blob: 76738005c8e8af43c3b084a48d4f752e36e2186d [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>
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
Li Zefan55782132009-06-09 13:43:05 +080030#include <trace/events/block.h>
Ingo Molnar0bfc2452008-11-26 11:59:56 +010031
Jens Axboe392ddc32008-12-23 12:42:54 +010032/*
33 * Test patch to inline a certain number of bi_io_vec's inside the bio
34 * itself, to shrink a bio data allocation from two mempool calls to one
35 */
36#define BIO_INLINE_VECS 4
37
Denis ChengRq6feef532008-10-09 08:57:05 +020038static mempool_t *bio_split_pool __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Linus Torvalds1da177e2005-04-16 15:20:36 -070040/*
41 * if you change this list, also change bvec_alloc or things will
42 * break badly! cannot be bigger than what you can fit into an
43 * unsigned short
44 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070045#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
Jens Axboebb799ca2008-12-10 15:35:05 +010046struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
48};
49#undef BV
50
51/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
53 * IO code that does not need private memory pools.
54 */
Martin K. Petersen51d654e2008-06-17 18:59:56 +020055struct bio_set *fs_bio_set;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Jens Axboebb799ca2008-12-10 15:35:05 +010057/*
58 * Our slab pool management
59 */
60struct bio_slab {
61 struct kmem_cache *slab;
62 unsigned int slab_ref;
63 unsigned int slab_size;
64 char name[8];
65};
66static DEFINE_MUTEX(bio_slab_lock);
67static struct bio_slab *bio_slabs;
68static unsigned int bio_slab_nr, bio_slab_max;
69
70static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
71{
72 unsigned int sz = sizeof(struct bio) + extra_size;
73 struct kmem_cache *slab = NULL;
74 struct bio_slab *bslab;
75 unsigned int i, entry = -1;
76
77 mutex_lock(&bio_slab_lock);
78
79 i = 0;
80 while (i < bio_slab_nr) {
81 struct bio_slab *bslab = &bio_slabs[i];
82
83 if (!bslab->slab && entry == -1)
84 entry = i;
85 else if (bslab->slab_size == sz) {
86 slab = bslab->slab;
87 bslab->slab_ref++;
88 break;
89 }
90 i++;
91 }
92
93 if (slab)
94 goto out_unlock;
95
96 if (bio_slab_nr == bio_slab_max && entry == -1) {
97 bio_slab_max <<= 1;
98 bio_slabs = krealloc(bio_slabs,
99 bio_slab_max * sizeof(struct bio_slab),
100 GFP_KERNEL);
101 if (!bio_slabs)
102 goto out_unlock;
103 }
104 if (entry == -1)
105 entry = bio_slab_nr++;
106
107 bslab = &bio_slabs[entry];
108
109 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
110 slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL);
111 if (!slab)
112 goto out_unlock;
113
114 printk("bio: create slab <%s> at %d\n", bslab->name, entry);
115 bslab->slab = slab;
116 bslab->slab_ref = 1;
117 bslab->slab_size = sz;
118out_unlock:
119 mutex_unlock(&bio_slab_lock);
120 return slab;
121}
122
123static void bio_put_slab(struct bio_set *bs)
124{
125 struct bio_slab *bslab = NULL;
126 unsigned int i;
127
128 mutex_lock(&bio_slab_lock);
129
130 for (i = 0; i < bio_slab_nr; i++) {
131 if (bs->bio_slab == bio_slabs[i].slab) {
132 bslab = &bio_slabs[i];
133 break;
134 }
135 }
136
137 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
138 goto out;
139
140 WARN_ON(!bslab->slab_ref);
141
142 if (--bslab->slab_ref)
143 goto out;
144
145 kmem_cache_destroy(bslab->slab);
146 bslab->slab = NULL;
147
148out:
149 mutex_unlock(&bio_slab_lock);
150}
151
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200152unsigned int bvec_nr_vecs(unsigned short idx)
153{
154 return bvec_slabs[idx].nr_vecs;
155}
156
Jens Axboebb799ca2008-12-10 15:35:05 +0100157void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
158{
159 BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
160
161 if (idx == BIOVEC_MAX_IDX)
162 mempool_free(bv, bs->bvec_pool);
163 else {
164 struct biovec_slab *bvs = bvec_slabs + idx;
165
166 kmem_cache_free(bvs->slab, bv);
167 }
168}
169
Jens Axboe7ff93452008-12-11 11:53:43 +0100170struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
171 struct bio_set *bs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172{
173 struct bio_vec *bvl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174
175 /*
Jens Axboe7ff93452008-12-11 11:53:43 +0100176 * see comment near bvec_array define!
177 */
178 switch (nr) {
179 case 1:
180 *idx = 0;
181 break;
182 case 2 ... 4:
183 *idx = 1;
184 break;
185 case 5 ... 16:
186 *idx = 2;
187 break;
188 case 17 ... 64:
189 *idx = 3;
190 break;
191 case 65 ... 128:
192 *idx = 4;
193 break;
194 case 129 ... BIO_MAX_PAGES:
195 *idx = 5;
196 break;
197 default:
198 return NULL;
199 }
200
201 /*
202 * idx now points to the pool we want to allocate from. only the
203 * 1-vec entry pool is mempool backed.
204 */
205 if (*idx == BIOVEC_MAX_IDX) {
206fallback:
207 bvl = mempool_alloc(bs->bvec_pool, gfp_mask);
208 } else {
209 struct biovec_slab *bvs = bvec_slabs + *idx;
210 gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200212 /*
Jens Axboe7ff93452008-12-11 11:53:43 +0100213 * Make this allocation restricted and don't dump info on
214 * allocation failures, since we'll fallback to the mempool
215 * in case of failure.
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200216 */
Jens Axboe7ff93452008-12-11 11:53:43 +0100217 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
218
219 /*
220 * Try a slab allocation. If this fails and __GFP_WAIT
221 * is set, retry with the 1-entry mempool
222 */
223 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
224 if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
225 *idx = BIOVEC_MAX_IDX;
226 goto fallback;
227 }
228 }
229
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 return bvl;
231}
232
Jens Axboe7ff93452008-12-11 11:53:43 +0100233void bio_free(struct bio *bio, struct bio_set *bs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234{
Jens Axboebb799ca2008-12-10 15:35:05 +0100235 void *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
Jens Axboe392ddc32008-12-23 12:42:54 +0100237 if (bio_has_allocated_vec(bio))
Jens Axboebb799ca2008-12-10 15:35:05 +0100238 bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
Jens Axboe992c5dd2007-07-18 13:18:08 +0200239
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200240 if (bio_integrity(bio))
Martin K. Petersen7878cba2009-06-26 15:37:49 +0200241 bio_integrity_free(bio, bs);
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200242
Jens Axboebb799ca2008-12-10 15:35:05 +0100243 /*
244 * If we have front padding, adjust the bio pointer before freeing
245 */
246 p = bio;
247 if (bs->front_pad)
248 p -= bs->front_pad;
249
250 mempool_free(p, bs->bio_pool);
Peter Osterlund36763472005-09-06 15:16:42 -0700251}
252
Arjan van de Ven858119e2006-01-14 13:20:43 -0800253void bio_init(struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254{
Jens Axboe2b94de52007-07-18 13:14:03 +0200255 memset(bio, 0, sizeof(*bio));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 bio->bi_flags = 1 << BIO_UPTODATE;
Jens Axboec7c22e42008-09-13 20:26:01 +0200257 bio->bi_comp_cpu = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 atomic_set(&bio->bi_cnt, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259}
260
261/**
262 * bio_alloc_bioset - allocate a bio for I/O
263 * @gfp_mask: the GFP_ mask given to the slab allocator
264 * @nr_iovecs: number of iovecs to pre-allocate
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200265 * @bs: the bio_set to allocate from. If %NULL, just use kmalloc
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 *
267 * Description:
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200268 * bio_alloc_bioset will first try its own mempool to satisfy the allocation.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 * If %__GFP_WAIT is set then we will block on the internal pool waiting
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200270 * for a &struct bio to become free. If a %NULL @bs is passed in, we will
271 * fall back to just using @kmalloc to allocate the required memory.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 *
Jens Axboebb799ca2008-12-10 15:35:05 +0100273 * Note that the caller must set ->bi_destructor on succesful return
274 * of a bio, to do the appropriate freeing of the bio once the reference
275 * count drops to zero.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 **/
Al Virodd0fc662005-10-07 07:46:04 +0100277struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278{
Tejun Heo451a9eb2009-04-15 19:50:51 +0200279 unsigned long idx = BIO_POOL_NONE;
Ingo Molnar34053972009-02-21 11:16:36 +0100280 struct bio_vec *bvl = NULL;
Tejun Heo451a9eb2009-04-15 19:50:51 +0200281 struct bio *bio;
282 void *p;
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200283
Tejun Heo451a9eb2009-04-15 19:50:51 +0200284 p = mempool_alloc(bs->bio_pool, gfp_mask);
285 if (unlikely(!p))
286 return NULL;
287 bio = p + bs->front_pad;
Ingo Molnar34053972009-02-21 11:16:36 +0100288
289 bio_init(bio);
290
291 if (unlikely(!nr_iovecs))
292 goto out_set;
293
294 if (nr_iovecs <= BIO_INLINE_VECS) {
295 bvl = bio->bi_inline_vecs;
296 nr_iovecs = BIO_INLINE_VECS;
297 } else {
298 bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
299 if (unlikely(!bvl))
300 goto err_free;
301
302 nr_iovecs = bvec_nr_vecs(idx);
303 }
Tejun Heo451a9eb2009-04-15 19:50:51 +0200304out_set:
Ingo Molnar34053972009-02-21 11:16:36 +0100305 bio->bi_flags |= idx << BIO_POOL_OFFSET;
306 bio->bi_max_vecs = nr_iovecs;
Ingo Molnar34053972009-02-21 11:16:36 +0100307 bio->bi_io_vec = bvl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 return bio;
Ingo Molnar34053972009-02-21 11:16:36 +0100309
310err_free:
Tejun Heo451a9eb2009-04-15 19:50:51 +0200311 mempool_free(p, bs->bio_pool);
Ingo Molnar34053972009-02-21 11:16:36 +0100312 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313}
314
Tejun Heo451a9eb2009-04-15 19:50:51 +0200315static void bio_fs_destructor(struct bio *bio)
316{
317 bio_free(bio, fs_bio_set);
318}
319
320/**
321 * bio_alloc - allocate a new bio, memory pool backed
322 * @gfp_mask: allocation mask to use
323 * @nr_iovecs: number of iovecs
324 *
325 * Allocate a new bio with @nr_iovecs bvecs. If @gfp_mask
326 * contains __GFP_WAIT, the allocation is guaranteed to succeed.
327 *
328 * RETURNS:
329 * Pointer to new bio on success, NULL on failure.
330 */
331struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
332{
333 struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
334
335 if (bio)
336 bio->bi_destructor = bio_fs_destructor;
337
338 return bio;
339}
340
341static void bio_kmalloc_destructor(struct bio *bio)
342{
343 if (bio_integrity(bio))
Martin K. Petersen7878cba2009-06-26 15:37:49 +0200344 bio_integrity_free(bio, fs_bio_set);
Tejun Heo451a9eb2009-04-15 19:50:51 +0200345 kfree(bio);
346}
347
Jens Axboe86c824b2009-04-15 09:00:07 +0200348/**
349 * bio_alloc - allocate a bio for I/O
350 * @gfp_mask: the GFP_ mask given to the slab allocator
351 * @nr_iovecs: number of iovecs to pre-allocate
352 *
353 * Description:
354 * bio_alloc will allocate a bio and associated bio_vec array that can hold
355 * at least @nr_iovecs entries. Allocations will be done from the
356 * fs_bio_set. Also see @bio_alloc_bioset.
357 *
358 * If %__GFP_WAIT is set, then bio_alloc will always be able to allocate
359 * a bio. This is due to the mempool guarantees. To make this work, callers
Nikanth Karthikesan76d93ff2009-04-22 13:38:58 +0530360 * must never allocate more than 1 bio at a time from this pool. Callers
Jens Axboe86c824b2009-04-15 09:00:07 +0200361 * that need to allocate more than 1 bio must always submit the previously
Nikanth Karthikesan76d93ff2009-04-22 13:38:58 +0530362 * allocated bio for IO before attempting to allocate a new one. Failure to
Jens Axboe86c824b2009-04-15 09:00:07 +0200363 * do so can cause livelocks under memory pressure.
364 *
365 **/
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200366struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs)
367{
Tejun Heo451a9eb2009-04-15 19:50:51 +0200368 struct bio *bio;
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200369
Tejun Heo451a9eb2009-04-15 19:50:51 +0200370 bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec),
371 gfp_mask);
372 if (unlikely(!bio))
373 return NULL;
374
375 bio_init(bio);
376 bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
377 bio->bi_max_vecs = nr_iovecs;
378 bio->bi_io_vec = bio->bi_inline_vecs;
379 bio->bi_destructor = bio_kmalloc_destructor;
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200380
381 return bio;
382}
383
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384void zero_fill_bio(struct bio *bio)
385{
386 unsigned long flags;
387 struct bio_vec *bv;
388 int i;
389
390 bio_for_each_segment(bv, bio, i) {
391 char *data = bvec_kmap_irq(bv, &flags);
392 memset(data, 0, bv->bv_len);
393 flush_dcache_page(bv->bv_page);
394 bvec_kunmap_irq(data, &flags);
395 }
396}
397EXPORT_SYMBOL(zero_fill_bio);
398
399/**
400 * bio_put - release a reference to a bio
401 * @bio: bio to release reference to
402 *
403 * Description:
404 * Put a reference to a &struct bio, either one you have gotten with
405 * bio_alloc or bio_get. The last put of a bio will free it.
406 **/
407void bio_put(struct bio *bio)
408{
409 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
410
411 /*
412 * last put frees it
413 */
414 if (atomic_dec_and_test(&bio->bi_cnt)) {
415 bio->bi_next = NULL;
416 bio->bi_destructor(bio);
417 }
418}
419
Jens Axboe165125e2007-07-24 09:28:11 +0200420inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421{
422 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
423 blk_recount_segments(q, bio);
424
425 return bio->bi_phys_segments;
426}
427
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428/**
429 * __bio_clone - clone a bio
430 * @bio: destination bio
431 * @bio_src: bio to clone
432 *
433 * Clone a &bio. Caller will own the returned bio, but not
434 * the actual data it points to. Reference count of returned
435 * bio will be one.
436 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800437void __bio_clone(struct bio *bio, struct bio *bio_src)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438{
Andrew Mortone525e152005-08-07 09:42:12 -0700439 memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
440 bio_src->bi_max_vecs * sizeof(struct bio_vec));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441
Jens Axboe5d840702008-01-25 12:44:44 +0100442 /*
443 * most users will be overriding ->bi_bdev with a new target,
444 * so we don't set nor calculate new physical/hw segment counts here
445 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 bio->bi_sector = bio_src->bi_sector;
447 bio->bi_bdev = bio_src->bi_bdev;
448 bio->bi_flags |= 1 << BIO_CLONED;
449 bio->bi_rw = bio_src->bi_rw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 bio->bi_vcnt = bio_src->bi_vcnt;
451 bio->bi_size = bio_src->bi_size;
Andrew Mortona5453be2005-07-28 01:07:18 -0700452 bio->bi_idx = bio_src->bi_idx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453}
454
455/**
456 * bio_clone - clone a bio
457 * @bio: bio to clone
458 * @gfp_mask: allocation priority
459 *
460 * Like __bio_clone, only also allocates the returned bio
461 */
Al Virodd0fc662005-10-07 07:46:04 +0100462struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463{
464 struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
465
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200466 if (!b)
467 return NULL;
468
469 b->bi_destructor = bio_fs_destructor;
470 __bio_clone(b, bio);
471
472 if (bio_integrity(bio)) {
473 int ret;
474
Martin K. Petersen7878cba2009-06-26 15:37:49 +0200475 ret = bio_integrity_clone(b, bio, gfp_mask, fs_bio_set);
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200476
Li Zefan059ea332009-03-09 10:42:45 +0100477 if (ret < 0) {
478 bio_put(b);
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200479 return NULL;
Li Zefan059ea332009-03-09 10:42:45 +0100480 }
Peter Osterlund36763472005-09-06 15:16:42 -0700481 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482
483 return b;
484}
485
486/**
487 * bio_get_nr_vecs - return approx number of vecs
488 * @bdev: I/O target
489 *
490 * Return the approximate number of pages we can send to this target.
491 * There's no guarantee that you will be able to fit this number of pages
492 * into a bio, it does not account for dynamic restrictions that vary
493 * on offset.
494 */
495int bio_get_nr_vecs(struct block_device *bdev)
496{
Jens Axboe165125e2007-07-24 09:28:11 +0200497 struct request_queue *q = bdev_get_queue(bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 int nr_pages;
499
Martin K. Petersenae03bf62009-05-22 17:17:50 -0400500 nr_pages = ((queue_max_sectors(q) << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
501 if (nr_pages > queue_max_phys_segments(q))
502 nr_pages = queue_max_phys_segments(q);
503 if (nr_pages > queue_max_hw_segments(q))
504 nr_pages = queue_max_hw_segments(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505
506 return nr_pages;
507}
508
Jens Axboe165125e2007-07-24 09:28:11 +0200509static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
Mike Christiedefd94b2005-12-05 02:37:06 -0600510 *page, unsigned int len, unsigned int offset,
511 unsigned short max_sectors)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512{
513 int retried_segments = 0;
514 struct bio_vec *bvec;
515
516 /*
517 * cloned bio must not modify vec list
518 */
519 if (unlikely(bio_flagged(bio, BIO_CLONED)))
520 return 0;
521
Jens Axboe80cfd542006-01-06 09:43:28 +0100522 if (((bio->bi_size + len) >> 9) > max_sectors)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 return 0;
524
Jens Axboe80cfd542006-01-06 09:43:28 +0100525 /*
526 * For filesystems with a blocksize smaller than the pagesize
527 * we will often be called with the same page as last time and
528 * a consecutive offset. Optimize this special case.
529 */
530 if (bio->bi_vcnt > 0) {
531 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
532
533 if (page == prev->bv_page &&
534 offset == prev->bv_offset + prev->bv_len) {
535 prev->bv_len += len;
Alasdair G Kergoncc371e62008-07-03 09:53:43 +0200536
537 if (q->merge_bvec_fn) {
538 struct bvec_merge_data bvm = {
539 .bi_bdev = bio->bi_bdev,
540 .bi_sector = bio->bi_sector,
541 .bi_size = bio->bi_size,
542 .bi_rw = bio->bi_rw,
543 };
544
545 if (q->merge_bvec_fn(q, &bvm, prev) < len) {
546 prev->bv_len -= len;
547 return 0;
548 }
Jens Axboe80cfd542006-01-06 09:43:28 +0100549 }
550
551 goto done;
552 }
553 }
554
555 if (bio->bi_vcnt >= bio->bi_max_vecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 return 0;
557
558 /*
559 * we might lose a segment or two here, but rather that than
560 * make this too complex.
561 */
562
Martin K. Petersenae03bf62009-05-22 17:17:50 -0400563 while (bio->bi_phys_segments >= queue_max_phys_segments(q)
564 || bio->bi_phys_segments >= queue_max_hw_segments(q)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
566 if (retried_segments)
567 return 0;
568
569 retried_segments = 1;
570 blk_recount_segments(q, bio);
571 }
572
573 /*
574 * setup the new entry, we might clear it again later if we
575 * cannot add the page
576 */
577 bvec = &bio->bi_io_vec[bio->bi_vcnt];
578 bvec->bv_page = page;
579 bvec->bv_len = len;
580 bvec->bv_offset = offset;
581
582 /*
583 * if queue has other restrictions (eg varying max sector size
584 * depending on offset), it can specify a merge_bvec_fn in the
585 * queue to get further control
586 */
587 if (q->merge_bvec_fn) {
Alasdair G Kergoncc371e62008-07-03 09:53:43 +0200588 struct bvec_merge_data bvm = {
589 .bi_bdev = bio->bi_bdev,
590 .bi_sector = bio->bi_sector,
591 .bi_size = bio->bi_size,
592 .bi_rw = bio->bi_rw,
593 };
594
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 /*
596 * merge_bvec_fn() returns number of bytes it can accept
597 * at this offset
598 */
Alasdair G Kergoncc371e62008-07-03 09:53:43 +0200599 if (q->merge_bvec_fn(q, &bvm, bvec) < len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 bvec->bv_page = NULL;
601 bvec->bv_len = 0;
602 bvec->bv_offset = 0;
603 return 0;
604 }
605 }
606
607 /* If we may be able to merge these biovecs, force a recount */
Mikulas Patockab8b3e162008-08-15 10:15:19 +0200608 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
610
611 bio->bi_vcnt++;
612 bio->bi_phys_segments++;
Jens Axboe80cfd542006-01-06 09:43:28 +0100613 done:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 bio->bi_size += len;
615 return len;
616}
617
618/**
Mike Christie6e68af62005-11-11 05:30:27 -0600619 * bio_add_pc_page - attempt to add page to bio
Jens Axboefddfdea2006-01-31 15:24:34 +0100620 * @q: the target queue
Mike Christie6e68af62005-11-11 05:30:27 -0600621 * @bio: destination bio
622 * @page: page to add
623 * @len: vec entry length
624 * @offset: vec entry offset
625 *
626 * Attempt to add a page to the bio_vec maplist. This can fail for a
627 * number of reasons, such as the bio being full or target block
628 * device limitations. The target block device must allow bio's
629 * smaller than PAGE_SIZE, so it is always possible to add a single
630 * page to an empty bio. This should only be used by REQ_PC bios.
631 */
Jens Axboe165125e2007-07-24 09:28:11 +0200632int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
Mike Christie6e68af62005-11-11 05:30:27 -0600633 unsigned int len, unsigned int offset)
634{
Martin K. Petersenae03bf62009-05-22 17:17:50 -0400635 return __bio_add_page(q, bio, page, len, offset,
636 queue_max_hw_sectors(q));
Mike Christie6e68af62005-11-11 05:30:27 -0600637}
638
639/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 * bio_add_page - attempt to add page to bio
641 * @bio: destination bio
642 * @page: page to add
643 * @len: vec entry length
644 * @offset: vec entry offset
645 *
646 * Attempt to add a page to the bio_vec maplist. This can fail for a
647 * number of reasons, such as the bio being full or target block
648 * device limitations. The target block device must allow bio's
649 * smaller than PAGE_SIZE, so it is always possible to add a single
650 * page to an empty bio.
651 */
652int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
653 unsigned int offset)
654{
Mike Christiedefd94b2005-12-05 02:37:06 -0600655 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
Martin K. Petersenae03bf62009-05-22 17:17:50 -0400656 return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657}
658
659struct bio_map_data {
660 struct bio_vec *iovecs;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200661 struct sg_iovec *sgvecs;
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900662 int nr_sgvecs;
663 int is_our_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664};
665
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200666static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900667 struct sg_iovec *iov, int iov_count,
668 int is_our_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669{
670 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200671 memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
672 bmd->nr_sgvecs = iov_count;
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900673 bmd->is_our_pages = is_our_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 bio->bi_private = bmd;
675}
676
677static void bio_free_map_data(struct bio_map_data *bmd)
678{
679 kfree(bmd->iovecs);
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200680 kfree(bmd->sgvecs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 kfree(bmd);
682}
683
FUJITA Tomonori76029ff2008-08-25 20:36:08 +0200684static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count,
685 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686{
FUJITA Tomonori76029ff2008-08-25 20:36:08 +0200687 struct bio_map_data *bmd = kmalloc(sizeof(*bmd), gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688
689 if (!bmd)
690 return NULL;
691
FUJITA Tomonori76029ff2008-08-25 20:36:08 +0200692 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200693 if (!bmd->iovecs) {
694 kfree(bmd);
695 return NULL;
696 }
697
FUJITA Tomonori76029ff2008-08-25 20:36:08 +0200698 bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200699 if (bmd->sgvecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 return bmd;
701
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200702 kfree(bmd->iovecs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 kfree(bmd);
704 return NULL;
705}
706
FUJITA Tomonoriaefcc282008-08-25 20:36:08 +0200707static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
FUJITA Tomonoriecb554a2009-07-09 14:46:53 +0200708 struct sg_iovec *iov, int iov_count,
709 int to_user, int from_user, int do_free_page)
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200710{
711 int ret = 0, i;
712 struct bio_vec *bvec;
713 int iov_idx = 0;
714 unsigned int iov_off = 0;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200715
716 __bio_for_each_segment(bvec, bio, i, 0) {
717 char *bv_addr = page_address(bvec->bv_page);
FUJITA Tomonoriaefcc282008-08-25 20:36:08 +0200718 unsigned int bv_len = iovecs[i].bv_len;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200719
720 while (bv_len && iov_idx < iov_count) {
721 unsigned int bytes;
Michal Simek0e0c6212009-06-10 12:57:07 -0700722 char __user *iov_addr;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200723
724 bytes = min_t(unsigned int,
725 iov[iov_idx].iov_len - iov_off, bv_len);
726 iov_addr = iov[iov_idx].iov_base + iov_off;
727
728 if (!ret) {
FUJITA Tomonoriecb554a2009-07-09 14:46:53 +0200729 if (to_user)
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200730 ret = copy_to_user(iov_addr, bv_addr,
731 bytes);
732
FUJITA Tomonoriecb554a2009-07-09 14:46:53 +0200733 if (from_user)
734 ret = copy_from_user(bv_addr, iov_addr,
735 bytes);
736
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200737 if (ret)
738 ret = -EFAULT;
739 }
740
741 bv_len -= bytes;
742 bv_addr += bytes;
743 iov_addr += bytes;
744 iov_off += bytes;
745
746 if (iov[iov_idx].iov_len == iov_off) {
747 iov_idx++;
748 iov_off = 0;
749 }
750 }
751
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900752 if (do_free_page)
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200753 __free_page(bvec->bv_page);
754 }
755
756 return ret;
757}
758
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759/**
760 * bio_uncopy_user - finish previously mapped bio
761 * @bio: bio being terminated
762 *
763 * Free pages allocated from bio_copy_user() and write back data
764 * to user space in case of a read.
765 */
766int bio_uncopy_user(struct bio *bio)
767{
768 struct bio_map_data *bmd = bio->bi_private;
FUJITA Tomonori81882762008-09-02 16:20:19 +0900769 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770
FUJITA Tomonori81882762008-09-02 16:20:19 +0900771 if (!bio_flagged(bio, BIO_NULL_MAPPED))
772 ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
FUJITA Tomonoriecb554a2009-07-09 14:46:53 +0200773 bmd->nr_sgvecs, bio_data_dir(bio) == READ,
774 0, bmd->is_our_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 bio_free_map_data(bmd);
776 bio_put(bio);
777 return ret;
778}
779
780/**
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200781 * bio_copy_user_iov - copy user data to bio
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 * @q: destination block queue
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900783 * @map_data: pointer to the rq_map_data holding pages (if necessary)
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200784 * @iov: the iovec.
785 * @iov_count: number of elements in the iovec
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 * @write_to_vm: bool indicating writing to pages or not
FUJITA Tomonoria3bce902008-08-28 16:17:05 +0900787 * @gfp_mask: memory allocation flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 *
789 * Prepares and returns a bio for indirect user io, bouncing data
790 * to/from kernel pages as necessary. Must be paired with
791 * call bio_uncopy_user() on io completion.
792 */
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900793struct bio *bio_copy_user_iov(struct request_queue *q,
794 struct rq_map_data *map_data,
795 struct sg_iovec *iov, int iov_count,
796 int write_to_vm, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 struct bio_map_data *bmd;
799 struct bio_vec *bvec;
800 struct page *page;
801 struct bio *bio;
802 int i, ret;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200803 int nr_pages = 0;
804 unsigned int len = 0;
FUJITA Tomonori56c451f2008-12-18 14:49:37 +0900805 unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200807 for (i = 0; i < iov_count; i++) {
808 unsigned long uaddr;
809 unsigned long end;
810 unsigned long start;
811
812 uaddr = (unsigned long)iov[i].iov_base;
813 end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
814 start = uaddr >> PAGE_SHIFT;
815
816 nr_pages += end - start;
817 len += iov[i].iov_len;
818 }
819
FUJITA Tomonori69838722009-04-28 20:24:29 +0200820 if (offset)
821 nr_pages++;
822
FUJITA Tomonoria3bce902008-08-28 16:17:05 +0900823 bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 if (!bmd)
825 return ERR_PTR(-ENOMEM);
826
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 ret = -ENOMEM;
Tejun Heoa9e9dc22009-04-15 22:10:27 +0900828 bio = bio_kmalloc(gfp_mask, nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 if (!bio)
830 goto out_bmd;
831
832 bio->bi_rw |= (!write_to_vm << BIO_RW);
833
834 ret = 0;
FUJITA Tomonori56c451f2008-12-18 14:49:37 +0900835
836 if (map_data) {
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +0900837 nr_pages = 1 << map_data->page_order;
FUJITA Tomonori56c451f2008-12-18 14:49:37 +0900838 i = map_data->offset / PAGE_SIZE;
839 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 while (len) {
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +0900841 unsigned int bytes = PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842
FUJITA Tomonori56c451f2008-12-18 14:49:37 +0900843 bytes -= offset;
844
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 if (bytes > len)
846 bytes = len;
847
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900848 if (map_data) {
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +0900849 if (i == map_data->nr_entries * nr_pages) {
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900850 ret = -ENOMEM;
851 break;
852 }
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +0900853
854 page = map_data->pages[i / nr_pages];
855 page += (i % nr_pages);
856
857 i++;
858 } else {
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900859 page = alloc_page(q->bounce_gfp | gfp_mask);
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +0900860 if (!page) {
861 ret = -ENOMEM;
862 break;
863 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 }
865
FUJITA Tomonori56c451f2008-12-18 14:49:37 +0900866 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868
869 len -= bytes;
FUJITA Tomonori56c451f2008-12-18 14:49:37 +0900870 offset = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 }
872
873 if (ret)
874 goto cleanup;
875
876 /*
877 * success
878 */
FUJITA Tomonoriecb554a2009-07-09 14:46:53 +0200879 if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
880 (map_data && map_data->from_user)) {
881 ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0);
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200882 if (ret)
883 goto cleanup;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 }
885
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900886 bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 return bio;
888cleanup:
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900889 if (!map_data)
890 bio_for_each_segment(bvec, bio, i)
891 __free_page(bvec->bv_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892
893 bio_put(bio);
894out_bmd:
895 bio_free_map_data(bmd);
896 return ERR_PTR(ret);
897}
898
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200899/**
900 * bio_copy_user - copy user data to bio
901 * @q: destination block queue
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900902 * @map_data: pointer to the rq_map_data holding pages (if necessary)
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200903 * @uaddr: start of user address
904 * @len: length in bytes
905 * @write_to_vm: bool indicating writing to pages or not
FUJITA Tomonoria3bce902008-08-28 16:17:05 +0900906 * @gfp_mask: memory allocation flags
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200907 *
908 * Prepares and returns a bio for indirect user io, bouncing data
909 * to/from kernel pages as necessary. Must be paired with
910 * call bio_uncopy_user() on io completion.
911 */
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900912struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
913 unsigned long uaddr, unsigned int len,
914 int write_to_vm, gfp_t gfp_mask)
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200915{
916 struct sg_iovec iov;
917
918 iov.iov_base = (void __user *)uaddr;
919 iov.iov_len = len;
920
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900921 return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +0200922}
923
Jens Axboe165125e2007-07-24 09:28:11 +0200924static struct bio *__bio_map_user_iov(struct request_queue *q,
James Bottomley f1970ba2005-06-20 14:06:52 +0200925 struct block_device *bdev,
926 struct sg_iovec *iov, int iov_count,
FUJITA Tomonoria3bce902008-08-28 16:17:05 +0900927 int write_to_vm, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928{
James Bottomley f1970ba2005-06-20 14:06:52 +0200929 int i, j;
930 int nr_pages = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 struct page **pages;
932 struct bio *bio;
James Bottomley f1970ba2005-06-20 14:06:52 +0200933 int cur_page = 0;
934 int ret, offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935
James Bottomley f1970ba2005-06-20 14:06:52 +0200936 for (i = 0; i < iov_count; i++) {
937 unsigned long uaddr = (unsigned long)iov[i].iov_base;
938 unsigned long len = iov[i].iov_len;
939 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
940 unsigned long start = uaddr >> PAGE_SHIFT;
941
942 nr_pages += end - start;
943 /*
Mike Christiead2d7222006-12-01 10:40:20 +0100944 * buffer must be aligned to at least hardsector size for now
James Bottomley f1970ba2005-06-20 14:06:52 +0200945 */
Mike Christiead2d7222006-12-01 10:40:20 +0100946 if (uaddr & queue_dma_alignment(q))
James Bottomley f1970ba2005-06-20 14:06:52 +0200947 return ERR_PTR(-EINVAL);
948 }
949
950 if (!nr_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 return ERR_PTR(-EINVAL);
952
Tejun Heoa9e9dc22009-04-15 22:10:27 +0900953 bio = bio_kmalloc(gfp_mask, nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 if (!bio)
955 return ERR_PTR(-ENOMEM);
956
957 ret = -ENOMEM;
FUJITA Tomonoria3bce902008-08-28 16:17:05 +0900958 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 if (!pages)
960 goto out;
961
James Bottomley f1970ba2005-06-20 14:06:52 +0200962 for (i = 0; i < iov_count; i++) {
963 unsigned long uaddr = (unsigned long)iov[i].iov_base;
964 unsigned long len = iov[i].iov_len;
965 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
966 unsigned long start = uaddr >> PAGE_SHIFT;
967 const int local_nr_pages = end - start;
968 const int page_limit = cur_page + local_nr_pages;
969
Nick Pigginf5dd33c2008-07-25 19:45:25 -0700970 ret = get_user_pages_fast(uaddr, local_nr_pages,
971 write_to_vm, &pages[cur_page]);
Jens Axboe99172152006-06-16 13:02:29 +0200972 if (ret < local_nr_pages) {
973 ret = -EFAULT;
James Bottomley f1970ba2005-06-20 14:06:52 +0200974 goto out_unmap;
Jens Axboe99172152006-06-16 13:02:29 +0200975 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976
James Bottomley f1970ba2005-06-20 14:06:52 +0200977 offset = uaddr & ~PAGE_MASK;
978 for (j = cur_page; j < page_limit; j++) {
979 unsigned int bytes = PAGE_SIZE - offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980
James Bottomley f1970ba2005-06-20 14:06:52 +0200981 if (len <= 0)
982 break;
983
984 if (bytes > len)
985 bytes = len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986
James Bottomley f1970ba2005-06-20 14:06:52 +0200987 /*
988 * sorry...
989 */
Mike Christiedefd94b2005-12-05 02:37:06 -0600990 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
991 bytes)
James Bottomley f1970ba2005-06-20 14:06:52 +0200992 break;
993
994 len -= bytes;
995 offset = 0;
996 }
997
998 cur_page = j;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 /*
James Bottomley f1970ba2005-06-20 14:06:52 +02001000 * release the pages we didn't map into the bio, if any
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 */
James Bottomley f1970ba2005-06-20 14:06:52 +02001002 while (j < page_limit)
1003 page_cache_release(pages[j++]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 }
1005
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 kfree(pages);
1007
1008 /*
1009 * set data direction, and check if mapped pages need bouncing
1010 */
1011 if (!write_to_vm)
1012 bio->bi_rw |= (1 << BIO_RW);
1013
James Bottomley f1970ba2005-06-20 14:06:52 +02001014 bio->bi_bdev = bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015 bio->bi_flags |= (1 << BIO_USER_MAPPED);
1016 return bio;
James Bottomley f1970ba2005-06-20 14:06:52 +02001017
1018 out_unmap:
1019 for (i = 0; i < nr_pages; i++) {
1020 if(!pages[i])
1021 break;
1022 page_cache_release(pages[i]);
1023 }
1024 out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 kfree(pages);
1026 bio_put(bio);
1027 return ERR_PTR(ret);
1028}
1029
1030/**
1031 * bio_map_user - map user address into bio
Jens Axboe165125e2007-07-24 09:28:11 +02001032 * @q: the struct request_queue for the bio
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 * @bdev: destination block device
1034 * @uaddr: start of user address
1035 * @len: length in bytes
1036 * @write_to_vm: bool indicating writing to pages or not
FUJITA Tomonoria3bce902008-08-28 16:17:05 +09001037 * @gfp_mask: memory allocation flags
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038 *
1039 * Map the user space address into a bio suitable for io to a block
1040 * device. Returns an error pointer in case of error.
1041 */
Jens Axboe165125e2007-07-24 09:28:11 +02001042struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
FUJITA Tomonoria3bce902008-08-28 16:17:05 +09001043 unsigned long uaddr, unsigned int len, int write_to_vm,
1044 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045{
James Bottomley f1970ba2005-06-20 14:06:52 +02001046 struct sg_iovec iov;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047
viro@ZenIV.linux.org.uk3f703532005-09-09 16:53:56 +01001048 iov.iov_base = (void __user *)uaddr;
James Bottomley f1970ba2005-06-20 14:06:52 +02001049 iov.iov_len = len;
1050
FUJITA Tomonoria3bce902008-08-28 16:17:05 +09001051 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
James Bottomley f1970ba2005-06-20 14:06:52 +02001052}
1053
1054/**
1055 * bio_map_user_iov - map user sg_iovec table into bio
Jens Axboe165125e2007-07-24 09:28:11 +02001056 * @q: the struct request_queue for the bio
James Bottomley f1970ba2005-06-20 14:06:52 +02001057 * @bdev: destination block device
1058 * @iov: the iovec.
1059 * @iov_count: number of elements in the iovec
1060 * @write_to_vm: bool indicating writing to pages or not
FUJITA Tomonoria3bce902008-08-28 16:17:05 +09001061 * @gfp_mask: memory allocation flags
James Bottomley f1970ba2005-06-20 14:06:52 +02001062 *
1063 * Map the user space address into a bio suitable for io to a block
1064 * device. Returns an error pointer in case of error.
1065 */
Jens Axboe165125e2007-07-24 09:28:11 +02001066struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
James Bottomley f1970ba2005-06-20 14:06:52 +02001067 struct sg_iovec *iov, int iov_count,
FUJITA Tomonoria3bce902008-08-28 16:17:05 +09001068 int write_to_vm, gfp_t gfp_mask)
James Bottomley f1970ba2005-06-20 14:06:52 +02001069{
1070 struct bio *bio;
James Bottomley f1970ba2005-06-20 14:06:52 +02001071
FUJITA Tomonoria3bce902008-08-28 16:17:05 +09001072 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
1073 gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 if (IS_ERR(bio))
1075 return bio;
1076
1077 /*
1078 * subtle -- if __bio_map_user() ended up bouncing a bio,
1079 * it would normally disappear when its bi_end_io is run.
1080 * however, we need it for the unmap, so grab an extra
1081 * reference to it
1082 */
1083 bio_get(bio);
1084
Mike Christie0e75f902006-12-01 10:40:55 +01001085 return bio;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086}
1087
1088static void __bio_unmap_user(struct bio *bio)
1089{
1090 struct bio_vec *bvec;
1091 int i;
1092
1093 /*
1094 * make sure we dirty pages we wrote to
1095 */
1096 __bio_for_each_segment(bvec, bio, i, 0) {
1097 if (bio_data_dir(bio) == READ)
1098 set_page_dirty_lock(bvec->bv_page);
1099
1100 page_cache_release(bvec->bv_page);
1101 }
1102
1103 bio_put(bio);
1104}
1105
1106/**
1107 * bio_unmap_user - unmap a bio
1108 * @bio: the bio being unmapped
1109 *
1110 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1111 * a process context.
1112 *
1113 * bio_unmap_user() may sleep.
1114 */
1115void bio_unmap_user(struct bio *bio)
1116{
1117 __bio_unmap_user(bio);
1118 bio_put(bio);
1119}
1120
NeilBrown6712ecf2007-09-27 12:47:43 +02001121static void bio_map_kern_endio(struct bio *bio, int err)
Jens Axboeb8238252005-06-20 14:05:27 +02001122{
Jens Axboeb8238252005-06-20 14:05:27 +02001123 bio_put(bio);
Jens Axboeb8238252005-06-20 14:05:27 +02001124}
1125
1126
Jens Axboe165125e2007-07-24 09:28:11 +02001127static struct bio *__bio_map_kern(struct request_queue *q, void *data,
Al Viro27496a82005-10-21 03:20:48 -04001128 unsigned int len, gfp_t gfp_mask)
Mike Christie df46b9a2005-06-20 14:04:44 +02001129{
1130 unsigned long kaddr = (unsigned long)data;
1131 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1132 unsigned long start = kaddr >> PAGE_SHIFT;
1133 const int nr_pages = end - start;
1134 int offset, i;
1135 struct bio *bio;
1136
Tejun Heoa9e9dc22009-04-15 22:10:27 +09001137 bio = bio_kmalloc(gfp_mask, nr_pages);
Mike Christie df46b9a2005-06-20 14:04:44 +02001138 if (!bio)
1139 return ERR_PTR(-ENOMEM);
1140
1141 offset = offset_in_page(kaddr);
1142 for (i = 0; i < nr_pages; i++) {
1143 unsigned int bytes = PAGE_SIZE - offset;
1144
1145 if (len <= 0)
1146 break;
1147
1148 if (bytes > len)
1149 bytes = len;
1150
Mike Christiedefd94b2005-12-05 02:37:06 -06001151 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1152 offset) < bytes)
Mike Christie df46b9a2005-06-20 14:04:44 +02001153 break;
1154
1155 data += bytes;
1156 len -= bytes;
1157 offset = 0;
1158 }
1159
Jens Axboeb8238252005-06-20 14:05:27 +02001160 bio->bi_end_io = bio_map_kern_endio;
Mike Christie df46b9a2005-06-20 14:04:44 +02001161 return bio;
1162}
1163
1164/**
1165 * bio_map_kern - map kernel address into bio
Jens Axboe165125e2007-07-24 09:28:11 +02001166 * @q: the struct request_queue for the bio
Mike Christie df46b9a2005-06-20 14:04:44 +02001167 * @data: pointer to buffer to map
1168 * @len: length in bytes
1169 * @gfp_mask: allocation flags for bio allocation
1170 *
1171 * Map the kernel address into a bio suitable for io to a block
1172 * device. Returns an error pointer in case of error.
1173 */
Jens Axboe165125e2007-07-24 09:28:11 +02001174struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
Al Viro27496a82005-10-21 03:20:48 -04001175 gfp_t gfp_mask)
Mike Christie df46b9a2005-06-20 14:04:44 +02001176{
1177 struct bio *bio;
1178
1179 bio = __bio_map_kern(q, data, len, gfp_mask);
1180 if (IS_ERR(bio))
1181 return bio;
1182
1183 if (bio->bi_size == len)
1184 return bio;
1185
1186 /*
1187 * Don't support partial mappings.
1188 */
1189 bio_put(bio);
1190 return ERR_PTR(-EINVAL);
1191}
1192
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001193static void bio_copy_kern_endio(struct bio *bio, int err)
1194{
1195 struct bio_vec *bvec;
1196 const int read = bio_data_dir(bio) == READ;
FUJITA Tomonori76029ff2008-08-25 20:36:08 +02001197 struct bio_map_data *bmd = bio->bi_private;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001198 int i;
FUJITA Tomonori76029ff2008-08-25 20:36:08 +02001199 char *p = bmd->sgvecs[0].iov_base;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001200
1201 __bio_for_each_segment(bvec, bio, i, 0) {
1202 char *addr = page_address(bvec->bv_page);
FUJITA Tomonori76029ff2008-08-25 20:36:08 +02001203 int len = bmd->iovecs[i].bv_len;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001204
Tejun Heo4fc981e2009-05-19 18:33:06 +09001205 if (read)
FUJITA Tomonori76029ff2008-08-25 20:36:08 +02001206 memcpy(p, addr, len);
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001207
1208 __free_page(bvec->bv_page);
FUJITA Tomonori76029ff2008-08-25 20:36:08 +02001209 p += len;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001210 }
1211
FUJITA Tomonori76029ff2008-08-25 20:36:08 +02001212 bio_free_map_data(bmd);
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001213 bio_put(bio);
1214}
1215
1216/**
1217 * bio_copy_kern - copy kernel address into bio
1218 * @q: the struct request_queue for the bio
1219 * @data: pointer to buffer to copy
1220 * @len: length in bytes
1221 * @gfp_mask: allocation flags for bio and page allocation
Randy Dunlapffee0252008-04-30 09:08:54 +02001222 * @reading: data direction is READ
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001223 *
1224 * copy the kernel address into a bio suitable for io to a block
1225 * device. Returns an error pointer in case of error.
1226 */
1227struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1228 gfp_t gfp_mask, int reading)
1229{
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001230 struct bio *bio;
1231 struct bio_vec *bvec;
FUJITA Tomonori4d8ab622008-08-28 15:05:57 +09001232 int i;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001233
FUJITA Tomonori4d8ab622008-08-28 15:05:57 +09001234 bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
1235 if (IS_ERR(bio))
1236 return bio;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001237
1238 if (!reading) {
1239 void *p = data;
1240
1241 bio_for_each_segment(bvec, bio, i) {
1242 char *addr = page_address(bvec->bv_page);
1243
1244 memcpy(addr, p, bvec->bv_len);
1245 p += bvec->bv_len;
1246 }
1247 }
1248
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001249 bio->bi_end_io = bio_copy_kern_endio;
FUJITA Tomonori76029ff2008-08-25 20:36:08 +02001250
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001251 return bio;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001252}
1253
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254/*
1255 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1256 * for performing direct-IO in BIOs.
1257 *
1258 * The problem is that we cannot run set_page_dirty() from interrupt context
1259 * because the required locks are not interrupt-safe. So what we can do is to
1260 * mark the pages dirty _before_ performing IO. And in interrupt context,
1261 * check that the pages are still dirty. If so, fine. If not, redirty them
1262 * in process context.
1263 *
1264 * We special-case compound pages here: normally this means reads into hugetlb
1265 * pages. The logic in here doesn't really work right for compound pages
1266 * because the VM does not uniformly chase down the head page in all cases.
1267 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1268 * handle them at all. So we skip compound pages here at an early stage.
1269 *
1270 * Note that this code is very hard to test under normal circumstances because
1271 * direct-io pins the pages with get_user_pages(). This makes
1272 * is_page_cache_freeable return false, and the VM will not clean the pages.
1273 * But other code (eg, pdflush) could clean the pages if they are mapped
1274 * pagecache.
1275 *
1276 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1277 * deferred bio dirtying paths.
1278 */
1279
1280/*
1281 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1282 */
1283void bio_set_pages_dirty(struct bio *bio)
1284{
1285 struct bio_vec *bvec = bio->bi_io_vec;
1286 int i;
1287
1288 for (i = 0; i < bio->bi_vcnt; i++) {
1289 struct page *page = bvec[i].bv_page;
1290
1291 if (page && !PageCompound(page))
1292 set_page_dirty_lock(page);
1293 }
1294}
1295
Adrian Bunk86b6c7a2008-02-18 13:48:32 +01001296static void bio_release_pages(struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297{
1298 struct bio_vec *bvec = bio->bi_io_vec;
1299 int i;
1300
1301 for (i = 0; i < bio->bi_vcnt; i++) {
1302 struct page *page = bvec[i].bv_page;
1303
1304 if (page)
1305 put_page(page);
1306 }
1307}
1308
1309/*
1310 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1311 * If they are, then fine. If, however, some pages are clean then they must
1312 * have been written out during the direct-IO read. So we take another ref on
1313 * the BIO and the offending pages and re-dirty the pages in process context.
1314 *
1315 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1316 * here on. It will run one page_cache_release() against each page and will
1317 * run one bio_put() against the BIO.
1318 */
1319
David Howells65f27f32006-11-22 14:55:48 +00001320static void bio_dirty_fn(struct work_struct *work);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321
David Howells65f27f32006-11-22 14:55:48 +00001322static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323static DEFINE_SPINLOCK(bio_dirty_lock);
1324static struct bio *bio_dirty_list;
1325
1326/*
1327 * This runs in process context
1328 */
David Howells65f27f32006-11-22 14:55:48 +00001329static void bio_dirty_fn(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330{
1331 unsigned long flags;
1332 struct bio *bio;
1333
1334 spin_lock_irqsave(&bio_dirty_lock, flags);
1335 bio = bio_dirty_list;
1336 bio_dirty_list = NULL;
1337 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1338
1339 while (bio) {
1340 struct bio *next = bio->bi_private;
1341
1342 bio_set_pages_dirty(bio);
1343 bio_release_pages(bio);
1344 bio_put(bio);
1345 bio = next;
1346 }
1347}
1348
1349void bio_check_pages_dirty(struct bio *bio)
1350{
1351 struct bio_vec *bvec = bio->bi_io_vec;
1352 int nr_clean_pages = 0;
1353 int i;
1354
1355 for (i = 0; i < bio->bi_vcnt; i++) {
1356 struct page *page = bvec[i].bv_page;
1357
1358 if (PageDirty(page) || PageCompound(page)) {
1359 page_cache_release(page);
1360 bvec[i].bv_page = NULL;
1361 } else {
1362 nr_clean_pages++;
1363 }
1364 }
1365
1366 if (nr_clean_pages) {
1367 unsigned long flags;
1368
1369 spin_lock_irqsave(&bio_dirty_lock, flags);
1370 bio->bi_private = bio_dirty_list;
1371 bio_dirty_list = bio;
1372 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1373 schedule_work(&bio_dirty_work);
1374 } else {
1375 bio_put(bio);
1376 }
1377}
1378
1379/**
1380 * bio_endio - end I/O on a bio
1381 * @bio: bio
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382 * @error: error, if any
1383 *
1384 * Description:
NeilBrown6712ecf2007-09-27 12:47:43 +02001385 * bio_endio() will end I/O on the whole bio. bio_endio() is the
NeilBrown5bb23a62007-09-27 12:46:13 +02001386 * preferred way to end I/O on a bio, it takes care of clearing
1387 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1388 * established -Exxxx (-EIO, for instance) error values in case
1389 * something went wrong. Noone should call bi_end_io() directly on a
1390 * bio unless they own it and thus know that it has an end_io
1391 * function.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392 **/
NeilBrown6712ecf2007-09-27 12:47:43 +02001393void bio_endio(struct bio *bio, int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394{
1395 if (error)
1396 clear_bit(BIO_UPTODATE, &bio->bi_flags);
NeilBrown9cc54d42007-09-27 12:46:12 +02001397 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1398 error = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399
NeilBrown5bb23a62007-09-27 12:46:13 +02001400 if (bio->bi_end_io)
NeilBrown6712ecf2007-09-27 12:47:43 +02001401 bio->bi_end_io(bio, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402}
1403
1404void bio_pair_release(struct bio_pair *bp)
1405{
1406 if (atomic_dec_and_test(&bp->cnt)) {
1407 struct bio *master = bp->bio1.bi_private;
1408
NeilBrown6712ecf2007-09-27 12:47:43 +02001409 bio_endio(master, bp->error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410 mempool_free(bp, bp->bio2.bi_private);
1411 }
1412}
1413
NeilBrown6712ecf2007-09-27 12:47:43 +02001414static void bio_pair_end_1(struct bio *bi, int err)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415{
1416 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1417
1418 if (err)
1419 bp->error = err;
1420
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421 bio_pair_release(bp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422}
1423
NeilBrown6712ecf2007-09-27 12:47:43 +02001424static void bio_pair_end_2(struct bio *bi, int err)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001425{
1426 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1427
1428 if (err)
1429 bp->error = err;
1430
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 bio_pair_release(bp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432}
1433
1434/*
Alberto Bertoglic7eee1b2009-01-25 23:36:14 -02001435 * split a bio - only worry about a bio with a single page in its iovec
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436 */
Denis ChengRq6feef532008-10-09 08:57:05 +02001437struct bio_pair *bio_split(struct bio *bi, int first_sectors)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438{
Denis ChengRq6feef532008-10-09 08:57:05 +02001439 struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440
1441 if (!bp)
1442 return bp;
1443
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +01001444 trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
Jens Axboe2056a782006-03-23 20:00:26 +01001445 bi->bi_sector + first_sectors);
1446
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 BUG_ON(bi->bi_vcnt != 1);
1448 BUG_ON(bi->bi_idx != 0);
1449 atomic_set(&bp->cnt, 3);
1450 bp->error = 0;
1451 bp->bio1 = *bi;
1452 bp->bio2 = *bi;
1453 bp->bio2.bi_sector += first_sectors;
1454 bp->bio2.bi_size -= first_sectors << 9;
1455 bp->bio1.bi_size = first_sectors << 9;
1456
1457 bp->bv1 = bi->bi_io_vec[0];
1458 bp->bv2 = bi->bi_io_vec[0];
1459 bp->bv2.bv_offset += first_sectors << 9;
1460 bp->bv2.bv_len -= first_sectors << 9;
1461 bp->bv1.bv_len = first_sectors << 9;
1462
1463 bp->bio1.bi_io_vec = &bp->bv1;
1464 bp->bio2.bi_io_vec = &bp->bv2;
1465
NeilBrowna2eb0c12006-05-22 22:35:27 -07001466 bp->bio1.bi_max_vecs = 1;
1467 bp->bio2.bi_max_vecs = 1;
1468
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 bp->bio1.bi_end_io = bio_pair_end_1;
1470 bp->bio2.bi_end_io = bio_pair_end_2;
1471
1472 bp->bio1.bi_private = bi;
Denis ChengRq6feef532008-10-09 08:57:05 +02001473 bp->bio2.bi_private = bio_split_pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +02001475 if (bio_integrity(bi))
1476 bio_integrity_split(bi, bp, first_sectors);
1477
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478 return bp;
1479}
1480
Martin K. Petersenad3316b2008-10-01 22:42:53 -04001481/**
1482 * bio_sector_offset - Find hardware sector offset in bio
1483 * @bio: bio to inspect
1484 * @index: bio_vec index
1485 * @offset: offset in bv_page
1486 *
1487 * Return the number of hardware sectors between beginning of bio
1488 * and an end point indicated by a bio_vec index and an offset
1489 * within that vector's page.
1490 */
1491sector_t bio_sector_offset(struct bio *bio, unsigned short index,
1492 unsigned int offset)
1493{
Martin K. Petersene1defc42009-05-22 17:17:49 -04001494 unsigned int sector_sz;
Martin K. Petersenad3316b2008-10-01 22:42:53 -04001495 struct bio_vec *bv;
1496 sector_t sectors;
1497 int i;
1498
Martin K. Petersene1defc42009-05-22 17:17:49 -04001499 sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
Martin K. Petersenad3316b2008-10-01 22:42:53 -04001500 sectors = 0;
1501
1502 if (index >= bio->bi_idx)
1503 index = bio->bi_vcnt - 1;
1504
1505 __bio_for_each_segment(bv, bio, i, 0) {
1506 if (i == index) {
1507 if (offset > bv->bv_offset)
1508 sectors += (offset - bv->bv_offset) / sector_sz;
1509 break;
1510 }
1511
1512 sectors += bv->bv_len / sector_sz;
1513 }
1514
1515 return sectors;
1516}
1517EXPORT_SYMBOL(bio_sector_offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518
1519/*
1520 * create memory pools for biovec's in a bio_set.
1521 * use the global biovec slabs created for general use.
1522 */
Jens Axboe59725112007-04-02 10:06:42 +02001523static int biovec_create_pools(struct bio_set *bs, int pool_entries)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524{
Jens Axboe7ff93452008-12-11 11:53:43 +01001525 struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526
Jens Axboe7ff93452008-12-11 11:53:43 +01001527 bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
1528 if (!bs->bvec_pool)
1529 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530
Linus Torvalds1da177e2005-04-16 15:20:36 -07001531 return 0;
1532}
1533
1534static void biovec_free_pools(struct bio_set *bs)
1535{
Jens Axboe7ff93452008-12-11 11:53:43 +01001536 mempool_destroy(bs->bvec_pool);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537}
1538
1539void bioset_free(struct bio_set *bs)
1540{
1541 if (bs->bio_pool)
1542 mempool_destroy(bs->bio_pool);
1543
Martin K. Petersen7878cba2009-06-26 15:37:49 +02001544 bioset_integrity_free(bs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545 biovec_free_pools(bs);
Jens Axboebb799ca2008-12-10 15:35:05 +01001546 bio_put_slab(bs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547
1548 kfree(bs);
1549}
1550
Jens Axboebb799ca2008-12-10 15:35:05 +01001551/**
1552 * bioset_create - Create a bio_set
1553 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1554 * @front_pad: Number of bytes to allocate in front of the returned bio
1555 *
1556 * Description:
1557 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1558 * to ask for a number of bytes to be allocated in front of the bio.
1559 * Front pad allocation is useful for embedding the bio inside
1560 * another structure, to avoid allocating extra data to go with the bio.
1561 * Note that the bio must be embedded at the END of that structure always,
1562 * or things will break badly.
1563 */
1564struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565{
Jens Axboe392ddc32008-12-23 12:42:54 +01001566 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
Jens Axboe1b434492008-10-22 20:32:58 +02001567 struct bio_set *bs;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001568
Jens Axboe1b434492008-10-22 20:32:58 +02001569 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 if (!bs)
1571 return NULL;
1572
Jens Axboebb799ca2008-12-10 15:35:05 +01001573 bs->front_pad = front_pad;
Jens Axboe1b434492008-10-22 20:32:58 +02001574
Jens Axboe392ddc32008-12-23 12:42:54 +01001575 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
Jens Axboebb799ca2008-12-10 15:35:05 +01001576 if (!bs->bio_slab) {
1577 kfree(bs);
1578 return NULL;
1579 }
1580
1581 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001582 if (!bs->bio_pool)
1583 goto bad;
1584
Martin K. Petersen7878cba2009-06-26 15:37:49 +02001585 if (bioset_integrity_create(bs, pool_size))
1586 goto bad;
1587
Jens Axboebb799ca2008-12-10 15:35:05 +01001588 if (!biovec_create_pools(bs, pool_size))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589 return bs;
1590
1591bad:
1592 bioset_free(bs);
1593 return NULL;
1594}
1595
1596static void __init biovec_init_slabs(void)
1597{
1598 int i;
1599
1600 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1601 int size;
1602 struct biovec_slab *bvs = bvec_slabs + i;
1603
Jens Axboea7fcd372008-12-05 16:10:29 +01001604#ifndef CONFIG_BLK_DEV_INTEGRITY
1605 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
1606 bvs->slab = NULL;
1607 continue;
1608 }
1609#endif
1610
Linus Torvalds1da177e2005-04-16 15:20:36 -07001611 size = bvs->nr_vecs * sizeof(struct bio_vec);
1612 bvs->slab = kmem_cache_create(bvs->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001613 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614 }
1615}
1616
1617static int __init init_bio(void)
1618{
Jens Axboebb799ca2008-12-10 15:35:05 +01001619 bio_slab_max = 2;
1620 bio_slab_nr = 0;
1621 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
1622 if (!bio_slabs)
1623 panic("bio: can't allocate bios\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624
Martin K. Petersen7878cba2009-06-26 15:37:49 +02001625 bio_integrity_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626 biovec_init_slabs();
1627
Jens Axboebb799ca2008-12-10 15:35:05 +01001628 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629 if (!fs_bio_set)
1630 panic("bio: can't allocate bios\n");
1631
Matthew Dobson0eaae62a2006-03-26 01:37:47 -08001632 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
1633 sizeof(struct bio_pair));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634 if (!bio_split_pool)
1635 panic("bio: can't create split pool\n");
1636
1637 return 0;
1638}
1639
1640subsys_initcall(init_bio);
1641
1642EXPORT_SYMBOL(bio_alloc);
Jens Axboe0a0d96b2008-09-11 13:17:37 +02001643EXPORT_SYMBOL(bio_kmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644EXPORT_SYMBOL(bio_put);
Peter Osterlund36763472005-09-06 15:16:42 -07001645EXPORT_SYMBOL(bio_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646EXPORT_SYMBOL(bio_endio);
1647EXPORT_SYMBOL(bio_init);
1648EXPORT_SYMBOL(__bio_clone);
1649EXPORT_SYMBOL(bio_clone);
1650EXPORT_SYMBOL(bio_phys_segments);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001651EXPORT_SYMBOL(bio_add_page);
Mike Christie6e68af62005-11-11 05:30:27 -06001652EXPORT_SYMBOL(bio_add_pc_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001653EXPORT_SYMBOL(bio_get_nr_vecs);
Jens Axboe40044ce2008-03-17 21:14:40 +01001654EXPORT_SYMBOL(bio_map_user);
1655EXPORT_SYMBOL(bio_unmap_user);
Mike Christie df46b9a2005-06-20 14:04:44 +02001656EXPORT_SYMBOL(bio_map_kern);
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001657EXPORT_SYMBOL(bio_copy_kern);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658EXPORT_SYMBOL(bio_pair_release);
1659EXPORT_SYMBOL(bio_split);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001660EXPORT_SYMBOL(bio_copy_user);
1661EXPORT_SYMBOL(bio_uncopy_user);
1662EXPORT_SYMBOL(bioset_create);
1663EXPORT_SYMBOL(bioset_free);
1664EXPORT_SYMBOL(bio_alloc_bioset);