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