blob: 1f3bb501c262bc9b94ad9e0b73c5af8acc511c90 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
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>
James Bottomley f1970ba2005-06-20 14:06:52 +020028#include <scsi/sg.h> /* for struct sg_iovec */
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30#define BIO_POOL_SIZE 256
31
32static kmem_cache_t *bio_slab;
33
34#define BIOVEC_NR_POOLS 6
35
36/*
37 * a small number of entries is fine, not going to be performance critical.
38 * basically we just need to survive
39 */
40#define BIO_SPLIT_ENTRIES 8
41mempool_t *bio_split_pool;
42
43struct biovec_slab {
44 int nr_vecs;
45 char *name;
46 kmem_cache_t *slab;
47};
48
49/*
50 * if you change this list, also change bvec_alloc or things will
51 * break badly! cannot be bigger than what you can fit into an
52 * unsigned short
53 */
54
55#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
Christoph Lameter6c036522005-07-07 17:56:59 -070056static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
58};
59#undef BV
60
61/*
62 * bio_set is used to allow other portions of the IO system to
63 * allocate their own private memory pools for bio and iovec structures.
64 * These memory pools in turn all allocate from the bio_slab
65 * and the bvec_slabs[].
66 */
67struct bio_set {
68 mempool_t *bio_pool;
69 mempool_t *bvec_pools[BIOVEC_NR_POOLS];
70};
71
72/*
73 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
74 * IO code that does not need private memory pools.
75 */
76static struct bio_set *fs_bio_set;
77
Al Virodd0fc662005-10-07 07:46:04 +010078static inline struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, struct bio_set *bs)
Linus Torvalds1da177e2005-04-16 15:20:36 -070079{
80 struct bio_vec *bvl;
81 struct biovec_slab *bp;
82
83 /*
84 * see comment near bvec_array define!
85 */
86 switch (nr) {
87 case 1 : *idx = 0; break;
88 case 2 ... 4: *idx = 1; break;
89 case 5 ... 16: *idx = 2; break;
90 case 17 ... 64: *idx = 3; break;
91 case 65 ... 128: *idx = 4; break;
92 case 129 ... BIO_MAX_PAGES: *idx = 5; break;
93 default:
94 return NULL;
95 }
96 /*
97 * idx now points to the pool we want to allocate from
98 */
99
100 bp = bvec_slabs + *idx;
101 bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask);
102 if (bvl)
103 memset(bvl, 0, bp->nr_vecs * sizeof(struct bio_vec));
104
105 return bvl;
106}
107
Peter Osterlund36763472005-09-06 15:16:42 -0700108void bio_free(struct bio *bio, struct bio_set *bio_set)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109{
110 const int pool_idx = BIO_POOL_IDX(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
112 BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
113
Peter Osterlund36763472005-09-06 15:16:42 -0700114 mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
115 mempool_free(bio, bio_set->bio_pool);
116}
117
118/*
119 * default destructor for a bio allocated with bio_alloc_bioset()
120 */
121static void bio_fs_destructor(struct bio *bio)
122{
123 bio_free(bio, fs_bio_set);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124}
125
Arjan van de Ven858119e2006-01-14 13:20:43 -0800126void bio_init(struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127{
128 bio->bi_next = NULL;
Jens Axboe0ea60b52006-01-09 14:45:10 +0100129 bio->bi_bdev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 bio->bi_flags = 1 << BIO_UPTODATE;
131 bio->bi_rw = 0;
132 bio->bi_vcnt = 0;
133 bio->bi_idx = 0;
134 bio->bi_phys_segments = 0;
135 bio->bi_hw_segments = 0;
136 bio->bi_hw_front_size = 0;
137 bio->bi_hw_back_size = 0;
138 bio->bi_size = 0;
139 bio->bi_max_vecs = 0;
140 bio->bi_end_io = NULL;
141 atomic_set(&bio->bi_cnt, 1);
142 bio->bi_private = NULL;
143}
144
145/**
146 * bio_alloc_bioset - allocate a bio for I/O
147 * @gfp_mask: the GFP_ mask given to the slab allocator
148 * @nr_iovecs: number of iovecs to pre-allocate
Martin Waitz67be2dd2005-05-01 08:59:26 -0700149 * @bs: the bio_set to allocate from
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 *
151 * Description:
152 * bio_alloc_bioset will first try it's on mempool to satisfy the allocation.
153 * If %__GFP_WAIT is set then we will block on the internal pool waiting
154 * for a &struct bio to become free.
155 *
156 * allocate bio and iovecs from the memory pools specified by the
157 * bio_set structure.
158 **/
Al Virodd0fc662005-10-07 07:46:04 +0100159struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160{
161 struct bio *bio = mempool_alloc(bs->bio_pool, gfp_mask);
162
163 if (likely(bio)) {
164 struct bio_vec *bvl = NULL;
165
166 bio_init(bio);
167 if (likely(nr_iovecs)) {
168 unsigned long idx;
169
170 bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
171 if (unlikely(!bvl)) {
172 mempool_free(bio, bs->bio_pool);
173 bio = NULL;
174 goto out;
175 }
176 bio->bi_flags |= idx << BIO_POOL_OFFSET;
177 bio->bi_max_vecs = bvec_slabs[idx].nr_vecs;
178 }
179 bio->bi_io_vec = bvl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 }
181out:
182 return bio;
183}
184
Al Virodd0fc662005-10-07 07:46:04 +0100185struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186{
Peter Osterlund36763472005-09-06 15:16:42 -0700187 struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
188
189 if (bio)
190 bio->bi_destructor = bio_fs_destructor;
191
192 return bio;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193}
194
195void zero_fill_bio(struct bio *bio)
196{
197 unsigned long flags;
198 struct bio_vec *bv;
199 int i;
200
201 bio_for_each_segment(bv, bio, i) {
202 char *data = bvec_kmap_irq(bv, &flags);
203 memset(data, 0, bv->bv_len);
204 flush_dcache_page(bv->bv_page);
205 bvec_kunmap_irq(data, &flags);
206 }
207}
208EXPORT_SYMBOL(zero_fill_bio);
209
210/**
211 * bio_put - release a reference to a bio
212 * @bio: bio to release reference to
213 *
214 * Description:
215 * Put a reference to a &struct bio, either one you have gotten with
216 * bio_alloc or bio_get. The last put of a bio will free it.
217 **/
218void bio_put(struct bio *bio)
219{
220 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
221
222 /*
223 * last put frees it
224 */
225 if (atomic_dec_and_test(&bio->bi_cnt)) {
226 bio->bi_next = NULL;
227 bio->bi_destructor(bio);
228 }
229}
230
231inline int bio_phys_segments(request_queue_t *q, struct bio *bio)
232{
233 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
234 blk_recount_segments(q, bio);
235
236 return bio->bi_phys_segments;
237}
238
239inline int bio_hw_segments(request_queue_t *q, struct bio *bio)
240{
241 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
242 blk_recount_segments(q, bio);
243
244 return bio->bi_hw_segments;
245}
246
247/**
248 * __bio_clone - clone a bio
249 * @bio: destination bio
250 * @bio_src: bio to clone
251 *
252 * Clone a &bio. Caller will own the returned bio, but not
253 * the actual data it points to. Reference count of returned
254 * bio will be one.
255 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800256void __bio_clone(struct bio *bio, struct bio *bio_src)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257{
258 request_queue_t *q = bdev_get_queue(bio_src->bi_bdev);
259
Andrew Mortone525e152005-08-07 09:42:12 -0700260 memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
261 bio_src->bi_max_vecs * sizeof(struct bio_vec));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
263 bio->bi_sector = bio_src->bi_sector;
264 bio->bi_bdev = bio_src->bi_bdev;
265 bio->bi_flags |= 1 << BIO_CLONED;
266 bio->bi_rw = bio_src->bi_rw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 bio->bi_vcnt = bio_src->bi_vcnt;
268 bio->bi_size = bio_src->bi_size;
Andrew Mortona5453be2005-07-28 01:07:18 -0700269 bio->bi_idx = bio_src->bi_idx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 bio_phys_segments(q, bio);
271 bio_hw_segments(q, bio);
272}
273
274/**
275 * bio_clone - clone a bio
276 * @bio: bio to clone
277 * @gfp_mask: allocation priority
278 *
279 * Like __bio_clone, only also allocates the returned bio
280 */
Al Virodd0fc662005-10-07 07:46:04 +0100281struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282{
283 struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
284
Peter Osterlund36763472005-09-06 15:16:42 -0700285 if (b) {
286 b->bi_destructor = bio_fs_destructor;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 __bio_clone(b, bio);
Peter Osterlund36763472005-09-06 15:16:42 -0700288 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289
290 return b;
291}
292
293/**
294 * bio_get_nr_vecs - return approx number of vecs
295 * @bdev: I/O target
296 *
297 * Return the approximate number of pages we can send to this target.
298 * There's no guarantee that you will be able to fit this number of pages
299 * into a bio, it does not account for dynamic restrictions that vary
300 * on offset.
301 */
302int bio_get_nr_vecs(struct block_device *bdev)
303{
304 request_queue_t *q = bdev_get_queue(bdev);
305 int nr_pages;
306
307 nr_pages = ((q->max_sectors << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
308 if (nr_pages > q->max_phys_segments)
309 nr_pages = q->max_phys_segments;
310 if (nr_pages > q->max_hw_segments)
311 nr_pages = q->max_hw_segments;
312
313 return nr_pages;
314}
315
316static int __bio_add_page(request_queue_t *q, struct bio *bio, struct page
Mike Christiedefd94b2005-12-05 02:37:06 -0600317 *page, unsigned int len, unsigned int offset,
318 unsigned short max_sectors)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319{
320 int retried_segments = 0;
321 struct bio_vec *bvec;
322
323 /*
324 * cloned bio must not modify vec list
325 */
326 if (unlikely(bio_flagged(bio, BIO_CLONED)))
327 return 0;
328
Jens Axboe80cfd542006-01-06 09:43:28 +0100329 if (((bio->bi_size + len) >> 9) > max_sectors)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 return 0;
331
Jens Axboe80cfd542006-01-06 09:43:28 +0100332 /*
333 * For filesystems with a blocksize smaller than the pagesize
334 * we will often be called with the same page as last time and
335 * a consecutive offset. Optimize this special case.
336 */
337 if (bio->bi_vcnt > 0) {
338 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
339
340 if (page == prev->bv_page &&
341 offset == prev->bv_offset + prev->bv_len) {
342 prev->bv_len += len;
343 if (q->merge_bvec_fn &&
344 q->merge_bvec_fn(q, bio, prev) < len) {
345 prev->bv_len -= len;
346 return 0;
347 }
348
349 goto done;
350 }
351 }
352
353 if (bio->bi_vcnt >= bio->bi_max_vecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 return 0;
355
356 /*
357 * we might lose a segment or two here, but rather that than
358 * make this too complex.
359 */
360
361 while (bio->bi_phys_segments >= q->max_phys_segments
362 || bio->bi_hw_segments >= q->max_hw_segments
363 || BIOVEC_VIRT_OVERSIZE(bio->bi_size)) {
364
365 if (retried_segments)
366 return 0;
367
368 retried_segments = 1;
369 blk_recount_segments(q, bio);
370 }
371
372 /*
373 * setup the new entry, we might clear it again later if we
374 * cannot add the page
375 */
376 bvec = &bio->bi_io_vec[bio->bi_vcnt];
377 bvec->bv_page = page;
378 bvec->bv_len = len;
379 bvec->bv_offset = offset;
380
381 /*
382 * if queue has other restrictions (eg varying max sector size
383 * depending on offset), it can specify a merge_bvec_fn in the
384 * queue to get further control
385 */
386 if (q->merge_bvec_fn) {
387 /*
388 * merge_bvec_fn() returns number of bytes it can accept
389 * at this offset
390 */
391 if (q->merge_bvec_fn(q, bio, bvec) < len) {
392 bvec->bv_page = NULL;
393 bvec->bv_len = 0;
394 bvec->bv_offset = 0;
395 return 0;
396 }
397 }
398
399 /* If we may be able to merge these biovecs, force a recount */
400 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec) ||
401 BIOVEC_VIRT_MERGEABLE(bvec-1, bvec)))
402 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
403
404 bio->bi_vcnt++;
405 bio->bi_phys_segments++;
406 bio->bi_hw_segments++;
Jens Axboe80cfd542006-01-06 09:43:28 +0100407 done:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 bio->bi_size += len;
409 return len;
410}
411
412/**
Mike Christie6e68af62005-11-11 05:30:27 -0600413 * bio_add_pc_page - attempt to add page to bio
Jens Axboefddfdea2006-01-31 15:24:34 +0100414 * @q: the target queue
Mike Christie6e68af62005-11-11 05:30:27 -0600415 * @bio: destination bio
416 * @page: page to add
417 * @len: vec entry length
418 * @offset: vec entry offset
419 *
420 * Attempt to add a page to the bio_vec maplist. This can fail for a
421 * number of reasons, such as the bio being full or target block
422 * device limitations. The target block device must allow bio's
423 * smaller than PAGE_SIZE, so it is always possible to add a single
424 * page to an empty bio. This should only be used by REQ_PC bios.
425 */
426int bio_add_pc_page(request_queue_t *q, struct bio *bio, struct page *page,
427 unsigned int len, unsigned int offset)
428{
Mike Christiedefd94b2005-12-05 02:37:06 -0600429 return __bio_add_page(q, bio, page, len, offset, q->max_hw_sectors);
Mike Christie6e68af62005-11-11 05:30:27 -0600430}
431
432/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 * bio_add_page - attempt to add page to bio
434 * @bio: destination bio
435 * @page: page to add
436 * @len: vec entry length
437 * @offset: vec entry offset
438 *
439 * Attempt to add a page to the bio_vec maplist. This can fail for a
440 * number of reasons, such as the bio being full or target block
441 * device limitations. The target block device must allow bio's
442 * smaller than PAGE_SIZE, so it is always possible to add a single
443 * page to an empty bio.
444 */
445int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
446 unsigned int offset)
447{
Mike Christiedefd94b2005-12-05 02:37:06 -0600448 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
449 return __bio_add_page(q, bio, page, len, offset, q->max_sectors);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450}
451
452struct bio_map_data {
453 struct bio_vec *iovecs;
454 void __user *userptr;
455};
456
457static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio)
458{
459 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
460 bio->bi_private = bmd;
461}
462
463static void bio_free_map_data(struct bio_map_data *bmd)
464{
465 kfree(bmd->iovecs);
466 kfree(bmd);
467}
468
469static struct bio_map_data *bio_alloc_map_data(int nr_segs)
470{
471 struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL);
472
473 if (!bmd)
474 return NULL;
475
476 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL);
477 if (bmd->iovecs)
478 return bmd;
479
480 kfree(bmd);
481 return NULL;
482}
483
484/**
485 * bio_uncopy_user - finish previously mapped bio
486 * @bio: bio being terminated
487 *
488 * Free pages allocated from bio_copy_user() and write back data
489 * to user space in case of a read.
490 */
491int bio_uncopy_user(struct bio *bio)
492{
493 struct bio_map_data *bmd = bio->bi_private;
494 const int read = bio_data_dir(bio) == READ;
495 struct bio_vec *bvec;
496 int i, ret = 0;
497
498 __bio_for_each_segment(bvec, bio, i, 0) {
499 char *addr = page_address(bvec->bv_page);
500 unsigned int len = bmd->iovecs[i].bv_len;
501
502 if (read && !ret && copy_to_user(bmd->userptr, addr, len))
503 ret = -EFAULT;
504
505 __free_page(bvec->bv_page);
506 bmd->userptr += len;
507 }
508 bio_free_map_data(bmd);
509 bio_put(bio);
510 return ret;
511}
512
513/**
514 * bio_copy_user - copy user data to bio
515 * @q: destination block queue
516 * @uaddr: start of user address
517 * @len: length in bytes
518 * @write_to_vm: bool indicating writing to pages or not
519 *
520 * Prepares and returns a bio for indirect user io, bouncing data
521 * to/from kernel pages as necessary. Must be paired with
522 * call bio_uncopy_user() on io completion.
523 */
524struct bio *bio_copy_user(request_queue_t *q, unsigned long uaddr,
525 unsigned int len, int write_to_vm)
526{
527 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
528 unsigned long start = uaddr >> PAGE_SHIFT;
529 struct bio_map_data *bmd;
530 struct bio_vec *bvec;
531 struct page *page;
532 struct bio *bio;
533 int i, ret;
534
535 bmd = bio_alloc_map_data(end - start);
536 if (!bmd)
537 return ERR_PTR(-ENOMEM);
538
539 bmd->userptr = (void __user *) uaddr;
540
541 ret = -ENOMEM;
542 bio = bio_alloc(GFP_KERNEL, end - start);
543 if (!bio)
544 goto out_bmd;
545
546 bio->bi_rw |= (!write_to_vm << BIO_RW);
547
548 ret = 0;
549 while (len) {
550 unsigned int bytes = PAGE_SIZE;
551
552 if (bytes > len)
553 bytes = len;
554
555 page = alloc_page(q->bounce_gfp | GFP_KERNEL);
556 if (!page) {
557 ret = -ENOMEM;
558 break;
559 }
560
Mike Christiedefd94b2005-12-05 02:37:06 -0600561 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 ret = -EINVAL;
563 break;
564 }
565
566 len -= bytes;
567 }
568
569 if (ret)
570 goto cleanup;
571
572 /*
573 * success
574 */
575 if (!write_to_vm) {
576 char __user *p = (char __user *) uaddr;
577
578 /*
579 * for a write, copy in data to kernel pages
580 */
581 ret = -EFAULT;
582 bio_for_each_segment(bvec, bio, i) {
583 char *addr = page_address(bvec->bv_page);
584
585 if (copy_from_user(addr, p, bvec->bv_len))
586 goto cleanup;
587 p += bvec->bv_len;
588 }
589 }
590
591 bio_set_map_data(bmd, bio);
592 return bio;
593cleanup:
594 bio_for_each_segment(bvec, bio, i)
595 __free_page(bvec->bv_page);
596
597 bio_put(bio);
598out_bmd:
599 bio_free_map_data(bmd);
600 return ERR_PTR(ret);
601}
602
James Bottomley f1970ba2005-06-20 14:06:52 +0200603static struct bio *__bio_map_user_iov(request_queue_t *q,
604 struct block_device *bdev,
605 struct sg_iovec *iov, int iov_count,
606 int write_to_vm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607{
James Bottomley f1970ba2005-06-20 14:06:52 +0200608 int i, j;
609 int nr_pages = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 struct page **pages;
611 struct bio *bio;
James Bottomley f1970ba2005-06-20 14:06:52 +0200612 int cur_page = 0;
613 int ret, offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614
James Bottomley f1970ba2005-06-20 14:06:52 +0200615 for (i = 0; i < iov_count; i++) {
616 unsigned long uaddr = (unsigned long)iov[i].iov_base;
617 unsigned long len = iov[i].iov_len;
618 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
619 unsigned long start = uaddr >> PAGE_SHIFT;
620
621 nr_pages += end - start;
622 /*
623 * transfer and buffer must be aligned to at least hardsector
624 * size for now, in the future we can relax this restriction
625 */
626 if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q)))
627 return ERR_PTR(-EINVAL);
628 }
629
630 if (!nr_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 return ERR_PTR(-EINVAL);
632
633 bio = bio_alloc(GFP_KERNEL, nr_pages);
634 if (!bio)
635 return ERR_PTR(-ENOMEM);
636
637 ret = -ENOMEM;
638 pages = kmalloc(nr_pages * sizeof(struct page *), GFP_KERNEL);
639 if (!pages)
640 goto out;
641
James Bottomley f1970ba2005-06-20 14:06:52 +0200642 memset(pages, 0, nr_pages * sizeof(struct page *));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643
James Bottomley f1970ba2005-06-20 14:06:52 +0200644 for (i = 0; i < iov_count; i++) {
645 unsigned long uaddr = (unsigned long)iov[i].iov_base;
646 unsigned long len = iov[i].iov_len;
647 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
648 unsigned long start = uaddr >> PAGE_SHIFT;
649 const int local_nr_pages = end - start;
650 const int page_limit = cur_page + local_nr_pages;
651
652 down_read(&current->mm->mmap_sem);
653 ret = get_user_pages(current, current->mm, uaddr,
654 local_nr_pages,
655 write_to_vm, 0, &pages[cur_page], NULL);
656 up_read(&current->mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657
James Bottomley f1970ba2005-06-20 14:06:52 +0200658 if (ret < local_nr_pages)
659 goto out_unmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661
James Bottomley f1970ba2005-06-20 14:06:52 +0200662 offset = uaddr & ~PAGE_MASK;
663 for (j = cur_page; j < page_limit; j++) {
664 unsigned int bytes = PAGE_SIZE - offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665
James Bottomley f1970ba2005-06-20 14:06:52 +0200666 if (len <= 0)
667 break;
668
669 if (bytes > len)
670 bytes = len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671
James Bottomley f1970ba2005-06-20 14:06:52 +0200672 /*
673 * sorry...
674 */
Mike Christiedefd94b2005-12-05 02:37:06 -0600675 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
676 bytes)
James Bottomley f1970ba2005-06-20 14:06:52 +0200677 break;
678
679 len -= bytes;
680 offset = 0;
681 }
682
683 cur_page = j;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 /*
James Bottomley f1970ba2005-06-20 14:06:52 +0200685 * release the pages we didn't map into the bio, if any
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 */
James Bottomley f1970ba2005-06-20 14:06:52 +0200687 while (j < page_limit)
688 page_cache_release(pages[j++]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 }
690
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 kfree(pages);
692
693 /*
694 * set data direction, and check if mapped pages need bouncing
695 */
696 if (!write_to_vm)
697 bio->bi_rw |= (1 << BIO_RW);
698
James Bottomley f1970ba2005-06-20 14:06:52 +0200699 bio->bi_bdev = bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 bio->bi_flags |= (1 << BIO_USER_MAPPED);
701 return bio;
James Bottomley f1970ba2005-06-20 14:06:52 +0200702
703 out_unmap:
704 for (i = 0; i < nr_pages; i++) {
705 if(!pages[i])
706 break;
707 page_cache_release(pages[i]);
708 }
709 out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 kfree(pages);
711 bio_put(bio);
712 return ERR_PTR(ret);
713}
714
715/**
716 * bio_map_user - map user address into bio
Martin Waitz67be2dd2005-05-01 08:59:26 -0700717 * @q: the request_queue_t for the bio
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 * @bdev: destination block device
719 * @uaddr: start of user address
720 * @len: length in bytes
721 * @write_to_vm: bool indicating writing to pages or not
722 *
723 * Map the user space address into a bio suitable for io to a block
724 * device. Returns an error pointer in case of error.
725 */
726struct bio *bio_map_user(request_queue_t *q, struct block_device *bdev,
727 unsigned long uaddr, unsigned int len, int write_to_vm)
728{
James Bottomley f1970ba2005-06-20 14:06:52 +0200729 struct sg_iovec iov;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730
viro@ZenIV.linux.org.uk3f703532005-09-09 16:53:56 +0100731 iov.iov_base = (void __user *)uaddr;
James Bottomley f1970ba2005-06-20 14:06:52 +0200732 iov.iov_len = len;
733
734 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm);
735}
736
737/**
738 * bio_map_user_iov - map user sg_iovec table into bio
739 * @q: the request_queue_t for the bio
740 * @bdev: destination block device
741 * @iov: the iovec.
742 * @iov_count: number of elements in the iovec
743 * @write_to_vm: bool indicating writing to pages or not
744 *
745 * Map the user space address into a bio suitable for io to a block
746 * device. Returns an error pointer in case of error.
747 */
748struct bio *bio_map_user_iov(request_queue_t *q, struct block_device *bdev,
749 struct sg_iovec *iov, int iov_count,
750 int write_to_vm)
751{
752 struct bio *bio;
753 int len = 0, i;
754
755 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756
757 if (IS_ERR(bio))
758 return bio;
759
760 /*
761 * subtle -- if __bio_map_user() ended up bouncing a bio,
762 * it would normally disappear when its bi_end_io is run.
763 * however, we need it for the unmap, so grab an extra
764 * reference to it
765 */
766 bio_get(bio);
767
James Bottomley f1970ba2005-06-20 14:06:52 +0200768 for (i = 0; i < iov_count; i++)
769 len += iov[i].iov_len;
770
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 if (bio->bi_size == len)
772 return bio;
773
774 /*
775 * don't support partial mappings
776 */
777 bio_endio(bio, bio->bi_size, 0);
778 bio_unmap_user(bio);
779 return ERR_PTR(-EINVAL);
780}
781
782static void __bio_unmap_user(struct bio *bio)
783{
784 struct bio_vec *bvec;
785 int i;
786
787 /*
788 * make sure we dirty pages we wrote to
789 */
790 __bio_for_each_segment(bvec, bio, i, 0) {
791 if (bio_data_dir(bio) == READ)
792 set_page_dirty_lock(bvec->bv_page);
793
794 page_cache_release(bvec->bv_page);
795 }
796
797 bio_put(bio);
798}
799
800/**
801 * bio_unmap_user - unmap a bio
802 * @bio: the bio being unmapped
803 *
804 * Unmap a bio previously mapped by bio_map_user(). Must be called with
805 * a process context.
806 *
807 * bio_unmap_user() may sleep.
808 */
809void bio_unmap_user(struct bio *bio)
810{
811 __bio_unmap_user(bio);
812 bio_put(bio);
813}
814
Jens Axboeb8238252005-06-20 14:05:27 +0200815static int bio_map_kern_endio(struct bio *bio, unsigned int bytes_done, int err)
816{
817 if (bio->bi_size)
818 return 1;
819
820 bio_put(bio);
821 return 0;
822}
823
824
Mike Christie df46b9a2005-06-20 14:04:44 +0200825static struct bio *__bio_map_kern(request_queue_t *q, void *data,
Al Viro27496a82005-10-21 03:20:48 -0400826 unsigned int len, gfp_t gfp_mask)
Mike Christie df46b9a2005-06-20 14:04:44 +0200827{
828 unsigned long kaddr = (unsigned long)data;
829 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
830 unsigned long start = kaddr >> PAGE_SHIFT;
831 const int nr_pages = end - start;
832 int offset, i;
833 struct bio *bio;
834
835 bio = bio_alloc(gfp_mask, nr_pages);
836 if (!bio)
837 return ERR_PTR(-ENOMEM);
838
839 offset = offset_in_page(kaddr);
840 for (i = 0; i < nr_pages; i++) {
841 unsigned int bytes = PAGE_SIZE - offset;
842
843 if (len <= 0)
844 break;
845
846 if (bytes > len)
847 bytes = len;
848
Mike Christiedefd94b2005-12-05 02:37:06 -0600849 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
850 offset) < bytes)
Mike Christie df46b9a2005-06-20 14:04:44 +0200851 break;
852
853 data += bytes;
854 len -= bytes;
855 offset = 0;
856 }
857
Jens Axboeb8238252005-06-20 14:05:27 +0200858 bio->bi_end_io = bio_map_kern_endio;
Mike Christie df46b9a2005-06-20 14:04:44 +0200859 return bio;
860}
861
862/**
863 * bio_map_kern - map kernel address into bio
864 * @q: the request_queue_t for the bio
865 * @data: pointer to buffer to map
866 * @len: length in bytes
867 * @gfp_mask: allocation flags for bio allocation
868 *
869 * Map the kernel address into a bio suitable for io to a block
870 * device. Returns an error pointer in case of error.
871 */
872struct bio *bio_map_kern(request_queue_t *q, void *data, unsigned int len,
Al Viro27496a82005-10-21 03:20:48 -0400873 gfp_t gfp_mask)
Mike Christie df46b9a2005-06-20 14:04:44 +0200874{
875 struct bio *bio;
876
877 bio = __bio_map_kern(q, data, len, gfp_mask);
878 if (IS_ERR(bio))
879 return bio;
880
881 if (bio->bi_size == len)
882 return bio;
883
884 /*
885 * Don't support partial mappings.
886 */
887 bio_put(bio);
888 return ERR_PTR(-EINVAL);
889}
890
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891/*
892 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
893 * for performing direct-IO in BIOs.
894 *
895 * The problem is that we cannot run set_page_dirty() from interrupt context
896 * because the required locks are not interrupt-safe. So what we can do is to
897 * mark the pages dirty _before_ performing IO. And in interrupt context,
898 * check that the pages are still dirty. If so, fine. If not, redirty them
899 * in process context.
900 *
901 * We special-case compound pages here: normally this means reads into hugetlb
902 * pages. The logic in here doesn't really work right for compound pages
903 * because the VM does not uniformly chase down the head page in all cases.
904 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
905 * handle them at all. So we skip compound pages here at an early stage.
906 *
907 * Note that this code is very hard to test under normal circumstances because
908 * direct-io pins the pages with get_user_pages(). This makes
909 * is_page_cache_freeable return false, and the VM will not clean the pages.
910 * But other code (eg, pdflush) could clean the pages if they are mapped
911 * pagecache.
912 *
913 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
914 * deferred bio dirtying paths.
915 */
916
917/*
918 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
919 */
920void bio_set_pages_dirty(struct bio *bio)
921{
922 struct bio_vec *bvec = bio->bi_io_vec;
923 int i;
924
925 for (i = 0; i < bio->bi_vcnt; i++) {
926 struct page *page = bvec[i].bv_page;
927
928 if (page && !PageCompound(page))
929 set_page_dirty_lock(page);
930 }
931}
932
933static void bio_release_pages(struct bio *bio)
934{
935 struct bio_vec *bvec = bio->bi_io_vec;
936 int i;
937
938 for (i = 0; i < bio->bi_vcnt; i++) {
939 struct page *page = bvec[i].bv_page;
940
941 if (page)
942 put_page(page);
943 }
944}
945
946/*
947 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
948 * If they are, then fine. If, however, some pages are clean then they must
949 * have been written out during the direct-IO read. So we take another ref on
950 * the BIO and the offending pages and re-dirty the pages in process context.
951 *
952 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
953 * here on. It will run one page_cache_release() against each page and will
954 * run one bio_put() against the BIO.
955 */
956
957static void bio_dirty_fn(void *data);
958
959static DECLARE_WORK(bio_dirty_work, bio_dirty_fn, NULL);
960static DEFINE_SPINLOCK(bio_dirty_lock);
961static struct bio *bio_dirty_list;
962
963/*
964 * This runs in process context
965 */
966static void bio_dirty_fn(void *data)
967{
968 unsigned long flags;
969 struct bio *bio;
970
971 spin_lock_irqsave(&bio_dirty_lock, flags);
972 bio = bio_dirty_list;
973 bio_dirty_list = NULL;
974 spin_unlock_irqrestore(&bio_dirty_lock, flags);
975
976 while (bio) {
977 struct bio *next = bio->bi_private;
978
979 bio_set_pages_dirty(bio);
980 bio_release_pages(bio);
981 bio_put(bio);
982 bio = next;
983 }
984}
985
986void bio_check_pages_dirty(struct bio *bio)
987{
988 struct bio_vec *bvec = bio->bi_io_vec;
989 int nr_clean_pages = 0;
990 int i;
991
992 for (i = 0; i < bio->bi_vcnt; i++) {
993 struct page *page = bvec[i].bv_page;
994
995 if (PageDirty(page) || PageCompound(page)) {
996 page_cache_release(page);
997 bvec[i].bv_page = NULL;
998 } else {
999 nr_clean_pages++;
1000 }
1001 }
1002
1003 if (nr_clean_pages) {
1004 unsigned long flags;
1005
1006 spin_lock_irqsave(&bio_dirty_lock, flags);
1007 bio->bi_private = bio_dirty_list;
1008 bio_dirty_list = bio;
1009 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1010 schedule_work(&bio_dirty_work);
1011 } else {
1012 bio_put(bio);
1013 }
1014}
1015
1016/**
1017 * bio_endio - end I/O on a bio
1018 * @bio: bio
1019 * @bytes_done: number of bytes completed
1020 * @error: error, if any
1021 *
1022 * Description:
1023 * bio_endio() will end I/O on @bytes_done number of bytes. This may be
1024 * just a partial part of the bio, or it may be the whole bio. bio_endio()
1025 * is the preferred way to end I/O on a bio, it takes care of decrementing
1026 * bi_size and clearing BIO_UPTODATE on error. @error is 0 on success, and
1027 * and one of the established -Exxxx (-EIO, for instance) error values in
1028 * case something went wrong. Noone should call bi_end_io() directly on
1029 * a bio unless they own it and thus know that it has an end_io function.
1030 **/
1031void bio_endio(struct bio *bio, unsigned int bytes_done, int error)
1032{
1033 if (error)
1034 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1035
1036 if (unlikely(bytes_done > bio->bi_size)) {
1037 printk("%s: want %u bytes done, only %u left\n", __FUNCTION__,
1038 bytes_done, bio->bi_size);
1039 bytes_done = bio->bi_size;
1040 }
1041
1042 bio->bi_size -= bytes_done;
1043 bio->bi_sector += (bytes_done >> 9);
1044
1045 if (bio->bi_end_io)
1046 bio->bi_end_io(bio, bytes_done, error);
1047}
1048
1049void bio_pair_release(struct bio_pair *bp)
1050{
1051 if (atomic_dec_and_test(&bp->cnt)) {
1052 struct bio *master = bp->bio1.bi_private;
1053
1054 bio_endio(master, master->bi_size, bp->error);
1055 mempool_free(bp, bp->bio2.bi_private);
1056 }
1057}
1058
1059static int bio_pair_end_1(struct bio * bi, unsigned int done, int err)
1060{
1061 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1062
1063 if (err)
1064 bp->error = err;
1065
1066 if (bi->bi_size)
1067 return 1;
1068
1069 bio_pair_release(bp);
1070 return 0;
1071}
1072
1073static int bio_pair_end_2(struct bio * bi, unsigned int done, int err)
1074{
1075 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1076
1077 if (err)
1078 bp->error = err;
1079
1080 if (bi->bi_size)
1081 return 1;
1082
1083 bio_pair_release(bp);
1084 return 0;
1085}
1086
1087/*
1088 * split a bio - only worry about a bio with a single page
1089 * in it's iovec
1090 */
1091struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors)
1092{
1093 struct bio_pair *bp = mempool_alloc(pool, GFP_NOIO);
1094
1095 if (!bp)
1096 return bp;
1097
1098 BUG_ON(bi->bi_vcnt != 1);
1099 BUG_ON(bi->bi_idx != 0);
1100 atomic_set(&bp->cnt, 3);
1101 bp->error = 0;
1102 bp->bio1 = *bi;
1103 bp->bio2 = *bi;
1104 bp->bio2.bi_sector += first_sectors;
1105 bp->bio2.bi_size -= first_sectors << 9;
1106 bp->bio1.bi_size = first_sectors << 9;
1107
1108 bp->bv1 = bi->bi_io_vec[0];
1109 bp->bv2 = bi->bi_io_vec[0];
1110 bp->bv2.bv_offset += first_sectors << 9;
1111 bp->bv2.bv_len -= first_sectors << 9;
1112 bp->bv1.bv_len = first_sectors << 9;
1113
1114 bp->bio1.bi_io_vec = &bp->bv1;
1115 bp->bio2.bi_io_vec = &bp->bv2;
1116
1117 bp->bio1.bi_end_io = bio_pair_end_1;
1118 bp->bio2.bi_end_io = bio_pair_end_2;
1119
1120 bp->bio1.bi_private = bi;
1121 bp->bio2.bi_private = pool;
1122
1123 return bp;
1124}
1125
Al Virodd0fc662005-10-07 07:46:04 +01001126static void *bio_pair_alloc(gfp_t gfp_flags, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127{
1128 return kmalloc(sizeof(struct bio_pair), gfp_flags);
1129}
1130
1131static void bio_pair_free(void *bp, void *data)
1132{
1133 kfree(bp);
1134}
1135
1136
1137/*
1138 * create memory pools for biovec's in a bio_set.
1139 * use the global biovec slabs created for general use.
1140 */
1141static int biovec_create_pools(struct bio_set *bs, int pool_entries, int scale)
1142{
1143 int i;
1144
1145 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1146 struct biovec_slab *bp = bvec_slabs + i;
1147 mempool_t **bvp = bs->bvec_pools + i;
1148
1149 if (i >= scale)
1150 pool_entries >>= 1;
1151
1152 *bvp = mempool_create(pool_entries, mempool_alloc_slab,
1153 mempool_free_slab, bp->slab);
1154 if (!*bvp)
1155 return -ENOMEM;
1156 }
1157 return 0;
1158}
1159
1160static void biovec_free_pools(struct bio_set *bs)
1161{
1162 int i;
1163
1164 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1165 mempool_t *bvp = bs->bvec_pools[i];
1166
1167 if (bvp)
1168 mempool_destroy(bvp);
1169 }
1170
1171}
1172
1173void bioset_free(struct bio_set *bs)
1174{
1175 if (bs->bio_pool)
1176 mempool_destroy(bs->bio_pool);
1177
1178 biovec_free_pools(bs);
1179
1180 kfree(bs);
1181}
1182
1183struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size, int scale)
1184{
1185 struct bio_set *bs = kmalloc(sizeof(*bs), GFP_KERNEL);
1186
1187 if (!bs)
1188 return NULL;
1189
1190 memset(bs, 0, sizeof(*bs));
1191 bs->bio_pool = mempool_create(bio_pool_size, mempool_alloc_slab,
1192 mempool_free_slab, bio_slab);
1193
1194 if (!bs->bio_pool)
1195 goto bad;
1196
1197 if (!biovec_create_pools(bs, bvec_pool_size, scale))
1198 return bs;
1199
1200bad:
1201 bioset_free(bs);
1202 return NULL;
1203}
1204
1205static void __init biovec_init_slabs(void)
1206{
1207 int i;
1208
1209 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1210 int size;
1211 struct biovec_slab *bvs = bvec_slabs + i;
1212
1213 size = bvs->nr_vecs * sizeof(struct bio_vec);
1214 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1215 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1216 }
1217}
1218
1219static int __init init_bio(void)
1220{
1221 int megabytes, bvec_pool_entries;
1222 int scale = BIOVEC_NR_POOLS;
1223
1224 bio_slab = kmem_cache_create("bio", sizeof(struct bio), 0,
1225 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1226
1227 biovec_init_slabs();
1228
1229 megabytes = nr_free_pages() >> (20 - PAGE_SHIFT);
1230
1231 /*
1232 * find out where to start scaling
1233 */
1234 if (megabytes <= 16)
1235 scale = 0;
1236 else if (megabytes <= 32)
1237 scale = 1;
1238 else if (megabytes <= 64)
1239 scale = 2;
1240 else if (megabytes <= 96)
1241 scale = 3;
1242 else if (megabytes <= 128)
1243 scale = 4;
1244
1245 /*
1246 * scale number of entries
1247 */
1248 bvec_pool_entries = megabytes * 2;
1249 if (bvec_pool_entries > 256)
1250 bvec_pool_entries = 256;
1251
1252 fs_bio_set = bioset_create(BIO_POOL_SIZE, bvec_pool_entries, scale);
1253 if (!fs_bio_set)
1254 panic("bio: can't allocate bios\n");
1255
1256 bio_split_pool = mempool_create(BIO_SPLIT_ENTRIES,
1257 bio_pair_alloc, bio_pair_free, NULL);
1258 if (!bio_split_pool)
1259 panic("bio: can't create split pool\n");
1260
1261 return 0;
1262}
1263
1264subsys_initcall(init_bio);
1265
1266EXPORT_SYMBOL(bio_alloc);
1267EXPORT_SYMBOL(bio_put);
Peter Osterlund36763472005-09-06 15:16:42 -07001268EXPORT_SYMBOL(bio_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269EXPORT_SYMBOL(bio_endio);
1270EXPORT_SYMBOL(bio_init);
1271EXPORT_SYMBOL(__bio_clone);
1272EXPORT_SYMBOL(bio_clone);
1273EXPORT_SYMBOL(bio_phys_segments);
1274EXPORT_SYMBOL(bio_hw_segments);
1275EXPORT_SYMBOL(bio_add_page);
Mike Christie6e68af62005-11-11 05:30:27 -06001276EXPORT_SYMBOL(bio_add_pc_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277EXPORT_SYMBOL(bio_get_nr_vecs);
1278EXPORT_SYMBOL(bio_map_user);
1279EXPORT_SYMBOL(bio_unmap_user);
Mike Christie df46b9a2005-06-20 14:04:44 +02001280EXPORT_SYMBOL(bio_map_kern);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281EXPORT_SYMBOL(bio_pair_release);
1282EXPORT_SYMBOL(bio_split);
1283EXPORT_SYMBOL(bio_split_pool);
1284EXPORT_SYMBOL(bio_copy_user);
1285EXPORT_SYMBOL(bio_uncopy_user);
1286EXPORT_SYMBOL(bioset_create);
1287EXPORT_SYMBOL(bioset_free);
1288EXPORT_SYMBOL(bio_alloc_bioset);