, i) |
1429 | flush_dcache_page(bvec->bv_page); |
1430 | } |
1431 | EXPORT_SYMBOL(bio_flush_dcache_pages); |
1432 | #endif |
1433 | |
1434 | /** |
1435 | * bio_endio - end I/O on a bio |
1436 | * @bio: bio |
1437 | * @error: error, if any |
1438 | * |
1439 | * Description: |
1440 | * bio_endio() will end I/O on the whole bio. bio_endio() is the |
1441 | * preferred way to end I/O on a bio, it takes care of clearing |
1442 | * BIO_UPTODATE on error. @error is 0 on success, and and one of the |
1443 | * established -Exxxx (-EIO, for instance) error values in case |
1444 | * something went wrong. No one should call bi_end_io() directly on a |
1445 | * bio unless they own it and thus know that it has an end_io |
1446 | * function. |
1447 | **/ |
1448 | void bio_endio(struct bio *bio, int error) |
1449 | { |
1450 | if (error) |
1451 | clear_bit(BIO_UPTODATE, &bio->bi_flags); |
1452 | else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) |
1453 | error = -EIO; |
1454 | |
1455 | if (bio->bi_end_io) |
1456 | bio->bi_end_io(bio, error); |
1457 | } |
1458 | EXPORT_SYMBOL(bio_endio); |
1459 | |
1460 | void bio_pair_release(struct bio_pair *bp) |
1461 | { |
1462 | if (atomic_dec_and_test(&bp->cnt)) { |
1463 | struct bio *master = bp->bio1.bi_private; |
1464 | |
1465 | bio_endio(master, bp->error); |
1466 | mempool_free(bp, bp->bio2.bi_private); |
1467 | } |
1468 | } |
1469 | EXPORT_SYMBOL(bio_pair_release); |
1470 | |
1471 | static void bio_pair_end_1(struct bio *bi, int err) |
1472 | { |
1473 | struct bio_pair *bp = container_of(bi, struct bio_pair, bio1); |
1474 | |
1475 | if (err) |
1476 | bp->error = err; |
1477 | |
1478 | bio_pair_release(bp); |
1479 | } |
1480 | |
1481 | static void bio_pair_end_2(struct bio *bi, int err) |
1482 | { |
1483 | struct bio_pair *bp = container_of(bi, struct bio_pair, bio2); |
1484 | |
1485 | if (err) |
1486 | bp->error = err; |
1487 | |
1488 | bio_pair_release(bp); |
1489 | } |
1490 | |
1491 | /* |
1492 | * split a bio - only worry about a bio with a single page in its iovec |
1493 | */ |
1494 | struct bio_pair *bio_split(struct bio *bi, int first_sectors) |
1495 | { |
1496 | struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO); |
1497 | |
1498 | if (!bp) |
1499 | return bp; |
1500 | |
1501 | trace_block_split(bdev_get_queue(bi->bi_bdev), bi, |
1502 | bi->bi_sector + first_sectors); |
1503 | |
1504 | BUG_ON(bi->bi_vcnt != 1); |
1505 | BUG_ON(bi->bi_idx != 0); |
1506 | atomic_set(&bp->cnt, 3); |
1507 | bp->error = 0; |
1508 | bp->bio1 = *bi; |
1509 | bp->bio2 = *bi; |
1510 | bp->bio2.bi_sector += first_sectors; |
1511 | bp->bio2.bi_size -= first_sectors << 9; |
1512 | bp->bio1.bi_size = first_sectors << 9; |
1513 | |
1514 | bp->bv1 = bi->bi_io_vec[0]; |
1515 | bp->bv2 = bi->bi_io_vec[0]; |
1516 | bp->bv2.bv_offset += first_sectors << 9; |
1517 | bp->bv2.bv_len -= first_sectors << 9; |
1518 | bp->bv1.bv_len = first_sectors << 9; |
1519 | |
1520 | bp->bio1.bi_io_vec = &bp->bv1; |
1521 | bp->bio2.bi_io_vec = &bp->bv2; |
1522 | |
1523 | bp->bio1.bi_max_vecs = 1; |
1524 | bp->bio2.bi_max_vecs = 1; |
1525 | |
1526 | bp->bio1.bi_end_io = bio_pair_end_1; |
1527 | bp->bio2.bi_end_io = bio_pair_end_2; |
1528 | |
1529 | bp->bio1.bi_private = bi; |
1530 | bp->bio2.bi_private = bio_split_pool; |
1531 | |
1532 | if (bio_integrity(bi)) |
1533 | bio_integrity_split(bi, bp, first_sectors); |
1534 | |
1535 | return bp; |
1536 | } |
1537 | EXPORT_SYMBOL(bio_split); |
1538 | |
1539 | /** |
1540 | * bio_sector_offset - Find hardware sector offset in bio |
1541 | * @bio: bio to inspect |
1542 | * @index: bio_vec index |
1543 | * @offset: offset in bv_page |
1544 | * |
1545 | * Return the number of hardware sectors between beginning of bio |
1546 | * and an end point indicated by a bio_vec index and an offset |
1547 | * within that vector's page. |
1548 | */ |
1549 | sector_t bio_sector_offset(struct bio *bio, unsigned short index, |
1550 | unsigned int offset) |
1551 | { |
1552 | unsigned int sector_sz; |
1553 | struct bio_vec *bv; |
1554 | sector_t sectors; |
1555 | int i; |
1556 | |
1557 | sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue); |
1558 | sectors = 0; |
1559 | |
1560 | if (index >= bio->bi_idx) |
1561 | index = bio->bi_vcnt - 1; |
1562 | |
1563 | __bio_for_each_segment(bv, bio, i, 0) { |
1564 | if (i == index) { |
1565 | if (offset > bv->bv_offset) |
1566 | sectors += (offset - bv->bv_offset) / sector_sz; |
1567 | break; |
1568 | } |
1569 | |
1570 | sectors += bv->bv_len / sector_sz; |
1571 | } |
1572 | |
1573 | return sectors; |
1574 | } |
1575 | EXPORT_SYMBOL(bio_sector_offset); |
1576 | |
1577 | /* |
1578 | * create memory pools for biovec's in a bio_set. |
1579 | * use the global biovec slabs created for general use. |
1580 | */ |
1581 | static int biovec_create_pools(struct bio_set *bs, int pool_entries) |
1582 | { |
1583 | struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX; |
1584 | |
1585 | bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab); |
1586 | if (!bs->bvec_pool) |
1587 | return -ENOMEM; |
1588 | |
1589 | return 0; |
1590 | } |
1591 | |
1592 | static void biovec_free_pools(struct bio_set *bs) |
1593 | { |
1594 | mempool_destroy(bs->bvec_pool); |
1595 | } |
1596 | |
1597 | void bioset_free(struct bio_set *bs) |
1598 | { |
1599 | if (bs->bio_pool) |
1600 | mempool_destroy(bs->bio_pool); |
1601 | |
1602 | bioset_integrity_free(bs); |
1603 | biovec_free_pools(bs); |
1604 | bio_put_slab(bs); |
1605 | |
1606 | kfree(bs); |
1607 | } |
1608 | EXPORT_SYMBOL(bioset_free); |
1609 | |
1610 | /** |
1611 | * bioset_create - Create a bio_set |
1612 | * @pool_size: Number of bio and bio_vecs to cache in the mempool |
1613 | * @front_pad: Number of bytes to allocate in front of the returned bio |
1614 | * |
1615 | * Description: |
1616 | * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller |
1617 | * to ask for a number of bytes to be allocated in front of the bio. |
1618 | * Front pad allocation is useful for embedding the bio inside |
1619 | * another structure, to avoid allocating extra data to go with the bio. |
1620 | * Note that the bio must be embedded at the END of that structure always, |
1621 | * or things will break badly. |
1622 | */ |
1623 | struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) |
1624 | { |
1625 | unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); |
1626 | struct bio_set *bs; |
1627 | |
1628 | bs = kzalloc(sizeof(*bs), GFP_KERNEL); |
1629 | if (!bs) |
1630 | return NULL; |
1631 | |
1632 | bs->front_pad = front_pad; |
1633 | |
1634 | bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad); |
1635 | if (!bs->bio_slab) { |
1636 | kfree(bs); |
1637 | return NULL; |
1638 | } |
1639 | |
1640 | bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab); |
1641 | if (!bs->bio_pool) |
1642 | goto bad; |
1643 | |
1644 | if (!biovec_create_pools(bs, pool_size)) |
1645 | return bs; |
1646 | |
1647 | bad: |
1648 | bioset_free(bs); |
1649 | return NULL; |
1650 | } |
1651 | EXPORT_SYMBOL(bioset_create); |
1652 | |
1653 | #ifdef CONFIG_BLK_CGROUP |
1654 | /** |
1655 | * bio_associate_current - associate a bio with %current |
1656 | * @bio: target bio |
1657 | * |
1658 | * Associate @bio with %current if it hasn't been associated yet. Block |
1659 | * layer will treat @bio as if it were issued by %current no matter which |
1660 | * task actually issues it. |
1661 | * |
1662 | * This function takes an extra reference of @task's io_context and blkcg |
1663 | * which will be put when @bio is released. The caller must own @bio, |
1664 | * ensure %current->io_context exists, and is responsible for synchronizing |
1665 | * calls to this function. |
1666 | */ |
1667 | int bio_associate_current(struct bio *bio) |
1668 | { |
1669 | struct io_context *ioc; |
1670 | struct cgroup_subsys_state *css; |
1671 | |
1672 | if (bio->bi_ioc) |
1673 | return -EBUSY; |
1674 | |
1675 | ioc = current->io_context; |
1676 | if (!ioc) |
1677 | return -ENOENT; |
1678 | |
1679 | /* acquire active ref on @ioc and associate */ |
1680 | get_io_context_active(ioc); |
1681 | bio->bi_ioc = ioc; |
1682 | |
1683 | /* associate blkcg if exists */ |
1684 | rcu_read_lock(); |
1685 | css = task_subsys_state(current, blkio_subsys_id); |
1686 | if (css && css_tryget(css)) |
1687 | bio->bi_css = css; |
1688 | rcu_read_unlock(); |
1689 | |
1690 | return 0; |
1691 | } |
1692 | |
1693 | /** |
1694 | * bio_disassociate_task - undo bio_associate_current() |
1695 | * @bio: target bio |
1696 | */ |
1697 | void bio_disassociate_task(struct bio *bio) |
1698 | { |
1699 | if (bio->bi_ioc) { |
1700 | put_io_context(bio->bi_ioc); |
1701 | bio->bi_ioc = NULL; |
1702 | } |
1703 | if (bio->bi_css) { |
1704 | css_put(bio->bi_css); |
1705 | bio->bi_css = NULL; |
1706 | } |
1707 | } |
1708 | |
1709 | #endif /* CONFIG_BLK_CGROUP */ |
1710 | |
1711 | static void __init biovec_init_slabs(void) |
1712 | { |
1713 | int i; |
1714 | |
1715 | for (i = 0; i < BIOVEC_NR_POOLS; i++) { |
1716 | int size; |
1717 | struct biovec_slab *bvs = bvec_slabs + i; |
1718 | |
1719 | if (bvs->nr_vecs <= BIO_INLINE_VECS) { |
1720 | bvs->slab = NULL; |
1721 | continue; |
1722 | } |
1723 | |
1724 | size = bvs->nr_vecs * sizeof(struct bio_vec); |
1725 | bvs->slab = kmem_cache_create(bvs->name, size, 0, |
1726 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1727 | } |
1728 | } |
1729 | |
1730 | static int __init init_bio(void) |
1731 | { |
1732 | bio_slab_max = 2; |
1733 | bio_slab_nr = 0; |
1734 | bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL); |
1735 | if (!bio_slabs) |
1736 | panic("bio: can't allocate bios\n"); |
1737 | |
1738 | bio_integrity_init(); |
1739 | biovec_init_slabs(); |
1740 | |
1741 | fs_bio_set = bioset_create(BIO_POOL_SIZE, 0); |
1742 | if (!fs_bio_set) |
1743 | panic("bio: can't allocate bios\n"); |
1744 | |
1745 | if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE)) |
1746 | panic("bio: can't create integrity pool\n"); |
1747 | |
1748 | bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES, |
1749 | sizeof(struct bio_pair)); |
1750 | if (!bio_split_pool) |
1751 | panic("bio: can't create split pool\n"); |
1752 | |
1753 | return 0; |
1754 | } |
1755 | subsys_initcall(init_bio); |
1756 |
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