blob: f95c8749499f9db7fe799594161a183ed9896910 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Jens Axboe0fe23472006-09-04 15:41:16 +02002 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
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>
Jens Axboe2056a782006-03-23 20:00:26 +010028#include <linux/blktrace_api.h>
James Bottomley f1970ba2005-06-20 14:06:52 +020029#include <scsi/sg.h> /* for struct sg_iovec */
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31#define BIO_POOL_SIZE 256
32
Eric Dumazetfa3536c2006-03-26 01:37:24 -080033static kmem_cache_t *bio_slab __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35#define BIOVEC_NR_POOLS 6
36
37/*
38 * a small number of entries is fine, not going to be performance critical.
39 * basically we just need to survive
40 */
41#define BIO_SPLIT_ENTRIES 8
Eric Dumazetfa3536c2006-03-26 01:37:24 -080042mempool_t *bio_split_pool __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
44struct biovec_slab {
45 int nr_vecs;
46 char *name;
47 kmem_cache_t *slab;
48};
49
50/*
51 * if you change this list, also change bvec_alloc or things will
52 * break badly! cannot be bigger than what you can fit into an
53 * unsigned short
54 */
55
56#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
Christoph Lameter6c036522005-07-07 17:56:59 -070057static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
59};
60#undef BV
61
62/*
63 * bio_set is used to allow other portions of the IO system to
64 * allocate their own private memory pools for bio and iovec structures.
65 * These memory pools in turn all allocate from the bio_slab
66 * and the bvec_slabs[].
67 */
68struct bio_set {
69 mempool_t *bio_pool;
70 mempool_t *bvec_pools[BIOVEC_NR_POOLS];
71};
72
73/*
74 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
75 * IO code that does not need private memory pools.
76 */
77static struct bio_set *fs_bio_set;
78
Al Virodd0fc662005-10-07 07:46:04 +010079static 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 -070080{
81 struct bio_vec *bvl;
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask);
Andreas Mohrbf02c082006-10-11 01:22:24 -0700101 if (bvl) {
102 struct biovec_slab *bp = bvec_slabs + *idx;
103
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 memset(bvl, 0, bp->nr_vecs * sizeof(struct bio_vec));
Andreas Mohrbf02c082006-10-11 01:22:24 -0700105 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
107 return bvl;
108}
109
Peter Osterlund36763472005-09-06 15:16:42 -0700110void bio_free(struct bio *bio, struct bio_set *bio_set)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111{
112 const int pool_idx = BIO_POOL_IDX(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
114 BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
115
Peter Osterlund36763472005-09-06 15:16:42 -0700116 mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
117 mempool_free(bio, bio_set->bio_pool);
118}
119
120/*
121 * default destructor for a bio allocated with bio_alloc_bioset()
122 */
123static void bio_fs_destructor(struct bio *bio)
124{
125 bio_free(bio, fs_bio_set);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126}
127
Arjan van de Ven858119e2006-01-14 13:20:43 -0800128void bio_init(struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129{
130 bio->bi_next = NULL;
Jens Axboe0ea60b52006-01-09 14:45:10 +0100131 bio->bi_bdev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 bio->bi_flags = 1 << BIO_UPTODATE;
133 bio->bi_rw = 0;
134 bio->bi_vcnt = 0;
135 bio->bi_idx = 0;
136 bio->bi_phys_segments = 0;
137 bio->bi_hw_segments = 0;
138 bio->bi_hw_front_size = 0;
139 bio->bi_hw_back_size = 0;
140 bio->bi_size = 0;
141 bio->bi_max_vecs = 0;
142 bio->bi_end_io = NULL;
143 atomic_set(&bio->bi_cnt, 1);
144 bio->bi_private = NULL;
145}
146
147/**
148 * bio_alloc_bioset - allocate a bio for I/O
149 * @gfp_mask: the GFP_ mask given to the slab allocator
150 * @nr_iovecs: number of iovecs to pre-allocate
Martin Waitz67be2dd2005-05-01 08:59:26 -0700151 * @bs: the bio_set to allocate from
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 *
153 * Description:
154 * bio_alloc_bioset will first try it's on mempool to satisfy the allocation.
155 * If %__GFP_WAIT is set then we will block on the internal pool waiting
156 * for a &struct bio to become free.
157 *
158 * allocate bio and iovecs from the memory pools specified by the
159 * bio_set structure.
160 **/
Al Virodd0fc662005-10-07 07:46:04 +0100161struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162{
163 struct bio *bio = mempool_alloc(bs->bio_pool, gfp_mask);
164
165 if (likely(bio)) {
166 struct bio_vec *bvl = NULL;
167
168 bio_init(bio);
169 if (likely(nr_iovecs)) {
Andreas Mohrbf02c082006-10-11 01:22:24 -0700170 unsigned long idx = 0; /* shut up gcc */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
172 bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
173 if (unlikely(!bvl)) {
174 mempool_free(bio, bs->bio_pool);
175 bio = NULL;
176 goto out;
177 }
178 bio->bi_flags |= idx << BIO_POOL_OFFSET;
179 bio->bi_max_vecs = bvec_slabs[idx].nr_vecs;
180 }
181 bio->bi_io_vec = bvl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 }
183out:
184 return bio;
185}
186
Al Virodd0fc662005-10-07 07:46:04 +0100187struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188{
Peter Osterlund36763472005-09-06 15:16:42 -0700189 struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
190
191 if (bio)
192 bio->bi_destructor = bio_fs_destructor;
193
194 return bio;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195}
196
197void zero_fill_bio(struct bio *bio)
198{
199 unsigned long flags;
200 struct bio_vec *bv;
201 int i;
202
203 bio_for_each_segment(bv, bio, i) {
204 char *data = bvec_kmap_irq(bv, &flags);
205 memset(data, 0, bv->bv_len);
206 flush_dcache_page(bv->bv_page);
207 bvec_kunmap_irq(data, &flags);
208 }
209}
210EXPORT_SYMBOL(zero_fill_bio);
211
212/**
213 * bio_put - release a reference to a bio
214 * @bio: bio to release reference to
215 *
216 * Description:
217 * Put a reference to a &struct bio, either one you have gotten with
218 * bio_alloc or bio_get. The last put of a bio will free it.
219 **/
220void bio_put(struct bio *bio)
221{
222 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
223
224 /*
225 * last put frees it
226 */
227 if (atomic_dec_and_test(&bio->bi_cnt)) {
228 bio->bi_next = NULL;
229 bio->bi_destructor(bio);
230 }
231}
232
233inline int bio_phys_segments(request_queue_t *q, struct bio *bio)
234{
235 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
236 blk_recount_segments(q, bio);
237
238 return bio->bi_phys_segments;
239}
240
241inline int bio_hw_segments(request_queue_t *q, struct bio *bio)
242{
243 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
244 blk_recount_segments(q, bio);
245
246 return bio->bi_hw_segments;
247}
248
249/**
250 * __bio_clone - clone a bio
251 * @bio: destination bio
252 * @bio_src: bio to clone
253 *
254 * Clone a &bio. Caller will own the returned bio, but not
255 * the actual data it points to. Reference count of returned
256 * bio will be one.
257 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800258void __bio_clone(struct bio *bio, struct bio *bio_src)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259{
260 request_queue_t *q = bdev_get_queue(bio_src->bi_bdev);
261
Andrew Mortone525e152005-08-07 09:42:12 -0700262 memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
263 bio_src->bi_max_vecs * sizeof(struct bio_vec));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
265 bio->bi_sector = bio_src->bi_sector;
266 bio->bi_bdev = bio_src->bi_bdev;
267 bio->bi_flags |= 1 << BIO_CLONED;
268 bio->bi_rw = bio_src->bi_rw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 bio->bi_vcnt = bio_src->bi_vcnt;
270 bio->bi_size = bio_src->bi_size;
Andrew Mortona5453be2005-07-28 01:07:18 -0700271 bio->bi_idx = bio_src->bi_idx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 bio_phys_segments(q, bio);
273 bio_hw_segments(q, bio);
274}
275
276/**
277 * bio_clone - clone a bio
278 * @bio: bio to clone
279 * @gfp_mask: allocation priority
280 *
281 * Like __bio_clone, only also allocates the returned bio
282 */
Al Virodd0fc662005-10-07 07:46:04 +0100283struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284{
285 struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
286
Peter Osterlund36763472005-09-06 15:16:42 -0700287 if (b) {
288 b->bi_destructor = bio_fs_destructor;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 __bio_clone(b, bio);
Peter Osterlund36763472005-09-06 15:16:42 -0700290 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291
292 return b;
293}
294
295/**
296 * bio_get_nr_vecs - return approx number of vecs
297 * @bdev: I/O target
298 *
299 * Return the approximate number of pages we can send to this target.
300 * There's no guarantee that you will be able to fit this number of pages
301 * into a bio, it does not account for dynamic restrictions that vary
302 * on offset.
303 */
304int bio_get_nr_vecs(struct block_device *bdev)
305{
306 request_queue_t *q = bdev_get_queue(bdev);
307 int nr_pages;
308
309 nr_pages = ((q->max_sectors << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
310 if (nr_pages > q->max_phys_segments)
311 nr_pages = q->max_phys_segments;
312 if (nr_pages > q->max_hw_segments)
313 nr_pages = q->max_hw_segments;
314
315 return nr_pages;
316}
317
318static int __bio_add_page(request_queue_t *q, struct bio *bio, struct page
Mike Christiedefd94b2005-12-05 02:37:06 -0600319 *page, unsigned int len, unsigned int offset,
320 unsigned short max_sectors)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321{
322 int retried_segments = 0;
323 struct bio_vec *bvec;
324
325 /*
326 * cloned bio must not modify vec list
327 */
328 if (unlikely(bio_flagged(bio, BIO_CLONED)))
329 return 0;
330
Jens Axboe80cfd542006-01-06 09:43:28 +0100331 if (((bio->bi_size + len) >> 9) > max_sectors)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 return 0;
333
Jens Axboe80cfd542006-01-06 09:43:28 +0100334 /*
335 * For filesystems with a blocksize smaller than the pagesize
336 * we will often be called with the same page as last time and
337 * a consecutive offset. Optimize this special case.
338 */
339 if (bio->bi_vcnt > 0) {
340 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
341
342 if (page == prev->bv_page &&
343 offset == prev->bv_offset + prev->bv_len) {
344 prev->bv_len += len;
345 if (q->merge_bvec_fn &&
346 q->merge_bvec_fn(q, bio, prev) < len) {
347 prev->bv_len -= len;
348 return 0;
349 }
350
351 goto done;
352 }
353 }
354
355 if (bio->bi_vcnt >= bio->bi_max_vecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 return 0;
357
358 /*
359 * we might lose a segment or two here, but rather that than
360 * make this too complex.
361 */
362
363 while (bio->bi_phys_segments >= q->max_phys_segments
364 || bio->bi_hw_segments >= q->max_hw_segments
365 || BIOVEC_VIRT_OVERSIZE(bio->bi_size)) {
366
367 if (retried_segments)
368 return 0;
369
370 retried_segments = 1;
371 blk_recount_segments(q, bio);
372 }
373
374 /*
375 * setup the new entry, we might clear it again later if we
376 * cannot add the page
377 */
378 bvec = &bio->bi_io_vec[bio->bi_vcnt];
379 bvec->bv_page = page;
380 bvec->bv_len = len;
381 bvec->bv_offset = offset;
382
383 /*
384 * if queue has other restrictions (eg varying max sector size
385 * depending on offset), it can specify a merge_bvec_fn in the
386 * queue to get further control
387 */
388 if (q->merge_bvec_fn) {
389 /*
390 * merge_bvec_fn() returns number of bytes it can accept
391 * at this offset
392 */
393 if (q->merge_bvec_fn(q, bio, bvec) < len) {
394 bvec->bv_page = NULL;
395 bvec->bv_len = 0;
396 bvec->bv_offset = 0;
397 return 0;
398 }
399 }
400
401 /* If we may be able to merge these biovecs, force a recount */
402 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec) ||
403 BIOVEC_VIRT_MERGEABLE(bvec-1, bvec)))
404 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
405
406 bio->bi_vcnt++;
407 bio->bi_phys_segments++;
408 bio->bi_hw_segments++;
Jens Axboe80cfd542006-01-06 09:43:28 +0100409 done:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 bio->bi_size += len;
411 return len;
412}
413
414/**
Mike Christie6e68af62005-11-11 05:30:27 -0600415 * bio_add_pc_page - attempt to add page to bio
Jens Axboefddfdea2006-01-31 15:24:34 +0100416 * @q: the target queue
Mike Christie6e68af62005-11-11 05:30:27 -0600417 * @bio: destination bio
418 * @page: page to add
419 * @len: vec entry length
420 * @offset: vec entry offset
421 *
422 * Attempt to add a page to the bio_vec maplist. This can fail for a
423 * number of reasons, such as the bio being full or target block
424 * device limitations. The target block device must allow bio's
425 * smaller than PAGE_SIZE, so it is always possible to add a single
426 * page to an empty bio. This should only be used by REQ_PC bios.
427 */
428int bio_add_pc_page(request_queue_t *q, struct bio *bio, struct page *page,
429 unsigned int len, unsigned int offset)
430{
Mike Christiedefd94b2005-12-05 02:37:06 -0600431 return __bio_add_page(q, bio, page, len, offset, q->max_hw_sectors);
Mike Christie6e68af62005-11-11 05:30:27 -0600432}
433
434/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 * bio_add_page - attempt to add page to bio
436 * @bio: destination bio
437 * @page: page to add
438 * @len: vec entry length
439 * @offset: vec entry offset
440 *
441 * Attempt to add a page to the bio_vec maplist. This can fail for a
442 * number of reasons, such as the bio being full or target block
443 * device limitations. The target block device must allow bio's
444 * smaller than PAGE_SIZE, so it is always possible to add a single
445 * page to an empty bio.
446 */
447int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
448 unsigned int offset)
449{
Mike Christiedefd94b2005-12-05 02:37:06 -0600450 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
451 return __bio_add_page(q, bio, page, len, offset, q->max_sectors);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452}
453
454struct bio_map_data {
455 struct bio_vec *iovecs;
456 void __user *userptr;
457};
458
459static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio)
460{
461 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
462 bio->bi_private = bmd;
463}
464
465static void bio_free_map_data(struct bio_map_data *bmd)
466{
467 kfree(bmd->iovecs);
468 kfree(bmd);
469}
470
471static struct bio_map_data *bio_alloc_map_data(int nr_segs)
472{
473 struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL);
474
475 if (!bmd)
476 return NULL;
477
478 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL);
479 if (bmd->iovecs)
480 return bmd;
481
482 kfree(bmd);
483 return NULL;
484}
485
486/**
487 * bio_uncopy_user - finish previously mapped bio
488 * @bio: bio being terminated
489 *
490 * Free pages allocated from bio_copy_user() and write back data
491 * to user space in case of a read.
492 */
493int bio_uncopy_user(struct bio *bio)
494{
495 struct bio_map_data *bmd = bio->bi_private;
496 const int read = bio_data_dir(bio) == READ;
497 struct bio_vec *bvec;
498 int i, ret = 0;
499
500 __bio_for_each_segment(bvec, bio, i, 0) {
501 char *addr = page_address(bvec->bv_page);
502 unsigned int len = bmd->iovecs[i].bv_len;
503
504 if (read && !ret && copy_to_user(bmd->userptr, addr, len))
505 ret = -EFAULT;
506
507 __free_page(bvec->bv_page);
508 bmd->userptr += len;
509 }
510 bio_free_map_data(bmd);
511 bio_put(bio);
512 return ret;
513}
514
515/**
516 * bio_copy_user - copy user data to bio
517 * @q: destination block queue
518 * @uaddr: start of user address
519 * @len: length in bytes
520 * @write_to_vm: bool indicating writing to pages or not
521 *
522 * Prepares and returns a bio for indirect user io, bouncing data
523 * to/from kernel pages as necessary. Must be paired with
524 * call bio_uncopy_user() on io completion.
525 */
526struct bio *bio_copy_user(request_queue_t *q, unsigned long uaddr,
527 unsigned int len, int write_to_vm)
528{
529 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
530 unsigned long start = uaddr >> PAGE_SHIFT;
531 struct bio_map_data *bmd;
532 struct bio_vec *bvec;
533 struct page *page;
534 struct bio *bio;
535 int i, ret;
536
537 bmd = bio_alloc_map_data(end - start);
538 if (!bmd)
539 return ERR_PTR(-ENOMEM);
540
541 bmd->userptr = (void __user *) uaddr;
542
543 ret = -ENOMEM;
544 bio = bio_alloc(GFP_KERNEL, end - start);
545 if (!bio)
546 goto out_bmd;
547
548 bio->bi_rw |= (!write_to_vm << BIO_RW);
549
550 ret = 0;
551 while (len) {
552 unsigned int bytes = PAGE_SIZE;
553
554 if (bytes > len)
555 bytes = len;
556
557 page = alloc_page(q->bounce_gfp | GFP_KERNEL);
558 if (!page) {
559 ret = -ENOMEM;
560 break;
561 }
562
Mike Christiedefd94b2005-12-05 02:37:06 -0600563 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 ret = -EINVAL;
565 break;
566 }
567
568 len -= bytes;
569 }
570
571 if (ret)
572 goto cleanup;
573
574 /*
575 * success
576 */
577 if (!write_to_vm) {
578 char __user *p = (char __user *) uaddr;
579
580 /*
581 * for a write, copy in data to kernel pages
582 */
583 ret = -EFAULT;
584 bio_for_each_segment(bvec, bio, i) {
585 char *addr = page_address(bvec->bv_page);
586
587 if (copy_from_user(addr, p, bvec->bv_len))
588 goto cleanup;
589 p += bvec->bv_len;
590 }
591 }
592
593 bio_set_map_data(bmd, bio);
594 return bio;
595cleanup:
596 bio_for_each_segment(bvec, bio, i)
597 __free_page(bvec->bv_page);
598
599 bio_put(bio);
600out_bmd:
601 bio_free_map_data(bmd);
602 return ERR_PTR(ret);
603}
604
James Bottomley f1970ba2005-06-20 14:06:52 +0200605static struct bio *__bio_map_user_iov(request_queue_t *q,
606 struct block_device *bdev,
607 struct sg_iovec *iov, int iov_count,
608 int write_to_vm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609{
James Bottomley f1970ba2005-06-20 14:06:52 +0200610 int i, j;
611 int nr_pages = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 struct page **pages;
613 struct bio *bio;
James Bottomley f1970ba2005-06-20 14:06:52 +0200614 int cur_page = 0;
615 int ret, offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616
James Bottomley f1970ba2005-06-20 14:06:52 +0200617 for (i = 0; i < iov_count; i++) {
618 unsigned long uaddr = (unsigned long)iov[i].iov_base;
619 unsigned long len = iov[i].iov_len;
620 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
621 unsigned long start = uaddr >> PAGE_SHIFT;
622
623 nr_pages += end - start;
624 /*
625 * transfer and buffer must be aligned to at least hardsector
626 * size for now, in the future we can relax this restriction
627 */
628 if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q)))
629 return ERR_PTR(-EINVAL);
630 }
631
632 if (!nr_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 return ERR_PTR(-EINVAL);
634
635 bio = bio_alloc(GFP_KERNEL, nr_pages);
636 if (!bio)
637 return ERR_PTR(-ENOMEM);
638
639 ret = -ENOMEM;
Oliver Neukum11b0b5a2006-03-25 03:08:13 -0800640 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 if (!pages)
642 goto out;
643
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
Jens Axboe99172152006-06-16 13:02:29 +0200658 if (ret < local_nr_pages) {
659 ret = -EFAULT;
James Bottomley f1970ba2005-06-20 14:06:52 +0200660 goto out_unmap;
Jens Axboe99172152006-06-16 13:02:29 +0200661 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662
James Bottomley f1970ba2005-06-20 14:06:52 +0200663 offset = uaddr & ~PAGE_MASK;
664 for (j = cur_page; j < page_limit; j++) {
665 unsigned int bytes = PAGE_SIZE - offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666
James Bottomley f1970ba2005-06-20 14:06:52 +0200667 if (len <= 0)
668 break;
669
670 if (bytes > len)
671 bytes = len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672
James Bottomley f1970ba2005-06-20 14:06:52 +0200673 /*
674 * sorry...
675 */
Mike Christiedefd94b2005-12-05 02:37:06 -0600676 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
677 bytes)
James Bottomley f1970ba2005-06-20 14:06:52 +0200678 break;
679
680 len -= bytes;
681 offset = 0;
682 }
683
684 cur_page = j;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 /*
James Bottomley f1970ba2005-06-20 14:06:52 +0200686 * release the pages we didn't map into the bio, if any
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 */
James Bottomley f1970ba2005-06-20 14:06:52 +0200688 while (j < page_limit)
689 page_cache_release(pages[j++]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 }
691
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 kfree(pages);
693
694 /*
695 * set data direction, and check if mapped pages need bouncing
696 */
697 if (!write_to_vm)
698 bio->bi_rw |= (1 << BIO_RW);
699
James Bottomley f1970ba2005-06-20 14:06:52 +0200700 bio->bi_bdev = bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 bio->bi_flags |= (1 << BIO_USER_MAPPED);
702 return bio;
James Bottomley f1970ba2005-06-20 14:06:52 +0200703
704 out_unmap:
705 for (i = 0; i < nr_pages; i++) {
706 if(!pages[i])
707 break;
708 page_cache_release(pages[i]);
709 }
710 out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 kfree(pages);
712 bio_put(bio);
713 return ERR_PTR(ret);
714}
715
716/**
717 * bio_map_user - map user address into bio
Martin Waitz67be2dd2005-05-01 08:59:26 -0700718 * @q: the request_queue_t for the bio
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 * @bdev: destination block device
720 * @uaddr: start of user address
721 * @len: length in bytes
722 * @write_to_vm: bool indicating writing to pages or not
723 *
724 * Map the user space address into a bio suitable for io to a block
725 * device. Returns an error pointer in case of error.
726 */
727struct bio *bio_map_user(request_queue_t *q, struct block_device *bdev,
728 unsigned long uaddr, unsigned int len, int write_to_vm)
729{
James Bottomley f1970ba2005-06-20 14:06:52 +0200730 struct sg_iovec iov;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731
viro@ZenIV.linux.org.uk3f703532005-09-09 16:53:56 +0100732 iov.iov_base = (void __user *)uaddr;
James Bottomley f1970ba2005-06-20 14:06:52 +0200733 iov.iov_len = len;
734
735 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm);
736}
737
738/**
739 * bio_map_user_iov - map user sg_iovec table into bio
740 * @q: the request_queue_t for the bio
741 * @bdev: destination block device
742 * @iov: the iovec.
743 * @iov_count: number of elements in the iovec
744 * @write_to_vm: bool indicating writing to pages or not
745 *
746 * Map the user space address into a bio suitable for io to a block
747 * device. Returns an error pointer in case of error.
748 */
749struct bio *bio_map_user_iov(request_queue_t *q, struct block_device *bdev,
750 struct sg_iovec *iov, int iov_count,
751 int write_to_vm)
752{
753 struct bio *bio;
754 int len = 0, i;
755
756 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757
758 if (IS_ERR(bio))
759 return bio;
760
761 /*
762 * subtle -- if __bio_map_user() ended up bouncing a bio,
763 * it would normally disappear when its bi_end_io is run.
764 * however, we need it for the unmap, so grab an extra
765 * reference to it
766 */
767 bio_get(bio);
768
James Bottomley f1970ba2005-06-20 14:06:52 +0200769 for (i = 0; i < iov_count; i++)
770 len += iov[i].iov_len;
771
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 if (bio->bi_size == len)
773 return bio;
774
775 /*
776 * don't support partial mappings
777 */
778 bio_endio(bio, bio->bi_size, 0);
779 bio_unmap_user(bio);
780 return ERR_PTR(-EINVAL);
781}
782
783static void __bio_unmap_user(struct bio *bio)
784{
785 struct bio_vec *bvec;
786 int i;
787
788 /*
789 * make sure we dirty pages we wrote to
790 */
791 __bio_for_each_segment(bvec, bio, i, 0) {
792 if (bio_data_dir(bio) == READ)
793 set_page_dirty_lock(bvec->bv_page);
794
795 page_cache_release(bvec->bv_page);
796 }
797
798 bio_put(bio);
799}
800
801/**
802 * bio_unmap_user - unmap a bio
803 * @bio: the bio being unmapped
804 *
805 * Unmap a bio previously mapped by bio_map_user(). Must be called with
806 * a process context.
807 *
808 * bio_unmap_user() may sleep.
809 */
810void bio_unmap_user(struct bio *bio)
811{
812 __bio_unmap_user(bio);
813 bio_put(bio);
814}
815
Jens Axboeb8238252005-06-20 14:05:27 +0200816static int bio_map_kern_endio(struct bio *bio, unsigned int bytes_done, int err)
817{
818 if (bio->bi_size)
819 return 1;
820
821 bio_put(bio);
822 return 0;
823}
824
825
Mike Christie df46b9a2005-06-20 14:04:44 +0200826static struct bio *__bio_map_kern(request_queue_t *q, void *data,
Al Viro27496a82005-10-21 03:20:48 -0400827 unsigned int len, gfp_t gfp_mask)
Mike Christie df46b9a2005-06-20 14:04:44 +0200828{
829 unsigned long kaddr = (unsigned long)data;
830 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
831 unsigned long start = kaddr >> PAGE_SHIFT;
832 const int nr_pages = end - start;
833 int offset, i;
834 struct bio *bio;
835
836 bio = bio_alloc(gfp_mask, nr_pages);
837 if (!bio)
838 return ERR_PTR(-ENOMEM);
839
840 offset = offset_in_page(kaddr);
841 for (i = 0; i < nr_pages; i++) {
842 unsigned int bytes = PAGE_SIZE - offset;
843
844 if (len <= 0)
845 break;
846
847 if (bytes > len)
848 bytes = len;
849
Mike Christiedefd94b2005-12-05 02:37:06 -0600850 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
851 offset) < bytes)
Mike Christie df46b9a2005-06-20 14:04:44 +0200852 break;
853
854 data += bytes;
855 len -= bytes;
856 offset = 0;
857 }
858
Jens Axboeb8238252005-06-20 14:05:27 +0200859 bio->bi_end_io = bio_map_kern_endio;
Mike Christie df46b9a2005-06-20 14:04:44 +0200860 return bio;
861}
862
863/**
864 * bio_map_kern - map kernel address into bio
865 * @q: the request_queue_t for the bio
866 * @data: pointer to buffer to map
867 * @len: length in bytes
868 * @gfp_mask: allocation flags for bio allocation
869 *
870 * Map the kernel address into a bio suitable for io to a block
871 * device. Returns an error pointer in case of error.
872 */
873struct bio *bio_map_kern(request_queue_t *q, void *data, unsigned int len,
Al Viro27496a82005-10-21 03:20:48 -0400874 gfp_t gfp_mask)
Mike Christie df46b9a2005-06-20 14:04:44 +0200875{
876 struct bio *bio;
877
878 bio = __bio_map_kern(q, data, len, gfp_mask);
879 if (IS_ERR(bio))
880 return bio;
881
882 if (bio->bi_size == len)
883 return bio;
884
885 /*
886 * Don't support partial mappings.
887 */
888 bio_put(bio);
889 return ERR_PTR(-EINVAL);
890}
891
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892/*
893 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
894 * for performing direct-IO in BIOs.
895 *
896 * The problem is that we cannot run set_page_dirty() from interrupt context
897 * because the required locks are not interrupt-safe. So what we can do is to
898 * mark the pages dirty _before_ performing IO. And in interrupt context,
899 * check that the pages are still dirty. If so, fine. If not, redirty them
900 * in process context.
901 *
902 * We special-case compound pages here: normally this means reads into hugetlb
903 * pages. The logic in here doesn't really work right for compound pages
904 * because the VM does not uniformly chase down the head page in all cases.
905 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
906 * handle them at all. So we skip compound pages here at an early stage.
907 *
908 * Note that this code is very hard to test under normal circumstances because
909 * direct-io pins the pages with get_user_pages(). This makes
910 * is_page_cache_freeable return false, and the VM will not clean the pages.
911 * But other code (eg, pdflush) could clean the pages if they are mapped
912 * pagecache.
913 *
914 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
915 * deferred bio dirtying paths.
916 */
917
918/*
919 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
920 */
921void bio_set_pages_dirty(struct bio *bio)
922{
923 struct bio_vec *bvec = bio->bi_io_vec;
924 int i;
925
926 for (i = 0; i < bio->bi_vcnt; i++) {
927 struct page *page = bvec[i].bv_page;
928
929 if (page && !PageCompound(page))
930 set_page_dirty_lock(page);
931 }
932}
933
934static void bio_release_pages(struct bio *bio)
935{
936 struct bio_vec *bvec = bio->bi_io_vec;
937 int i;
938
939 for (i = 0; i < bio->bi_vcnt; i++) {
940 struct page *page = bvec[i].bv_page;
941
942 if (page)
943 put_page(page);
944 }
945}
946
947/*
948 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
949 * If they are, then fine. If, however, some pages are clean then they must
950 * have been written out during the direct-IO read. So we take another ref on
951 * the BIO and the offending pages and re-dirty the pages in process context.
952 *
953 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
954 * here on. It will run one page_cache_release() against each page and will
955 * run one bio_put() against the BIO.
956 */
957
958static void bio_dirty_fn(void *data);
959
960static DECLARE_WORK(bio_dirty_work, bio_dirty_fn, NULL);
961static DEFINE_SPINLOCK(bio_dirty_lock);
962static struct bio *bio_dirty_list;
963
964/*
965 * This runs in process context
966 */
967static void bio_dirty_fn(void *data)
968{
969 unsigned long flags;
970 struct bio *bio;
971
972 spin_lock_irqsave(&bio_dirty_lock, flags);
973 bio = bio_dirty_list;
974 bio_dirty_list = NULL;
975 spin_unlock_irqrestore(&bio_dirty_lock, flags);
976
977 while (bio) {
978 struct bio *next = bio->bi_private;
979
980 bio_set_pages_dirty(bio);
981 bio_release_pages(bio);
982 bio_put(bio);
983 bio = next;
984 }
985}
986
987void bio_check_pages_dirty(struct bio *bio)
988{
989 struct bio_vec *bvec = bio->bi_io_vec;
990 int nr_clean_pages = 0;
991 int i;
992
993 for (i = 0; i < bio->bi_vcnt; i++) {
994 struct page *page = bvec[i].bv_page;
995
996 if (PageDirty(page) || PageCompound(page)) {
997 page_cache_release(page);
998 bvec[i].bv_page = NULL;
999 } else {
1000 nr_clean_pages++;
1001 }
1002 }
1003
1004 if (nr_clean_pages) {
1005 unsigned long flags;
1006
1007 spin_lock_irqsave(&bio_dirty_lock, flags);
1008 bio->bi_private = bio_dirty_list;
1009 bio_dirty_list = bio;
1010 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1011 schedule_work(&bio_dirty_work);
1012 } else {
1013 bio_put(bio);
1014 }
1015}
1016
1017/**
1018 * bio_endio - end I/O on a bio
1019 * @bio: bio
1020 * @bytes_done: number of bytes completed
1021 * @error: error, if any
1022 *
1023 * Description:
1024 * bio_endio() will end I/O on @bytes_done number of bytes. This may be
1025 * just a partial part of the bio, or it may be the whole bio. bio_endio()
1026 * is the preferred way to end I/O on a bio, it takes care of decrementing
1027 * bi_size and clearing BIO_UPTODATE on error. @error is 0 on success, and
1028 * and one of the established -Exxxx (-EIO, for instance) error values in
1029 * case something went wrong. Noone should call bi_end_io() directly on
1030 * a bio unless they own it and thus know that it has an end_io function.
1031 **/
1032void bio_endio(struct bio *bio, unsigned int bytes_done, int error)
1033{
1034 if (error)
1035 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1036
1037 if (unlikely(bytes_done > bio->bi_size)) {
1038 printk("%s: want %u bytes done, only %u left\n", __FUNCTION__,
1039 bytes_done, bio->bi_size);
1040 bytes_done = bio->bi_size;
1041 }
1042
1043 bio->bi_size -= bytes_done;
1044 bio->bi_sector += (bytes_done >> 9);
1045
1046 if (bio->bi_end_io)
1047 bio->bi_end_io(bio, bytes_done, error);
1048}
1049
1050void bio_pair_release(struct bio_pair *bp)
1051{
1052 if (atomic_dec_and_test(&bp->cnt)) {
1053 struct bio *master = bp->bio1.bi_private;
1054
1055 bio_endio(master, master->bi_size, bp->error);
1056 mempool_free(bp, bp->bio2.bi_private);
1057 }
1058}
1059
1060static int bio_pair_end_1(struct bio * bi, unsigned int done, int err)
1061{
1062 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1063
1064 if (err)
1065 bp->error = err;
1066
1067 if (bi->bi_size)
1068 return 1;
1069
1070 bio_pair_release(bp);
1071 return 0;
1072}
1073
1074static int bio_pair_end_2(struct bio * bi, unsigned int done, int err)
1075{
1076 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1077
1078 if (err)
1079 bp->error = err;
1080
1081 if (bi->bi_size)
1082 return 1;
1083
1084 bio_pair_release(bp);
1085 return 0;
1086}
1087
1088/*
1089 * split a bio - only worry about a bio with a single page
1090 * in it's iovec
1091 */
1092struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors)
1093{
1094 struct bio_pair *bp = mempool_alloc(pool, GFP_NOIO);
1095
1096 if (!bp)
1097 return bp;
1098
Jens Axboe2056a782006-03-23 20:00:26 +01001099 blk_add_trace_pdu_int(bdev_get_queue(bi->bi_bdev), BLK_TA_SPLIT, bi,
1100 bi->bi_sector + first_sectors);
1101
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 BUG_ON(bi->bi_vcnt != 1);
1103 BUG_ON(bi->bi_idx != 0);
1104 atomic_set(&bp->cnt, 3);
1105 bp->error = 0;
1106 bp->bio1 = *bi;
1107 bp->bio2 = *bi;
1108 bp->bio2.bi_sector += first_sectors;
1109 bp->bio2.bi_size -= first_sectors << 9;
1110 bp->bio1.bi_size = first_sectors << 9;
1111
1112 bp->bv1 = bi->bi_io_vec[0];
1113 bp->bv2 = bi->bi_io_vec[0];
1114 bp->bv2.bv_offset += first_sectors << 9;
1115 bp->bv2.bv_len -= first_sectors << 9;
1116 bp->bv1.bv_len = first_sectors << 9;
1117
1118 bp->bio1.bi_io_vec = &bp->bv1;
1119 bp->bio2.bi_io_vec = &bp->bv2;
1120
NeilBrowna2eb0c12006-05-22 22:35:27 -07001121 bp->bio1.bi_max_vecs = 1;
1122 bp->bio2.bi_max_vecs = 1;
1123
Linus Torvalds1da177e2005-04-16 15:20:36 -07001124 bp->bio1.bi_end_io = bio_pair_end_1;
1125 bp->bio2.bi_end_io = bio_pair_end_2;
1126
1127 bp->bio1.bi_private = bi;
1128 bp->bio2.bi_private = pool;
1129
1130 return bp;
1131}
1132
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133
1134/*
1135 * create memory pools for biovec's in a bio_set.
1136 * use the global biovec slabs created for general use.
1137 */
1138static int biovec_create_pools(struct bio_set *bs, int pool_entries, int scale)
1139{
1140 int i;
1141
1142 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1143 struct biovec_slab *bp = bvec_slabs + i;
1144 mempool_t **bvp = bs->bvec_pools + i;
1145
Milan Broz50be3452006-09-04 15:37:57 +02001146 if (pool_entries > 1 && i >= scale)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 pool_entries >>= 1;
1148
Matthew Dobson93d23412006-03-26 01:37:50 -08001149 *bvp = mempool_create_slab_pool(pool_entries, bp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150 if (!*bvp)
1151 return -ENOMEM;
1152 }
1153 return 0;
1154}
1155
1156static void biovec_free_pools(struct bio_set *bs)
1157{
1158 int i;
1159
1160 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1161 mempool_t *bvp = bs->bvec_pools[i];
1162
1163 if (bvp)
1164 mempool_destroy(bvp);
1165 }
1166
1167}
1168
1169void bioset_free(struct bio_set *bs)
1170{
1171 if (bs->bio_pool)
1172 mempool_destroy(bs->bio_pool);
1173
1174 biovec_free_pools(bs);
1175
1176 kfree(bs);
1177}
1178
1179struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size, int scale)
1180{
Oliver Neukum11b0b5a2006-03-25 03:08:13 -08001181 struct bio_set *bs = kzalloc(sizeof(*bs), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182
1183 if (!bs)
1184 return NULL;
1185
Matthew Dobson93d23412006-03-26 01:37:50 -08001186 bs->bio_pool = mempool_create_slab_pool(bio_pool_size, bio_slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 if (!bs->bio_pool)
1188 goto bad;
1189
1190 if (!biovec_create_pools(bs, bvec_pool_size, scale))
1191 return bs;
1192
1193bad:
1194 bioset_free(bs);
1195 return NULL;
1196}
1197
1198static void __init biovec_init_slabs(void)
1199{
1200 int i;
1201
1202 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1203 int size;
1204 struct biovec_slab *bvs = bvec_slabs + i;
1205
1206 size = bvs->nr_vecs * sizeof(struct bio_vec);
1207 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1208 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1209 }
1210}
1211
1212static int __init init_bio(void)
1213{
1214 int megabytes, bvec_pool_entries;
1215 int scale = BIOVEC_NR_POOLS;
1216
1217 bio_slab = kmem_cache_create("bio", sizeof(struct bio), 0,
1218 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1219
1220 biovec_init_slabs();
1221
1222 megabytes = nr_free_pages() >> (20 - PAGE_SHIFT);
1223
1224 /*
1225 * find out where to start scaling
1226 */
1227 if (megabytes <= 16)
1228 scale = 0;
1229 else if (megabytes <= 32)
1230 scale = 1;
1231 else if (megabytes <= 64)
1232 scale = 2;
1233 else if (megabytes <= 96)
1234 scale = 3;
1235 else if (megabytes <= 128)
1236 scale = 4;
1237
1238 /*
Benjamin LaHaiseb0e6e962006-03-23 03:01:08 -08001239 * Limit number of entries reserved -- mempools are only used when
1240 * the system is completely unable to allocate memory, so we only
1241 * need enough to make progress.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242 */
Benjamin LaHaiseb0e6e962006-03-23 03:01:08 -08001243 bvec_pool_entries = 1 + scale;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244
1245 fs_bio_set = bioset_create(BIO_POOL_SIZE, bvec_pool_entries, scale);
1246 if (!fs_bio_set)
1247 panic("bio: can't allocate bios\n");
1248
Matthew Dobson0eaae62a2006-03-26 01:37:47 -08001249 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
1250 sizeof(struct bio_pair));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 if (!bio_split_pool)
1252 panic("bio: can't create split pool\n");
1253
1254 return 0;
1255}
1256
1257subsys_initcall(init_bio);
1258
1259EXPORT_SYMBOL(bio_alloc);
1260EXPORT_SYMBOL(bio_put);
Peter Osterlund36763472005-09-06 15:16:42 -07001261EXPORT_SYMBOL(bio_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262EXPORT_SYMBOL(bio_endio);
1263EXPORT_SYMBOL(bio_init);
1264EXPORT_SYMBOL(__bio_clone);
1265EXPORT_SYMBOL(bio_clone);
1266EXPORT_SYMBOL(bio_phys_segments);
1267EXPORT_SYMBOL(bio_hw_segments);
1268EXPORT_SYMBOL(bio_add_page);
Mike Christie6e68af62005-11-11 05:30:27 -06001269EXPORT_SYMBOL(bio_add_pc_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270EXPORT_SYMBOL(bio_get_nr_vecs);
1271EXPORT_SYMBOL(bio_map_user);
1272EXPORT_SYMBOL(bio_unmap_user);
Mike Christie df46b9a2005-06-20 14:04:44 +02001273EXPORT_SYMBOL(bio_map_kern);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274EXPORT_SYMBOL(bio_pair_release);
1275EXPORT_SYMBOL(bio_split);
1276EXPORT_SYMBOL(bio_split_pool);
1277EXPORT_SYMBOL(bio_copy_user);
1278EXPORT_SYMBOL(bio_uncopy_user);
1279EXPORT_SYMBOL(bioset_create);
1280EXPORT_SYMBOL(bioset_free);
1281EXPORT_SYMBOL(bio_alloc_bioset);