blob: 1f2d4649b188015076353340055a4ebdd1e0a6b1 [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>
28
29#define BIO_POOL_SIZE 256
30
31static kmem_cache_t *bio_slab;
32
33#define BIOVEC_NR_POOLS 6
34
35/*
36 * a small number of entries is fine, not going to be performance critical.
37 * basically we just need to survive
38 */
39#define BIO_SPLIT_ENTRIES 8
40mempool_t *bio_split_pool;
41
42struct biovec_slab {
43 int nr_vecs;
44 char *name;
45 kmem_cache_t *slab;
46};
47
48/*
49 * if you change this list, also change bvec_alloc or things will
50 * break badly! cannot be bigger than what you can fit into an
51 * unsigned short
52 */
53
54#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
Christoph Lameter6c036522005-07-07 17:56:59 -070055static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
57};
58#undef BV
59
60/*
61 * bio_set is used to allow other portions of the IO system to
62 * allocate their own private memory pools for bio and iovec structures.
63 * These memory pools in turn all allocate from the bio_slab
64 * and the bvec_slabs[].
65 */
66struct bio_set {
67 mempool_t *bio_pool;
68 mempool_t *bvec_pools[BIOVEC_NR_POOLS];
69};
70
71/*
72 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
73 * IO code that does not need private memory pools.
74 */
75static struct bio_set *fs_bio_set;
76
77static inline struct bio_vec *bvec_alloc_bs(unsigned int __nocast gfp_mask, int nr, unsigned long *idx, struct bio_set *bs)
78{
79 struct bio_vec *bvl;
80 struct biovec_slab *bp;
81
82 /*
83 * see comment near bvec_array define!
84 */
85 switch (nr) {
86 case 1 : *idx = 0; break;
87 case 2 ... 4: *idx = 1; break;
88 case 5 ... 16: *idx = 2; break;
89 case 17 ... 64: *idx = 3; break;
90 case 65 ... 128: *idx = 4; break;
91 case 129 ... BIO_MAX_PAGES: *idx = 5; break;
92 default:
93 return NULL;
94 }
95 /*
96 * idx now points to the pool we want to allocate from
97 */
98
99 bp = bvec_slabs + *idx;
100 bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask);
101 if (bvl)
102 memset(bvl, 0, bp->nr_vecs * sizeof(struct bio_vec));
103
104 return bvl;
105}
106
107/*
108 * default destructor for a bio allocated with bio_alloc_bioset()
109 */
110static void bio_destructor(struct bio *bio)
111{
112 const int pool_idx = BIO_POOL_IDX(bio);
113 struct bio_set *bs = bio->bi_set;
114
115 BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
116
117 mempool_free(bio->bi_io_vec, bs->bvec_pools[pool_idx]);
118 mempool_free(bio, bs->bio_pool);
119}
120
121inline void bio_init(struct bio *bio)
122{
123 bio->bi_next = NULL;
124 bio->bi_flags = 1 << BIO_UPTODATE;
125 bio->bi_rw = 0;
126 bio->bi_vcnt = 0;
127 bio->bi_idx = 0;
128 bio->bi_phys_segments = 0;
129 bio->bi_hw_segments = 0;
130 bio->bi_hw_front_size = 0;
131 bio->bi_hw_back_size = 0;
132 bio->bi_size = 0;
133 bio->bi_max_vecs = 0;
134 bio->bi_end_io = NULL;
135 atomic_set(&bio->bi_cnt, 1);
136 bio->bi_private = NULL;
137}
138
139/**
140 * bio_alloc_bioset - allocate a bio for I/O
141 * @gfp_mask: the GFP_ mask given to the slab allocator
142 * @nr_iovecs: number of iovecs to pre-allocate
Martin Waitz67be2dd2005-05-01 08:59:26 -0700143 * @bs: the bio_set to allocate from
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 *
145 * Description:
146 * bio_alloc_bioset will first try it's on mempool to satisfy the allocation.
147 * If %__GFP_WAIT is set then we will block on the internal pool waiting
148 * for a &struct bio to become free.
149 *
150 * allocate bio and iovecs from the memory pools specified by the
151 * bio_set structure.
152 **/
153struct bio *bio_alloc_bioset(unsigned int __nocast gfp_mask, int nr_iovecs, struct bio_set *bs)
154{
155 struct bio *bio = mempool_alloc(bs->bio_pool, gfp_mask);
156
157 if (likely(bio)) {
158 struct bio_vec *bvl = NULL;
159
160 bio_init(bio);
161 if (likely(nr_iovecs)) {
162 unsigned long idx;
163
164 bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
165 if (unlikely(!bvl)) {
166 mempool_free(bio, bs->bio_pool);
167 bio = NULL;
168 goto out;
169 }
170 bio->bi_flags |= idx << BIO_POOL_OFFSET;
171 bio->bi_max_vecs = bvec_slabs[idx].nr_vecs;
172 }
173 bio->bi_io_vec = bvl;
174 bio->bi_destructor = bio_destructor;
175 bio->bi_set = bs;
176 }
177out:
178 return bio;
179}
180
181struct bio *bio_alloc(unsigned int __nocast gfp_mask, int nr_iovecs)
182{
183 return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
184}
185
186void zero_fill_bio(struct bio *bio)
187{
188 unsigned long flags;
189 struct bio_vec *bv;
190 int i;
191
192 bio_for_each_segment(bv, bio, i) {
193 char *data = bvec_kmap_irq(bv, &flags);
194 memset(data, 0, bv->bv_len);
195 flush_dcache_page(bv->bv_page);
196 bvec_kunmap_irq(data, &flags);
197 }
198}
199EXPORT_SYMBOL(zero_fill_bio);
200
201/**
202 * bio_put - release a reference to a bio
203 * @bio: bio to release reference to
204 *
205 * Description:
206 * Put a reference to a &struct bio, either one you have gotten with
207 * bio_alloc or bio_get. The last put of a bio will free it.
208 **/
209void bio_put(struct bio *bio)
210{
211 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
212
213 /*
214 * last put frees it
215 */
216 if (atomic_dec_and_test(&bio->bi_cnt)) {
217 bio->bi_next = NULL;
218 bio->bi_destructor(bio);
219 }
220}
221
222inline int bio_phys_segments(request_queue_t *q, struct bio *bio)
223{
224 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
225 blk_recount_segments(q, bio);
226
227 return bio->bi_phys_segments;
228}
229
230inline int bio_hw_segments(request_queue_t *q, struct bio *bio)
231{
232 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
233 blk_recount_segments(q, bio);
234
235 return bio->bi_hw_segments;
236}
237
238/**
239 * __bio_clone - clone a bio
240 * @bio: destination bio
241 * @bio_src: bio to clone
242 *
243 * Clone a &bio. Caller will own the returned bio, but not
244 * the actual data it points to. Reference count of returned
245 * bio will be one.
246 */
247inline void __bio_clone(struct bio *bio, struct bio *bio_src)
248{
249 request_queue_t *q = bdev_get_queue(bio_src->bi_bdev);
250
Andrew Mortone525e152005-08-07 09:42:12 -0700251 memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
252 bio_src->bi_max_vecs * sizeof(struct bio_vec));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253
254 bio->bi_sector = bio_src->bi_sector;
255 bio->bi_bdev = bio_src->bi_bdev;
256 bio->bi_flags |= 1 << BIO_CLONED;
257 bio->bi_rw = bio_src->bi_rw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 bio->bi_vcnt = bio_src->bi_vcnt;
259 bio->bi_size = bio_src->bi_size;
Andrew Mortona5453be2005-07-28 01:07:18 -0700260 bio->bi_idx = bio_src->bi_idx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 bio_phys_segments(q, bio);
262 bio_hw_segments(q, bio);
263}
264
265/**
266 * bio_clone - clone a bio
267 * @bio: bio to clone
268 * @gfp_mask: allocation priority
269 *
270 * Like __bio_clone, only also allocates the returned bio
271 */
272struct bio *bio_clone(struct bio *bio, unsigned int __nocast gfp_mask)
273{
274 struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
275
276 if (b)
277 __bio_clone(b, bio);
278
279 return b;
280}
281
282/**
283 * bio_get_nr_vecs - return approx number of vecs
284 * @bdev: I/O target
285 *
286 * Return the approximate number of pages we can send to this target.
287 * There's no guarantee that you will be able to fit this number of pages
288 * into a bio, it does not account for dynamic restrictions that vary
289 * on offset.
290 */
291int bio_get_nr_vecs(struct block_device *bdev)
292{
293 request_queue_t *q = bdev_get_queue(bdev);
294 int nr_pages;
295
296 nr_pages = ((q->max_sectors << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
297 if (nr_pages > q->max_phys_segments)
298 nr_pages = q->max_phys_segments;
299 if (nr_pages > q->max_hw_segments)
300 nr_pages = q->max_hw_segments;
301
302 return nr_pages;
303}
304
305static int __bio_add_page(request_queue_t *q, struct bio *bio, struct page
306 *page, unsigned int len, unsigned int offset)
307{
308 int retried_segments = 0;
309 struct bio_vec *bvec;
310
311 /*
312 * cloned bio must not modify vec list
313 */
314 if (unlikely(bio_flagged(bio, BIO_CLONED)))
315 return 0;
316
317 if (bio->bi_vcnt >= bio->bi_max_vecs)
318 return 0;
319
320 if (((bio->bi_size + len) >> 9) > q->max_sectors)
321 return 0;
322
323 /*
324 * we might lose a segment or two here, but rather that than
325 * make this too complex.
326 */
327
328 while (bio->bi_phys_segments >= q->max_phys_segments
329 || bio->bi_hw_segments >= q->max_hw_segments
330 || BIOVEC_VIRT_OVERSIZE(bio->bi_size)) {
331
332 if (retried_segments)
333 return 0;
334
335 retried_segments = 1;
336 blk_recount_segments(q, bio);
337 }
338
339 /*
340 * setup the new entry, we might clear it again later if we
341 * cannot add the page
342 */
343 bvec = &bio->bi_io_vec[bio->bi_vcnt];
344 bvec->bv_page = page;
345 bvec->bv_len = len;
346 bvec->bv_offset = offset;
347
348 /*
349 * if queue has other restrictions (eg varying max sector size
350 * depending on offset), it can specify a merge_bvec_fn in the
351 * queue to get further control
352 */
353 if (q->merge_bvec_fn) {
354 /*
355 * merge_bvec_fn() returns number of bytes it can accept
356 * at this offset
357 */
358 if (q->merge_bvec_fn(q, bio, bvec) < len) {
359 bvec->bv_page = NULL;
360 bvec->bv_len = 0;
361 bvec->bv_offset = 0;
362 return 0;
363 }
364 }
365
366 /* If we may be able to merge these biovecs, force a recount */
367 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec) ||
368 BIOVEC_VIRT_MERGEABLE(bvec-1, bvec)))
369 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
370
371 bio->bi_vcnt++;
372 bio->bi_phys_segments++;
373 bio->bi_hw_segments++;
374 bio->bi_size += len;
375 return len;
376}
377
378/**
379 * bio_add_page - attempt to add page to bio
380 * @bio: destination bio
381 * @page: page to add
382 * @len: vec entry length
383 * @offset: vec entry offset
384 *
385 * Attempt to add a page to the bio_vec maplist. This can fail for a
386 * number of reasons, such as the bio being full or target block
387 * device limitations. The target block device must allow bio's
388 * smaller than PAGE_SIZE, so it is always possible to add a single
389 * page to an empty bio.
390 */
391int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
392 unsigned int offset)
393{
394 return __bio_add_page(bdev_get_queue(bio->bi_bdev), bio, page,
395 len, offset);
396}
397
398struct bio_map_data {
399 struct bio_vec *iovecs;
400 void __user *userptr;
401};
402
403static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio)
404{
405 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
406 bio->bi_private = bmd;
407}
408
409static void bio_free_map_data(struct bio_map_data *bmd)
410{
411 kfree(bmd->iovecs);
412 kfree(bmd);
413}
414
415static struct bio_map_data *bio_alloc_map_data(int nr_segs)
416{
417 struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL);
418
419 if (!bmd)
420 return NULL;
421
422 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL);
423 if (bmd->iovecs)
424 return bmd;
425
426 kfree(bmd);
427 return NULL;
428}
429
430/**
431 * bio_uncopy_user - finish previously mapped bio
432 * @bio: bio being terminated
433 *
434 * Free pages allocated from bio_copy_user() and write back data
435 * to user space in case of a read.
436 */
437int bio_uncopy_user(struct bio *bio)
438{
439 struct bio_map_data *bmd = bio->bi_private;
440 const int read = bio_data_dir(bio) == READ;
441 struct bio_vec *bvec;
442 int i, ret = 0;
443
444 __bio_for_each_segment(bvec, bio, i, 0) {
445 char *addr = page_address(bvec->bv_page);
446 unsigned int len = bmd->iovecs[i].bv_len;
447
448 if (read && !ret && copy_to_user(bmd->userptr, addr, len))
449 ret = -EFAULT;
450
451 __free_page(bvec->bv_page);
452 bmd->userptr += len;
453 }
454 bio_free_map_data(bmd);
455 bio_put(bio);
456 return ret;
457}
458
459/**
460 * bio_copy_user - copy user data to bio
461 * @q: destination block queue
462 * @uaddr: start of user address
463 * @len: length in bytes
464 * @write_to_vm: bool indicating writing to pages or not
465 *
466 * Prepares and returns a bio for indirect user io, bouncing data
467 * to/from kernel pages as necessary. Must be paired with
468 * call bio_uncopy_user() on io completion.
469 */
470struct bio *bio_copy_user(request_queue_t *q, unsigned long uaddr,
471 unsigned int len, int write_to_vm)
472{
473 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
474 unsigned long start = uaddr >> PAGE_SHIFT;
475 struct bio_map_data *bmd;
476 struct bio_vec *bvec;
477 struct page *page;
478 struct bio *bio;
479 int i, ret;
480
481 bmd = bio_alloc_map_data(end - start);
482 if (!bmd)
483 return ERR_PTR(-ENOMEM);
484
485 bmd->userptr = (void __user *) uaddr;
486
487 ret = -ENOMEM;
488 bio = bio_alloc(GFP_KERNEL, end - start);
489 if (!bio)
490 goto out_bmd;
491
492 bio->bi_rw |= (!write_to_vm << BIO_RW);
493
494 ret = 0;
495 while (len) {
496 unsigned int bytes = PAGE_SIZE;
497
498 if (bytes > len)
499 bytes = len;
500
501 page = alloc_page(q->bounce_gfp | GFP_KERNEL);
502 if (!page) {
503 ret = -ENOMEM;
504 break;
505 }
506
507 if (__bio_add_page(q, bio, page, bytes, 0) < bytes) {
508 ret = -EINVAL;
509 break;
510 }
511
512 len -= bytes;
513 }
514
515 if (ret)
516 goto cleanup;
517
518 /*
519 * success
520 */
521 if (!write_to_vm) {
522 char __user *p = (char __user *) uaddr;
523
524 /*
525 * for a write, copy in data to kernel pages
526 */
527 ret = -EFAULT;
528 bio_for_each_segment(bvec, bio, i) {
529 char *addr = page_address(bvec->bv_page);
530
531 if (copy_from_user(addr, p, bvec->bv_len))
532 goto cleanup;
533 p += bvec->bv_len;
534 }
535 }
536
537 bio_set_map_data(bmd, bio);
538 return bio;
539cleanup:
540 bio_for_each_segment(bvec, bio, i)
541 __free_page(bvec->bv_page);
542
543 bio_put(bio);
544out_bmd:
545 bio_free_map_data(bmd);
546 return ERR_PTR(ret);
547}
548
549static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev,
550 unsigned long uaddr, unsigned int len,
551 int write_to_vm)
552{
553 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
554 unsigned long start = uaddr >> PAGE_SHIFT;
555 const int nr_pages = end - start;
556 int ret, offset, i;
557 struct page **pages;
558 struct bio *bio;
559
560 /*
561 * transfer and buffer must be aligned to at least hardsector
562 * size for now, in the future we can relax this restriction
563 */
564 if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q)))
565 return ERR_PTR(-EINVAL);
566
567 bio = bio_alloc(GFP_KERNEL, nr_pages);
568 if (!bio)
569 return ERR_PTR(-ENOMEM);
570
571 ret = -ENOMEM;
572 pages = kmalloc(nr_pages * sizeof(struct page *), GFP_KERNEL);
573 if (!pages)
574 goto out;
575
576 down_read(&current->mm->mmap_sem);
577 ret = get_user_pages(current, current->mm, uaddr, nr_pages,
578 write_to_vm, 0, pages, NULL);
579 up_read(&current->mm->mmap_sem);
580
581 if (ret < nr_pages)
582 goto out;
583
584 bio->bi_bdev = bdev;
585
586 offset = uaddr & ~PAGE_MASK;
587 for (i = 0; i < nr_pages; i++) {
588 unsigned int bytes = PAGE_SIZE - offset;
589
590 if (len <= 0)
591 break;
592
593 if (bytes > len)
594 bytes = len;
595
596 /*
597 * sorry...
598 */
599 if (__bio_add_page(q, bio, pages[i], bytes, offset) < bytes)
600 break;
601
602 len -= bytes;
603 offset = 0;
604 }
605
606 /*
607 * release the pages we didn't map into the bio, if any
608 */
609 while (i < nr_pages)
610 page_cache_release(pages[i++]);
611
612 kfree(pages);
613
614 /*
615 * set data direction, and check if mapped pages need bouncing
616 */
617 if (!write_to_vm)
618 bio->bi_rw |= (1 << BIO_RW);
619
620 bio->bi_flags |= (1 << BIO_USER_MAPPED);
621 return bio;
622out:
623 kfree(pages);
624 bio_put(bio);
625 return ERR_PTR(ret);
626}
627
628/**
629 * bio_map_user - map user address into bio
Martin Waitz67be2dd2005-05-01 08:59:26 -0700630 * @q: the request_queue_t for the bio
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 * @bdev: destination block device
632 * @uaddr: start of user address
633 * @len: length in bytes
634 * @write_to_vm: bool indicating writing to pages or not
635 *
636 * Map the user space address into a bio suitable for io to a block
637 * device. Returns an error pointer in case of error.
638 */
639struct bio *bio_map_user(request_queue_t *q, struct block_device *bdev,
640 unsigned long uaddr, unsigned int len, int write_to_vm)
641{
642 struct bio *bio;
643
644 bio = __bio_map_user(q, bdev, uaddr, len, write_to_vm);
645
646 if (IS_ERR(bio))
647 return bio;
648
649 /*
650 * subtle -- if __bio_map_user() ended up bouncing a bio,
651 * it would normally disappear when its bi_end_io is run.
652 * however, we need it for the unmap, so grab an extra
653 * reference to it
654 */
655 bio_get(bio);
656
657 if (bio->bi_size == len)
658 return bio;
659
660 /*
661 * don't support partial mappings
662 */
663 bio_endio(bio, bio->bi_size, 0);
664 bio_unmap_user(bio);
665 return ERR_PTR(-EINVAL);
666}
667
668static void __bio_unmap_user(struct bio *bio)
669{
670 struct bio_vec *bvec;
671 int i;
672
673 /*
674 * make sure we dirty pages we wrote to
675 */
676 __bio_for_each_segment(bvec, bio, i, 0) {
677 if (bio_data_dir(bio) == READ)
678 set_page_dirty_lock(bvec->bv_page);
679
680 page_cache_release(bvec->bv_page);
681 }
682
683 bio_put(bio);
684}
685
686/**
687 * bio_unmap_user - unmap a bio
688 * @bio: the bio being unmapped
689 *
690 * Unmap a bio previously mapped by bio_map_user(). Must be called with
691 * a process context.
692 *
693 * bio_unmap_user() may sleep.
694 */
695void bio_unmap_user(struct bio *bio)
696{
697 __bio_unmap_user(bio);
698 bio_put(bio);
699}
700
701/*
702 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
703 * for performing direct-IO in BIOs.
704 *
705 * The problem is that we cannot run set_page_dirty() from interrupt context
706 * because the required locks are not interrupt-safe. So what we can do is to
707 * mark the pages dirty _before_ performing IO. And in interrupt context,
708 * check that the pages are still dirty. If so, fine. If not, redirty them
709 * in process context.
710 *
711 * We special-case compound pages here: normally this means reads into hugetlb
712 * pages. The logic in here doesn't really work right for compound pages
713 * because the VM does not uniformly chase down the head page in all cases.
714 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
715 * handle them at all. So we skip compound pages here at an early stage.
716 *
717 * Note that this code is very hard to test under normal circumstances because
718 * direct-io pins the pages with get_user_pages(). This makes
719 * is_page_cache_freeable return false, and the VM will not clean the pages.
720 * But other code (eg, pdflush) could clean the pages if they are mapped
721 * pagecache.
722 *
723 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
724 * deferred bio dirtying paths.
725 */
726
727/*
728 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
729 */
730void bio_set_pages_dirty(struct bio *bio)
731{
732 struct bio_vec *bvec = bio->bi_io_vec;
733 int i;
734
735 for (i = 0; i < bio->bi_vcnt; i++) {
736 struct page *page = bvec[i].bv_page;
737
738 if (page && !PageCompound(page))
739 set_page_dirty_lock(page);
740 }
741}
742
743static void bio_release_pages(struct bio *bio)
744{
745 struct bio_vec *bvec = bio->bi_io_vec;
746 int i;
747
748 for (i = 0; i < bio->bi_vcnt; i++) {
749 struct page *page = bvec[i].bv_page;
750
751 if (page)
752 put_page(page);
753 }
754}
755
756/*
757 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
758 * If they are, then fine. If, however, some pages are clean then they must
759 * have been written out during the direct-IO read. So we take another ref on
760 * the BIO and the offending pages and re-dirty the pages in process context.
761 *
762 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
763 * here on. It will run one page_cache_release() against each page and will
764 * run one bio_put() against the BIO.
765 */
766
767static void bio_dirty_fn(void *data);
768
769static DECLARE_WORK(bio_dirty_work, bio_dirty_fn, NULL);
770static DEFINE_SPINLOCK(bio_dirty_lock);
771static struct bio *bio_dirty_list;
772
773/*
774 * This runs in process context
775 */
776static void bio_dirty_fn(void *data)
777{
778 unsigned long flags;
779 struct bio *bio;
780
781 spin_lock_irqsave(&bio_dirty_lock, flags);
782 bio = bio_dirty_list;
783 bio_dirty_list = NULL;
784 spin_unlock_irqrestore(&bio_dirty_lock, flags);
785
786 while (bio) {
787 struct bio *next = bio->bi_private;
788
789 bio_set_pages_dirty(bio);
790 bio_release_pages(bio);
791 bio_put(bio);
792 bio = next;
793 }
794}
795
796void bio_check_pages_dirty(struct bio *bio)
797{
798 struct bio_vec *bvec = bio->bi_io_vec;
799 int nr_clean_pages = 0;
800 int i;
801
802 for (i = 0; i < bio->bi_vcnt; i++) {
803 struct page *page = bvec[i].bv_page;
804
805 if (PageDirty(page) || PageCompound(page)) {
806 page_cache_release(page);
807 bvec[i].bv_page = NULL;
808 } else {
809 nr_clean_pages++;
810 }
811 }
812
813 if (nr_clean_pages) {
814 unsigned long flags;
815
816 spin_lock_irqsave(&bio_dirty_lock, flags);
817 bio->bi_private = bio_dirty_list;
818 bio_dirty_list = bio;
819 spin_unlock_irqrestore(&bio_dirty_lock, flags);
820 schedule_work(&bio_dirty_work);
821 } else {
822 bio_put(bio);
823 }
824}
825
826/**
827 * bio_endio - end I/O on a bio
828 * @bio: bio
829 * @bytes_done: number of bytes completed
830 * @error: error, if any
831 *
832 * Description:
833 * bio_endio() will end I/O on @bytes_done number of bytes. This may be
834 * just a partial part of the bio, or it may be the whole bio. bio_endio()
835 * is the preferred way to end I/O on a bio, it takes care of decrementing
836 * bi_size and clearing BIO_UPTODATE on error. @error is 0 on success, and
837 * and one of the established -Exxxx (-EIO, for instance) error values in
838 * case something went wrong. Noone should call bi_end_io() directly on
839 * a bio unless they own it and thus know that it has an end_io function.
840 **/
841void bio_endio(struct bio *bio, unsigned int bytes_done, int error)
842{
843 if (error)
844 clear_bit(BIO_UPTODATE, &bio->bi_flags);
845
846 if (unlikely(bytes_done > bio->bi_size)) {
847 printk("%s: want %u bytes done, only %u left\n", __FUNCTION__,
848 bytes_done, bio->bi_size);
849 bytes_done = bio->bi_size;
850 }
851
852 bio->bi_size -= bytes_done;
853 bio->bi_sector += (bytes_done >> 9);
854
855 if (bio->bi_end_io)
856 bio->bi_end_io(bio, bytes_done, error);
857}
858
859void bio_pair_release(struct bio_pair *bp)
860{
861 if (atomic_dec_and_test(&bp->cnt)) {
862 struct bio *master = bp->bio1.bi_private;
863
864 bio_endio(master, master->bi_size, bp->error);
865 mempool_free(bp, bp->bio2.bi_private);
866 }
867}
868
869static int bio_pair_end_1(struct bio * bi, unsigned int done, int err)
870{
871 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
872
873 if (err)
874 bp->error = err;
875
876 if (bi->bi_size)
877 return 1;
878
879 bio_pair_release(bp);
880 return 0;
881}
882
883static int bio_pair_end_2(struct bio * bi, unsigned int done, int err)
884{
885 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
886
887 if (err)
888 bp->error = err;
889
890 if (bi->bi_size)
891 return 1;
892
893 bio_pair_release(bp);
894 return 0;
895}
896
897/*
898 * split a bio - only worry about a bio with a single page
899 * in it's iovec
900 */
901struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors)
902{
903 struct bio_pair *bp = mempool_alloc(pool, GFP_NOIO);
904
905 if (!bp)
906 return bp;
907
908 BUG_ON(bi->bi_vcnt != 1);
909 BUG_ON(bi->bi_idx != 0);
910 atomic_set(&bp->cnt, 3);
911 bp->error = 0;
912 bp->bio1 = *bi;
913 bp->bio2 = *bi;
914 bp->bio2.bi_sector += first_sectors;
915 bp->bio2.bi_size -= first_sectors << 9;
916 bp->bio1.bi_size = first_sectors << 9;
917
918 bp->bv1 = bi->bi_io_vec[0];
919 bp->bv2 = bi->bi_io_vec[0];
920 bp->bv2.bv_offset += first_sectors << 9;
921 bp->bv2.bv_len -= first_sectors << 9;
922 bp->bv1.bv_len = first_sectors << 9;
923
924 bp->bio1.bi_io_vec = &bp->bv1;
925 bp->bio2.bi_io_vec = &bp->bv2;
926
927 bp->bio1.bi_end_io = bio_pair_end_1;
928 bp->bio2.bi_end_io = bio_pair_end_2;
929
930 bp->bio1.bi_private = bi;
931 bp->bio2.bi_private = pool;
932
933 return bp;
934}
935
936static void *bio_pair_alloc(unsigned int __nocast gfp_flags, void *data)
937{
938 return kmalloc(sizeof(struct bio_pair), gfp_flags);
939}
940
941static void bio_pair_free(void *bp, void *data)
942{
943 kfree(bp);
944}
945
946
947/*
948 * create memory pools for biovec's in a bio_set.
949 * use the global biovec slabs created for general use.
950 */
951static int biovec_create_pools(struct bio_set *bs, int pool_entries, int scale)
952{
953 int i;
954
955 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
956 struct biovec_slab *bp = bvec_slabs + i;
957 mempool_t **bvp = bs->bvec_pools + i;
958
959 if (i >= scale)
960 pool_entries >>= 1;
961
962 *bvp = mempool_create(pool_entries, mempool_alloc_slab,
963 mempool_free_slab, bp->slab);
964 if (!*bvp)
965 return -ENOMEM;
966 }
967 return 0;
968}
969
970static void biovec_free_pools(struct bio_set *bs)
971{
972 int i;
973
974 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
975 mempool_t *bvp = bs->bvec_pools[i];
976
977 if (bvp)
978 mempool_destroy(bvp);
979 }
980
981}
982
983void bioset_free(struct bio_set *bs)
984{
985 if (bs->bio_pool)
986 mempool_destroy(bs->bio_pool);
987
988 biovec_free_pools(bs);
989
990 kfree(bs);
991}
992
993struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size, int scale)
994{
995 struct bio_set *bs = kmalloc(sizeof(*bs), GFP_KERNEL);
996
997 if (!bs)
998 return NULL;
999
1000 memset(bs, 0, sizeof(*bs));
1001 bs->bio_pool = mempool_create(bio_pool_size, mempool_alloc_slab,
1002 mempool_free_slab, bio_slab);
1003
1004 if (!bs->bio_pool)
1005 goto bad;
1006
1007 if (!biovec_create_pools(bs, bvec_pool_size, scale))
1008 return bs;
1009
1010bad:
1011 bioset_free(bs);
1012 return NULL;
1013}
1014
1015static void __init biovec_init_slabs(void)
1016{
1017 int i;
1018
1019 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1020 int size;
1021 struct biovec_slab *bvs = bvec_slabs + i;
1022
1023 size = bvs->nr_vecs * sizeof(struct bio_vec);
1024 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1025 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1026 }
1027}
1028
1029static int __init init_bio(void)
1030{
1031 int megabytes, bvec_pool_entries;
1032 int scale = BIOVEC_NR_POOLS;
1033
1034 bio_slab = kmem_cache_create("bio", sizeof(struct bio), 0,
1035 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1036
1037 biovec_init_slabs();
1038
1039 megabytes = nr_free_pages() >> (20 - PAGE_SHIFT);
1040
1041 /*
1042 * find out where to start scaling
1043 */
1044 if (megabytes <= 16)
1045 scale = 0;
1046 else if (megabytes <= 32)
1047 scale = 1;
1048 else if (megabytes <= 64)
1049 scale = 2;
1050 else if (megabytes <= 96)
1051 scale = 3;
1052 else if (megabytes <= 128)
1053 scale = 4;
1054
1055 /*
1056 * scale number of entries
1057 */
1058 bvec_pool_entries = megabytes * 2;
1059 if (bvec_pool_entries > 256)
1060 bvec_pool_entries = 256;
1061
1062 fs_bio_set = bioset_create(BIO_POOL_SIZE, bvec_pool_entries, scale);
1063 if (!fs_bio_set)
1064 panic("bio: can't allocate bios\n");
1065
1066 bio_split_pool = mempool_create(BIO_SPLIT_ENTRIES,
1067 bio_pair_alloc, bio_pair_free, NULL);
1068 if (!bio_split_pool)
1069 panic("bio: can't create split pool\n");
1070
1071 return 0;
1072}
1073
1074subsys_initcall(init_bio);
1075
1076EXPORT_SYMBOL(bio_alloc);
1077EXPORT_SYMBOL(bio_put);
1078EXPORT_SYMBOL(bio_endio);
1079EXPORT_SYMBOL(bio_init);
1080EXPORT_SYMBOL(__bio_clone);
1081EXPORT_SYMBOL(bio_clone);
1082EXPORT_SYMBOL(bio_phys_segments);
1083EXPORT_SYMBOL(bio_hw_segments);
1084EXPORT_SYMBOL(bio_add_page);
1085EXPORT_SYMBOL(bio_get_nr_vecs);
1086EXPORT_SYMBOL(bio_map_user);
1087EXPORT_SYMBOL(bio_unmap_user);
1088EXPORT_SYMBOL(bio_pair_release);
1089EXPORT_SYMBOL(bio_split);
1090EXPORT_SYMBOL(bio_split_pool);
1091EXPORT_SYMBOL(bio_copy_user);
1092EXPORT_SYMBOL(bio_uncopy_user);
1093EXPORT_SYMBOL(bioset_create);
1094EXPORT_SYMBOL(bioset_free);
1095EXPORT_SYMBOL(bio_alloc_bioset);