Loading...
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
38static 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) }
46static 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 */
55struct bio_set *fs_bio_set;
56
57/*
58 * Our slab pool management
59 */
60struct bio_slab {
61 struct kmem_cache *slab;
62 unsigned int slab_ref;
63 unsigned int slab_size;
64 char name[8];
65};
66static DEFINE_MUTEX(bio_slab_lock);
67static struct bio_slab *bio_slabs;
68static unsigned int bio_slab_nr, bio_slab_max;
69
70static 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;
118out_unlock:
119 mutex_unlock(&bio_slab_lock);
120 return slab;
121}
122
123static 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
148out:
149 mutex_unlock(&bio_slab_lock);
150}
151
152unsigned int bvec_nr_vecs(unsigned short idx)
153{
154 return bvec_slabs[idx].nr_vecs;
155}
156
157void 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
170struct 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) {
206fallback:
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
233void 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}
252EXPORT_SYMBOL(bio_free);
253
254void 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}
261EXPORT_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 **/
278struct 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 }
305out_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
311err_free:
312 mempool_free(p, bs->bio_pool);
313 return NULL;
314}
315EXPORT_SYMBOL(bio_alloc_bioset);
316
317static 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 */
341struct 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}
350EXPORT_SYMBOL(bio_alloc);
351
352static 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 **/
369struct 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}
389EXPORT_SYMBOL(bio_kmalloc);
390
391void 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}
404EXPORT_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 **/
414void 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}
426EXPORT_SYMBOL(bio_put);
427
428inline 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}
435EXPORT_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 */
446void __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}
463EXPORT_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 */
472struct 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}
495EXPORT_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 */
506int 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}
517EXPORT_SYMBOL(bio_get_nr_vecs);
518
519static 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 */
647int 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}
653EXPORT_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 */
667int 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}
673EXPORT_SYMBOL(bio_add_page);
674
675struct bio_map_data {
676 struct bio_vec *iovecs;
677 struct sg_iovec *sgvecs;
678 int nr_sgvecs;
679 int is_our_pages;
680};
681
682static 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
693static void bio_free_map_data(struct bio_map_data *bmd)
694{
695 kfree(bmd->iovecs);
696 kfree(bmd->sgvecs);
697 kfree(bmd);
698}
699
700static 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
727static 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 */
786int 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}
799EXPORT_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 */
814struct 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;
916cleanup:
917 if (!map_data)
918 bio_for_each_segment(bvec, bio, i)
919 __free_page(bvec->bv_page);
920
921 bio_put(bio);
922out_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 */
940struct 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}
951EXPORT_SYMBOL(bio_copy_user);
952
953static 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 */
1077struct 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}
1088EXPORT_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 */
1102struct 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
1124static 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 */
1151void bio_unmap_user(struct bio *bio)
1152{
1153 __bio_unmap_user(bio);
1154 bio_put(bio);
1155}
1156EXPORT_SYMBOL(bio_unmap_user);
1157
1158static void bio_map_kern_endio(struct bio *bio, int err)
1159{
1160 bio_put(bio);
1161}
1162
1163static 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 */
1210struct 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}
1228EXPORT_SYMBOL(bio_map_kern);
1229
1230static 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 */
1264struct 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}
1290EXPORT_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 */
1321void 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
1334static 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
1358static void bio_dirty_fn(struct work_struct *work);
1359
1360static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1361static DEFINE_SPINLOCK(bio_dirty_lock);
1362static struct bio *bio_dirty_list;
1363
1364/*
1365 * This runs in process context
1366 */
1367static 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
1387void 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
1418void 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}
1426EXPORT_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 **/
1443void 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}
1453EXPORT_SYMBOL(bio_endio);
1454
1455void 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}
1464EXPORT_SYMBOL(bio_pair_release);
1465
1466static 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
1476static 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 */
1489struct 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}
1532EXPORT_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 */
1544sector_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}
1570EXPORT_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 */
1576static 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
1587static void biovec_free_pools(struct bio_set *bs)
1588{
1589 mempool_destroy(bs->bvec_pool);
1590}
1591
1592void 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}
1603EXPORT_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 */
1618struct 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
1642bad:
1643 bioset_free(bs);
1644 return NULL;
1645}
1646EXPORT_SYMBOL(bioset_create);
1647
1648static 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
1667static 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}
1692subsys_initcall(init_bio);
1/*
2 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public Licens
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
16 *
17 */
18#include <linux/mm.h>
19#include <linux/swap.h>
20#include <linux/bio.h>
21#include <linux/blkdev.h>
22#include <linux/uio.h>
23#include <linux/iocontext.h>
24#include <linux/slab.h>
25#include <linux/init.h>
26#include <linux/kernel.h>
27#include <linux/export.h>
28#include <linux/mempool.h>
29#include <linux/workqueue.h>
30#include <linux/cgroup.h>
31#include <scsi/sg.h> /* for struct sg_iovec */
32
33#include <trace/events/block.h>
34
35/*
36 * Test patch to inline a certain number of bi_io_vec's inside the bio
37 * itself, to shrink a bio data allocation from two mempool calls to one
38 */
39#define BIO_INLINE_VECS 4
40
41/*
42 * if you change this list, also change bvec_alloc or things will
43 * break badly! cannot be bigger than what you can fit into an
44 * unsigned short
45 */
46#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
47static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
48 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
49};
50#undef BV
51
52/*
53 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
54 * IO code that does not need private memory pools.
55 */
56struct bio_set *fs_bio_set;
57EXPORT_SYMBOL(fs_bio_set);
58
59/*
60 * Our slab pool management
61 */
62struct bio_slab {
63 struct kmem_cache *slab;
64 unsigned int slab_ref;
65 unsigned int slab_size;
66 char name[8];
67};
68static DEFINE_MUTEX(bio_slab_lock);
69static struct bio_slab *bio_slabs;
70static unsigned int bio_slab_nr, bio_slab_max;
71
72static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
73{
74 unsigned int sz = sizeof(struct bio) + extra_size;
75 struct kmem_cache *slab = NULL;
76 struct bio_slab *bslab, *new_bio_slabs;
77 unsigned int new_bio_slab_max;
78 unsigned int i, entry = -1;
79
80 mutex_lock(&bio_slab_lock);
81
82 i = 0;
83 while (i < bio_slab_nr) {
84 bslab = &bio_slabs[i];
85
86 if (!bslab->slab && entry == -1)
87 entry = i;
88 else if (bslab->slab_size == sz) {
89 slab = bslab->slab;
90 bslab->slab_ref++;
91 break;
92 }
93 i++;
94 }
95
96 if (slab)
97 goto out_unlock;
98
99 if (bio_slab_nr == bio_slab_max && entry == -1) {
100 new_bio_slab_max = bio_slab_max << 1;
101 new_bio_slabs = krealloc(bio_slabs,
102 new_bio_slab_max * sizeof(struct bio_slab),
103 GFP_KERNEL);
104 if (!new_bio_slabs)
105 goto out_unlock;
106 bio_slab_max = new_bio_slab_max;
107 bio_slabs = new_bio_slabs;
108 }
109 if (entry == -1)
110 entry = bio_slab_nr++;
111
112 bslab = &bio_slabs[entry];
113
114 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
115 slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL);
116 if (!slab)
117 goto out_unlock;
118
119 bslab->slab = slab;
120 bslab->slab_ref = 1;
121 bslab->slab_size = sz;
122out_unlock:
123 mutex_unlock(&bio_slab_lock);
124 return slab;
125}
126
127static void bio_put_slab(struct bio_set *bs)
128{
129 struct bio_slab *bslab = NULL;
130 unsigned int i;
131
132 mutex_lock(&bio_slab_lock);
133
134 for (i = 0; i < bio_slab_nr; i++) {
135 if (bs->bio_slab == bio_slabs[i].slab) {
136 bslab = &bio_slabs[i];
137 break;
138 }
139 }
140
141 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
142 goto out;
143
144 WARN_ON(!bslab->slab_ref);
145
146 if (--bslab->slab_ref)
147 goto out;
148
149 kmem_cache_destroy(bslab->slab);
150 bslab->slab = NULL;
151
152out:
153 mutex_unlock(&bio_slab_lock);
154}
155
156unsigned int bvec_nr_vecs(unsigned short idx)
157{
158 return bvec_slabs[idx].nr_vecs;
159}
160
161void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
162{
163 BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
164
165 if (idx == BIOVEC_MAX_IDX)
166 mempool_free(bv, pool);
167 else {
168 struct biovec_slab *bvs = bvec_slabs + idx;
169
170 kmem_cache_free(bvs->slab, bv);
171 }
172}
173
174struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
175 mempool_t *pool)
176{
177 struct bio_vec *bvl;
178
179 /*
180 * see comment near bvec_array define!
181 */
182 switch (nr) {
183 case 1:
184 *idx = 0;
185 break;
186 case 2 ... 4:
187 *idx = 1;
188 break;
189 case 5 ... 16:
190 *idx = 2;
191 break;
192 case 17 ... 64:
193 *idx = 3;
194 break;
195 case 65 ... 128:
196 *idx = 4;
197 break;
198 case 129 ... BIO_MAX_PAGES:
199 *idx = 5;
200 break;
201 default:
202 return NULL;
203 }
204
205 /*
206 * idx now points to the pool we want to allocate from. only the
207 * 1-vec entry pool is mempool backed.
208 */
209 if (*idx == BIOVEC_MAX_IDX) {
210fallback:
211 bvl = mempool_alloc(pool, gfp_mask);
212 } else {
213 struct biovec_slab *bvs = bvec_slabs + *idx;
214 gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
215
216 /*
217 * Make this allocation restricted and don't dump info on
218 * allocation failures, since we'll fallback to the mempool
219 * in case of failure.
220 */
221 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
222
223 /*
224 * Try a slab allocation. If this fails and __GFP_WAIT
225 * is set, retry with the 1-entry mempool
226 */
227 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
228 if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
229 *idx = BIOVEC_MAX_IDX;
230 goto fallback;
231 }
232 }
233
234 return bvl;
235}
236
237static void __bio_free(struct bio *bio)
238{
239 bio_disassociate_task(bio);
240
241 if (bio_integrity(bio))
242 bio_integrity_free(bio);
243}
244
245static void bio_free(struct bio *bio)
246{
247 struct bio_set *bs = bio->bi_pool;
248 void *p;
249
250 __bio_free(bio);
251
252 if (bs) {
253 if (bio_flagged(bio, BIO_OWNS_VEC))
254 bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
255
256 /*
257 * If we have front padding, adjust the bio pointer before freeing
258 */
259 p = bio;
260 p -= bs->front_pad;
261
262 mempool_free(p, bs->bio_pool);
263 } else {
264 /* Bio was allocated by bio_kmalloc() */
265 kfree(bio);
266 }
267}
268
269void bio_init(struct bio *bio)
270{
271 memset(bio, 0, sizeof(*bio));
272 bio->bi_flags = 1 << BIO_UPTODATE;
273 atomic_set(&bio->bi_remaining, 1);
274 atomic_set(&bio->bi_cnt, 1);
275}
276EXPORT_SYMBOL(bio_init);
277
278/**
279 * bio_reset - reinitialize a bio
280 * @bio: bio to reset
281 *
282 * Description:
283 * After calling bio_reset(), @bio will be in the same state as a freshly
284 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
285 * preserved are the ones that are initialized by bio_alloc_bioset(). See
286 * comment in struct bio.
287 */
288void bio_reset(struct bio *bio)
289{
290 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
291
292 __bio_free(bio);
293
294 memset(bio, 0, BIO_RESET_BYTES);
295 bio->bi_flags = flags|(1 << BIO_UPTODATE);
296 atomic_set(&bio->bi_remaining, 1);
297}
298EXPORT_SYMBOL(bio_reset);
299
300static void bio_chain_endio(struct bio *bio, int error)
301{
302 bio_endio(bio->bi_private, error);
303 bio_put(bio);
304}
305
306/**
307 * bio_chain - chain bio completions
308 *
309 * The caller won't have a bi_end_io called when @bio completes - instead,
310 * @parent's bi_end_io won't be called until both @parent and @bio have
311 * completed; the chained bio will also be freed when it completes.
312 *
313 * The caller must not set bi_private or bi_end_io in @bio.
314 */
315void bio_chain(struct bio *bio, struct bio *parent)
316{
317 BUG_ON(bio->bi_private || bio->bi_end_io);
318
319 bio->bi_private = parent;
320 bio->bi_end_io = bio_chain_endio;
321 atomic_inc(&parent->bi_remaining);
322}
323EXPORT_SYMBOL(bio_chain);
324
325static void bio_alloc_rescue(struct work_struct *work)
326{
327 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
328 struct bio *bio;
329
330 while (1) {
331 spin_lock(&bs->rescue_lock);
332 bio = bio_list_pop(&bs->rescue_list);
333 spin_unlock(&bs->rescue_lock);
334
335 if (!bio)
336 break;
337
338 generic_make_request(bio);
339 }
340}
341
342static void punt_bios_to_rescuer(struct bio_set *bs)
343{
344 struct bio_list punt, nopunt;
345 struct bio *bio;
346
347 /*
348 * In order to guarantee forward progress we must punt only bios that
349 * were allocated from this bio_set; otherwise, if there was a bio on
350 * there for a stacking driver higher up in the stack, processing it
351 * could require allocating bios from this bio_set, and doing that from
352 * our own rescuer would be bad.
353 *
354 * Since bio lists are singly linked, pop them all instead of trying to
355 * remove from the middle of the list:
356 */
357
358 bio_list_init(&punt);
359 bio_list_init(&nopunt);
360
361 while ((bio = bio_list_pop(current->bio_list)))
362 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
363
364 *current->bio_list = nopunt;
365
366 spin_lock(&bs->rescue_lock);
367 bio_list_merge(&bs->rescue_list, &punt);
368 spin_unlock(&bs->rescue_lock);
369
370 queue_work(bs->rescue_workqueue, &bs->rescue_work);
371}
372
373/**
374 * bio_alloc_bioset - allocate a bio for I/O
375 * @gfp_mask: the GFP_ mask given to the slab allocator
376 * @nr_iovecs: number of iovecs to pre-allocate
377 * @bs: the bio_set to allocate from.
378 *
379 * Description:
380 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
381 * backed by the @bs's mempool.
382 *
383 * When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
384 * able to allocate a bio. This is due to the mempool guarantees. To make this
385 * work, callers must never allocate more than 1 bio at a time from this pool.
386 * Callers that need to allocate more than 1 bio must always submit the
387 * previously allocated bio for IO before attempting to allocate a new one.
388 * Failure to do so can cause deadlocks under memory pressure.
389 *
390 * Note that when running under generic_make_request() (i.e. any block
391 * driver), bios are not submitted until after you return - see the code in
392 * generic_make_request() that converts recursion into iteration, to prevent
393 * stack overflows.
394 *
395 * This would normally mean allocating multiple bios under
396 * generic_make_request() would be susceptible to deadlocks, but we have
397 * deadlock avoidance code that resubmits any blocked bios from a rescuer
398 * thread.
399 *
400 * However, we do not guarantee forward progress for allocations from other
401 * mempools. Doing multiple allocations from the same mempool under
402 * generic_make_request() should be avoided - instead, use bio_set's front_pad
403 * for per bio allocations.
404 *
405 * RETURNS:
406 * Pointer to new bio on success, NULL on failure.
407 */
408struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
409{
410 gfp_t saved_gfp = gfp_mask;
411 unsigned front_pad;
412 unsigned inline_vecs;
413 unsigned long idx = BIO_POOL_NONE;
414 struct bio_vec *bvl = NULL;
415 struct bio *bio;
416 void *p;
417
418 if (!bs) {
419 if (nr_iovecs > UIO_MAXIOV)
420 return NULL;
421
422 p = kmalloc(sizeof(struct bio) +
423 nr_iovecs * sizeof(struct bio_vec),
424 gfp_mask);
425 front_pad = 0;
426 inline_vecs = nr_iovecs;
427 } else {
428 /*
429 * generic_make_request() converts recursion to iteration; this
430 * means if we're running beneath it, any bios we allocate and
431 * submit will not be submitted (and thus freed) until after we
432 * return.
433 *
434 * This exposes us to a potential deadlock if we allocate
435 * multiple bios from the same bio_set() while running
436 * underneath generic_make_request(). If we were to allocate
437 * multiple bios (say a stacking block driver that was splitting
438 * bios), we would deadlock if we exhausted the mempool's
439 * reserve.
440 *
441 * We solve this, and guarantee forward progress, with a rescuer
442 * workqueue per bio_set. If we go to allocate and there are
443 * bios on current->bio_list, we first try the allocation
444 * without __GFP_WAIT; if that fails, we punt those bios we
445 * would be blocking to the rescuer workqueue before we retry
446 * with the original gfp_flags.
447 */
448
449 if (current->bio_list && !bio_list_empty(current->bio_list))
450 gfp_mask &= ~__GFP_WAIT;
451
452 p = mempool_alloc(bs->bio_pool, gfp_mask);
453 if (!p && gfp_mask != saved_gfp) {
454 punt_bios_to_rescuer(bs);
455 gfp_mask = saved_gfp;
456 p = mempool_alloc(bs->bio_pool, gfp_mask);
457 }
458
459 front_pad = bs->front_pad;
460 inline_vecs = BIO_INLINE_VECS;
461 }
462
463 if (unlikely(!p))
464 return NULL;
465
466 bio = p + front_pad;
467 bio_init(bio);
468
469 if (nr_iovecs > inline_vecs) {
470 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
471 if (!bvl && gfp_mask != saved_gfp) {
472 punt_bios_to_rescuer(bs);
473 gfp_mask = saved_gfp;
474 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
475 }
476
477 if (unlikely(!bvl))
478 goto err_free;
479
480 bio->bi_flags |= 1 << BIO_OWNS_VEC;
481 } else if (nr_iovecs) {
482 bvl = bio->bi_inline_vecs;
483 }
484
485 bio->bi_pool = bs;
486 bio->bi_flags |= idx << BIO_POOL_OFFSET;
487 bio->bi_max_vecs = nr_iovecs;
488 bio->bi_io_vec = bvl;
489 return bio;
490
491err_free:
492 mempool_free(p, bs->bio_pool);
493 return NULL;
494}
495EXPORT_SYMBOL(bio_alloc_bioset);
496
497void zero_fill_bio(struct bio *bio)
498{
499 unsigned long flags;
500 struct bio_vec bv;
501 struct bvec_iter iter;
502
503 bio_for_each_segment(bv, bio, iter) {
504 char *data = bvec_kmap_irq(&bv, &flags);
505 memset(data, 0, bv.bv_len);
506 flush_dcache_page(bv.bv_page);
507 bvec_kunmap_irq(data, &flags);
508 }
509}
510EXPORT_SYMBOL(zero_fill_bio);
511
512/**
513 * bio_put - release a reference to a bio
514 * @bio: bio to release reference to
515 *
516 * Description:
517 * Put a reference to a &struct bio, either one you have gotten with
518 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
519 **/
520void bio_put(struct bio *bio)
521{
522 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
523
524 /*
525 * last put frees it
526 */
527 if (atomic_dec_and_test(&bio->bi_cnt))
528 bio_free(bio);
529}
530EXPORT_SYMBOL(bio_put);
531
532inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
533{
534 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
535 blk_recount_segments(q, bio);
536
537 return bio->bi_phys_segments;
538}
539EXPORT_SYMBOL(bio_phys_segments);
540
541/**
542 * __bio_clone_fast - clone a bio that shares the original bio's biovec
543 * @bio: destination bio
544 * @bio_src: bio to clone
545 *
546 * Clone a &bio. Caller will own the returned bio, but not
547 * the actual data it points to. Reference count of returned
548 * bio will be one.
549 *
550 * Caller must ensure that @bio_src is not freed before @bio.
551 */
552void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
553{
554 BUG_ON(bio->bi_pool && BIO_POOL_IDX(bio) != BIO_POOL_NONE);
555
556 /*
557 * most users will be overriding ->bi_bdev with a new target,
558 * so we don't set nor calculate new physical/hw segment counts here
559 */
560 bio->bi_bdev = bio_src->bi_bdev;
561 bio->bi_flags |= 1 << BIO_CLONED;
562 bio->bi_rw = bio_src->bi_rw;
563 bio->bi_iter = bio_src->bi_iter;
564 bio->bi_io_vec = bio_src->bi_io_vec;
565}
566EXPORT_SYMBOL(__bio_clone_fast);
567
568/**
569 * bio_clone_fast - clone a bio that shares the original bio's biovec
570 * @bio: bio to clone
571 * @gfp_mask: allocation priority
572 * @bs: bio_set to allocate from
573 *
574 * Like __bio_clone_fast, only also allocates the returned bio
575 */
576struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
577{
578 struct bio *b;
579
580 b = bio_alloc_bioset(gfp_mask, 0, bs);
581 if (!b)
582 return NULL;
583
584 __bio_clone_fast(b, bio);
585
586 if (bio_integrity(bio)) {
587 int ret;
588
589 ret = bio_integrity_clone(b, bio, gfp_mask);
590
591 if (ret < 0) {
592 bio_put(b);
593 return NULL;
594 }
595 }
596
597 return b;
598}
599EXPORT_SYMBOL(bio_clone_fast);
600
601/**
602 * bio_clone_bioset - clone a bio
603 * @bio_src: bio to clone
604 * @gfp_mask: allocation priority
605 * @bs: bio_set to allocate from
606 *
607 * Clone bio. Caller will own the returned bio, but not the actual data it
608 * points to. Reference count of returned bio will be one.
609 */
610struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
611 struct bio_set *bs)
612{
613 struct bvec_iter iter;
614 struct bio_vec bv;
615 struct bio *bio;
616
617 /*
618 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
619 * bio_src->bi_io_vec to bio->bi_io_vec.
620 *
621 * We can't do that anymore, because:
622 *
623 * - The point of cloning the biovec is to produce a bio with a biovec
624 * the caller can modify: bi_idx and bi_bvec_done should be 0.
625 *
626 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if
627 * we tried to clone the whole thing bio_alloc_bioset() would fail.
628 * But the clone should succeed as long as the number of biovecs we
629 * actually need to allocate is fewer than BIO_MAX_PAGES.
630 *
631 * - Lastly, bi_vcnt should not be looked at or relied upon by code
632 * that does not own the bio - reason being drivers don't use it for
633 * iterating over the biovec anymore, so expecting it to be kept up
634 * to date (i.e. for clones that share the parent biovec) is just
635 * asking for trouble and would force extra work on
636 * __bio_clone_fast() anyways.
637 */
638
639 bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
640 if (!bio)
641 return NULL;
642
643 bio->bi_bdev = bio_src->bi_bdev;
644 bio->bi_rw = bio_src->bi_rw;
645 bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
646 bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
647
648 if (bio->bi_rw & REQ_DISCARD)
649 goto integrity_clone;
650
651 if (bio->bi_rw & REQ_WRITE_SAME) {
652 bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
653 goto integrity_clone;
654 }
655
656 bio_for_each_segment(bv, bio_src, iter)
657 bio->bi_io_vec[bio->bi_vcnt++] = bv;
658
659integrity_clone:
660 if (bio_integrity(bio_src)) {
661 int ret;
662
663 ret = bio_integrity_clone(bio, bio_src, gfp_mask);
664 if (ret < 0) {
665 bio_put(bio);
666 return NULL;
667 }
668 }
669
670 return bio;
671}
672EXPORT_SYMBOL(bio_clone_bioset);
673
674/**
675 * bio_get_nr_vecs - return approx number of vecs
676 * @bdev: I/O target
677 *
678 * Return the approximate number of pages we can send to this target.
679 * There's no guarantee that you will be able to fit this number of pages
680 * into a bio, it does not account for dynamic restrictions that vary
681 * on offset.
682 */
683int bio_get_nr_vecs(struct block_device *bdev)
684{
685 struct request_queue *q = bdev_get_queue(bdev);
686 int nr_pages;
687
688 nr_pages = min_t(unsigned,
689 queue_max_segments(q),
690 queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
691
692 return min_t(unsigned, nr_pages, BIO_MAX_PAGES);
693
694}
695EXPORT_SYMBOL(bio_get_nr_vecs);
696
697static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
698 *page, unsigned int len, unsigned int offset,
699 unsigned int max_sectors)
700{
701 int retried_segments = 0;
702 struct bio_vec *bvec;
703
704 /*
705 * cloned bio must not modify vec list
706 */
707 if (unlikely(bio_flagged(bio, BIO_CLONED)))
708 return 0;
709
710 if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
711 return 0;
712
713 /*
714 * For filesystems with a blocksize smaller than the pagesize
715 * we will often be called with the same page as last time and
716 * a consecutive offset. Optimize this special case.
717 */
718 if (bio->bi_vcnt > 0) {
719 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
720
721 if (page == prev->bv_page &&
722 offset == prev->bv_offset + prev->bv_len) {
723 unsigned int prev_bv_len = prev->bv_len;
724 prev->bv_len += len;
725
726 if (q->merge_bvec_fn) {
727 struct bvec_merge_data bvm = {
728 /* prev_bvec is already charged in
729 bi_size, discharge it in order to
730 simulate merging updated prev_bvec
731 as new bvec. */
732 .bi_bdev = bio->bi_bdev,
733 .bi_sector = bio->bi_iter.bi_sector,
734 .bi_size = bio->bi_iter.bi_size -
735 prev_bv_len,
736 .bi_rw = bio->bi_rw,
737 };
738
739 if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
740 prev->bv_len -= len;
741 return 0;
742 }
743 }
744
745 goto done;
746 }
747 }
748
749 if (bio->bi_vcnt >= bio->bi_max_vecs)
750 return 0;
751
752 /*
753 * we might lose a segment or two here, but rather that than
754 * make this too complex.
755 */
756
757 while (bio->bi_phys_segments >= queue_max_segments(q)) {
758
759 if (retried_segments)
760 return 0;
761
762 retried_segments = 1;
763 blk_recount_segments(q, bio);
764 }
765
766 /*
767 * setup the new entry, we might clear it again later if we
768 * cannot add the page
769 */
770 bvec = &bio->bi_io_vec[bio->bi_vcnt];
771 bvec->bv_page = page;
772 bvec->bv_len = len;
773 bvec->bv_offset = offset;
774
775 /*
776 * if queue has other restrictions (eg varying max sector size
777 * depending on offset), it can specify a merge_bvec_fn in the
778 * queue to get further control
779 */
780 if (q->merge_bvec_fn) {
781 struct bvec_merge_data bvm = {
782 .bi_bdev = bio->bi_bdev,
783 .bi_sector = bio->bi_iter.bi_sector,
784 .bi_size = bio->bi_iter.bi_size,
785 .bi_rw = bio->bi_rw,
786 };
787
788 /*
789 * merge_bvec_fn() returns number of bytes it can accept
790 * at this offset
791 */
792 if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
793 bvec->bv_page = NULL;
794 bvec->bv_len = 0;
795 bvec->bv_offset = 0;
796 return 0;
797 }
798 }
799
800 /* If we may be able to merge these biovecs, force a recount */
801 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
802 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
803
804 bio->bi_vcnt++;
805 bio->bi_phys_segments++;
806 done:
807 bio->bi_iter.bi_size += len;
808 return len;
809}
810
811/**
812 * bio_add_pc_page - attempt to add page to bio
813 * @q: the target queue
814 * @bio: destination bio
815 * @page: page to add
816 * @len: vec entry length
817 * @offset: vec entry offset
818 *
819 * Attempt to add a page to the bio_vec maplist. This can fail for a
820 * number of reasons, such as the bio being full or target block device
821 * limitations. The target block device must allow bio's up to PAGE_SIZE,
822 * so it is always possible to add a single page to an empty bio.
823 *
824 * This should only be used by REQ_PC bios.
825 */
826int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
827 unsigned int len, unsigned int offset)
828{
829 return __bio_add_page(q, bio, page, len, offset,
830 queue_max_hw_sectors(q));
831}
832EXPORT_SYMBOL(bio_add_pc_page);
833
834/**
835 * bio_add_page - attempt to add page to bio
836 * @bio: destination bio
837 * @page: page to add
838 * @len: vec entry length
839 * @offset: vec entry offset
840 *
841 * Attempt to add a page to the bio_vec maplist. This can fail for a
842 * number of reasons, such as the bio being full or target block device
843 * limitations. The target block device must allow bio's up to PAGE_SIZE,
844 * so it is always possible to add a single page to an empty bio.
845 */
846int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
847 unsigned int offset)
848{
849 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
850 return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
851}
852EXPORT_SYMBOL(bio_add_page);
853
854struct submit_bio_ret {
855 struct completion event;
856 int error;
857};
858
859static void submit_bio_wait_endio(struct bio *bio, int error)
860{
861 struct submit_bio_ret *ret = bio->bi_private;
862
863 ret->error = error;
864 complete(&ret->event);
865}
866
867/**
868 * submit_bio_wait - submit a bio, and wait until it completes
869 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
870 * @bio: The &struct bio which describes the I/O
871 *
872 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
873 * bio_endio() on failure.
874 */
875int submit_bio_wait(int rw, struct bio *bio)
876{
877 struct submit_bio_ret ret;
878
879 rw |= REQ_SYNC;
880 init_completion(&ret.event);
881 bio->bi_private = &ret;
882 bio->bi_end_io = submit_bio_wait_endio;
883 submit_bio(rw, bio);
884 wait_for_completion(&ret.event);
885
886 return ret.error;
887}
888EXPORT_SYMBOL(submit_bio_wait);
889
890/**
891 * bio_advance - increment/complete a bio by some number of bytes
892 * @bio: bio to advance
893 * @bytes: number of bytes to complete
894 *
895 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
896 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
897 * be updated on the last bvec as well.
898 *
899 * @bio will then represent the remaining, uncompleted portion of the io.
900 */
901void bio_advance(struct bio *bio, unsigned bytes)
902{
903 if (bio_integrity(bio))
904 bio_integrity_advance(bio, bytes);
905
906 bio_advance_iter(bio, &bio->bi_iter, bytes);
907}
908EXPORT_SYMBOL(bio_advance);
909
910/**
911 * bio_alloc_pages - allocates a single page for each bvec in a bio
912 * @bio: bio to allocate pages for
913 * @gfp_mask: flags for allocation
914 *
915 * Allocates pages up to @bio->bi_vcnt.
916 *
917 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
918 * freed.
919 */
920int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
921{
922 int i;
923 struct bio_vec *bv;
924
925 bio_for_each_segment_all(bv, bio, i) {
926 bv->bv_page = alloc_page(gfp_mask);
927 if (!bv->bv_page) {
928 while (--bv >= bio->bi_io_vec)
929 __free_page(bv->bv_page);
930 return -ENOMEM;
931 }
932 }
933
934 return 0;
935}
936EXPORT_SYMBOL(bio_alloc_pages);
937
938/**
939 * bio_copy_data - copy contents of data buffers from one chain of bios to
940 * another
941 * @src: source bio list
942 * @dst: destination bio list
943 *
944 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
945 * @src and @dst as linked lists of bios.
946 *
947 * Stops when it reaches the end of either @src or @dst - that is, copies
948 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
949 */
950void bio_copy_data(struct bio *dst, struct bio *src)
951{
952 struct bvec_iter src_iter, dst_iter;
953 struct bio_vec src_bv, dst_bv;
954 void *src_p, *dst_p;
955 unsigned bytes;
956
957 src_iter = src->bi_iter;
958 dst_iter = dst->bi_iter;
959
960 while (1) {
961 if (!src_iter.bi_size) {
962 src = src->bi_next;
963 if (!src)
964 break;
965
966 src_iter = src->bi_iter;
967 }
968
969 if (!dst_iter.bi_size) {
970 dst = dst->bi_next;
971 if (!dst)
972 break;
973
974 dst_iter = dst->bi_iter;
975 }
976
977 src_bv = bio_iter_iovec(src, src_iter);
978 dst_bv = bio_iter_iovec(dst, dst_iter);
979
980 bytes = min(src_bv.bv_len, dst_bv.bv_len);
981
982 src_p = kmap_atomic(src_bv.bv_page);
983 dst_p = kmap_atomic(dst_bv.bv_page);
984
985 memcpy(dst_p + dst_bv.bv_offset,
986 src_p + src_bv.bv_offset,
987 bytes);
988
989 kunmap_atomic(dst_p);
990 kunmap_atomic(src_p);
991
992 bio_advance_iter(src, &src_iter, bytes);
993 bio_advance_iter(dst, &dst_iter, bytes);
994 }
995}
996EXPORT_SYMBOL(bio_copy_data);
997
998struct bio_map_data {
999 int nr_sgvecs;
1000 int is_our_pages;
1001 struct sg_iovec sgvecs[];
1002};
1003
1004static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
1005 const struct sg_iovec *iov, int iov_count,
1006 int is_our_pages)
1007{
1008 memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
1009 bmd->nr_sgvecs = iov_count;
1010 bmd->is_our_pages = is_our_pages;
1011 bio->bi_private = bmd;
1012}
1013
1014static struct bio_map_data *bio_alloc_map_data(int nr_segs,
1015 unsigned int iov_count,
1016 gfp_t gfp_mask)
1017{
1018 if (iov_count > UIO_MAXIOV)
1019 return NULL;
1020
1021 return kmalloc(sizeof(struct bio_map_data) +
1022 sizeof(struct sg_iovec) * iov_count, gfp_mask);
1023}
1024
1025static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_count,
1026 int to_user, int from_user, int do_free_page)
1027{
1028 int ret = 0, i;
1029 struct bio_vec *bvec;
1030 int iov_idx = 0;
1031 unsigned int iov_off = 0;
1032
1033 bio_for_each_segment_all(bvec, bio, i) {
1034 char *bv_addr = page_address(bvec->bv_page);
1035 unsigned int bv_len = bvec->bv_len;
1036
1037 while (bv_len && iov_idx < iov_count) {
1038 unsigned int bytes;
1039 char __user *iov_addr;
1040
1041 bytes = min_t(unsigned int,
1042 iov[iov_idx].iov_len - iov_off, bv_len);
1043 iov_addr = iov[iov_idx].iov_base + iov_off;
1044
1045 if (!ret) {
1046 if (to_user)
1047 ret = copy_to_user(iov_addr, bv_addr,
1048 bytes);
1049
1050 if (from_user)
1051 ret = copy_from_user(bv_addr, iov_addr,
1052 bytes);
1053
1054 if (ret)
1055 ret = -EFAULT;
1056 }
1057
1058 bv_len -= bytes;
1059 bv_addr += bytes;
1060 iov_addr += bytes;
1061 iov_off += bytes;
1062
1063 if (iov[iov_idx].iov_len == iov_off) {
1064 iov_idx++;
1065 iov_off = 0;
1066 }
1067 }
1068
1069 if (do_free_page)
1070 __free_page(bvec->bv_page);
1071 }
1072
1073 return ret;
1074}
1075
1076/**
1077 * bio_uncopy_user - finish previously mapped bio
1078 * @bio: bio being terminated
1079 *
1080 * Free pages allocated from bio_copy_user() and write back data
1081 * to user space in case of a read.
1082 */
1083int bio_uncopy_user(struct bio *bio)
1084{
1085 struct bio_map_data *bmd = bio->bi_private;
1086 struct bio_vec *bvec;
1087 int ret = 0, i;
1088
1089 if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
1090 /*
1091 * if we're in a workqueue, the request is orphaned, so
1092 * don't copy into a random user address space, just free.
1093 */
1094 if (current->mm)
1095 ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs,
1096 bio_data_dir(bio) == READ,
1097 0, bmd->is_our_pages);
1098 else if (bmd->is_our_pages)
1099 bio_for_each_segment_all(bvec, bio, i)
1100 __free_page(bvec->bv_page);
1101 }
1102 kfree(bmd);
1103 bio_put(bio);
1104 return ret;
1105}
1106EXPORT_SYMBOL(bio_uncopy_user);
1107
1108/**
1109 * bio_copy_user_iov - copy user data to bio
1110 * @q: destination block queue
1111 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1112 * @iov: the iovec.
1113 * @iov_count: number of elements in the iovec
1114 * @write_to_vm: bool indicating writing to pages or not
1115 * @gfp_mask: memory allocation flags
1116 *
1117 * Prepares and returns a bio for indirect user io, bouncing data
1118 * to/from kernel pages as necessary. Must be paired with
1119 * call bio_uncopy_user() on io completion.
1120 */
1121struct bio *bio_copy_user_iov(struct request_queue *q,
1122 struct rq_map_data *map_data,
1123 const struct sg_iovec *iov, int iov_count,
1124 int write_to_vm, gfp_t gfp_mask)
1125{
1126 struct bio_map_data *bmd;
1127 struct bio_vec *bvec;
1128 struct page *page;
1129 struct bio *bio;
1130 int i, ret;
1131 int nr_pages = 0;
1132 unsigned int len = 0;
1133 unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
1134
1135 for (i = 0; i < iov_count; i++) {
1136 unsigned long uaddr;
1137 unsigned long end;
1138 unsigned long start;
1139
1140 uaddr = (unsigned long)iov[i].iov_base;
1141 end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1142 start = uaddr >> PAGE_SHIFT;
1143
1144 /*
1145 * Overflow, abort
1146 */
1147 if (end < start)
1148 return ERR_PTR(-EINVAL);
1149
1150 nr_pages += end - start;
1151 len += iov[i].iov_len;
1152 }
1153
1154 if (offset)
1155 nr_pages++;
1156
1157 bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
1158 if (!bmd)
1159 return ERR_PTR(-ENOMEM);
1160
1161 ret = -ENOMEM;
1162 bio = bio_kmalloc(gfp_mask, nr_pages);
1163 if (!bio)
1164 goto out_bmd;
1165
1166 if (!write_to_vm)
1167 bio->bi_rw |= REQ_WRITE;
1168
1169 ret = 0;
1170
1171 if (map_data) {
1172 nr_pages = 1 << map_data->page_order;
1173 i = map_data->offset / PAGE_SIZE;
1174 }
1175 while (len) {
1176 unsigned int bytes = PAGE_SIZE;
1177
1178 bytes -= offset;
1179
1180 if (bytes > len)
1181 bytes = len;
1182
1183 if (map_data) {
1184 if (i == map_data->nr_entries * nr_pages) {
1185 ret = -ENOMEM;
1186 break;
1187 }
1188
1189 page = map_data->pages[i / nr_pages];
1190 page += (i % nr_pages);
1191
1192 i++;
1193 } else {
1194 page = alloc_page(q->bounce_gfp | gfp_mask);
1195 if (!page) {
1196 ret = -ENOMEM;
1197 break;
1198 }
1199 }
1200
1201 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
1202 break;
1203
1204 len -= bytes;
1205 offset = 0;
1206 }
1207
1208 if (ret)
1209 goto cleanup;
1210
1211 /*
1212 * success
1213 */
1214 if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
1215 (map_data && map_data->from_user)) {
1216 ret = __bio_copy_iov(bio, iov, iov_count, 0, 1, 0);
1217 if (ret)
1218 goto cleanup;
1219 }
1220
1221 bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
1222 return bio;
1223cleanup:
1224 if (!map_data)
1225 bio_for_each_segment_all(bvec, bio, i)
1226 __free_page(bvec->bv_page);
1227
1228 bio_put(bio);
1229out_bmd:
1230 kfree(bmd);
1231 return ERR_PTR(ret);
1232}
1233
1234/**
1235 * bio_copy_user - copy user data to bio
1236 * @q: destination block queue
1237 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1238 * @uaddr: start of user address
1239 * @len: length in bytes
1240 * @write_to_vm: bool indicating writing to pages or not
1241 * @gfp_mask: memory allocation flags
1242 *
1243 * Prepares and returns a bio for indirect user io, bouncing data
1244 * to/from kernel pages as necessary. Must be paired with
1245 * call bio_uncopy_user() on io completion.
1246 */
1247struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
1248 unsigned long uaddr, unsigned int len,
1249 int write_to_vm, gfp_t gfp_mask)
1250{
1251 struct sg_iovec iov;
1252
1253 iov.iov_base = (void __user *)uaddr;
1254 iov.iov_len = len;
1255
1256 return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
1257}
1258EXPORT_SYMBOL(bio_copy_user);
1259
1260static struct bio *__bio_map_user_iov(struct request_queue *q,
1261 struct block_device *bdev,
1262 const struct sg_iovec *iov, int iov_count,
1263 int write_to_vm, gfp_t gfp_mask)
1264{
1265 int i, j;
1266 int nr_pages = 0;
1267 struct page **pages;
1268 struct bio *bio;
1269 int cur_page = 0;
1270 int ret, offset;
1271
1272 for (i = 0; i < iov_count; i++) {
1273 unsigned long uaddr = (unsigned long)iov[i].iov_base;
1274 unsigned long len = iov[i].iov_len;
1275 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1276 unsigned long start = uaddr >> PAGE_SHIFT;
1277
1278 /*
1279 * Overflow, abort
1280 */
1281 if (end < start)
1282 return ERR_PTR(-EINVAL);
1283
1284 nr_pages += end - start;
1285 /*
1286 * buffer must be aligned to at least hardsector size for now
1287 */
1288 if (uaddr & queue_dma_alignment(q))
1289 return ERR_PTR(-EINVAL);
1290 }
1291
1292 if (!nr_pages)
1293 return ERR_PTR(-EINVAL);
1294
1295 bio = bio_kmalloc(gfp_mask, nr_pages);
1296 if (!bio)
1297 return ERR_PTR(-ENOMEM);
1298
1299 ret = -ENOMEM;
1300 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
1301 if (!pages)
1302 goto out;
1303
1304 for (i = 0; i < iov_count; i++) {
1305 unsigned long uaddr = (unsigned long)iov[i].iov_base;
1306 unsigned long len = iov[i].iov_len;
1307 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1308 unsigned long start = uaddr >> PAGE_SHIFT;
1309 const int local_nr_pages = end - start;
1310 const int page_limit = cur_page + local_nr_pages;
1311
1312 ret = get_user_pages_fast(uaddr, local_nr_pages,
1313 write_to_vm, &pages[cur_page]);
1314 if (ret < local_nr_pages) {
1315 ret = -EFAULT;
1316 goto out_unmap;
1317 }
1318
1319 offset = uaddr & ~PAGE_MASK;
1320 for (j = cur_page; j < page_limit; j++) {
1321 unsigned int bytes = PAGE_SIZE - offset;
1322
1323 if (len <= 0)
1324 break;
1325
1326 if (bytes > len)
1327 bytes = len;
1328
1329 /*
1330 * sorry...
1331 */
1332 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
1333 bytes)
1334 break;
1335
1336 len -= bytes;
1337 offset = 0;
1338 }
1339
1340 cur_page = j;
1341 /*
1342 * release the pages we didn't map into the bio, if any
1343 */
1344 while (j < page_limit)
1345 page_cache_release(pages[j++]);
1346 }
1347
1348 kfree(pages);
1349
1350 /*
1351 * set data direction, and check if mapped pages need bouncing
1352 */
1353 if (!write_to_vm)
1354 bio->bi_rw |= REQ_WRITE;
1355
1356 bio->bi_bdev = bdev;
1357 bio->bi_flags |= (1 << BIO_USER_MAPPED);
1358 return bio;
1359
1360 out_unmap:
1361 for (i = 0; i < nr_pages; i++) {
1362 if(!pages[i])
1363 break;
1364 page_cache_release(pages[i]);
1365 }
1366 out:
1367 kfree(pages);
1368 bio_put(bio);
1369 return ERR_PTR(ret);
1370}
1371
1372/**
1373 * bio_map_user - map user address into bio
1374 * @q: the struct request_queue for the bio
1375 * @bdev: destination block device
1376 * @uaddr: start of user address
1377 * @len: length in bytes
1378 * @write_to_vm: bool indicating writing to pages or not
1379 * @gfp_mask: memory allocation flags
1380 *
1381 * Map the user space address into a bio suitable for io to a block
1382 * device. Returns an error pointer in case of error.
1383 */
1384struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1385 unsigned long uaddr, unsigned int len, int write_to_vm,
1386 gfp_t gfp_mask)
1387{
1388 struct sg_iovec iov;
1389
1390 iov.iov_base = (void __user *)uaddr;
1391 iov.iov_len = len;
1392
1393 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1394}
1395EXPORT_SYMBOL(bio_map_user);
1396
1397/**
1398 * bio_map_user_iov - map user sg_iovec table into bio
1399 * @q: the struct request_queue for the bio
1400 * @bdev: destination block device
1401 * @iov: the iovec.
1402 * @iov_count: number of elements in the iovec
1403 * @write_to_vm: bool indicating writing to pages or not
1404 * @gfp_mask: memory allocation flags
1405 *
1406 * Map the user space address into a bio suitable for io to a block
1407 * device. Returns an error pointer in case of error.
1408 */
1409struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1410 const struct sg_iovec *iov, int iov_count,
1411 int write_to_vm, gfp_t gfp_mask)
1412{
1413 struct bio *bio;
1414
1415 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
1416 gfp_mask);
1417 if (IS_ERR(bio))
1418 return bio;
1419
1420 /*
1421 * subtle -- if __bio_map_user() ended up bouncing a bio,
1422 * it would normally disappear when its bi_end_io is run.
1423 * however, we need it for the unmap, so grab an extra
1424 * reference to it
1425 */
1426 bio_get(bio);
1427
1428 return bio;
1429}
1430
1431static void __bio_unmap_user(struct bio *bio)
1432{
1433 struct bio_vec *bvec;
1434 int i;
1435
1436 /*
1437 * make sure we dirty pages we wrote to
1438 */
1439 bio_for_each_segment_all(bvec, bio, i) {
1440 if (bio_data_dir(bio) == READ)
1441 set_page_dirty_lock(bvec->bv_page);
1442
1443 page_cache_release(bvec->bv_page);
1444 }
1445
1446 bio_put(bio);
1447}
1448
1449/**
1450 * bio_unmap_user - unmap a bio
1451 * @bio: the bio being unmapped
1452 *
1453 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1454 * a process context.
1455 *
1456 * bio_unmap_user() may sleep.
1457 */
1458void bio_unmap_user(struct bio *bio)
1459{
1460 __bio_unmap_user(bio);
1461 bio_put(bio);
1462}
1463EXPORT_SYMBOL(bio_unmap_user);
1464
1465static void bio_map_kern_endio(struct bio *bio, int err)
1466{
1467 bio_put(bio);
1468}
1469
1470static struct bio *__bio_map_kern(struct request_queue *q, void *data,
1471 unsigned int len, gfp_t gfp_mask)
1472{
1473 unsigned long kaddr = (unsigned long)data;
1474 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1475 unsigned long start = kaddr >> PAGE_SHIFT;
1476 const int nr_pages = end - start;
1477 int offset, i;
1478 struct bio *bio;
1479
1480 bio = bio_kmalloc(gfp_mask, nr_pages);
1481 if (!bio)
1482 return ERR_PTR(-ENOMEM);
1483
1484 offset = offset_in_page(kaddr);
1485 for (i = 0; i < nr_pages; i++) {
1486 unsigned int bytes = PAGE_SIZE - offset;
1487
1488 if (len <= 0)
1489 break;
1490
1491 if (bytes > len)
1492 bytes = len;
1493
1494 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1495 offset) < bytes)
1496 break;
1497
1498 data += bytes;
1499 len -= bytes;
1500 offset = 0;
1501 }
1502
1503 bio->bi_end_io = bio_map_kern_endio;
1504 return bio;
1505}
1506
1507/**
1508 * bio_map_kern - map kernel address into bio
1509 * @q: the struct request_queue for the bio
1510 * @data: pointer to buffer to map
1511 * @len: length in bytes
1512 * @gfp_mask: allocation flags for bio allocation
1513 *
1514 * Map the kernel address into a bio suitable for io to a block
1515 * device. Returns an error pointer in case of error.
1516 */
1517struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1518 gfp_t gfp_mask)
1519{
1520 struct bio *bio;
1521
1522 bio = __bio_map_kern(q, data, len, gfp_mask);
1523 if (IS_ERR(bio))
1524 return bio;
1525
1526 if (bio->bi_iter.bi_size == len)
1527 return bio;
1528
1529 /*
1530 * Don't support partial mappings.
1531 */
1532 bio_put(bio);
1533 return ERR_PTR(-EINVAL);
1534}
1535EXPORT_SYMBOL(bio_map_kern);
1536
1537static void bio_copy_kern_endio(struct bio *bio, int err)
1538{
1539 struct bio_vec *bvec;
1540 const int read = bio_data_dir(bio) == READ;
1541 struct bio_map_data *bmd = bio->bi_private;
1542 int i;
1543 char *p = bmd->sgvecs[0].iov_base;
1544
1545 bio_for_each_segment_all(bvec, bio, i) {
1546 char *addr = page_address(bvec->bv_page);
1547
1548 if (read)
1549 memcpy(p, addr, bvec->bv_len);
1550
1551 __free_page(bvec->bv_page);
1552 p += bvec->bv_len;
1553 }
1554
1555 kfree(bmd);
1556 bio_put(bio);
1557}
1558
1559/**
1560 * bio_copy_kern - copy kernel address into bio
1561 * @q: the struct request_queue for the bio
1562 * @data: pointer to buffer to copy
1563 * @len: length in bytes
1564 * @gfp_mask: allocation flags for bio and page allocation
1565 * @reading: data direction is READ
1566 *
1567 * copy the kernel address into a bio suitable for io to a block
1568 * device. Returns an error pointer in case of error.
1569 */
1570struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1571 gfp_t gfp_mask, int reading)
1572{
1573 struct bio *bio;
1574 struct bio_vec *bvec;
1575 int i;
1576
1577 bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
1578 if (IS_ERR(bio))
1579 return bio;
1580
1581 if (!reading) {
1582 void *p = data;
1583
1584 bio_for_each_segment_all(bvec, bio, i) {
1585 char *addr = page_address(bvec->bv_page);
1586
1587 memcpy(addr, p, bvec->bv_len);
1588 p += bvec->bv_len;
1589 }
1590 }
1591
1592 bio->bi_end_io = bio_copy_kern_endio;
1593
1594 return bio;
1595}
1596EXPORT_SYMBOL(bio_copy_kern);
1597
1598/*
1599 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1600 * for performing direct-IO in BIOs.
1601 *
1602 * The problem is that we cannot run set_page_dirty() from interrupt context
1603 * because the required locks are not interrupt-safe. So what we can do is to
1604 * mark the pages dirty _before_ performing IO. And in interrupt context,
1605 * check that the pages are still dirty. If so, fine. If not, redirty them
1606 * in process context.
1607 *
1608 * We special-case compound pages here: normally this means reads into hugetlb
1609 * pages. The logic in here doesn't really work right for compound pages
1610 * because the VM does not uniformly chase down the head page in all cases.
1611 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1612 * handle them at all. So we skip compound pages here at an early stage.
1613 *
1614 * Note that this code is very hard to test under normal circumstances because
1615 * direct-io pins the pages with get_user_pages(). This makes
1616 * is_page_cache_freeable return false, and the VM will not clean the pages.
1617 * But other code (eg, flusher threads) could clean the pages if they are mapped
1618 * pagecache.
1619 *
1620 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1621 * deferred bio dirtying paths.
1622 */
1623
1624/*
1625 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1626 */
1627void bio_set_pages_dirty(struct bio *bio)
1628{
1629 struct bio_vec *bvec;
1630 int i;
1631
1632 bio_for_each_segment_all(bvec, bio, i) {
1633 struct page *page = bvec->bv_page;
1634
1635 if (page && !PageCompound(page))
1636 set_page_dirty_lock(page);
1637 }
1638}
1639
1640static void bio_release_pages(struct bio *bio)
1641{
1642 struct bio_vec *bvec;
1643 int i;
1644
1645 bio_for_each_segment_all(bvec, bio, i) {
1646 struct page *page = bvec->bv_page;
1647
1648 if (page)
1649 put_page(page);
1650 }
1651}
1652
1653/*
1654 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1655 * If they are, then fine. If, however, some pages are clean then they must
1656 * have been written out during the direct-IO read. So we take another ref on
1657 * the BIO and the offending pages and re-dirty the pages in process context.
1658 *
1659 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1660 * here on. It will run one page_cache_release() against each page and will
1661 * run one bio_put() against the BIO.
1662 */
1663
1664static void bio_dirty_fn(struct work_struct *work);
1665
1666static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1667static DEFINE_SPINLOCK(bio_dirty_lock);
1668static struct bio *bio_dirty_list;
1669
1670/*
1671 * This runs in process context
1672 */
1673static void bio_dirty_fn(struct work_struct *work)
1674{
1675 unsigned long flags;
1676 struct bio *bio;
1677
1678 spin_lock_irqsave(&bio_dirty_lock, flags);
1679 bio = bio_dirty_list;
1680 bio_dirty_list = NULL;
1681 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1682
1683 while (bio) {
1684 struct bio *next = bio->bi_private;
1685
1686 bio_set_pages_dirty(bio);
1687 bio_release_pages(bio);
1688 bio_put(bio);
1689 bio = next;
1690 }
1691}
1692
1693void bio_check_pages_dirty(struct bio *bio)
1694{
1695 struct bio_vec *bvec;
1696 int nr_clean_pages = 0;
1697 int i;
1698
1699 bio_for_each_segment_all(bvec, bio, i) {
1700 struct page *page = bvec->bv_page;
1701
1702 if (PageDirty(page) || PageCompound(page)) {
1703 page_cache_release(page);
1704 bvec->bv_page = NULL;
1705 } else {
1706 nr_clean_pages++;
1707 }
1708 }
1709
1710 if (nr_clean_pages) {
1711 unsigned long flags;
1712
1713 spin_lock_irqsave(&bio_dirty_lock, flags);
1714 bio->bi_private = bio_dirty_list;
1715 bio_dirty_list = bio;
1716 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1717 schedule_work(&bio_dirty_work);
1718 } else {
1719 bio_put(bio);
1720 }
1721}
1722
1723#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1724void bio_flush_dcache_pages(struct bio *bi)
1725{
1726 struct bio_vec bvec;
1727 struct bvec_iter iter;
1728
1729 bio_for_each_segment(bvec, bi, iter)
1730 flush_dcache_page(bvec.bv_page);
1731}
1732EXPORT_SYMBOL(bio_flush_dcache_pages);
1733#endif
1734
1735/**
1736 * bio_endio - end I/O on a bio
1737 * @bio: bio
1738 * @error: error, if any
1739 *
1740 * Description:
1741 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1742 * preferred way to end I/O on a bio, it takes care of clearing
1743 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1744 * established -Exxxx (-EIO, for instance) error values in case
1745 * something went wrong. No one should call bi_end_io() directly on a
1746 * bio unless they own it and thus know that it has an end_io
1747 * function.
1748 **/
1749void bio_endio(struct bio *bio, int error)
1750{
1751 while (bio) {
1752 BUG_ON(atomic_read(&bio->bi_remaining) <= 0);
1753
1754 if (error)
1755 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1756 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1757 error = -EIO;
1758
1759 if (!atomic_dec_and_test(&bio->bi_remaining))
1760 return;
1761
1762 /*
1763 * Need to have a real endio function for chained bios,
1764 * otherwise various corner cases will break (like stacking
1765 * block devices that save/restore bi_end_io) - however, we want
1766 * to avoid unbounded recursion and blowing the stack. Tail call
1767 * optimization would handle this, but compiling with frame
1768 * pointers also disables gcc's sibling call optimization.
1769 */
1770 if (bio->bi_end_io == bio_chain_endio) {
1771 struct bio *parent = bio->bi_private;
1772 bio_put(bio);
1773 bio = parent;
1774 } else {
1775 if (bio->bi_end_io)
1776 bio->bi_end_io(bio, error);
1777 bio = NULL;
1778 }
1779 }
1780}
1781EXPORT_SYMBOL(bio_endio);
1782
1783/**
1784 * bio_endio_nodec - end I/O on a bio, without decrementing bi_remaining
1785 * @bio: bio
1786 * @error: error, if any
1787 *
1788 * For code that has saved and restored bi_end_io; thing hard before using this
1789 * function, probably you should've cloned the entire bio.
1790 **/
1791void bio_endio_nodec(struct bio *bio, int error)
1792{
1793 atomic_inc(&bio->bi_remaining);
1794 bio_endio(bio, error);
1795}
1796EXPORT_SYMBOL(bio_endio_nodec);
1797
1798/**
1799 * bio_split - split a bio
1800 * @bio: bio to split
1801 * @sectors: number of sectors to split from the front of @bio
1802 * @gfp: gfp mask
1803 * @bs: bio set to allocate from
1804 *
1805 * Allocates and returns a new bio which represents @sectors from the start of
1806 * @bio, and updates @bio to represent the remaining sectors.
1807 *
1808 * The newly allocated bio will point to @bio's bi_io_vec; it is the caller's
1809 * responsibility to ensure that @bio is not freed before the split.
1810 */
1811struct bio *bio_split(struct bio *bio, int sectors,
1812 gfp_t gfp, struct bio_set *bs)
1813{
1814 struct bio *split = NULL;
1815
1816 BUG_ON(sectors <= 0);
1817 BUG_ON(sectors >= bio_sectors(bio));
1818
1819 split = bio_clone_fast(bio, gfp, bs);
1820 if (!split)
1821 return NULL;
1822
1823 split->bi_iter.bi_size = sectors << 9;
1824
1825 if (bio_integrity(split))
1826 bio_integrity_trim(split, 0, sectors);
1827
1828 bio_advance(bio, split->bi_iter.bi_size);
1829
1830 return split;
1831}
1832EXPORT_SYMBOL(bio_split);
1833
1834/**
1835 * bio_trim - trim a bio
1836 * @bio: bio to trim
1837 * @offset: number of sectors to trim from the front of @bio
1838 * @size: size we want to trim @bio to, in sectors
1839 */
1840void bio_trim(struct bio *bio, int offset, int size)
1841{
1842 /* 'bio' is a cloned bio which we need to trim to match
1843 * the given offset and size.
1844 */
1845
1846 size <<= 9;
1847 if (offset == 0 && size == bio->bi_iter.bi_size)
1848 return;
1849
1850 clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1851
1852 bio_advance(bio, offset << 9);
1853
1854 bio->bi_iter.bi_size = size;
1855}
1856EXPORT_SYMBOL_GPL(bio_trim);
1857
1858/*
1859 * create memory pools for biovec's in a bio_set.
1860 * use the global biovec slabs created for general use.
1861 */
1862mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries)
1863{
1864 struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
1865
1866 return mempool_create_slab_pool(pool_entries, bp->slab);
1867}
1868
1869void bioset_free(struct bio_set *bs)
1870{
1871 if (bs->rescue_workqueue)
1872 destroy_workqueue(bs->rescue_workqueue);
1873
1874 if (bs->bio_pool)
1875 mempool_destroy(bs->bio_pool);
1876
1877 if (bs->bvec_pool)
1878 mempool_destroy(bs->bvec_pool);
1879
1880 bioset_integrity_free(bs);
1881 bio_put_slab(bs);
1882
1883 kfree(bs);
1884}
1885EXPORT_SYMBOL(bioset_free);
1886
1887/**
1888 * bioset_create - Create a bio_set
1889 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1890 * @front_pad: Number of bytes to allocate in front of the returned bio
1891 *
1892 * Description:
1893 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1894 * to ask for a number of bytes to be allocated in front of the bio.
1895 * Front pad allocation is useful for embedding the bio inside
1896 * another structure, to avoid allocating extra data to go with the bio.
1897 * Note that the bio must be embedded at the END of that structure always,
1898 * or things will break badly.
1899 */
1900struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
1901{
1902 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1903 struct bio_set *bs;
1904
1905 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1906 if (!bs)
1907 return NULL;
1908
1909 bs->front_pad = front_pad;
1910
1911 spin_lock_init(&bs->rescue_lock);
1912 bio_list_init(&bs->rescue_list);
1913 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1914
1915 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1916 if (!bs->bio_slab) {
1917 kfree(bs);
1918 return NULL;
1919 }
1920
1921 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
1922 if (!bs->bio_pool)
1923 goto bad;
1924
1925 bs->bvec_pool = biovec_create_pool(bs, pool_size);
1926 if (!bs->bvec_pool)
1927 goto bad;
1928
1929 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
1930 if (!bs->rescue_workqueue)
1931 goto bad;
1932
1933 return bs;
1934bad:
1935 bioset_free(bs);
1936 return NULL;
1937}
1938EXPORT_SYMBOL(bioset_create);
1939
1940#ifdef CONFIG_BLK_CGROUP
1941/**
1942 * bio_associate_current - associate a bio with %current
1943 * @bio: target bio
1944 *
1945 * Associate @bio with %current if it hasn't been associated yet. Block
1946 * layer will treat @bio as if it were issued by %current no matter which
1947 * task actually issues it.
1948 *
1949 * This function takes an extra reference of @task's io_context and blkcg
1950 * which will be put when @bio is released. The caller must own @bio,
1951 * ensure %current->io_context exists, and is responsible for synchronizing
1952 * calls to this function.
1953 */
1954int bio_associate_current(struct bio *bio)
1955{
1956 struct io_context *ioc;
1957 struct cgroup_subsys_state *css;
1958
1959 if (bio->bi_ioc)
1960 return -EBUSY;
1961
1962 ioc = current->io_context;
1963 if (!ioc)
1964 return -ENOENT;
1965
1966 /* acquire active ref on @ioc and associate */
1967 get_io_context_active(ioc);
1968 bio->bi_ioc = ioc;
1969
1970 /* associate blkcg if exists */
1971 rcu_read_lock();
1972 css = task_css(current, blkio_cgrp_id);
1973 if (css && css_tryget(css))
1974 bio->bi_css = css;
1975 rcu_read_unlock();
1976
1977 return 0;
1978}
1979
1980/**
1981 * bio_disassociate_task - undo bio_associate_current()
1982 * @bio: target bio
1983 */
1984void bio_disassociate_task(struct bio *bio)
1985{
1986 if (bio->bi_ioc) {
1987 put_io_context(bio->bi_ioc);
1988 bio->bi_ioc = NULL;
1989 }
1990 if (bio->bi_css) {
1991 css_put(bio->bi_css);
1992 bio->bi_css = NULL;
1993 }
1994}
1995
1996#endif /* CONFIG_BLK_CGROUP */
1997
1998static void __init biovec_init_slabs(void)
1999{
2000 int i;
2001
2002 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
2003 int size;
2004 struct biovec_slab *bvs = bvec_slabs + i;
2005
2006 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
2007 bvs->slab = NULL;
2008 continue;
2009 }
2010
2011 size = bvs->nr_vecs * sizeof(struct bio_vec);
2012 bvs->slab = kmem_cache_create(bvs->name, size, 0,
2013 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2014 }
2015}
2016
2017static int __init init_bio(void)
2018{
2019 bio_slab_max = 2;
2020 bio_slab_nr = 0;
2021 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
2022 if (!bio_slabs)
2023 panic("bio: can't allocate bios\n");
2024
2025 bio_integrity_init();
2026 biovec_init_slabs();
2027
2028 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
2029 if (!fs_bio_set)
2030 panic("bio: can't allocate bios\n");
2031
2032 if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
2033 panic("bio: can't create integrity pool\n");
2034
2035 return 0;
2036}
2037subsys_initcall(init_bio);