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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>
Kent Overstreeta27bb332013-05-07 16:19:08 -070022#include <linux/uio.h>
Tejun Heo852c7882012-03-05 13:15:27 -080023#include <linux/iocontext.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/slab.h>
25#include <linux/init.h>
26#include <linux/kernel.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -050027#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/mempool.h>
29#include <linux/workqueue.h>
Tejun Heo852c7882012-03-05 13:15:27 -080030#include <linux/cgroup.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
Li Zefan55782132009-06-09 13:43:05 +080032#include <trace/events/block.h>
Ingo Molnar0bfc2452008-11-26 11:59:56 +010033
Jens Axboe392ddc32008-12-23 12:42:54 +010034/*
35 * Test patch to inline a certain number of bi_io_vec's inside the bio
36 * itself, to shrink a bio data allocation from two mempool calls to one
37 */
38#define BIO_INLINE_VECS 4
39
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) }
Martin K. Petersendf677142011-03-08 08:28:01 +010046static struct 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;
Kent Overstreet3f86a822012-09-06 15:35:01 -070056EXPORT_SYMBOL(fs_bio_set);
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
Jens Axboebb799ca2008-12-10 15:35:05 +010058/*
59 * Our slab pool management
60 */
61struct bio_slab {
62 struct kmem_cache *slab;
63 unsigned int slab_ref;
64 unsigned int slab_size;
65 char name[8];
66};
67static DEFINE_MUTEX(bio_slab_lock);
68static struct bio_slab *bio_slabs;
69static unsigned int bio_slab_nr, bio_slab_max;
70
71static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
72{
73 unsigned int sz = sizeof(struct bio) + extra_size;
74 struct kmem_cache *slab = NULL;
Alexey Khoroshilov389d7b22012-08-09 15:19:25 +020075 struct bio_slab *bslab, *new_bio_slabs;
Anna Leuschner386bc352012-10-22 21:53:36 +020076 unsigned int new_bio_slab_max;
Jens Axboebb799ca2008-12-10 15:35:05 +010077 unsigned int i, entry = -1;
78
79 mutex_lock(&bio_slab_lock);
80
81 i = 0;
82 while (i < bio_slab_nr) {
Thiago Farinaf06f1352010-01-19 14:07:09 +010083 bslab = &bio_slabs[i];
Jens Axboebb799ca2008-12-10 15:35:05 +010084
85 if (!bslab->slab && entry == -1)
86 entry = i;
87 else if (bslab->slab_size == sz) {
88 slab = bslab->slab;
89 bslab->slab_ref++;
90 break;
91 }
92 i++;
93 }
94
95 if (slab)
96 goto out_unlock;
97
98 if (bio_slab_nr == bio_slab_max && entry == -1) {
Anna Leuschner386bc352012-10-22 21:53:36 +020099 new_bio_slab_max = bio_slab_max << 1;
Alexey Khoroshilov389d7b22012-08-09 15:19:25 +0200100 new_bio_slabs = krealloc(bio_slabs,
Anna Leuschner386bc352012-10-22 21:53:36 +0200101 new_bio_slab_max * sizeof(struct bio_slab),
Alexey Khoroshilov389d7b22012-08-09 15:19:25 +0200102 GFP_KERNEL);
103 if (!new_bio_slabs)
Jens Axboebb799ca2008-12-10 15:35:05 +0100104 goto out_unlock;
Anna Leuschner386bc352012-10-22 21:53:36 +0200105 bio_slab_max = new_bio_slab_max;
Alexey Khoroshilov389d7b22012-08-09 15:19:25 +0200106 bio_slabs = new_bio_slabs;
Jens Axboebb799ca2008-12-10 15:35:05 +0100107 }
108 if (entry == -1)
109 entry = bio_slab_nr++;
110
111 bslab = &bio_slabs[entry];
112
113 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
Mikulas Patocka6a241482014-03-28 15:51:55 -0400114 slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN,
115 SLAB_HWCACHE_ALIGN, NULL);
Jens Axboebb799ca2008-12-10 15:35:05 +0100116 if (!slab)
117 goto out_unlock;
118
Jens Axboebb799ca2008-12-10 15:35:05 +0100119 bslab->slab = slab;
120 bslab->slab_ref = 1;
121 bslab->slab_size = sz;
122out_unlock:
123 mutex_unlock(&bio_slab_lock);
124 return slab;
125}
126
127static void bio_put_slab(struct bio_set *bs)
128{
129 struct bio_slab *bslab = NULL;
130 unsigned int i;
131
132 mutex_lock(&bio_slab_lock);
133
134 for (i = 0; i < bio_slab_nr; i++) {
135 if (bs->bio_slab == bio_slabs[i].slab) {
136 bslab = &bio_slabs[i];
137 break;
138 }
139 }
140
141 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
142 goto out;
143
144 WARN_ON(!bslab->slab_ref);
145
146 if (--bslab->slab_ref)
147 goto out;
148
149 kmem_cache_destroy(bslab->slab);
150 bslab->slab = NULL;
151
152out:
153 mutex_unlock(&bio_slab_lock);
154}
155
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200156unsigned int bvec_nr_vecs(unsigned short idx)
157{
158 return bvec_slabs[idx].nr_vecs;
159}
160
Kent Overstreet9f060e22012-10-12 15:29:33 -0700161void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
Jens Axboebb799ca2008-12-10 15:35:05 +0100162{
163 BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
164
165 if (idx == BIOVEC_MAX_IDX)
Kent Overstreet9f060e22012-10-12 15:29:33 -0700166 mempool_free(bv, pool);
Jens Axboebb799ca2008-12-10 15:35:05 +0100167 else {
168 struct biovec_slab *bvs = bvec_slabs + idx;
169
170 kmem_cache_free(bvs->slab, bv);
171 }
172}
173
Kent Overstreet9f060e22012-10-12 15:29:33 -0700174struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
175 mempool_t *pool)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176{
177 struct bio_vec *bvl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
179 /*
Jens Axboe7ff93452008-12-11 11:53:43 +0100180 * see comment near bvec_array define!
181 */
182 switch (nr) {
183 case 1:
184 *idx = 0;
185 break;
186 case 2 ... 4:
187 *idx = 1;
188 break;
189 case 5 ... 16:
190 *idx = 2;
191 break;
192 case 17 ... 64:
193 *idx = 3;
194 break;
195 case 65 ... 128:
196 *idx = 4;
197 break;
198 case 129 ... BIO_MAX_PAGES:
199 *idx = 5;
200 break;
201 default:
202 return NULL;
203 }
204
205 /*
206 * idx now points to the pool we want to allocate from. only the
207 * 1-vec entry pool is mempool backed.
208 */
209 if (*idx == BIOVEC_MAX_IDX) {
210fallback:
Kent Overstreet9f060e22012-10-12 15:29:33 -0700211 bvl = mempool_alloc(pool, gfp_mask);
Jens Axboe7ff93452008-12-11 11:53:43 +0100212 } else {
213 struct biovec_slab *bvs = bvec_slabs + *idx;
Mel Gormand0164ad2015-11-06 16:28:21 -0800214 gfp_t __gfp_mask = gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_IO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200216 /*
Jens Axboe7ff93452008-12-11 11:53:43 +0100217 * Make this allocation restricted and don't dump info on
218 * allocation failures, since we'll fallback to the mempool
219 * in case of failure.
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200220 */
Jens Axboe7ff93452008-12-11 11:53:43 +0100221 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
222
223 /*
Mel Gormand0164ad2015-11-06 16:28:21 -0800224 * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM
Jens Axboe7ff93452008-12-11 11:53:43 +0100225 * is set, retry with the 1-entry mempool
226 */
227 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
Mel Gormand0164ad2015-11-06 16:28:21 -0800228 if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) {
Jens Axboe7ff93452008-12-11 11:53:43 +0100229 *idx = BIOVEC_MAX_IDX;
230 goto fallback;
231 }
232 }
233
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 return bvl;
235}
236
Kent Overstreet4254bba2012-09-06 15:35:00 -0700237static void __bio_free(struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238{
Kent Overstreet4254bba2012-09-06 15:35:00 -0700239 bio_disassociate_task(bio);
Jens Axboe992c5dd2007-07-18 13:18:08 +0200240
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200241 if (bio_integrity(bio))
Kent Overstreet1e2a410f2012-09-06 15:34:56 -0700242 bio_integrity_free(bio);
Kent Overstreet4254bba2012-09-06 15:35:00 -0700243}
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200244
Kent Overstreet4254bba2012-09-06 15:35:00 -0700245static void bio_free(struct bio *bio)
246{
247 struct bio_set *bs = bio->bi_pool;
248 void *p;
249
250 __bio_free(bio);
251
252 if (bs) {
Kent Overstreeta38352e2012-05-25 13:03:11 -0700253 if (bio_flagged(bio, BIO_OWNS_VEC))
Kent Overstreet9f060e22012-10-12 15:29:33 -0700254 bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
Kent Overstreet4254bba2012-09-06 15:35:00 -0700255
256 /*
257 * If we have front padding, adjust the bio pointer before freeing
258 */
259 p = bio;
Jens Axboebb799ca2008-12-10 15:35:05 +0100260 p -= bs->front_pad;
261
Kent Overstreet4254bba2012-09-06 15:35:00 -0700262 mempool_free(p, bs->bio_pool);
263 } else {
264 /* Bio was allocated by bio_kmalloc() */
265 kfree(bio);
266 }
Peter Osterlund36763472005-09-06 15:16:42 -0700267}
268
Arjan van de Ven858119e2006-01-14 13:20:43 -0800269void bio_init(struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270{
Jens Axboe2b94de52007-07-18 13:14:03 +0200271 memset(bio, 0, sizeof(*bio));
Jens Axboec4cf5262015-04-17 16:15:18 -0600272 atomic_set(&bio->__bi_remaining, 1);
Jens Axboedac56212015-04-17 16:23:59 -0600273 atomic_set(&bio->__bi_cnt, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274}
H Hartley Sweetena112a712009-09-26 16:19:21 +0200275EXPORT_SYMBOL(bio_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276
277/**
Kent Overstreetf44b48c2012-09-06 15:34:58 -0700278 * bio_reset - reinitialize a bio
279 * @bio: bio to reset
280 *
281 * Description:
282 * After calling bio_reset(), @bio will be in the same state as a freshly
283 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
284 * preserved are the ones that are initialized by bio_alloc_bioset(). See
285 * comment in struct bio.
286 */
287void bio_reset(struct bio *bio)
288{
289 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
290
Kent Overstreet4254bba2012-09-06 15:35:00 -0700291 __bio_free(bio);
Kent Overstreetf44b48c2012-09-06 15:34:58 -0700292
293 memset(bio, 0, BIO_RESET_BYTES);
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200294 bio->bi_flags = flags;
Jens Axboec4cf5262015-04-17 16:15:18 -0600295 atomic_set(&bio->__bi_remaining, 1);
Kent Overstreetf44b48c2012-09-06 15:34:58 -0700296}
297EXPORT_SYMBOL(bio_reset);
298
Christoph Hellwig38f8baa2016-03-11 17:34:51 +0100299static struct bio *__bio_chain_endio(struct bio *bio)
Kent Overstreet196d38b2013-11-23 18:34:15 -0800300{
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200301 struct bio *parent = bio->bi_private;
302
Christoph Hellwigaf3e3a52016-03-11 17:34:50 +0100303 if (!parent->bi_error)
304 parent->bi_error = bio->bi_error;
Kent Overstreet196d38b2013-11-23 18:34:15 -0800305 bio_put(bio);
Christoph Hellwig38f8baa2016-03-11 17:34:51 +0100306 return parent;
307}
308
309static void bio_chain_endio(struct bio *bio)
310{
311 bio_endio(__bio_chain_endio(bio));
Kent Overstreet196d38b2013-11-23 18:34:15 -0800312}
313
Mike Snitzer326e1db2015-05-22 09:14:03 -0400314/*
315 * Increment chain count for the bio. Make sure the CHAIN flag update
316 * is visible before the raised count.
317 */
318static inline void bio_inc_remaining(struct bio *bio)
319{
Jens Axboeb7c44ed2015-07-24 12:37:59 -0600320 bio_set_flag(bio, BIO_CHAIN);
Mike Snitzer326e1db2015-05-22 09:14:03 -0400321 smp_mb__before_atomic();
322 atomic_inc(&bio->__bi_remaining);
323}
324
Kent Overstreet196d38b2013-11-23 18:34:15 -0800325/**
326 * bio_chain - chain bio completions
Randy Dunlap1051a902014-04-20 16:03:31 -0700327 * @bio: the target bio
328 * @parent: the @bio's parent bio
Kent Overstreet196d38b2013-11-23 18:34:15 -0800329 *
330 * The caller won't have a bi_end_io called when @bio completes - instead,
331 * @parent's bi_end_io won't be called until both @parent and @bio have
332 * completed; the chained bio will also be freed when it completes.
333 *
334 * The caller must not set bi_private or bi_end_io in @bio.
335 */
336void bio_chain(struct bio *bio, struct bio *parent)
337{
338 BUG_ON(bio->bi_private || bio->bi_end_io);
339
340 bio->bi_private = parent;
341 bio->bi_end_io = bio_chain_endio;
Jens Axboec4cf5262015-04-17 16:15:18 -0600342 bio_inc_remaining(parent);
Kent Overstreet196d38b2013-11-23 18:34:15 -0800343}
344EXPORT_SYMBOL(bio_chain);
345
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -0700346static void bio_alloc_rescue(struct work_struct *work)
347{
348 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
349 struct bio *bio;
350
351 while (1) {
352 spin_lock(&bs->rescue_lock);
353 bio = bio_list_pop(&bs->rescue_list);
354 spin_unlock(&bs->rescue_lock);
355
356 if (!bio)
357 break;
358
359 generic_make_request(bio);
360 }
361}
362
363static void punt_bios_to_rescuer(struct bio_set *bs)
364{
365 struct bio_list punt, nopunt;
366 struct bio *bio;
367
368 /*
369 * In order to guarantee forward progress we must punt only bios that
370 * were allocated from this bio_set; otherwise, if there was a bio on
371 * there for a stacking driver higher up in the stack, processing it
372 * could require allocating bios from this bio_set, and doing that from
373 * our own rescuer would be bad.
374 *
375 * Since bio lists are singly linked, pop them all instead of trying to
376 * remove from the middle of the list:
377 */
378
379 bio_list_init(&punt);
380 bio_list_init(&nopunt);
381
382 while ((bio = bio_list_pop(current->bio_list)))
383 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
384
385 *current->bio_list = nopunt;
386
387 spin_lock(&bs->rescue_lock);
388 bio_list_merge(&bs->rescue_list, &punt);
389 spin_unlock(&bs->rescue_lock);
390
391 queue_work(bs->rescue_workqueue, &bs->rescue_work);
392}
393
Kent Overstreetf44b48c2012-09-06 15:34:58 -0700394/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 * bio_alloc_bioset - allocate a bio for I/O
396 * @gfp_mask: the GFP_ mask given to the slab allocator
397 * @nr_iovecs: number of iovecs to pre-allocate
Jaak Ristiojadb18efa2010-01-15 12:05:07 +0200398 * @bs: the bio_set to allocate from.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 *
400 * Description:
Kent Overstreet3f86a822012-09-06 15:35:01 -0700401 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
402 * backed by the @bs's mempool.
403 *
Mel Gormand0164ad2015-11-06 16:28:21 -0800404 * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will
405 * always be able to allocate a bio. This is due to the mempool guarantees.
406 * To make this work, callers must never allocate more than 1 bio at a time
407 * from this pool. Callers that need to allocate more than 1 bio must always
408 * submit the previously allocated bio for IO before attempting to allocate
409 * a new one. Failure to do so can cause deadlocks under memory pressure.
Kent Overstreet3f86a822012-09-06 15:35:01 -0700410 *
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -0700411 * Note that when running under generic_make_request() (i.e. any block
412 * driver), bios are not submitted until after you return - see the code in
413 * generic_make_request() that converts recursion into iteration, to prevent
414 * stack overflows.
415 *
416 * This would normally mean allocating multiple bios under
417 * generic_make_request() would be susceptible to deadlocks, but we have
418 * deadlock avoidance code that resubmits any blocked bios from a rescuer
419 * thread.
420 *
421 * However, we do not guarantee forward progress for allocations from other
422 * mempools. Doing multiple allocations from the same mempool under
423 * generic_make_request() should be avoided - instead, use bio_set's front_pad
424 * for per bio allocations.
425 *
Kent Overstreet3f86a822012-09-06 15:35:01 -0700426 * RETURNS:
427 * Pointer to new bio on success, NULL on failure.
428 */
Al Virodd0fc662005-10-07 07:46:04 +0100429struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430{
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -0700431 gfp_t saved_gfp = gfp_mask;
Kent Overstreet3f86a822012-09-06 15:35:01 -0700432 unsigned front_pad;
433 unsigned inline_vecs;
Tejun Heo451a9eb2009-04-15 19:50:51 +0200434 unsigned long idx = BIO_POOL_NONE;
Ingo Molnar34053972009-02-21 11:16:36 +0100435 struct bio_vec *bvl = NULL;
Tejun Heo451a9eb2009-04-15 19:50:51 +0200436 struct bio *bio;
437 void *p;
Jens Axboe0a0d96b2008-09-11 13:17:37 +0200438
Kent Overstreet3f86a822012-09-06 15:35:01 -0700439 if (!bs) {
440 if (nr_iovecs > UIO_MAXIOV)
441 return NULL;
442
443 p = kmalloc(sizeof(struct bio) +
444 nr_iovecs * sizeof(struct bio_vec),
445 gfp_mask);
446 front_pad = 0;
447 inline_vecs = nr_iovecs;
448 } else {
Junichi Nomurad8f429e2014-10-03 17:27:12 -0400449 /* should not use nobvec bioset for nr_iovecs > 0 */
450 if (WARN_ON_ONCE(!bs->bvec_pool && nr_iovecs > 0))
451 return NULL;
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -0700452 /*
453 * generic_make_request() converts recursion to iteration; this
454 * means if we're running beneath it, any bios we allocate and
455 * submit will not be submitted (and thus freed) until after we
456 * return.
457 *
458 * This exposes us to a potential deadlock if we allocate
459 * multiple bios from the same bio_set() while running
460 * underneath generic_make_request(). If we were to allocate
461 * multiple bios (say a stacking block driver that was splitting
462 * bios), we would deadlock if we exhausted the mempool's
463 * reserve.
464 *
465 * We solve this, and guarantee forward progress, with a rescuer
466 * workqueue per bio_set. If we go to allocate and there are
467 * bios on current->bio_list, we first try the allocation
Mel Gormand0164ad2015-11-06 16:28:21 -0800468 * without __GFP_DIRECT_RECLAIM; if that fails, we punt those
469 * bios we would be blocking to the rescuer workqueue before
470 * we retry with the original gfp_flags.
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -0700471 */
472
473 if (current->bio_list && !bio_list_empty(current->bio_list))
Mel Gormand0164ad2015-11-06 16:28:21 -0800474 gfp_mask &= ~__GFP_DIRECT_RECLAIM;
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -0700475
Kent Overstreet3f86a822012-09-06 15:35:01 -0700476 p = mempool_alloc(bs->bio_pool, gfp_mask);
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -0700477 if (!p && gfp_mask != saved_gfp) {
478 punt_bios_to_rescuer(bs);
479 gfp_mask = saved_gfp;
480 p = mempool_alloc(bs->bio_pool, gfp_mask);
481 }
482
Kent Overstreet3f86a822012-09-06 15:35:01 -0700483 front_pad = bs->front_pad;
484 inline_vecs = BIO_INLINE_VECS;
485 }
486
Tejun Heo451a9eb2009-04-15 19:50:51 +0200487 if (unlikely(!p))
488 return NULL;
Ingo Molnar34053972009-02-21 11:16:36 +0100489
Kent Overstreet3f86a822012-09-06 15:35:01 -0700490 bio = p + front_pad;
Ingo Molnar34053972009-02-21 11:16:36 +0100491 bio_init(bio);
492
Kent Overstreet3f86a822012-09-06 15:35:01 -0700493 if (nr_iovecs > inline_vecs) {
Kent Overstreet9f060e22012-10-12 15:29:33 -0700494 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -0700495 if (!bvl && gfp_mask != saved_gfp) {
496 punt_bios_to_rescuer(bs);
497 gfp_mask = saved_gfp;
Kent Overstreet9f060e22012-10-12 15:29:33 -0700498 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -0700499 }
500
Ingo Molnar34053972009-02-21 11:16:36 +0100501 if (unlikely(!bvl))
502 goto err_free;
Kent Overstreeta38352e2012-05-25 13:03:11 -0700503
Jens Axboeb7c44ed2015-07-24 12:37:59 -0600504 bio_set_flag(bio, BIO_OWNS_VEC);
Kent Overstreet3f86a822012-09-06 15:35:01 -0700505 } else if (nr_iovecs) {
506 bvl = bio->bi_inline_vecs;
Ingo Molnar34053972009-02-21 11:16:36 +0100507 }
Kent Overstreet3f86a822012-09-06 15:35:01 -0700508
509 bio->bi_pool = bs;
Ingo Molnar34053972009-02-21 11:16:36 +0100510 bio->bi_flags |= idx << BIO_POOL_OFFSET;
511 bio->bi_max_vecs = nr_iovecs;
Ingo Molnar34053972009-02-21 11:16:36 +0100512 bio->bi_io_vec = bvl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 return bio;
Ingo Molnar34053972009-02-21 11:16:36 +0100514
515err_free:
Tejun Heo451a9eb2009-04-15 19:50:51 +0200516 mempool_free(p, bs->bio_pool);
Ingo Molnar34053972009-02-21 11:16:36 +0100517 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518}
H Hartley Sweetena112a712009-09-26 16:19:21 +0200519EXPORT_SYMBOL(bio_alloc_bioset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521void zero_fill_bio(struct bio *bio)
522{
523 unsigned long flags;
Kent Overstreet79886132013-11-23 17:19:00 -0800524 struct bio_vec bv;
525 struct bvec_iter iter;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526
Kent Overstreet79886132013-11-23 17:19:00 -0800527 bio_for_each_segment(bv, bio, iter) {
528 char *data = bvec_kmap_irq(&bv, &flags);
529 memset(data, 0, bv.bv_len);
530 flush_dcache_page(bv.bv_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 bvec_kunmap_irq(data, &flags);
532 }
533}
534EXPORT_SYMBOL(zero_fill_bio);
535
536/**
537 * bio_put - release a reference to a bio
538 * @bio: bio to release reference to
539 *
540 * Description:
541 * Put a reference to a &struct bio, either one you have gotten with
Alberto Bertogliad0bf112009-11-02 11:39:22 +0100542 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 **/
544void bio_put(struct bio *bio)
545{
Jens Axboedac56212015-04-17 16:23:59 -0600546 if (!bio_flagged(bio, BIO_REFFED))
Kent Overstreet4254bba2012-09-06 15:35:00 -0700547 bio_free(bio);
Jens Axboedac56212015-04-17 16:23:59 -0600548 else {
549 BIO_BUG_ON(!atomic_read(&bio->__bi_cnt));
550
551 /*
552 * last put frees it
553 */
554 if (atomic_dec_and_test(&bio->__bi_cnt))
555 bio_free(bio);
556 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557}
H Hartley Sweetena112a712009-09-26 16:19:21 +0200558EXPORT_SYMBOL(bio_put);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559
Jens Axboe165125e2007-07-24 09:28:11 +0200560inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561{
562 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
563 blk_recount_segments(q, bio);
564
565 return bio->bi_phys_segments;
566}
H Hartley Sweetena112a712009-09-26 16:19:21 +0200567EXPORT_SYMBOL(bio_phys_segments);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569/**
Kent Overstreet59d276f2013-11-23 18:19:27 -0800570 * __bio_clone_fast - clone a bio that shares the original bio's biovec
571 * @bio: destination bio
572 * @bio_src: bio to clone
573 *
574 * Clone a &bio. Caller will own the returned bio, but not
575 * the actual data it points to. Reference count of returned
576 * bio will be one.
577 *
578 * Caller must ensure that @bio_src is not freed before @bio.
579 */
580void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
581{
582 BUG_ON(bio->bi_pool && BIO_POOL_IDX(bio) != BIO_POOL_NONE);
583
584 /*
585 * most users will be overriding ->bi_bdev with a new target,
586 * so we don't set nor calculate new physical/hw segment counts here
587 */
588 bio->bi_bdev = bio_src->bi_bdev;
Jens Axboeb7c44ed2015-07-24 12:37:59 -0600589 bio_set_flag(bio, BIO_CLONED);
Kent Overstreet59d276f2013-11-23 18:19:27 -0800590 bio->bi_rw = bio_src->bi_rw;
591 bio->bi_iter = bio_src->bi_iter;
592 bio->bi_io_vec = bio_src->bi_io_vec;
593}
594EXPORT_SYMBOL(__bio_clone_fast);
595
596/**
597 * bio_clone_fast - clone a bio that shares the original bio's biovec
598 * @bio: bio to clone
599 * @gfp_mask: allocation priority
600 * @bs: bio_set to allocate from
601 *
602 * Like __bio_clone_fast, only also allocates the returned bio
603 */
604struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
605{
606 struct bio *b;
607
608 b = bio_alloc_bioset(gfp_mask, 0, bs);
609 if (!b)
610 return NULL;
611
612 __bio_clone_fast(b, bio);
613
614 if (bio_integrity(bio)) {
615 int ret;
616
617 ret = bio_integrity_clone(b, bio, gfp_mask);
618
619 if (ret < 0) {
620 bio_put(b);
621 return NULL;
622 }
623 }
624
625 return b;
626}
627EXPORT_SYMBOL(bio_clone_fast);
628
629/**
Kent Overstreetbdb53202013-11-23 17:26:46 -0800630 * bio_clone_bioset - clone a bio
631 * @bio_src: bio to clone
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 * @gfp_mask: allocation priority
Kent Overstreetbf800ef2012-09-06 15:35:02 -0700633 * @bs: bio_set to allocate from
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 *
Kent Overstreetbdb53202013-11-23 17:26:46 -0800635 * Clone bio. Caller will own the returned bio, but not the actual data it
636 * points to. Reference count of returned bio will be one.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 */
Kent Overstreetbdb53202013-11-23 17:26:46 -0800638struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
Kent Overstreetbf800ef2012-09-06 15:35:02 -0700639 struct bio_set *bs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640{
Kent Overstreetbdb53202013-11-23 17:26:46 -0800641 struct bvec_iter iter;
642 struct bio_vec bv;
643 struct bio *bio;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644
Kent Overstreetbdb53202013-11-23 17:26:46 -0800645 /*
646 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
647 * bio_src->bi_io_vec to bio->bi_io_vec.
648 *
649 * We can't do that anymore, because:
650 *
651 * - The point of cloning the biovec is to produce a bio with a biovec
652 * the caller can modify: bi_idx and bi_bvec_done should be 0.
653 *
654 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if
655 * we tried to clone the whole thing bio_alloc_bioset() would fail.
656 * But the clone should succeed as long as the number of biovecs we
657 * actually need to allocate is fewer than BIO_MAX_PAGES.
658 *
659 * - Lastly, bi_vcnt should not be looked at or relied upon by code
660 * that does not own the bio - reason being drivers don't use it for
661 * iterating over the biovec anymore, so expecting it to be kept up
662 * to date (i.e. for clones that share the parent biovec) is just
663 * asking for trouble and would force extra work on
664 * __bio_clone_fast() anyways.
665 */
666
Kent Overstreet8423ae32014-02-10 17:45:50 -0800667 bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
Kent Overstreetbdb53202013-11-23 17:26:46 -0800668 if (!bio)
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200669 return NULL;
670
Kent Overstreetbdb53202013-11-23 17:26:46 -0800671 bio->bi_bdev = bio_src->bi_bdev;
672 bio->bi_rw = bio_src->bi_rw;
673 bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
674 bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200675
Kent Overstreet8423ae32014-02-10 17:45:50 -0800676 if (bio->bi_rw & REQ_DISCARD)
677 goto integrity_clone;
678
679 if (bio->bi_rw & REQ_WRITE_SAME) {
680 bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
681 goto integrity_clone;
682 }
683
Kent Overstreetbdb53202013-11-23 17:26:46 -0800684 bio_for_each_segment(bv, bio_src, iter)
685 bio->bi_io_vec[bio->bi_vcnt++] = bv;
686
Kent Overstreet8423ae32014-02-10 17:45:50 -0800687integrity_clone:
Kent Overstreetbdb53202013-11-23 17:26:46 -0800688 if (bio_integrity(bio_src)) {
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200689 int ret;
690
Kent Overstreetbdb53202013-11-23 17:26:46 -0800691 ret = bio_integrity_clone(bio, bio_src, gfp_mask);
Li Zefan059ea332009-03-09 10:42:45 +0100692 if (ret < 0) {
Kent Overstreetbdb53202013-11-23 17:26:46 -0800693 bio_put(bio);
Martin K. Petersen7ba1ba12008-06-30 20:04:41 +0200694 return NULL;
Li Zefan059ea332009-03-09 10:42:45 +0100695 }
Peter Osterlund36763472005-09-06 15:16:42 -0700696 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697
Kent Overstreetbdb53202013-11-23 17:26:46 -0800698 return bio;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699}
Kent Overstreetbf800ef2012-09-06 15:35:02 -0700700EXPORT_SYMBOL(bio_clone_bioset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701
702/**
Kent Overstreetc66a14d2013-11-23 22:30:22 -0800703 * bio_add_pc_page - attempt to add page to bio
704 * @q: the target queue
705 * @bio: destination bio
706 * @page: page to add
707 * @len: vec entry length
708 * @offset: vec entry offset
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 *
Kent Overstreetc66a14d2013-11-23 22:30:22 -0800710 * Attempt to add a page to the bio_vec maplist. This can fail for a
711 * number of reasons, such as the bio being full or target block device
712 * limitations. The target block device must allow bio's up to PAGE_SIZE,
713 * so it is always possible to add a single page to an empty bio.
714 *
715 * This should only be used by REQ_PC bios.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 */
Kent Overstreetc66a14d2013-11-23 22:30:22 -0800717int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
718 *page, unsigned int len, unsigned int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719{
720 int retried_segments = 0;
721 struct bio_vec *bvec;
722
723 /*
724 * cloned bio must not modify vec list
725 */
726 if (unlikely(bio_flagged(bio, BIO_CLONED)))
727 return 0;
728
Kent Overstreetc66a14d2013-11-23 22:30:22 -0800729 if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 return 0;
731
Jens Axboe80cfd542006-01-06 09:43:28 +0100732 /*
733 * For filesystems with a blocksize smaller than the pagesize
734 * we will often be called with the same page as last time and
735 * a consecutive offset. Optimize this special case.
736 */
737 if (bio->bi_vcnt > 0) {
738 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
739
740 if (page == prev->bv_page &&
741 offset == prev->bv_offset + prev->bv_len) {
742 prev->bv_len += len;
Maurizio Lombardifcbf6a02014-12-10 14:16:53 -0800743 bio->bi_iter.bi_size += len;
Jens Axboe80cfd542006-01-06 09:43:28 +0100744 goto done;
745 }
Jens Axboe66cb45a2014-06-24 16:22:24 -0600746
747 /*
748 * If the queue doesn't support SG gaps and adding this
749 * offset would create a gap, disallow it.
750 */
Keith Busch03100aa2015-08-19 14:24:05 -0700751 if (bvec_gap_to_prev(q, prev, offset))
Jens Axboe66cb45a2014-06-24 16:22:24 -0600752 return 0;
Jens Axboe80cfd542006-01-06 09:43:28 +0100753 }
754
755 if (bio->bi_vcnt >= bio->bi_max_vecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 return 0;
757
758 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 * setup the new entry, we might clear it again later if we
760 * cannot add the page
761 */
762 bvec = &bio->bi_io_vec[bio->bi_vcnt];
763 bvec->bv_page = page;
764 bvec->bv_len = len;
765 bvec->bv_offset = offset;
Maurizio Lombardifcbf6a02014-12-10 14:16:53 -0800766 bio->bi_vcnt++;
767 bio->bi_phys_segments++;
768 bio->bi_iter.bi_size += len;
769
770 /*
771 * Perform a recount if the number of segments is greater
772 * than queue_max_segments(q).
773 */
774
775 while (bio->bi_phys_segments > queue_max_segments(q)) {
776
777 if (retried_segments)
778 goto failed;
779
780 retried_segments = 1;
781 blk_recount_segments(q, bio);
782 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 /* If we may be able to merge these biovecs, force a recount */
Maurizio Lombardifcbf6a02014-12-10 14:16:53 -0800785 if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
Jens Axboeb7c44ed2015-07-24 12:37:59 -0600786 bio_clear_flag(bio, BIO_SEG_VALID);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787
Jens Axboe80cfd542006-01-06 09:43:28 +0100788 done:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 return len;
Maurizio Lombardifcbf6a02014-12-10 14:16:53 -0800790
791 failed:
792 bvec->bv_page = NULL;
793 bvec->bv_len = 0;
794 bvec->bv_offset = 0;
795 bio->bi_vcnt--;
796 bio->bi_iter.bi_size -= len;
797 blk_recount_segments(q, bio);
798 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799}
H Hartley Sweetena112a712009-09-26 16:19:21 +0200800EXPORT_SYMBOL(bio_add_pc_page);
Mike Christie6e68af62005-11-11 05:30:27 -0600801
802/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 * bio_add_page - attempt to add page to bio
804 * @bio: destination bio
805 * @page: page to add
806 * @len: vec entry length
807 * @offset: vec entry offset
808 *
Kent Overstreetc66a14d2013-11-23 22:30:22 -0800809 * Attempt to add a page to the bio_vec maplist. This will only fail
810 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 */
Kent Overstreetc66a14d2013-11-23 22:30:22 -0800812int bio_add_page(struct bio *bio, struct page *page,
813 unsigned int len, unsigned int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814{
Kent Overstreetc66a14d2013-11-23 22:30:22 -0800815 struct bio_vec *bv;
Jens Axboe762380a2014-06-05 13:38:39 -0600816
Kent Overstreetc66a14d2013-11-23 22:30:22 -0800817 /*
818 * cloned bio must not modify vec list
819 */
820 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
821 return 0;
Jens Axboe58a49152014-06-10 12:53:56 -0600822
Kent Overstreetc66a14d2013-11-23 22:30:22 -0800823 /*
824 * For filesystems with a blocksize smaller than the pagesize
825 * we will often be called with the same page as last time and
826 * a consecutive offset. Optimize this special case.
827 */
828 if (bio->bi_vcnt > 0) {
829 bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
830
831 if (page == bv->bv_page &&
832 offset == bv->bv_offset + bv->bv_len) {
833 bv->bv_len += len;
834 goto done;
835 }
836 }
837
838 if (bio->bi_vcnt >= bio->bi_max_vecs)
839 return 0;
840
841 bv = &bio->bi_io_vec[bio->bi_vcnt];
842 bv->bv_page = page;
843 bv->bv_len = len;
844 bv->bv_offset = offset;
845
846 bio->bi_vcnt++;
847done:
848 bio->bi_iter.bi_size += len;
849 return len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850}
H Hartley Sweetena112a712009-09-26 16:19:21 +0200851EXPORT_SYMBOL(bio_add_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852
Kent Overstreet9e882242012-09-10 14:41:12 -0700853struct submit_bio_ret {
854 struct completion event;
855 int error;
856};
857
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200858static void submit_bio_wait_endio(struct bio *bio)
Kent Overstreet9e882242012-09-10 14:41:12 -0700859{
860 struct submit_bio_ret *ret = bio->bi_private;
861
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200862 ret->error = bio->bi_error;
Kent Overstreet9e882242012-09-10 14:41:12 -0700863 complete(&ret->event);
864}
865
866/**
867 * submit_bio_wait - submit a bio, and wait until it completes
868 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
869 * @bio: The &struct bio which describes the I/O
870 *
871 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
872 * bio_endio() on failure.
873 */
874int submit_bio_wait(int rw, struct bio *bio)
875{
876 struct submit_bio_ret ret;
877
878 rw |= REQ_SYNC;
879 init_completion(&ret.event);
880 bio->bi_private = &ret;
881 bio->bi_end_io = submit_bio_wait_endio;
882 submit_bio(rw, bio);
Stephane Gasparinid57d6112016-02-09 17:07:38 +0100883 wait_for_completion_io(&ret.event);
Kent Overstreet9e882242012-09-10 14:41:12 -0700884
885 return ret.error;
886}
887EXPORT_SYMBOL(submit_bio_wait);
888
Kent Overstreet054bdf62012-09-28 13:17:55 -0700889/**
890 * bio_advance - increment/complete a bio by some number of bytes
891 * @bio: bio to advance
892 * @bytes: number of bytes to complete
893 *
894 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
895 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
896 * be updated on the last bvec as well.
897 *
898 * @bio will then represent the remaining, uncompleted portion of the io.
899 */
900void bio_advance(struct bio *bio, unsigned bytes)
901{
902 if (bio_integrity(bio))
903 bio_integrity_advance(bio, bytes);
904
Kent Overstreet4550dd62013-08-07 14:26:21 -0700905 bio_advance_iter(bio, &bio->bi_iter, bytes);
Kent Overstreet054bdf62012-09-28 13:17:55 -0700906}
907EXPORT_SYMBOL(bio_advance);
908
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700909/**
Kent Overstreeta0787602012-09-10 14:03:28 -0700910 * bio_alloc_pages - allocates a single page for each bvec in a bio
911 * @bio: bio to allocate pages for
912 * @gfp_mask: flags for allocation
913 *
914 * Allocates pages up to @bio->bi_vcnt.
915 *
916 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
917 * freed.
918 */
919int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
920{
921 int i;
922 struct bio_vec *bv;
923
924 bio_for_each_segment_all(bv, bio, i) {
925 bv->bv_page = alloc_page(gfp_mask);
926 if (!bv->bv_page) {
927 while (--bv >= bio->bi_io_vec)
928 __free_page(bv->bv_page);
929 return -ENOMEM;
930 }
931 }
932
933 return 0;
934}
935EXPORT_SYMBOL(bio_alloc_pages);
936
937/**
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700938 * bio_copy_data - copy contents of data buffers from one chain of bios to
939 * another
940 * @src: source bio list
941 * @dst: destination bio list
942 *
943 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
944 * @src and @dst as linked lists of bios.
945 *
946 * Stops when it reaches the end of either @src or @dst - that is, copies
947 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
948 */
949void bio_copy_data(struct bio *dst, struct bio *src)
950{
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700951 struct bvec_iter src_iter, dst_iter;
952 struct bio_vec src_bv, dst_bv;
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700953 void *src_p, *dst_p;
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700954 unsigned bytes;
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700955
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700956 src_iter = src->bi_iter;
957 dst_iter = dst->bi_iter;
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700958
959 while (1) {
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700960 if (!src_iter.bi_size) {
961 src = src->bi_next;
962 if (!src)
963 break;
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700964
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700965 src_iter = src->bi_iter;
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700966 }
967
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700968 if (!dst_iter.bi_size) {
969 dst = dst->bi_next;
970 if (!dst)
971 break;
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700972
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700973 dst_iter = dst->bi_iter;
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700974 }
975
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700976 src_bv = bio_iter_iovec(src, src_iter);
977 dst_bv = bio_iter_iovec(dst, dst_iter);
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700978
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700979 bytes = min(src_bv.bv_len, dst_bv.bv_len);
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700980
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700981 src_p = kmap_atomic(src_bv.bv_page);
982 dst_p = kmap_atomic(dst_bv.bv_page);
983
984 memcpy(dst_p + dst_bv.bv_offset,
985 src_p + src_bv.bv_offset,
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700986 bytes);
987
988 kunmap_atomic(dst_p);
989 kunmap_atomic(src_p);
990
Kent Overstreet1cb9dda2013-08-07 14:26:39 -0700991 bio_advance_iter(src, &src_iter, bytes);
992 bio_advance_iter(dst, &dst_iter, bytes);
Kent Overstreet16ac3d62012-09-10 13:57:51 -0700993 }
994}
995EXPORT_SYMBOL(bio_copy_data);
996
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997struct bio_map_data {
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900998 int is_our_pages;
Kent Overstreet26e49cf2015-01-18 16:16:31 +0100999 struct iov_iter iter;
1000 struct iovec iov[];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001};
1002
Fabian Frederick7410b3c2014-04-22 15:09:07 -06001003static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count,
FUJITA Tomonori76029ff2008-08-25 20:36:08 +02001004 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005{
Jens Axboef3f63c12010-10-29 11:46:56 -06001006 if (iov_count > UIO_MAXIOV)
1007 return NULL;
1008
Kent Overstreetc8db4442013-11-22 19:39:06 -08001009 return kmalloc(sizeof(struct bio_map_data) +
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001010 sizeof(struct iovec) * iov_count, gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011}
1012
Dongsu Park9124d3f2015-01-18 16:16:34 +01001013/**
1014 * bio_copy_from_iter - copy all pages from iov_iter to bio
1015 * @bio: The &struct bio which describes the I/O as destination
1016 * @iter: iov_iter as source
1017 *
1018 * Copy all pages from iov_iter to bio.
1019 * Returns 0 on success, or error on failure.
1020 */
1021static int bio_copy_from_iter(struct bio *bio, struct iov_iter iter)
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001022{
Dongsu Park9124d3f2015-01-18 16:16:34 +01001023 int i;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001024 struct bio_vec *bvec;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001025
Kent Overstreetd74c6d52013-02-06 12:23:11 -08001026 bio_for_each_segment_all(bvec, bio, i) {
Dongsu Park9124d3f2015-01-18 16:16:34 +01001027 ssize_t ret;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001028
Dongsu Park9124d3f2015-01-18 16:16:34 +01001029 ret = copy_page_from_iter(bvec->bv_page,
1030 bvec->bv_offset,
1031 bvec->bv_len,
1032 &iter);
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001033
Dongsu Park9124d3f2015-01-18 16:16:34 +01001034 if (!iov_iter_count(&iter))
1035 break;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001036
Dongsu Park9124d3f2015-01-18 16:16:34 +01001037 if (ret < bvec->bv_len)
1038 return -EFAULT;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001039 }
1040
Dongsu Park9124d3f2015-01-18 16:16:34 +01001041 return 0;
1042}
1043
1044/**
1045 * bio_copy_to_iter - copy all pages from bio to iov_iter
1046 * @bio: The &struct bio which describes the I/O as source
1047 * @iter: iov_iter as destination
1048 *
1049 * Copy all pages from bio to iov_iter.
1050 * Returns 0 on success, or error on failure.
1051 */
1052static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
1053{
1054 int i;
1055 struct bio_vec *bvec;
1056
1057 bio_for_each_segment_all(bvec, bio, i) {
1058 ssize_t ret;
1059
1060 ret = copy_page_to_iter(bvec->bv_page,
1061 bvec->bv_offset,
1062 bvec->bv_len,
1063 &iter);
1064
1065 if (!iov_iter_count(&iter))
1066 break;
1067
1068 if (ret < bvec->bv_len)
1069 return -EFAULT;
1070 }
1071
1072 return 0;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001073}
1074
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001075static void bio_free_pages(struct bio *bio)
1076{
1077 struct bio_vec *bvec;
1078 int i;
1079
1080 bio_for_each_segment_all(bvec, bio, i)
1081 __free_page(bvec->bv_page);
1082}
1083
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084/**
1085 * bio_uncopy_user - finish previously mapped bio
1086 * @bio: bio being terminated
1087 *
Christoph Hellwigddad8dd2015-01-18 16:16:29 +01001088 * Free pages allocated from bio_copy_user_iov() and write back data
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 * to user space in case of a read.
1090 */
1091int bio_uncopy_user(struct bio *bio)
1092{
1093 struct bio_map_data *bmd = bio->bi_private;
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001094 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095
Roland Dreier35dc2482013-08-05 17:55:01 -07001096 if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
1097 /*
1098 * if we're in a workqueue, the request is orphaned, so
Hannes Reinecke2d99b552016-02-12 09:39:15 +01001099 * don't copy into a random user address space, just free
1100 * and return -EINTR so user space doesn't expect any data.
Roland Dreier35dc2482013-08-05 17:55:01 -07001101 */
Hannes Reinecke2d99b552016-02-12 09:39:15 +01001102 if (!current->mm)
1103 ret = -EINTR;
1104 else if (bio_data_dir(bio) == READ)
Dongsu Park9124d3f2015-01-18 16:16:34 +01001105 ret = bio_copy_to_iter(bio, bmd->iter);
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001106 if (bmd->is_our_pages)
1107 bio_free_pages(bio);
Roland Dreier35dc2482013-08-05 17:55:01 -07001108 }
Kent Overstreetc8db4442013-11-22 19:39:06 -08001109 kfree(bmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110 bio_put(bio);
1111 return ret;
1112}
H Hartley Sweetena112a712009-09-26 16:19:21 +02001113EXPORT_SYMBOL(bio_uncopy_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114
1115/**
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001116 * bio_copy_user_iov - copy user data to bio
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001117 * @q: destination block queue
1118 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1119 * @iter: iovec iterator
1120 * @gfp_mask: memory allocation flags
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 *
1122 * Prepares and returns a bio for indirect user io, bouncing data
1123 * to/from kernel pages as necessary. Must be paired with
1124 * call bio_uncopy_user() on io completion.
1125 */
FUJITA Tomonori152e2832008-08-28 16:17:06 +09001126struct bio *bio_copy_user_iov(struct request_queue *q,
1127 struct rq_map_data *map_data,
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001128 const struct iov_iter *iter,
1129 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 struct bio_map_data *bmd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132 struct page *page;
1133 struct bio *bio;
1134 int i, ret;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001135 int nr_pages = 0;
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001136 unsigned int len = iter->count;
Geliang Tangbd5cece2015-11-21 17:27:31 +08001137 unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001139 for (i = 0; i < iter->nr_segs; i++) {
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001140 unsigned long uaddr;
1141 unsigned long end;
1142 unsigned long start;
1143
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001144 uaddr = (unsigned long) iter->iov[i].iov_base;
1145 end = (uaddr + iter->iov[i].iov_len + PAGE_SIZE - 1)
1146 >> PAGE_SHIFT;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001147 start = uaddr >> PAGE_SHIFT;
1148
Jens Axboecb4644c2010-11-10 14:36:25 +01001149 /*
1150 * Overflow, abort
1151 */
1152 if (end < start)
1153 return ERR_PTR(-EINVAL);
1154
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001155 nr_pages += end - start;
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001156 }
1157
FUJITA Tomonori69838722009-04-28 20:24:29 +02001158 if (offset)
1159 nr_pages++;
1160
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001161 bmd = bio_alloc_map_data(iter->nr_segs, gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 if (!bmd)
1163 return ERR_PTR(-ENOMEM);
1164
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001165 /*
1166 * We need to do a deep copy of the iov_iter including the iovecs.
1167 * The caller provided iov might point to an on-stack or otherwise
1168 * shortlived one.
1169 */
1170 bmd->is_our_pages = map_data ? 0 : 1;
1171 memcpy(bmd->iov, iter->iov, sizeof(struct iovec) * iter->nr_segs);
1172 iov_iter_init(&bmd->iter, iter->type, bmd->iov,
1173 iter->nr_segs, iter->count);
1174
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175 ret = -ENOMEM;
Tejun Heoa9e9dc22009-04-15 22:10:27 +09001176 bio = bio_kmalloc(gfp_mask, nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 if (!bio)
1178 goto out_bmd;
1179
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001180 if (iter->type & WRITE)
Christoph Hellwig7b6d91d2010-08-07 18:20:39 +02001181 bio->bi_rw |= REQ_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182
1183 ret = 0;
FUJITA Tomonori56c451f2008-12-18 14:49:37 +09001184
1185 if (map_data) {
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +09001186 nr_pages = 1 << map_data->page_order;
FUJITA Tomonori56c451f2008-12-18 14:49:37 +09001187 i = map_data->offset / PAGE_SIZE;
1188 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 while (len) {
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +09001190 unsigned int bytes = PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191
FUJITA Tomonori56c451f2008-12-18 14:49:37 +09001192 bytes -= offset;
1193
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 if (bytes > len)
1195 bytes = len;
1196
FUJITA Tomonori152e2832008-08-28 16:17:06 +09001197 if (map_data) {
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +09001198 if (i == map_data->nr_entries * nr_pages) {
FUJITA Tomonori152e2832008-08-28 16:17:06 +09001199 ret = -ENOMEM;
1200 break;
1201 }
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +09001202
1203 page = map_data->pages[i / nr_pages];
1204 page += (i % nr_pages);
1205
1206 i++;
1207 } else {
FUJITA Tomonori152e2832008-08-28 16:17:06 +09001208 page = alloc_page(q->bounce_gfp | gfp_mask);
FUJITA Tomonorie623ddb2008-12-18 14:49:36 +09001209 if (!page) {
1210 ret = -ENOMEM;
1211 break;
1212 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 }
1214
FUJITA Tomonori56c451f2008-12-18 14:49:37 +09001215 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217
1218 len -= bytes;
FUJITA Tomonori56c451f2008-12-18 14:49:37 +09001219 offset = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 }
1221
1222 if (ret)
1223 goto cleanup;
1224
1225 /*
1226 * success
1227 */
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001228 if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||
FUJITA Tomonoriecb554a2009-07-09 14:46:53 +02001229 (map_data && map_data->from_user)) {
Dongsu Park9124d3f2015-01-18 16:16:34 +01001230 ret = bio_copy_from_iter(bio, *iter);
FUJITA Tomonoric5dec1c2008-04-11 12:56:49 +02001231 if (ret)
1232 goto cleanup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233 }
1234
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001235 bio->bi_private = bmd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 return bio;
1237cleanup:
FUJITA Tomonori152e2832008-08-28 16:17:06 +09001238 if (!map_data)
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001239 bio_free_pages(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 bio_put(bio);
1241out_bmd:
Kent Overstreetc8db4442013-11-22 19:39:06 -08001242 kfree(bmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 return ERR_PTR(ret);
1244}
1245
Christoph Hellwig37f19e52015-01-18 16:16:33 +01001246/**
1247 * bio_map_user_iov - map user iovec into bio
1248 * @q: the struct request_queue for the bio
1249 * @iter: iovec iterator
1250 * @gfp_mask: memory allocation flags
1251 *
1252 * Map the user space address into a bio suitable for io to a block
1253 * device. Returns an error pointer in case of error.
1254 */
1255struct bio *bio_map_user_iov(struct request_queue *q,
1256 const struct iov_iter *iter,
1257 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258{
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001259 int j;
James Bottomley f1970ba2005-06-20 14:06:52 +02001260 int nr_pages = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 struct page **pages;
1262 struct bio *bio;
James Bottomley f1970ba2005-06-20 14:06:52 +02001263 int cur_page = 0;
1264 int ret, offset;
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001265 struct iov_iter i;
1266 struct iovec iov;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001268 iov_for_each(iov, i, *iter) {
1269 unsigned long uaddr = (unsigned long) iov.iov_base;
1270 unsigned long len = iov.iov_len;
James Bottomley f1970ba2005-06-20 14:06:52 +02001271 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1272 unsigned long start = uaddr >> PAGE_SHIFT;
1273
Jens Axboecb4644c2010-11-10 14:36:25 +01001274 /*
1275 * Overflow, abort
1276 */
1277 if (end < start)
1278 return ERR_PTR(-EINVAL);
1279
James Bottomley f1970ba2005-06-20 14:06:52 +02001280 nr_pages += end - start;
1281 /*
Mike Christiead2d7222006-12-01 10:40:20 +01001282 * buffer must be aligned to at least hardsector size for now
James Bottomley f1970ba2005-06-20 14:06:52 +02001283 */
Mike Christiead2d7222006-12-01 10:40:20 +01001284 if (uaddr & queue_dma_alignment(q))
James Bottomley f1970ba2005-06-20 14:06:52 +02001285 return ERR_PTR(-EINVAL);
1286 }
1287
1288 if (!nr_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001289 return ERR_PTR(-EINVAL);
1290
Tejun Heoa9e9dc22009-04-15 22:10:27 +09001291 bio = bio_kmalloc(gfp_mask, nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 if (!bio)
1293 return ERR_PTR(-ENOMEM);
1294
1295 ret = -ENOMEM;
FUJITA Tomonoria3bce902008-08-28 16:17:05 +09001296 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 if (!pages)
1298 goto out;
1299
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001300 iov_for_each(iov, i, *iter) {
1301 unsigned long uaddr = (unsigned long) iov.iov_base;
1302 unsigned long len = iov.iov_len;
James Bottomley f1970ba2005-06-20 14:06:52 +02001303 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1304 unsigned long start = uaddr >> PAGE_SHIFT;
1305 const int local_nr_pages = end - start;
1306 const int page_limit = cur_page + local_nr_pages;
Jens Axboecb4644c2010-11-10 14:36:25 +01001307
Nick Pigginf5dd33c2008-07-25 19:45:25 -07001308 ret = get_user_pages_fast(uaddr, local_nr_pages,
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001309 (iter->type & WRITE) != WRITE,
1310 &pages[cur_page]);
Jens Axboe99172152006-06-16 13:02:29 +02001311 if (ret < local_nr_pages) {
1312 ret = -EFAULT;
James Bottomley f1970ba2005-06-20 14:06:52 +02001313 goto out_unmap;
Jens Axboe99172152006-06-16 13:02:29 +02001314 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315
Geliang Tangbd5cece2015-11-21 17:27:31 +08001316 offset = offset_in_page(uaddr);
James Bottomley f1970ba2005-06-20 14:06:52 +02001317 for (j = cur_page; j < page_limit; j++) {
1318 unsigned int bytes = PAGE_SIZE - offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319
James Bottomley f1970ba2005-06-20 14:06:52 +02001320 if (len <= 0)
1321 break;
1322
1323 if (bytes > len)
1324 bytes = len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325
James Bottomley f1970ba2005-06-20 14:06:52 +02001326 /*
1327 * sorry...
1328 */
Mike Christiedefd94b2005-12-05 02:37:06 -06001329 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
1330 bytes)
James Bottomley f1970ba2005-06-20 14:06:52 +02001331 break;
1332
1333 len -= bytes;
1334 offset = 0;
1335 }
1336
1337 cur_page = j;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 /*
James Bottomley f1970ba2005-06-20 14:06:52 +02001339 * release the pages we didn't map into the bio, if any
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 */
James Bottomley f1970ba2005-06-20 14:06:52 +02001341 while (j < page_limit)
1342 page_cache_release(pages[j++]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343 }
1344
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345 kfree(pages);
1346
1347 /*
1348 * set data direction, and check if mapped pages need bouncing
1349 */
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001350 if (iter->type & WRITE)
Christoph Hellwig7b6d91d2010-08-07 18:20:39 +02001351 bio->bi_rw |= REQ_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352
Jens Axboeb7c44ed2015-07-24 12:37:59 -06001353 bio_set_flag(bio, BIO_USER_MAPPED);
Christoph Hellwig37f19e52015-01-18 16:16:33 +01001354
1355 /*
1356 * subtle -- if __bio_map_user() ended up bouncing a bio,
1357 * it would normally disappear when its bi_end_io is run.
1358 * however, we need it for the unmap, so grab an extra
1359 * reference to it
1360 */
1361 bio_get(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362 return bio;
James Bottomley f1970ba2005-06-20 14:06:52 +02001363
1364 out_unmap:
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001365 for (j = 0; j < nr_pages; j++) {
1366 if (!pages[j])
James Bottomley f1970ba2005-06-20 14:06:52 +02001367 break;
Kent Overstreet26e49cf2015-01-18 16:16:31 +01001368 page_cache_release(pages[j]);
James Bottomley f1970ba2005-06-20 14:06:52 +02001369 }
1370 out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371 kfree(pages);
1372 bio_put(bio);
1373 return ERR_PTR(ret);
1374}
1375
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376static void __bio_unmap_user(struct bio *bio)
1377{
1378 struct bio_vec *bvec;
1379 int i;
1380
1381 /*
1382 * make sure we dirty pages we wrote to
1383 */
Kent Overstreetd74c6d52013-02-06 12:23:11 -08001384 bio_for_each_segment_all(bvec, bio, i) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385 if (bio_data_dir(bio) == READ)
1386 set_page_dirty_lock(bvec->bv_page);
1387
1388 page_cache_release(bvec->bv_page);
1389 }
1390
1391 bio_put(bio);
1392}
1393
1394/**
1395 * bio_unmap_user - unmap a bio
1396 * @bio: the bio being unmapped
1397 *
1398 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1399 * a process context.
1400 *
1401 * bio_unmap_user() may sleep.
1402 */
1403void bio_unmap_user(struct bio *bio)
1404{
1405 __bio_unmap_user(bio);
1406 bio_put(bio);
1407}
H Hartley Sweetena112a712009-09-26 16:19:21 +02001408EXPORT_SYMBOL(bio_unmap_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001409
Christoph Hellwig4246a0b2015-07-20 15:29:37 +02001410static void bio_map_kern_endio(struct bio *bio)
Jens Axboeb8238252005-06-20 14:05:27 +02001411{
Jens Axboeb8238252005-06-20 14:05:27 +02001412 bio_put(bio);
Jens Axboeb8238252005-06-20 14:05:27 +02001413}
1414
Christoph Hellwig75c72b82015-01-18 16:16:32 +01001415/**
1416 * bio_map_kern - map kernel address into bio
1417 * @q: the struct request_queue for the bio
1418 * @data: pointer to buffer to map
1419 * @len: length in bytes
1420 * @gfp_mask: allocation flags for bio allocation
1421 *
1422 * Map the kernel address into a bio suitable for io to a block
1423 * device. Returns an error pointer in case of error.
1424 */
1425struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1426 gfp_t gfp_mask)
Mike Christie df46b9a2005-06-20 14:04:44 +02001427{
1428 unsigned long kaddr = (unsigned long)data;
1429 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1430 unsigned long start = kaddr >> PAGE_SHIFT;
1431 const int nr_pages = end - start;
1432 int offset, i;
1433 struct bio *bio;
1434
Tejun Heoa9e9dc22009-04-15 22:10:27 +09001435 bio = bio_kmalloc(gfp_mask, nr_pages);
Mike Christie df46b9a2005-06-20 14:04:44 +02001436 if (!bio)
1437 return ERR_PTR(-ENOMEM);
1438
1439 offset = offset_in_page(kaddr);
1440 for (i = 0; i < nr_pages; i++) {
1441 unsigned int bytes = PAGE_SIZE - offset;
1442
1443 if (len <= 0)
1444 break;
1445
1446 if (bytes > len)
1447 bytes = len;
1448
Mike Christiedefd94b2005-12-05 02:37:06 -06001449 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
Christoph Hellwig75c72b82015-01-18 16:16:32 +01001450 offset) < bytes) {
1451 /* we don't support partial mappings */
1452 bio_put(bio);
1453 return ERR_PTR(-EINVAL);
1454 }
Mike Christie df46b9a2005-06-20 14:04:44 +02001455
1456 data += bytes;
1457 len -= bytes;
1458 offset = 0;
1459 }
1460
Jens Axboeb8238252005-06-20 14:05:27 +02001461 bio->bi_end_io = bio_map_kern_endio;
Mike Christie df46b9a2005-06-20 14:04:44 +02001462 return bio;
1463}
H Hartley Sweetena112a712009-09-26 16:19:21 +02001464EXPORT_SYMBOL(bio_map_kern);
Mike Christie df46b9a2005-06-20 14:04:44 +02001465
Christoph Hellwig4246a0b2015-07-20 15:29:37 +02001466static void bio_copy_kern_endio(struct bio *bio)
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001467{
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001468 bio_free_pages(bio);
1469 bio_put(bio);
1470}
1471
Christoph Hellwig4246a0b2015-07-20 15:29:37 +02001472static void bio_copy_kern_endio_read(struct bio *bio)
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001473{
Christoph Hellwig42d26832015-01-18 16:16:28 +01001474 char *p = bio->bi_private;
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001475 struct bio_vec *bvec;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001476 int i;
1477
Kent Overstreetd74c6d52013-02-06 12:23:11 -08001478 bio_for_each_segment_all(bvec, bio, i) {
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001479 memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
Kent Overstreetc8db4442013-11-22 19:39:06 -08001480 p += bvec->bv_len;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001481 }
1482
Christoph Hellwig4246a0b2015-07-20 15:29:37 +02001483 bio_copy_kern_endio(bio);
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001484}
1485
1486/**
1487 * bio_copy_kern - copy kernel address into bio
1488 * @q: the struct request_queue for the bio
1489 * @data: pointer to buffer to copy
1490 * @len: length in bytes
1491 * @gfp_mask: allocation flags for bio and page allocation
Randy Dunlapffee0252008-04-30 09:08:54 +02001492 * @reading: data direction is READ
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001493 *
1494 * copy the kernel address into a bio suitable for io to a block
1495 * device. Returns an error pointer in case of error.
1496 */
1497struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1498 gfp_t gfp_mask, int reading)
1499{
Christoph Hellwig42d26832015-01-18 16:16:28 +01001500 unsigned long kaddr = (unsigned long)data;
1501 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1502 unsigned long start = kaddr >> PAGE_SHIFT;
Christoph Hellwig42d26832015-01-18 16:16:28 +01001503 struct bio *bio;
1504 void *p = data;
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001505 int nr_pages = 0;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001506
Christoph Hellwig42d26832015-01-18 16:16:28 +01001507 /*
1508 * Overflow, abort
1509 */
1510 if (end < start)
1511 return ERR_PTR(-EINVAL);
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001512
Christoph Hellwig42d26832015-01-18 16:16:28 +01001513 nr_pages = end - start;
1514 bio = bio_kmalloc(gfp_mask, nr_pages);
1515 if (!bio)
1516 return ERR_PTR(-ENOMEM);
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001517
Christoph Hellwig42d26832015-01-18 16:16:28 +01001518 while (len) {
1519 struct page *page;
1520 unsigned int bytes = PAGE_SIZE;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001521
Christoph Hellwig42d26832015-01-18 16:16:28 +01001522 if (bytes > len)
1523 bytes = len;
1524
1525 page = alloc_page(q->bounce_gfp | gfp_mask);
1526 if (!page)
1527 goto cleanup;
1528
1529 if (!reading)
1530 memcpy(page_address(page), p, bytes);
1531
1532 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
1533 break;
1534
1535 len -= bytes;
1536 p += bytes;
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001537 }
1538
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001539 if (reading) {
1540 bio->bi_end_io = bio_copy_kern_endio_read;
1541 bio->bi_private = data;
1542 } else {
1543 bio->bi_end_io = bio_copy_kern_endio;
Christoph Hellwig42d26832015-01-18 16:16:28 +01001544 bio->bi_rw |= REQ_WRITE;
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001545 }
FUJITA Tomonori76029ff2008-08-25 20:36:08 +02001546
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001547 return bio;
Christoph Hellwig42d26832015-01-18 16:16:28 +01001548
1549cleanup:
Christoph Hellwig1dfa0f62015-01-18 16:16:30 +01001550 bio_free_pages(bio);
Christoph Hellwig42d26832015-01-18 16:16:28 +01001551 bio_put(bio);
1552 return ERR_PTR(-ENOMEM);
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001553}
H Hartley Sweetena112a712009-09-26 16:19:21 +02001554EXPORT_SYMBOL(bio_copy_kern);
FUJITA Tomonori68154e92008-04-25 12:47:50 +02001555
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556/*
1557 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1558 * for performing direct-IO in BIOs.
1559 *
1560 * The problem is that we cannot run set_page_dirty() from interrupt context
1561 * because the required locks are not interrupt-safe. So what we can do is to
1562 * mark the pages dirty _before_ performing IO. And in interrupt context,
1563 * check that the pages are still dirty. If so, fine. If not, redirty them
1564 * in process context.
1565 *
1566 * We special-case compound pages here: normally this means reads into hugetlb
1567 * pages. The logic in here doesn't really work right for compound pages
1568 * because the VM does not uniformly chase down the head page in all cases.
1569 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1570 * handle them at all. So we skip compound pages here at an early stage.
1571 *
1572 * Note that this code is very hard to test under normal circumstances because
1573 * direct-io pins the pages with get_user_pages(). This makes
1574 * is_page_cache_freeable return false, and the VM will not clean the pages.
Artem Bityutskiy0d5c3eb2012-07-25 18:12:08 +03001575 * But other code (eg, flusher threads) could clean the pages if they are mapped
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576 * pagecache.
1577 *
1578 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1579 * deferred bio dirtying paths.
1580 */
1581
1582/*
1583 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1584 */
1585void bio_set_pages_dirty(struct bio *bio)
1586{
Kent Overstreetcb34e052012-09-05 15:22:02 -07001587 struct bio_vec *bvec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588 int i;
1589
Kent Overstreetcb34e052012-09-05 15:22:02 -07001590 bio_for_each_segment_all(bvec, bio, i) {
1591 struct page *page = bvec->bv_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001592
1593 if (page && !PageCompound(page))
1594 set_page_dirty_lock(page);
1595 }
1596}
1597
Adrian Bunk86b6c7a2008-02-18 13:48:32 +01001598static void bio_release_pages(struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001599{
Kent Overstreetcb34e052012-09-05 15:22:02 -07001600 struct bio_vec *bvec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001601 int i;
1602
Kent Overstreetcb34e052012-09-05 15:22:02 -07001603 bio_for_each_segment_all(bvec, bio, i) {
1604 struct page *page = bvec->bv_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001605
1606 if (page)
1607 put_page(page);
1608 }
1609}
1610
1611/*
1612 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1613 * If they are, then fine. If, however, some pages are clean then they must
1614 * have been written out during the direct-IO read. So we take another ref on
1615 * the BIO and the offending pages and re-dirty the pages in process context.
1616 *
1617 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1618 * here on. It will run one page_cache_release() against each page and will
1619 * run one bio_put() against the BIO.
1620 */
1621
David Howells65f27f32006-11-22 14:55:48 +00001622static void bio_dirty_fn(struct work_struct *work);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001623
David Howells65f27f32006-11-22 14:55:48 +00001624static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001625static DEFINE_SPINLOCK(bio_dirty_lock);
1626static struct bio *bio_dirty_list;
1627
1628/*
1629 * This runs in process context
1630 */
David Howells65f27f32006-11-22 14:55:48 +00001631static void bio_dirty_fn(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001632{
1633 unsigned long flags;
1634 struct bio *bio;
1635
1636 spin_lock_irqsave(&bio_dirty_lock, flags);
1637 bio = bio_dirty_list;
1638 bio_dirty_list = NULL;
1639 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1640
1641 while (bio) {
1642 struct bio *next = bio->bi_private;
1643
1644 bio_set_pages_dirty(bio);
1645 bio_release_pages(bio);
1646 bio_put(bio);
1647 bio = next;
1648 }
1649}
1650
1651void bio_check_pages_dirty(struct bio *bio)
1652{
Kent Overstreetcb34e052012-09-05 15:22:02 -07001653 struct bio_vec *bvec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654 int nr_clean_pages = 0;
1655 int i;
1656
Kent Overstreetcb34e052012-09-05 15:22:02 -07001657 bio_for_each_segment_all(bvec, bio, i) {
1658 struct page *page = bvec->bv_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659
1660 if (PageDirty(page) || PageCompound(page)) {
1661 page_cache_release(page);
Kent Overstreetcb34e052012-09-05 15:22:02 -07001662 bvec->bv_page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663 } else {
1664 nr_clean_pages++;
1665 }
1666 }
1667
1668 if (nr_clean_pages) {
1669 unsigned long flags;
1670
1671 spin_lock_irqsave(&bio_dirty_lock, flags);
1672 bio->bi_private = bio_dirty_list;
1673 bio_dirty_list = bio;
1674 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1675 schedule_work(&bio_dirty_work);
1676 } else {
1677 bio_put(bio);
1678 }
1679}
1680
Gu Zheng394ffa52014-11-24 11:05:22 +08001681void generic_start_io_acct(int rw, unsigned long sectors,
1682 struct hd_struct *part)
1683{
1684 int cpu = part_stat_lock();
1685
1686 part_round_stats(cpu, part);
1687 part_stat_inc(cpu, part, ios[rw]);
1688 part_stat_add(cpu, part, sectors[rw], sectors);
1689 part_inc_in_flight(part, rw);
1690
1691 part_stat_unlock();
1692}
1693EXPORT_SYMBOL(generic_start_io_acct);
1694
1695void generic_end_io_acct(int rw, struct hd_struct *part,
1696 unsigned long start_time)
1697{
1698 unsigned long duration = jiffies - start_time;
1699 int cpu = part_stat_lock();
1700
1701 part_stat_add(cpu, part, ticks[rw], duration);
1702 part_round_stats(cpu, part);
1703 part_dec_in_flight(part, rw);
1704
1705 part_stat_unlock();
1706}
1707EXPORT_SYMBOL(generic_end_io_acct);
1708
Ilya Loginov2d4dc892009-11-26 09:16:19 +01001709#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1710void bio_flush_dcache_pages(struct bio *bi)
1711{
Kent Overstreet79886132013-11-23 17:19:00 -08001712 struct bio_vec bvec;
1713 struct bvec_iter iter;
Ilya Loginov2d4dc892009-11-26 09:16:19 +01001714
Kent Overstreet79886132013-11-23 17:19:00 -08001715 bio_for_each_segment(bvec, bi, iter)
1716 flush_dcache_page(bvec.bv_page);
Ilya Loginov2d4dc892009-11-26 09:16:19 +01001717}
1718EXPORT_SYMBOL(bio_flush_dcache_pages);
1719#endif
1720
Jens Axboec4cf5262015-04-17 16:15:18 -06001721static inline bool bio_remaining_done(struct bio *bio)
1722{
1723 /*
1724 * If we're not chaining, then ->__bi_remaining is always 1 and
1725 * we always end io on the first invocation.
1726 */
1727 if (!bio_flagged(bio, BIO_CHAIN))
1728 return true;
1729
1730 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
1731
Mike Snitzer326e1db2015-05-22 09:14:03 -04001732 if (atomic_dec_and_test(&bio->__bi_remaining)) {
Jens Axboeb7c44ed2015-07-24 12:37:59 -06001733 bio_clear_flag(bio, BIO_CHAIN);
Jens Axboec4cf5262015-04-17 16:15:18 -06001734 return true;
Mike Snitzer326e1db2015-05-22 09:14:03 -04001735 }
Jens Axboec4cf5262015-04-17 16:15:18 -06001736
1737 return false;
1738}
1739
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740/**
1741 * bio_endio - end I/O on a bio
1742 * @bio: bio
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743 *
1744 * Description:
Christoph Hellwig4246a0b2015-07-20 15:29:37 +02001745 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1746 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1747 * bio unless they own it and thus know that it has an end_io function.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748 **/
Christoph Hellwig4246a0b2015-07-20 15:29:37 +02001749void bio_endio(struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750{
Christoph Hellwigba8c6962016-03-11 17:34:52 +01001751again:
Christoph Hellwig2b885512016-03-11 17:34:53 +01001752 if (!bio_remaining_done(bio))
Christoph Hellwigba8c6962016-03-11 17:34:52 +01001753 return;
Kent Overstreet196d38b2013-11-23 18:34:15 -08001754
Christoph Hellwigba8c6962016-03-11 17:34:52 +01001755 /*
1756 * Need to have a real endio function for chained bios, otherwise
1757 * various corner cases will break (like stacking block devices that
1758 * save/restore bi_end_io) - however, we want to avoid unbounded
1759 * recursion and blowing the stack. Tail call optimization would
1760 * handle this, but compiling with frame pointers also disables
1761 * gcc's sibling call optimization.
1762 */
1763 if (bio->bi_end_io == bio_chain_endio) {
1764 bio = __bio_chain_endio(bio);
1765 goto again;
Kent Overstreet196d38b2013-11-23 18:34:15 -08001766 }
Christoph Hellwigba8c6962016-03-11 17:34:52 +01001767
1768 if (bio->bi_end_io)
1769 bio->bi_end_io(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770}
H Hartley Sweetena112a712009-09-26 16:19:21 +02001771EXPORT_SYMBOL(bio_endio);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001772
Kent Overstreet196d38b2013-11-23 18:34:15 -08001773/**
Kent Overstreet20d01892013-11-23 18:21:01 -08001774 * bio_split - split a bio
1775 * @bio: bio to split
1776 * @sectors: number of sectors to split from the front of @bio
1777 * @gfp: gfp mask
1778 * @bs: bio set to allocate from
1779 *
1780 * Allocates and returns a new bio which represents @sectors from the start of
1781 * @bio, and updates @bio to represent the remaining sectors.
1782 *
Martin K. Petersenf3f5da62015-07-22 07:57:12 -04001783 * Unless this is a discard request the newly allocated bio will point
1784 * to @bio's bi_io_vec; it is the caller's responsibility to ensure that
1785 * @bio is not freed before the split.
Kent Overstreet20d01892013-11-23 18:21:01 -08001786 */
1787struct bio *bio_split(struct bio *bio, int sectors,
1788 gfp_t gfp, struct bio_set *bs)
1789{
1790 struct bio *split = NULL;
1791
1792 BUG_ON(sectors <= 0);
1793 BUG_ON(sectors >= bio_sectors(bio));
1794
Martin K. Petersenf3f5da62015-07-22 07:57:12 -04001795 /*
1796 * Discards need a mutable bio_vec to accommodate the payload
1797 * required by the DSM TRIM and UNMAP commands.
1798 */
1799 if (bio->bi_rw & REQ_DISCARD)
1800 split = bio_clone_bioset(bio, gfp, bs);
1801 else
1802 split = bio_clone_fast(bio, gfp, bs);
1803
Kent Overstreet20d01892013-11-23 18:21:01 -08001804 if (!split)
1805 return NULL;
1806
1807 split->bi_iter.bi_size = sectors << 9;
1808
1809 if (bio_integrity(split))
1810 bio_integrity_trim(split, 0, sectors);
1811
1812 bio_advance(bio, split->bi_iter.bi_size);
1813
1814 return split;
1815}
1816EXPORT_SYMBOL(bio_split);
1817
Martin K. Petersenad3316b2008-10-01 22:42:53 -04001818/**
Kent Overstreet6678d832013-08-07 11:14:32 -07001819 * bio_trim - trim a bio
1820 * @bio: bio to trim
1821 * @offset: number of sectors to trim from the front of @bio
1822 * @size: size we want to trim @bio to, in sectors
1823 */
1824void bio_trim(struct bio *bio, int offset, int size)
1825{
1826 /* 'bio' is a cloned bio which we need to trim to match
1827 * the given offset and size.
Kent Overstreet6678d832013-08-07 11:14:32 -07001828 */
Kent Overstreet6678d832013-08-07 11:14:32 -07001829
1830 size <<= 9;
Kent Overstreet4f024f32013-10-11 15:44:27 -07001831 if (offset == 0 && size == bio->bi_iter.bi_size)
Kent Overstreet6678d832013-08-07 11:14:32 -07001832 return;
1833
Jens Axboeb7c44ed2015-07-24 12:37:59 -06001834 bio_clear_flag(bio, BIO_SEG_VALID);
Kent Overstreet6678d832013-08-07 11:14:32 -07001835
1836 bio_advance(bio, offset << 9);
1837
Kent Overstreet4f024f32013-10-11 15:44:27 -07001838 bio->bi_iter.bi_size = size;
Kent Overstreet6678d832013-08-07 11:14:32 -07001839}
1840EXPORT_SYMBOL_GPL(bio_trim);
1841
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842/*
1843 * create memory pools for biovec's in a bio_set.
1844 * use the global biovec slabs created for general use.
1845 */
Fabian Fredericka6c39cb4f2014-04-22 15:09:05 -06001846mempool_t *biovec_create_pool(int pool_entries)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847{
Jens Axboe7ff93452008-12-11 11:53:43 +01001848 struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849
Kent Overstreet9f060e22012-10-12 15:29:33 -07001850 return mempool_create_slab_pool(pool_entries, bp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851}
1852
1853void bioset_free(struct bio_set *bs)
1854{
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -07001855 if (bs->rescue_workqueue)
1856 destroy_workqueue(bs->rescue_workqueue);
1857
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858 if (bs->bio_pool)
1859 mempool_destroy(bs->bio_pool);
1860
Kent Overstreet9f060e22012-10-12 15:29:33 -07001861 if (bs->bvec_pool)
1862 mempool_destroy(bs->bvec_pool);
1863
Martin K. Petersen7878cba2009-06-26 15:37:49 +02001864 bioset_integrity_free(bs);
Jens Axboebb799ca2008-12-10 15:35:05 +01001865 bio_put_slab(bs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866
1867 kfree(bs);
1868}
H Hartley Sweetena112a712009-09-26 16:19:21 +02001869EXPORT_SYMBOL(bioset_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870
Junichi Nomurad8f429e2014-10-03 17:27:12 -04001871static struct bio_set *__bioset_create(unsigned int pool_size,
1872 unsigned int front_pad,
1873 bool create_bvec_pool)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001874{
Jens Axboe392ddc32008-12-23 12:42:54 +01001875 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
Jens Axboe1b434492008-10-22 20:32:58 +02001876 struct bio_set *bs;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877
Jens Axboe1b434492008-10-22 20:32:58 +02001878 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879 if (!bs)
1880 return NULL;
1881
Jens Axboebb799ca2008-12-10 15:35:05 +01001882 bs->front_pad = front_pad;
Jens Axboe1b434492008-10-22 20:32:58 +02001883
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -07001884 spin_lock_init(&bs->rescue_lock);
1885 bio_list_init(&bs->rescue_list);
1886 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1887
Jens Axboe392ddc32008-12-23 12:42:54 +01001888 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
Jens Axboebb799ca2008-12-10 15:35:05 +01001889 if (!bs->bio_slab) {
1890 kfree(bs);
1891 return NULL;
1892 }
1893
1894 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895 if (!bs->bio_pool)
1896 goto bad;
1897
Junichi Nomurad8f429e2014-10-03 17:27:12 -04001898 if (create_bvec_pool) {
1899 bs->bvec_pool = biovec_create_pool(pool_size);
1900 if (!bs->bvec_pool)
1901 goto bad;
1902 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001903
Kent Overstreetdf2cb6d2012-09-10 14:33:46 -07001904 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
1905 if (!bs->rescue_workqueue)
1906 goto bad;
1907
1908 return bs;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001909bad:
1910 bioset_free(bs);
1911 return NULL;
1912}
Junichi Nomurad8f429e2014-10-03 17:27:12 -04001913
1914/**
1915 * bioset_create - Create a bio_set
1916 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1917 * @front_pad: Number of bytes to allocate in front of the returned bio
1918 *
1919 * Description:
1920 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1921 * to ask for a number of bytes to be allocated in front of the bio.
1922 * Front pad allocation is useful for embedding the bio inside
1923 * another structure, to avoid allocating extra data to go with the bio.
1924 * Note that the bio must be embedded at the END of that structure always,
1925 * or things will break badly.
1926 */
1927struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
1928{
1929 return __bioset_create(pool_size, front_pad, true);
1930}
H Hartley Sweetena112a712009-09-26 16:19:21 +02001931EXPORT_SYMBOL(bioset_create);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001932
Junichi Nomurad8f429e2014-10-03 17:27:12 -04001933/**
1934 * bioset_create_nobvec - Create a bio_set without bio_vec mempool
1935 * @pool_size: Number of bio to cache in the mempool
1936 * @front_pad: Number of bytes to allocate in front of the returned bio
1937 *
1938 * Description:
1939 * Same functionality as bioset_create() except that mempool is not
1940 * created for bio_vecs. Saving some memory for bio_clone_fast() users.
1941 */
1942struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_pad)
1943{
1944 return __bioset_create(pool_size, front_pad, false);
1945}
1946EXPORT_SYMBOL(bioset_create_nobvec);
1947
Tejun Heo852c7882012-03-05 13:15:27 -08001948#ifdef CONFIG_BLK_CGROUP
Tejun Heo1d933cf2015-05-22 17:13:24 -04001949
1950/**
1951 * bio_associate_blkcg - associate a bio with the specified blkcg
1952 * @bio: target bio
1953 * @blkcg_css: css of the blkcg to associate
1954 *
1955 * Associate @bio with the blkcg specified by @blkcg_css. Block layer will
1956 * treat @bio as if it were issued by a task which belongs to the blkcg.
1957 *
1958 * This function takes an extra reference of @blkcg_css which will be put
1959 * when @bio is released. The caller must own @bio and is responsible for
1960 * synchronizing calls to this function.
1961 */
1962int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css)
1963{
1964 if (unlikely(bio->bi_css))
1965 return -EBUSY;
1966 css_get(blkcg_css);
1967 bio->bi_css = blkcg_css;
1968 return 0;
1969}
Tejun Heo5aa2a962015-07-23 14:27:09 -04001970EXPORT_SYMBOL_GPL(bio_associate_blkcg);
Tejun Heo1d933cf2015-05-22 17:13:24 -04001971
Tejun Heo852c7882012-03-05 13:15:27 -08001972/**
1973 * bio_associate_current - associate a bio with %current
1974 * @bio: target bio
1975 *
1976 * Associate @bio with %current if it hasn't been associated yet. Block
1977 * layer will treat @bio as if it were issued by %current no matter which
1978 * task actually issues it.
1979 *
1980 * This function takes an extra reference of @task's io_context and blkcg
1981 * which will be put when @bio is released. The caller must own @bio,
1982 * ensure %current->io_context exists, and is responsible for synchronizing
1983 * calls to this function.
1984 */
1985int bio_associate_current(struct bio *bio)
1986{
1987 struct io_context *ioc;
Tejun Heo852c7882012-03-05 13:15:27 -08001988
Tejun Heo1d933cf2015-05-22 17:13:24 -04001989 if (bio->bi_css)
Tejun Heo852c7882012-03-05 13:15:27 -08001990 return -EBUSY;
1991
1992 ioc = current->io_context;
1993 if (!ioc)
1994 return -ENOENT;
1995
Tejun Heo852c7882012-03-05 13:15:27 -08001996 get_io_context_active(ioc);
1997 bio->bi_ioc = ioc;
Tejun Heoc165b3e2015-08-18 14:55:29 -07001998 bio->bi_css = task_get_css(current, io_cgrp_id);
Tejun Heo852c7882012-03-05 13:15:27 -08001999 return 0;
2000}
Tejun Heo5aa2a962015-07-23 14:27:09 -04002001EXPORT_SYMBOL_GPL(bio_associate_current);
Tejun Heo852c7882012-03-05 13:15:27 -08002002
2003/**
2004 * bio_disassociate_task - undo bio_associate_current()
2005 * @bio: target bio
2006 */
2007void bio_disassociate_task(struct bio *bio)
2008{
2009 if (bio->bi_ioc) {
2010 put_io_context(bio->bi_ioc);
2011 bio->bi_ioc = NULL;
2012 }
2013 if (bio->bi_css) {
2014 css_put(bio->bi_css);
2015 bio->bi_css = NULL;
2016 }
2017}
2018
2019#endif /* CONFIG_BLK_CGROUP */
2020
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021static void __init biovec_init_slabs(void)
2022{
2023 int i;
2024
2025 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
2026 int size;
2027 struct biovec_slab *bvs = bvec_slabs + i;
2028
Jens Axboea7fcd372008-12-05 16:10:29 +01002029 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
2030 bvs->slab = NULL;
2031 continue;
2032 }
Jens Axboea7fcd372008-12-05 16:10:29 +01002033
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034 size = bvs->nr_vecs * sizeof(struct bio_vec);
2035 bvs->slab = kmem_cache_create(bvs->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09002036 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 }
2038}
2039
2040static int __init init_bio(void)
2041{
Jens Axboebb799ca2008-12-10 15:35:05 +01002042 bio_slab_max = 2;
2043 bio_slab_nr = 0;
2044 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
2045 if (!bio_slabs)
2046 panic("bio: can't allocate bios\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002047
Martin K. Petersen7878cba2009-06-26 15:37:49 +02002048 bio_integrity_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049 biovec_init_slabs();
2050
Jens Axboebb799ca2008-12-10 15:35:05 +01002051 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052 if (!fs_bio_set)
2053 panic("bio: can't allocate bios\n");
2054
Martin K. Petersena91a2782011-03-17 11:11:05 +01002055 if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
2056 panic("bio: can't create integrity pool\n");
2057
Linus Torvalds1da177e2005-04-16 15:20:36 -07002058 return 0;
2059}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002060subsys_initcall(init_bio);