bio.c 40.7 KB
Newer Older
L
Linus Torvalds 已提交
1
/*
2
 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
L
Linus Torvalds 已提交
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 *
 */
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
22
#include <linux/iocontext.h>
L
Linus Torvalds 已提交
23 24 25
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
26
#include <linux/export.h>
L
Linus Torvalds 已提交
27 28
#include <linux/mempool.h>
#include <linux/workqueue.h>
29
#include <linux/cgroup.h>
30
#include <scsi/sg.h>		/* for struct sg_iovec */
L
Linus Torvalds 已提交
31

32
#include <trace/events/block.h>
33

34 35 36 37 38 39
/*
 * Test patch to inline a certain number of bi_io_vec's inside the bio
 * itself, to shrink a bio data allocation from two mempool calls to one
 */
#define BIO_INLINE_VECS		4

D
Denis ChengRq 已提交
40
static mempool_t *bio_split_pool __read_mostly;
L
Linus Torvalds 已提交
41 42 43 44 45 46 47

/*
 * if you change this list, also change bvec_alloc or things will
 * break badly! cannot be bigger than what you can fit into an
 * unsigned short
 */
#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
48
static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
L
Linus Torvalds 已提交
49 50 51 52 53 54 55 56
	BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
};
#undef BV

/*
 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
 * IO code that does not need private memory pools.
 */
57
struct bio_set *fs_bio_set;
L
Linus Torvalds 已提交
58

59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
/*
 * Our slab pool management
 */
struct bio_slab {
	struct kmem_cache *slab;
	unsigned int slab_ref;
	unsigned int slab_size;
	char name[8];
};
static DEFINE_MUTEX(bio_slab_lock);
static struct bio_slab *bio_slabs;
static unsigned int bio_slab_nr, bio_slab_max;

static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
{
	unsigned int sz = sizeof(struct bio) + extra_size;
	struct kmem_cache *slab = NULL;
76
	struct bio_slab *bslab, *new_bio_slabs;
77 78 79 80 81 82
	unsigned int i, entry = -1;

	mutex_lock(&bio_slab_lock);

	i = 0;
	while (i < bio_slab_nr) {
83
		bslab = &bio_slabs[i];
84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

		if (!bslab->slab && entry == -1)
			entry = i;
		else if (bslab->slab_size == sz) {
			slab = bslab->slab;
			bslab->slab_ref++;
			break;
		}
		i++;
	}

	if (slab)
		goto out_unlock;

	if (bio_slab_nr == bio_slab_max && entry == -1) {
		bio_slab_max <<= 1;
100 101 102 103
		new_bio_slabs = krealloc(bio_slabs,
					 bio_slab_max * sizeof(struct bio_slab),
					 GFP_KERNEL);
		if (!new_bio_slabs)
104
			goto out_unlock;
105
		bio_slabs = new_bio_slabs;
106 107 108 109 110 111 112 113 114 115 116
	}
	if (entry == -1)
		entry = bio_slab_nr++;

	bslab = &bio_slabs[entry];

	snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
	slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL);
	if (!slab)
		goto out_unlock;

117
	printk(KERN_INFO "bio: create slab <%s> at %d\n", bslab->name, entry);
118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
	bslab->slab = slab;
	bslab->slab_ref = 1;
	bslab->slab_size = sz;
out_unlock:
	mutex_unlock(&bio_slab_lock);
	return slab;
}

static void bio_put_slab(struct bio_set *bs)
{
	struct bio_slab *bslab = NULL;
	unsigned int i;

	mutex_lock(&bio_slab_lock);

	for (i = 0; i < bio_slab_nr; i++) {
		if (bs->bio_slab == bio_slabs[i].slab) {
			bslab = &bio_slabs[i];
			break;
		}
	}

	if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
		goto out;

	WARN_ON(!bslab->slab_ref);

	if (--bslab->slab_ref)
		goto out;

	kmem_cache_destroy(bslab->slab);
	bslab->slab = NULL;

out:
	mutex_unlock(&bio_slab_lock);
}

155 156 157 158 159
unsigned int bvec_nr_vecs(unsigned short idx)
{
	return bvec_slabs[idx].nr_vecs;
}

160 161 162 163 164 165 166 167 168 169 170 171 172
void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
{
	BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);

	if (idx == BIOVEC_MAX_IDX)
		mempool_free(bv, bs->bvec_pool);
	else {
		struct biovec_slab *bvs = bvec_slabs + idx;

		kmem_cache_free(bvs->slab, bv);
	}
}

173 174
struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
			      struct bio_set *bs)
L
Linus Torvalds 已提交
175 176 177
{
	struct bio_vec *bvl;

178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214
	/*
	 * see comment near bvec_array define!
	 */
	switch (nr) {
	case 1:
		*idx = 0;
		break;
	case 2 ... 4:
		*idx = 1;
		break;
	case 5 ... 16:
		*idx = 2;
		break;
	case 17 ... 64:
		*idx = 3;
		break;
	case 65 ... 128:
		*idx = 4;
		break;
	case 129 ... BIO_MAX_PAGES:
		*idx = 5;
		break;
	default:
		return NULL;
	}

	/*
	 * idx now points to the pool we want to allocate from. only the
	 * 1-vec entry pool is mempool backed.
	 */
	if (*idx == BIOVEC_MAX_IDX) {
fallback:
		bvl = mempool_alloc(bs->bvec_pool, gfp_mask);
	} else {
		struct biovec_slab *bvs = bvec_slabs + *idx;
		gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);

J
Jens Axboe 已提交
215
		/*
216 217 218
		 * Make this allocation restricted and don't dump info on
		 * allocation failures, since we'll fallback to the mempool
		 * in case of failure.
J
Jens Axboe 已提交
219
		 */
220
		__gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
L
Linus Torvalds 已提交
221

J
Jens Axboe 已提交
222
		/*
223 224
		 * Try a slab allocation. If this fails and __GFP_WAIT
		 * is set, retry with the 1-entry mempool
J
Jens Axboe 已提交
225
		 */
226 227 228 229 230 231 232
		bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
		if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
			*idx = BIOVEC_MAX_IDX;
			goto fallback;
		}
	}

L
Linus Torvalds 已提交
233 234 235
	return bvl;
}

236
void bio_free(struct bio *bio, struct bio_set *bs)
L
Linus Torvalds 已提交
237
{
238
	void *p;
L
Linus Torvalds 已提交
239

240
	if (bio_has_allocated_vec(bio))
241
		bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
L
Linus Torvalds 已提交
242

243
	if (bio_integrity(bio))
244
		bio_integrity_free(bio);
245

246 247 248 249 250 251 252 253
	/*
	 * If we have front padding, adjust the bio pointer before freeing
	 */
	p = bio;
	if (bs->front_pad)
		p -= bs->front_pad;

	mempool_free(p, bs->bio_pool);
P
Peter Osterlund 已提交
254
}
255
EXPORT_SYMBOL(bio_free);
P
Peter Osterlund 已提交
256

257
void bio_init(struct bio *bio)
L
Linus Torvalds 已提交
258
{
J
Jens Axboe 已提交
259
	memset(bio, 0, sizeof(*bio));
L
Linus Torvalds 已提交
260 261 262
	bio->bi_flags = 1 << BIO_UPTODATE;
	atomic_set(&bio->bi_cnt, 1);
}
263
EXPORT_SYMBOL(bio_init);
L
Linus Torvalds 已提交
264 265 266 267 268

/**
 * bio_alloc_bioset - allocate a bio for I/O
 * @gfp_mask:   the GFP_ mask given to the slab allocator
 * @nr_iovecs:	number of iovecs to pre-allocate
269
 * @bs:		the bio_set to allocate from.
L
Linus Torvalds 已提交
270 271
 *
 * Description:
272
 *   bio_alloc_bioset will try its own mempool to satisfy the allocation.
L
Linus Torvalds 已提交
273
 *   If %__GFP_WAIT is set then we will block on the internal pool waiting
274
 *   for a &struct bio to become free.
L
Linus Torvalds 已提交
275
 **/
A
Al Viro 已提交
276
struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
L
Linus Torvalds 已提交
277
{
T
Tejun Heo 已提交
278
	unsigned long idx = BIO_POOL_NONE;
I
Ingo Molnar 已提交
279
	struct bio_vec *bvl = NULL;
T
Tejun Heo 已提交
280 281 282 283 284 285 286
	struct bio *bio;
	void *p;

	p = mempool_alloc(bs->bio_pool, gfp_mask);
	if (unlikely(!p))
		return NULL;
	bio = p + bs->front_pad;
L
Linus Torvalds 已提交
287

I
Ingo Molnar 已提交
288
	bio_init(bio);
289
	bio->bi_pool = bs;
I
Ingo Molnar 已提交
290 291 292 293 294 295 296 297 298 299 300 301 302

	if (unlikely(!nr_iovecs))
		goto out_set;

	if (nr_iovecs <= BIO_INLINE_VECS) {
		bvl = bio->bi_inline_vecs;
		nr_iovecs = BIO_INLINE_VECS;
	} else {
		bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
		if (unlikely(!bvl))
			goto err_free;

		nr_iovecs = bvec_nr_vecs(idx);
L
Linus Torvalds 已提交
303
	}
T
Tejun Heo 已提交
304
out_set:
I
Ingo Molnar 已提交
305 306 307
	bio->bi_flags |= idx << BIO_POOL_OFFSET;
	bio->bi_max_vecs = nr_iovecs;
	bio->bi_io_vec = bvl;
L
Linus Torvalds 已提交
308
	return bio;
I
Ingo Molnar 已提交
309 310

err_free:
T
Tejun Heo 已提交
311
	mempool_free(p, bs->bio_pool);
I
Ingo Molnar 已提交
312
	return NULL;
L
Linus Torvalds 已提交
313
}
314
EXPORT_SYMBOL(bio_alloc_bioset);
L
Linus Torvalds 已提交
315

T
Tejun Heo 已提交
316 317 318 319 320
/**
 *	bio_alloc - allocate a new bio, memory pool backed
 *	@gfp_mask: allocation mask to use
 *	@nr_iovecs: number of iovecs
 *
321 322 323 324 325 326 327 328 329 330
 *	bio_alloc will allocate a bio and associated bio_vec array that can hold
 *	at least @nr_iovecs entries. Allocations will be done from the
 *	fs_bio_set. Also see @bio_alloc_bioset and @bio_kmalloc.
 *
 *	If %__GFP_WAIT is set, then bio_alloc will always be able to allocate
 *	a bio. This is due to the mempool guarantees. To make this work, callers
 *	must never allocate more than 1 bio at a time from this pool. Callers
 *	that need to allocate more than 1 bio must always submit the previously
 *	allocated bio for IO before attempting to allocate a new one. Failure to
 *	do so can cause livelocks under memory pressure.
T
Tejun Heo 已提交
331 332 333 334
 *
 *	RETURNS:
 *	Pointer to new bio on success, NULL on failure.
 */
335
struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
T
Tejun Heo 已提交
336
{
337
	return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
T
Tejun Heo 已提交
338
}
339
EXPORT_SYMBOL(bio_alloc);
T
Tejun Heo 已提交
340 341 342 343

static void bio_kmalloc_destructor(struct bio *bio)
{
	if (bio_integrity(bio))
344
		bio_integrity_free(bio);
T
Tejun Heo 已提交
345 346 347
	kfree(bio);
}

348
/**
349
 * bio_kmalloc - allocate a bio for I/O using kmalloc()
350 351 352 353
 * @gfp_mask:   the GFP_ mask given to the slab allocator
 * @nr_iovecs:	number of iovecs to pre-allocate
 *
 * Description:
354 355
 *   Allocate a new bio with @nr_iovecs bvecs.  If @gfp_mask contains
 *   %__GFP_WAIT, the allocation is guaranteed to succeed.
356 357
 *
 **/
358
struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
J
Jens Axboe 已提交
359
{
T
Tejun Heo 已提交
360
	struct bio *bio;
J
Jens Axboe 已提交
361

362 363 364
	if (nr_iovecs > UIO_MAXIOV)
		return NULL;

T
Tejun Heo 已提交
365 366 367 368 369 370 371 372 373 374
	bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec),
		      gfp_mask);
	if (unlikely(!bio))
		return NULL;

	bio_init(bio);
	bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
	bio->bi_max_vecs = nr_iovecs;
	bio->bi_io_vec = bio->bi_inline_vecs;
	bio->bi_destructor = bio_kmalloc_destructor;
J
Jens Axboe 已提交
375 376 377

	return bio;
}
378
EXPORT_SYMBOL(bio_kmalloc);
J
Jens Axboe 已提交
379

L
Linus Torvalds 已提交
380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400
void zero_fill_bio(struct bio *bio)
{
	unsigned long flags;
	struct bio_vec *bv;
	int i;

	bio_for_each_segment(bv, bio, i) {
		char *data = bvec_kmap_irq(bv, &flags);
		memset(data, 0, bv->bv_len);
		flush_dcache_page(bv->bv_page);
		bvec_kunmap_irq(data, &flags);
	}
}
EXPORT_SYMBOL(zero_fill_bio);

/**
 * bio_put - release a reference to a bio
 * @bio:   bio to release reference to
 *
 * Description:
 *   Put a reference to a &struct bio, either one you have gotten with
401
 *   bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
L
Linus Torvalds 已提交
402 403 404 405 406 407 408 409 410
 **/
void bio_put(struct bio *bio)
{
	BIO_BUG_ON(!atomic_read(&bio->bi_cnt));

	/*
	 * last put frees it
	 */
	if (atomic_dec_and_test(&bio->bi_cnt)) {
411
		bio_disassociate_task(bio);
L
Linus Torvalds 已提交
412
		bio->bi_next = NULL;
413 414 415 416 417 418 419 420 421 422

		/*
		 * This if statement is temporary - bi_pool is replacing
		 * bi_destructor, but bi_destructor will be taken out in another
		 * patch.
		 */
		if (bio->bi_pool)
			bio_free(bio, bio->bi_pool);
		else
			bio->bi_destructor(bio);
L
Linus Torvalds 已提交
423 424
	}
}
425
EXPORT_SYMBOL(bio_put);
L
Linus Torvalds 已提交
426

427
inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
L
Linus Torvalds 已提交
428 429 430 431 432 433
{
	if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
		blk_recount_segments(q, bio);

	return bio->bi_phys_segments;
}
434
EXPORT_SYMBOL(bio_phys_segments);
L
Linus Torvalds 已提交
435 436 437 438 439 440 441 442 443 444

/**
 * 	__bio_clone	-	clone a bio
 * 	@bio: destination bio
 * 	@bio_src: bio to clone
 *
 *	Clone a &bio. Caller will own the returned bio, but not
 *	the actual data it points to. Reference count of returned
 * 	bio will be one.
 */
445
void __bio_clone(struct bio *bio, struct bio *bio_src)
L
Linus Torvalds 已提交
446
{
447 448
	memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
		bio_src->bi_max_vecs * sizeof(struct bio_vec));
L
Linus Torvalds 已提交
449

450 451 452 453
	/*
	 * most users will be overriding ->bi_bdev with a new target,
	 * so we don't set nor calculate new physical/hw segment counts here
	 */
L
Linus Torvalds 已提交
454 455 456 457 458 459
	bio->bi_sector = bio_src->bi_sector;
	bio->bi_bdev = bio_src->bi_bdev;
	bio->bi_flags |= 1 << BIO_CLONED;
	bio->bi_rw = bio_src->bi_rw;
	bio->bi_vcnt = bio_src->bi_vcnt;
	bio->bi_size = bio_src->bi_size;
A
Andrew Morton 已提交
460
	bio->bi_idx = bio_src->bi_idx;
L
Linus Torvalds 已提交
461
}
462
EXPORT_SYMBOL(__bio_clone);
L
Linus Torvalds 已提交
463 464 465 466 467 468 469 470

/**
 *	bio_clone	-	clone a bio
 *	@bio: bio to clone
 *	@gfp_mask: allocation priority
 *
 * 	Like __bio_clone, only also allocates the returned bio
 */
A
Al Viro 已提交
471
struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
L
Linus Torvalds 已提交
472
{
473
	struct bio *b = bio_alloc(gfp_mask, bio->bi_max_vecs);
L
Linus Torvalds 已提交
474

475 476 477 478 479 480 481 482
	if (!b)
		return NULL;

	__bio_clone(b, bio);

	if (bio_integrity(bio)) {
		int ret;

483
		ret = bio_integrity_clone(b, bio, gfp_mask);
484

L
Li Zefan 已提交
485 486
		if (ret < 0) {
			bio_put(b);
487
			return NULL;
L
Li Zefan 已提交
488
		}
P
Peter Osterlund 已提交
489
	}
L
Linus Torvalds 已提交
490 491 492

	return b;
}
493
EXPORT_SYMBOL(bio_clone);
L
Linus Torvalds 已提交
494 495 496 497 498 499 500 501 502 503 504 505

/**
 *	bio_get_nr_vecs		- return approx number of vecs
 *	@bdev:  I/O target
 *
 *	Return the approximate number of pages we can send to this target.
 *	There's no guarantee that you will be able to fit this number of pages
 *	into a bio, it does not account for dynamic restrictions that vary
 *	on offset.
 */
int bio_get_nr_vecs(struct block_device *bdev)
{
506
	struct request_queue *q = bdev_get_queue(bdev);
507 508 509
	int nr_pages;

	nr_pages = min_t(unsigned,
510 511
		     queue_max_segments(q),
		     queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
512 513 514

	return min_t(unsigned, nr_pages, BIO_MAX_PAGES);

L
Linus Torvalds 已提交
515
}
516
EXPORT_SYMBOL(bio_get_nr_vecs);
L
Linus Torvalds 已提交
517

518
static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
519 520
			  *page, unsigned int len, unsigned int offset,
			  unsigned short max_sectors)
L
Linus Torvalds 已提交
521 522 523 524 525 526 527 528 529 530
{
	int retried_segments = 0;
	struct bio_vec *bvec;

	/*
	 * cloned bio must not modify vec list
	 */
	if (unlikely(bio_flagged(bio, BIO_CLONED)))
		return 0;

531
	if (((bio->bi_size + len) >> 9) > max_sectors)
L
Linus Torvalds 已提交
532 533
		return 0;

534 535 536 537 538 539 540 541 542 543
	/*
	 * For filesystems with a blocksize smaller than the pagesize
	 * we will often be called with the same page as last time and
	 * a consecutive offset.  Optimize this special case.
	 */
	if (bio->bi_vcnt > 0) {
		struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];

		if (page == prev->bv_page &&
		    offset == prev->bv_offset + prev->bv_len) {
544
			unsigned int prev_bv_len = prev->bv_len;
545
			prev->bv_len += len;
546 547 548

			if (q->merge_bvec_fn) {
				struct bvec_merge_data bvm = {
549 550 551 552
					/* prev_bvec is already charged in
					   bi_size, discharge it in order to
					   simulate merging updated prev_bvec
					   as new bvec. */
553 554
					.bi_bdev = bio->bi_bdev,
					.bi_sector = bio->bi_sector,
555
					.bi_size = bio->bi_size - prev_bv_len,
556 557 558
					.bi_rw = bio->bi_rw,
				};

559
				if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
560 561 562
					prev->bv_len -= len;
					return 0;
				}
563 564 565 566 567 568 569
			}

			goto done;
		}
	}

	if (bio->bi_vcnt >= bio->bi_max_vecs)
L
Linus Torvalds 已提交
570 571 572 573 574 575 576
		return 0;

	/*
	 * we might lose a segment or two here, but rather that than
	 * make this too complex.
	 */

577
	while (bio->bi_phys_segments >= queue_max_segments(q)) {
L
Linus Torvalds 已提交
578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600

		if (retried_segments)
			return 0;

		retried_segments = 1;
		blk_recount_segments(q, bio);
	}

	/*
	 * setup the new entry, we might clear it again later if we
	 * cannot add the page
	 */
	bvec = &bio->bi_io_vec[bio->bi_vcnt];
	bvec->bv_page = page;
	bvec->bv_len = len;
	bvec->bv_offset = offset;

	/*
	 * if queue has other restrictions (eg varying max sector size
	 * depending on offset), it can specify a merge_bvec_fn in the
	 * queue to get further control
	 */
	if (q->merge_bvec_fn) {
601 602 603 604 605 606 607
		struct bvec_merge_data bvm = {
			.bi_bdev = bio->bi_bdev,
			.bi_sector = bio->bi_sector,
			.bi_size = bio->bi_size,
			.bi_rw = bio->bi_rw,
		};

L
Linus Torvalds 已提交
608 609 610 611
		/*
		 * merge_bvec_fn() returns number of bytes it can accept
		 * at this offset
		 */
612
		if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
L
Linus Torvalds 已提交
613 614 615 616 617 618 619 620
			bvec->bv_page = NULL;
			bvec->bv_len = 0;
			bvec->bv_offset = 0;
			return 0;
		}
	}

	/* If we may be able to merge these biovecs, force a recount */
621
	if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
L
Linus Torvalds 已提交
622 623 624 625
		bio->bi_flags &= ~(1 << BIO_SEG_VALID);

	bio->bi_vcnt++;
	bio->bi_phys_segments++;
626
 done:
L
Linus Torvalds 已提交
627 628 629 630
	bio->bi_size += len;
	return len;
}

631 632
/**
 *	bio_add_pc_page	-	attempt to add page to bio
J
Jens Axboe 已提交
633
 *	@q: the target queue
634 635 636 637 638 639
 *	@bio: destination bio
 *	@page: page to add
 *	@len: vec entry length
 *	@offset: vec entry offset
 *
 *	Attempt to add a page to the bio_vec maplist. This can fail for a
640 641 642 643 644
 *	number of reasons, such as the bio being full or target block device
 *	limitations. The target block device must allow bio's up to PAGE_SIZE,
 *	so it is always possible to add a single page to an empty bio.
 *
 *	This should only be used by REQ_PC bios.
645
 */
646
int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
647 648
		    unsigned int len, unsigned int offset)
{
649 650
	return __bio_add_page(q, bio, page, len, offset,
			      queue_max_hw_sectors(q));
651
}
652
EXPORT_SYMBOL(bio_add_pc_page);
653

L
Linus Torvalds 已提交
654 655 656 657 658 659 660 661
/**
 *	bio_add_page	-	attempt to add page to bio
 *	@bio: destination bio
 *	@page: page to add
 *	@len: vec entry length
 *	@offset: vec entry offset
 *
 *	Attempt to add a page to the bio_vec maplist. This can fail for a
662 663 664
 *	number of reasons, such as the bio being full or target block device
 *	limitations. The target block device must allow bio's up to PAGE_SIZE,
 *	so it is always possible to add a single page to an empty bio.
L
Linus Torvalds 已提交
665 666 667 668
 */
int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
		 unsigned int offset)
{
669
	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
670
	return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
L
Linus Torvalds 已提交
671
}
672
EXPORT_SYMBOL(bio_add_page);
L
Linus Torvalds 已提交
673 674 675

struct bio_map_data {
	struct bio_vec *iovecs;
676
	struct sg_iovec *sgvecs;
677 678
	int nr_sgvecs;
	int is_our_pages;
L
Linus Torvalds 已提交
679 680
};

681
static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
682 683
			     struct sg_iovec *iov, int iov_count,
			     int is_our_pages)
L
Linus Torvalds 已提交
684 685
{
	memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
686 687
	memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
	bmd->nr_sgvecs = iov_count;
688
	bmd->is_our_pages = is_our_pages;
L
Linus Torvalds 已提交
689 690 691 692 693 694
	bio->bi_private = bmd;
}

static void bio_free_map_data(struct bio_map_data *bmd)
{
	kfree(bmd->iovecs);
695
	kfree(bmd->sgvecs);
L
Linus Torvalds 已提交
696 697 698
	kfree(bmd);
}

699 700
static struct bio_map_data *bio_alloc_map_data(int nr_segs,
					       unsigned int iov_count,
701
					       gfp_t gfp_mask)
L
Linus Torvalds 已提交
702
{
703 704 705 706
	struct bio_map_data *bmd;

	if (iov_count > UIO_MAXIOV)
		return NULL;
L
Linus Torvalds 已提交
707

708
	bmd = kmalloc(sizeof(*bmd), gfp_mask);
L
Linus Torvalds 已提交
709 710 711
	if (!bmd)
		return NULL;

712
	bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
713 714 715 716 717
	if (!bmd->iovecs) {
		kfree(bmd);
		return NULL;
	}

718
	bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
719
	if (bmd->sgvecs)
L
Linus Torvalds 已提交
720 721
		return bmd;

722
	kfree(bmd->iovecs);
L
Linus Torvalds 已提交
723 724 725 726
	kfree(bmd);
	return NULL;
}

727
static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
728 729
			  struct sg_iovec *iov, int iov_count,
			  int to_user, int from_user, int do_free_page)
730 731 732 733 734 735 736 737
{
	int ret = 0, i;
	struct bio_vec *bvec;
	int iov_idx = 0;
	unsigned int iov_off = 0;

	__bio_for_each_segment(bvec, bio, i, 0) {
		char *bv_addr = page_address(bvec->bv_page);
738
		unsigned int bv_len = iovecs[i].bv_len;
739 740 741

		while (bv_len && iov_idx < iov_count) {
			unsigned int bytes;
742
			char __user *iov_addr;
743 744 745 746 747 748

			bytes = min_t(unsigned int,
				      iov[iov_idx].iov_len - iov_off, bv_len);
			iov_addr = iov[iov_idx].iov_base + iov_off;

			if (!ret) {
749
				if (to_user)
750 751 752
					ret = copy_to_user(iov_addr, bv_addr,
							   bytes);

753 754 755 756
				if (from_user)
					ret = copy_from_user(bv_addr, iov_addr,
							     bytes);

757 758 759 760 761 762 763 764 765 766 767 768 769 770 771
				if (ret)
					ret = -EFAULT;
			}

			bv_len -= bytes;
			bv_addr += bytes;
			iov_addr += bytes;
			iov_off += bytes;

			if (iov[iov_idx].iov_len == iov_off) {
				iov_idx++;
				iov_off = 0;
			}
		}

772
		if (do_free_page)
773 774 775 776 777 778
			__free_page(bvec->bv_page);
	}

	return ret;
}

L
Linus Torvalds 已提交
779 780 781 782 783 784 785 786 787 788
/**
 *	bio_uncopy_user	-	finish previously mapped bio
 *	@bio: bio being terminated
 *
 *	Free pages allocated from bio_copy_user() and write back data
 *	to user space in case of a read.
 */
int bio_uncopy_user(struct bio *bio)
{
	struct bio_map_data *bmd = bio->bi_private;
789
	int ret = 0;
L
Linus Torvalds 已提交
790

791 792
	if (!bio_flagged(bio, BIO_NULL_MAPPED))
		ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
793 794
				     bmd->nr_sgvecs, bio_data_dir(bio) == READ,
				     0, bmd->is_our_pages);
L
Linus Torvalds 已提交
795 796 797 798
	bio_free_map_data(bmd);
	bio_put(bio);
	return ret;
}
799
EXPORT_SYMBOL(bio_uncopy_user);
L
Linus Torvalds 已提交
800 801

/**
802
 *	bio_copy_user_iov	-	copy user data to bio
L
Linus Torvalds 已提交
803
 *	@q: destination block queue
804
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
805 806
 *	@iov:	the iovec.
 *	@iov_count: number of elements in the iovec
L
Linus Torvalds 已提交
807
 *	@write_to_vm: bool indicating writing to pages or not
808
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
809 810 811 812 813
 *
 *	Prepares and returns a bio for indirect user io, bouncing data
 *	to/from kernel pages as necessary. Must be paired with
 *	call bio_uncopy_user() on io completion.
 */
814 815 816 817
struct bio *bio_copy_user_iov(struct request_queue *q,
			      struct rq_map_data *map_data,
			      struct sg_iovec *iov, int iov_count,
			      int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
818 819 820 821 822 823
{
	struct bio_map_data *bmd;
	struct bio_vec *bvec;
	struct page *page;
	struct bio *bio;
	int i, ret;
824 825
	int nr_pages = 0;
	unsigned int len = 0;
826
	unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
L
Linus Torvalds 已提交
827

828 829 830 831 832 833 834 835 836
	for (i = 0; i < iov_count; i++) {
		unsigned long uaddr;
		unsigned long end;
		unsigned long start;

		uaddr = (unsigned long)iov[i].iov_base;
		end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
		start = uaddr >> PAGE_SHIFT;

837 838 839 840 841 842
		/*
		 * Overflow, abort
		 */
		if (end < start)
			return ERR_PTR(-EINVAL);

843 844 845 846
		nr_pages += end - start;
		len += iov[i].iov_len;
	}

847 848 849
	if (offset)
		nr_pages++;

850
	bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
L
Linus Torvalds 已提交
851 852 853 854
	if (!bmd)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
855
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
856 857 858
	if (!bio)
		goto out_bmd;

859 860
	if (!write_to_vm)
		bio->bi_rw |= REQ_WRITE;
L
Linus Torvalds 已提交
861 862

	ret = 0;
863 864

	if (map_data) {
865
		nr_pages = 1 << map_data->page_order;
866 867
		i = map_data->offset / PAGE_SIZE;
	}
L
Linus Torvalds 已提交
868
	while (len) {
869
		unsigned int bytes = PAGE_SIZE;
L
Linus Torvalds 已提交
870

871 872
		bytes -= offset;

L
Linus Torvalds 已提交
873 874 875
		if (bytes > len)
			bytes = len;

876
		if (map_data) {
877
			if (i == map_data->nr_entries * nr_pages) {
878 879 880
				ret = -ENOMEM;
				break;
			}
881 882 883 884 885 886

			page = map_data->pages[i / nr_pages];
			page += (i % nr_pages);

			i++;
		} else {
887
			page = alloc_page(q->bounce_gfp | gfp_mask);
888 889 890 891
			if (!page) {
				ret = -ENOMEM;
				break;
			}
L
Linus Torvalds 已提交
892 893
		}

894
		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
L
Linus Torvalds 已提交
895 896 897
			break;

		len -= bytes;
898
		offset = 0;
L
Linus Torvalds 已提交
899 900 901 902 903 904 905 906
	}

	if (ret)
		goto cleanup;

	/*
	 * success
	 */
907 908 909
	if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
	    (map_data && map_data->from_user)) {
		ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0);
910 911
		if (ret)
			goto cleanup;
L
Linus Torvalds 已提交
912 913
	}

914
	bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
L
Linus Torvalds 已提交
915 916
	return bio;
cleanup:
917 918 919
	if (!map_data)
		bio_for_each_segment(bvec, bio, i)
			__free_page(bvec->bv_page);
L
Linus Torvalds 已提交
920 921 922 923 924 925 926

	bio_put(bio);
out_bmd:
	bio_free_map_data(bmd);
	return ERR_PTR(ret);
}

927 928 929
/**
 *	bio_copy_user	-	copy user data to bio
 *	@q: destination block queue
930
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
931 932 933
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
934
 *	@gfp_mask: memory allocation flags
935 936 937 938 939
 *
 *	Prepares and returns a bio for indirect user io, bouncing data
 *	to/from kernel pages as necessary. Must be paired with
 *	call bio_uncopy_user() on io completion.
 */
940 941 942
struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
			  unsigned long uaddr, unsigned int len,
			  int write_to_vm, gfp_t gfp_mask)
943 944 945 946 947 948
{
	struct sg_iovec iov;

	iov.iov_base = (void __user *)uaddr;
	iov.iov_len = len;

949
	return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
950
}
951
EXPORT_SYMBOL(bio_copy_user);
952

953
static struct bio *__bio_map_user_iov(struct request_queue *q,
954 955
				      struct block_device *bdev,
				      struct sg_iovec *iov, int iov_count,
956
				      int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
957
{
958 959
	int i, j;
	int nr_pages = 0;
L
Linus Torvalds 已提交
960 961
	struct page **pages;
	struct bio *bio;
962 963
	int cur_page = 0;
	int ret, offset;
L
Linus Torvalds 已提交
964

965 966 967 968 969 970
	for (i = 0; i < iov_count; i++) {
		unsigned long uaddr = (unsigned long)iov[i].iov_base;
		unsigned long len = iov[i].iov_len;
		unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
		unsigned long start = uaddr >> PAGE_SHIFT;

971 972 973 974 975 976
		/*
		 * Overflow, abort
		 */
		if (end < start)
			return ERR_PTR(-EINVAL);

977 978
		nr_pages += end - start;
		/*
979
		 * buffer must be aligned to at least hardsector size for now
980
		 */
981
		if (uaddr & queue_dma_alignment(q))
982 983 984 985
			return ERR_PTR(-EINVAL);
	}

	if (!nr_pages)
L
Linus Torvalds 已提交
986 987
		return ERR_PTR(-EINVAL);

988
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
989 990 991 992
	if (!bio)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
993
	pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
L
Linus Torvalds 已提交
994 995 996
	if (!pages)
		goto out;

997 998 999 1000 1001 1002 1003
	for (i = 0; i < iov_count; i++) {
		unsigned long uaddr = (unsigned long)iov[i].iov_base;
		unsigned long len = iov[i].iov_len;
		unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
		unsigned long start = uaddr >> PAGE_SHIFT;
		const int local_nr_pages = end - start;
		const int page_limit = cur_page + local_nr_pages;
1004

N
Nick Piggin 已提交
1005 1006
		ret = get_user_pages_fast(uaddr, local_nr_pages,
				write_to_vm, &pages[cur_page]);
1007 1008
		if (ret < local_nr_pages) {
			ret = -EFAULT;
1009
			goto out_unmap;
1010
		}
1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024

		offset = uaddr & ~PAGE_MASK;
		for (j = cur_page; j < page_limit; j++) {
			unsigned int bytes = PAGE_SIZE - offset;

			if (len <= 0)
				break;
			
			if (bytes > len)
				bytes = len;

			/*
			 * sorry...
			 */
1025 1026
			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
					    bytes)
1027 1028 1029 1030 1031
				break;

			len -= bytes;
			offset = 0;
		}
L
Linus Torvalds 已提交
1032

1033
		cur_page = j;
L
Linus Torvalds 已提交
1034
		/*
1035
		 * release the pages we didn't map into the bio, if any
L
Linus Torvalds 已提交
1036
		 */
1037 1038
		while (j < page_limit)
			page_cache_release(pages[j++]);
L
Linus Torvalds 已提交
1039 1040 1041 1042 1043 1044 1045 1046
	}

	kfree(pages);

	/*
	 * set data direction, and check if mapped pages need bouncing
	 */
	if (!write_to_vm)
1047
		bio->bi_rw |= REQ_WRITE;
L
Linus Torvalds 已提交
1048

1049
	bio->bi_bdev = bdev;
L
Linus Torvalds 已提交
1050 1051
	bio->bi_flags |= (1 << BIO_USER_MAPPED);
	return bio;
1052 1053 1054 1055 1056 1057 1058 1059

 out_unmap:
	for (i = 0; i < nr_pages; i++) {
		if(!pages[i])
			break;
		page_cache_release(pages[i]);
	}
 out:
L
Linus Torvalds 已提交
1060 1061 1062 1063 1064 1065 1066
	kfree(pages);
	bio_put(bio);
	return ERR_PTR(ret);
}

/**
 *	bio_map_user	-	map user address into bio
1067
 *	@q: the struct request_queue for the bio
L
Linus Torvalds 已提交
1068 1069 1070 1071
 *	@bdev: destination block device
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
1072
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
1073 1074 1075 1076
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1077
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1078 1079
			 unsigned long uaddr, unsigned int len, int write_to_vm,
			 gfp_t gfp_mask)
1080 1081 1082
{
	struct sg_iovec iov;

1083
	iov.iov_base = (void __user *)uaddr;
1084 1085
	iov.iov_len = len;

1086
	return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1087
}
1088
EXPORT_SYMBOL(bio_map_user);
1089 1090 1091

/**
 *	bio_map_user_iov - map user sg_iovec table into bio
1092
 *	@q: the struct request_queue for the bio
1093 1094 1095 1096
 *	@bdev: destination block device
 *	@iov:	the iovec.
 *	@iov_count: number of elements in the iovec
 *	@write_to_vm: bool indicating writing to pages or not
1097
 *	@gfp_mask: memory allocation flags
1098 1099 1100 1101
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1102
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1103
			     struct sg_iovec *iov, int iov_count,
1104
			     int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
1105 1106 1107
{
	struct bio *bio;

1108 1109
	bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
				 gfp_mask);
L
Linus Torvalds 已提交
1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120
	if (IS_ERR(bio))
		return bio;

	/*
	 * subtle -- if __bio_map_user() ended up bouncing a bio,
	 * it would normally disappear when its bi_end_io is run.
	 * however, we need it for the unmap, so grab an extra
	 * reference to it
	 */
	bio_get(bio);

1121
	return bio;
L
Linus Torvalds 已提交
1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155
}

static void __bio_unmap_user(struct bio *bio)
{
	struct bio_vec *bvec;
	int i;

	/*
	 * make sure we dirty pages we wrote to
	 */
	__bio_for_each_segment(bvec, bio, i, 0) {
		if (bio_data_dir(bio) == READ)
			set_page_dirty_lock(bvec->bv_page);

		page_cache_release(bvec->bv_page);
	}

	bio_put(bio);
}

/**
 *	bio_unmap_user	-	unmap a bio
 *	@bio:		the bio being unmapped
 *
 *	Unmap a bio previously mapped by bio_map_user(). Must be called with
 *	a process context.
 *
 *	bio_unmap_user() may sleep.
 */
void bio_unmap_user(struct bio *bio)
{
	__bio_unmap_user(bio);
	bio_put(bio);
}
1156
EXPORT_SYMBOL(bio_unmap_user);
L
Linus Torvalds 已提交
1157

1158
static void bio_map_kern_endio(struct bio *bio, int err)
1159 1160 1161 1162
{
	bio_put(bio);
}

1163
static struct bio *__bio_map_kern(struct request_queue *q, void *data,
A
Al Viro 已提交
1164
				  unsigned int len, gfp_t gfp_mask)
M
Mike Christie 已提交
1165 1166 1167 1168 1169 1170 1171 1172
{
	unsigned long kaddr = (unsigned long)data;
	unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
	unsigned long start = kaddr >> PAGE_SHIFT;
	const int nr_pages = end - start;
	int offset, i;
	struct bio *bio;

1173
	bio = bio_kmalloc(gfp_mask, nr_pages);
M
Mike Christie 已提交
1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186
	if (!bio)
		return ERR_PTR(-ENOMEM);

	offset = offset_in_page(kaddr);
	for (i = 0; i < nr_pages; i++) {
		unsigned int bytes = PAGE_SIZE - offset;

		if (len <= 0)
			break;

		if (bytes > len)
			bytes = len;

1187 1188
		if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
				    offset) < bytes)
M
Mike Christie 已提交
1189 1190 1191 1192 1193 1194 1195
			break;

		data += bytes;
		len -= bytes;
		offset = 0;
	}

1196
	bio->bi_end_io = bio_map_kern_endio;
M
Mike Christie 已提交
1197 1198 1199 1200 1201
	return bio;
}

/**
 *	bio_map_kern	-	map kernel address into bio
1202
 *	@q: the struct request_queue for the bio
M
Mike Christie 已提交
1203 1204 1205 1206 1207 1208 1209
 *	@data: pointer to buffer to map
 *	@len: length in bytes
 *	@gfp_mask: allocation flags for bio allocation
 *
 *	Map the kernel address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1210
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
A
Al Viro 已提交
1211
			 gfp_t gfp_mask)
M
Mike Christie 已提交
1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227
{
	struct bio *bio;

	bio = __bio_map_kern(q, data, len, gfp_mask);
	if (IS_ERR(bio))
		return bio;

	if (bio->bi_size == len)
		return bio;

	/*
	 * Don't support partial mappings.
	 */
	bio_put(bio);
	return ERR_PTR(-EINVAL);
}
1228
EXPORT_SYMBOL(bio_map_kern);
M
Mike Christie 已提交
1229

1230 1231 1232 1233
static void bio_copy_kern_endio(struct bio *bio, int err)
{
	struct bio_vec *bvec;
	const int read = bio_data_dir(bio) == READ;
1234
	struct bio_map_data *bmd = bio->bi_private;
1235
	int i;
1236
	char *p = bmd->sgvecs[0].iov_base;
1237 1238 1239

	__bio_for_each_segment(bvec, bio, i, 0) {
		char *addr = page_address(bvec->bv_page);
1240
		int len = bmd->iovecs[i].bv_len;
1241

1242
		if (read)
1243
			memcpy(p, addr, len);
1244 1245

		__free_page(bvec->bv_page);
1246
		p += len;
1247 1248
	}

1249
	bio_free_map_data(bmd);
1250 1251 1252 1253 1254 1255 1256 1257 1258
	bio_put(bio);
}

/**
 *	bio_copy_kern	-	copy kernel address into bio
 *	@q: the struct request_queue for the bio
 *	@data: pointer to buffer to copy
 *	@len: length in bytes
 *	@gfp_mask: allocation flags for bio and page allocation
1259
 *	@reading: data direction is READ
1260 1261 1262 1263 1264 1265 1266 1267 1268
 *
 *	copy the kernel address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
			  gfp_t gfp_mask, int reading)
{
	struct bio *bio;
	struct bio_vec *bvec;
1269
	int i;
1270

1271 1272 1273
	bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
	if (IS_ERR(bio))
		return bio;
1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286

	if (!reading) {
		void *p = data;

		bio_for_each_segment(bvec, bio, i) {
			char *addr = page_address(bvec->bv_page);

			memcpy(addr, p, bvec->bv_len);
			p += bvec->bv_len;
		}
	}

	bio->bi_end_io = bio_copy_kern_endio;
1287

1288 1289
	return bio;
}
1290
EXPORT_SYMBOL(bio_copy_kern);
1291

L
Linus Torvalds 已提交
1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310
/*
 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
 * for performing direct-IO in BIOs.
 *
 * The problem is that we cannot run set_page_dirty() from interrupt context
 * because the required locks are not interrupt-safe.  So what we can do is to
 * mark the pages dirty _before_ performing IO.  And in interrupt context,
 * check that the pages are still dirty.   If so, fine.  If not, redirty them
 * in process context.
 *
 * We special-case compound pages here: normally this means reads into hugetlb
 * pages.  The logic in here doesn't really work right for compound pages
 * because the VM does not uniformly chase down the head page in all cases.
 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
 * handle them at all.  So we skip compound pages here at an early stage.
 *
 * Note that this code is very hard to test under normal circumstances because
 * direct-io pins the pages with get_user_pages().  This makes
 * is_page_cache_freeable return false, and the VM will not clean the pages.
1311
 * But other code (eg, flusher threads) could clean the pages if they are mapped
L
Linus Torvalds 已提交
1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333
 * pagecache.
 *
 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
 * deferred bio dirtying paths.
 */

/*
 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
 */
void bio_set_pages_dirty(struct bio *bio)
{
	struct bio_vec *bvec = bio->bi_io_vec;
	int i;

	for (i = 0; i < bio->bi_vcnt; i++) {
		struct page *page = bvec[i].bv_page;

		if (page && !PageCompound(page))
			set_page_dirty_lock(page);
	}
}

1334
static void bio_release_pages(struct bio *bio)
L
Linus Torvalds 已提交
1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357
{
	struct bio_vec *bvec = bio->bi_io_vec;
	int i;

	for (i = 0; i < bio->bi_vcnt; i++) {
		struct page *page = bvec[i].bv_page;

		if (page)
			put_page(page);
	}
}

/*
 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
 * If they are, then fine.  If, however, some pages are clean then they must
 * have been written out during the direct-IO read.  So we take another ref on
 * the BIO and the offending pages and re-dirty the pages in process context.
 *
 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
 * here on.  It will run one page_cache_release() against each page and will
 * run one bio_put() against the BIO.
 */

1358
static void bio_dirty_fn(struct work_struct *work);
L
Linus Torvalds 已提交
1359

1360
static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
L
Linus Torvalds 已提交
1361 1362 1363 1364 1365 1366
static DEFINE_SPINLOCK(bio_dirty_lock);
static struct bio *bio_dirty_list;

/*
 * This runs in process context
 */
1367
static void bio_dirty_fn(struct work_struct *work)
L
Linus Torvalds 已提交
1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416
{
	unsigned long flags;
	struct bio *bio;

	spin_lock_irqsave(&bio_dirty_lock, flags);
	bio = bio_dirty_list;
	bio_dirty_list = NULL;
	spin_unlock_irqrestore(&bio_dirty_lock, flags);

	while (bio) {
		struct bio *next = bio->bi_private;

		bio_set_pages_dirty(bio);
		bio_release_pages(bio);
		bio_put(bio);
		bio = next;
	}
}

void bio_check_pages_dirty(struct bio *bio)
{
	struct bio_vec *bvec = bio->bi_io_vec;
	int nr_clean_pages = 0;
	int i;

	for (i = 0; i < bio->bi_vcnt; i++) {
		struct page *page = bvec[i].bv_page;

		if (PageDirty(page) || PageCompound(page)) {
			page_cache_release(page);
			bvec[i].bv_page = NULL;
		} else {
			nr_clean_pages++;
		}
	}

	if (nr_clean_pages) {
		unsigned long flags;

		spin_lock_irqsave(&bio_dirty_lock, flags);
		bio->bi_private = bio_dirty_list;
		bio_dirty_list = bio;
		spin_unlock_irqrestore(&bio_dirty_lock, flags);
		schedule_work(&bio_dirty_work);
	} else {
		bio_put(bio);
	}
}

1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
void bio_flush_dcache_pages(struct bio *bi)
{
	int i;
	struct bio_vec *bvec;

	bio_for_each_segment(bvec, bi, i)
		flush_dcache_page(bvec->bv_page);
}
EXPORT_SYMBOL(bio_flush_dcache_pages);
#endif

L
Linus Torvalds 已提交
1429 1430 1431 1432 1433 1434
/**
 * bio_endio - end I/O on a bio
 * @bio:	bio
 * @error:	error, if any
 *
 * Description:
1435
 *   bio_endio() will end I/O on the whole bio. bio_endio() is the
N
NeilBrown 已提交
1436 1437 1438
 *   preferred way to end I/O on a bio, it takes care of clearing
 *   BIO_UPTODATE on error. @error is 0 on success, and and one of the
 *   established -Exxxx (-EIO, for instance) error values in case
L
Lucas De Marchi 已提交
1439
 *   something went wrong. No one should call bi_end_io() directly on a
N
NeilBrown 已提交
1440 1441
 *   bio unless they own it and thus know that it has an end_io
 *   function.
L
Linus Torvalds 已提交
1442
 **/
1443
void bio_endio(struct bio *bio, int error)
L
Linus Torvalds 已提交
1444 1445 1446
{
	if (error)
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
N
NeilBrown 已提交
1447 1448
	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
		error = -EIO;
L
Linus Torvalds 已提交
1449

N
NeilBrown 已提交
1450
	if (bio->bi_end_io)
1451
		bio->bi_end_io(bio, error);
L
Linus Torvalds 已提交
1452
}
1453
EXPORT_SYMBOL(bio_endio);
L
Linus Torvalds 已提交
1454 1455 1456 1457 1458 1459

void bio_pair_release(struct bio_pair *bp)
{
	if (atomic_dec_and_test(&bp->cnt)) {
		struct bio *master = bp->bio1.bi_private;

1460
		bio_endio(master, bp->error);
L
Linus Torvalds 已提交
1461 1462 1463
		mempool_free(bp, bp->bio2.bi_private);
	}
}
1464
EXPORT_SYMBOL(bio_pair_release);
L
Linus Torvalds 已提交
1465

1466
static void bio_pair_end_1(struct bio *bi, int err)
L
Linus Torvalds 已提交
1467 1468 1469 1470 1471 1472 1473 1474 1475
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

1476
static void bio_pair_end_2(struct bio *bi, int err)
L
Linus Torvalds 已提交
1477 1478 1479 1480 1481 1482 1483 1484 1485 1486
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

/*
1487
 * split a bio - only worry about a bio with a single page in its iovec
L
Linus Torvalds 已提交
1488
 */
D
Denis ChengRq 已提交
1489
struct bio_pair *bio_split(struct bio *bi, int first_sectors)
L
Linus Torvalds 已提交
1490
{
D
Denis ChengRq 已提交
1491
	struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
L
Linus Torvalds 已提交
1492 1493 1494 1495

	if (!bp)
		return bp;

1496
	trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1497 1498
				bi->bi_sector + first_sectors);

L
Linus Torvalds 已提交
1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517
	BUG_ON(bi->bi_vcnt != 1);
	BUG_ON(bi->bi_idx != 0);
	atomic_set(&bp->cnt, 3);
	bp->error = 0;
	bp->bio1 = *bi;
	bp->bio2 = *bi;
	bp->bio2.bi_sector += first_sectors;
	bp->bio2.bi_size -= first_sectors << 9;
	bp->bio1.bi_size = first_sectors << 9;

	bp->bv1 = bi->bi_io_vec[0];
	bp->bv2 = bi->bi_io_vec[0];
	bp->bv2.bv_offset += first_sectors << 9;
	bp->bv2.bv_len -= first_sectors << 9;
	bp->bv1.bv_len = first_sectors << 9;

	bp->bio1.bi_io_vec = &bp->bv1;
	bp->bio2.bi_io_vec = &bp->bv2;

1518 1519 1520
	bp->bio1.bi_max_vecs = 1;
	bp->bio2.bi_max_vecs = 1;

L
Linus Torvalds 已提交
1521 1522 1523 1524
	bp->bio1.bi_end_io = bio_pair_end_1;
	bp->bio2.bi_end_io = bio_pair_end_2;

	bp->bio1.bi_private = bi;
D
Denis ChengRq 已提交
1525
	bp->bio2.bi_private = bio_split_pool;
L
Linus Torvalds 已提交
1526

1527 1528 1529
	if (bio_integrity(bi))
		bio_integrity_split(bi, bp, first_sectors);

L
Linus Torvalds 已提交
1530 1531
	return bp;
}
1532
EXPORT_SYMBOL(bio_split);
L
Linus Torvalds 已提交
1533

1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546
/**
 *      bio_sector_offset - Find hardware sector offset in bio
 *      @bio:           bio to inspect
 *      @index:         bio_vec index
 *      @offset:        offset in bv_page
 *
 *      Return the number of hardware sectors between beginning of bio
 *      and an end point indicated by a bio_vec index and an offset
 *      within that vector's page.
 */
sector_t bio_sector_offset(struct bio *bio, unsigned short index,
			   unsigned int offset)
{
1547
	unsigned int sector_sz;
1548 1549 1550 1551
	struct bio_vec *bv;
	sector_t sectors;
	int i;

1552
	sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570
	sectors = 0;

	if (index >= bio->bi_idx)
		index = bio->bi_vcnt - 1;

	__bio_for_each_segment(bv, bio, i, 0) {
		if (i == index) {
			if (offset > bv->bv_offset)
				sectors += (offset - bv->bv_offset) / sector_sz;
			break;
		}

		sectors += bv->bv_len / sector_sz;
	}

	return sectors;
}
EXPORT_SYMBOL(bio_sector_offset);
L
Linus Torvalds 已提交
1571 1572 1573 1574 1575

/*
 * create memory pools for biovec's in a bio_set.
 * use the global biovec slabs created for general use.
 */
1576
static int biovec_create_pools(struct bio_set *bs, int pool_entries)
L
Linus Torvalds 已提交
1577
{
1578
	struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
L
Linus Torvalds 已提交
1579

1580 1581 1582
	bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
	if (!bs->bvec_pool)
		return -ENOMEM;
L
Linus Torvalds 已提交
1583 1584 1585 1586 1587 1588

	return 0;
}

static void biovec_free_pools(struct bio_set *bs)
{
1589
	mempool_destroy(bs->bvec_pool);
L
Linus Torvalds 已提交
1590 1591 1592 1593 1594 1595 1596
}

void bioset_free(struct bio_set *bs)
{
	if (bs->bio_pool)
		mempool_destroy(bs->bio_pool);

1597
	bioset_integrity_free(bs);
L
Linus Torvalds 已提交
1598
	biovec_free_pools(bs);
1599
	bio_put_slab(bs);
L
Linus Torvalds 已提交
1600 1601 1602

	kfree(bs);
}
1603
EXPORT_SYMBOL(bioset_free);
L
Linus Torvalds 已提交
1604

1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618
/**
 * bioset_create  - Create a bio_set
 * @pool_size:	Number of bio and bio_vecs to cache in the mempool
 * @front_pad:	Number of bytes to allocate in front of the returned bio
 *
 * Description:
 *    Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
 *    to ask for a number of bytes to be allocated in front of the bio.
 *    Front pad allocation is useful for embedding the bio inside
 *    another structure, to avoid allocating extra data to go with the bio.
 *    Note that the bio must be embedded at the END of that structure always,
 *    or things will break badly.
 */
struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
L
Linus Torvalds 已提交
1619
{
1620
	unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1621
	struct bio_set *bs;
L
Linus Torvalds 已提交
1622

1623
	bs = kzalloc(sizeof(*bs), GFP_KERNEL);
L
Linus Torvalds 已提交
1624 1625 1626
	if (!bs)
		return NULL;

1627
	bs->front_pad = front_pad;
1628

1629
	bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1630 1631 1632 1633 1634 1635
	if (!bs->bio_slab) {
		kfree(bs);
		return NULL;
	}

	bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
L
Linus Torvalds 已提交
1636 1637 1638
	if (!bs->bio_pool)
		goto bad;

1639
	if (!biovec_create_pools(bs, pool_size))
L
Linus Torvalds 已提交
1640 1641 1642 1643 1644 1645
		return bs;

bad:
	bioset_free(bs);
	return NULL;
}
1646
EXPORT_SYMBOL(bioset_create);
L
Linus Torvalds 已提交
1647

1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705
#ifdef CONFIG_BLK_CGROUP
/**
 * bio_associate_current - associate a bio with %current
 * @bio: target bio
 *
 * Associate @bio with %current if it hasn't been associated yet.  Block
 * layer will treat @bio as if it were issued by %current no matter which
 * task actually issues it.
 *
 * This function takes an extra reference of @task's io_context and blkcg
 * which will be put when @bio is released.  The caller must own @bio,
 * ensure %current->io_context exists, and is responsible for synchronizing
 * calls to this function.
 */
int bio_associate_current(struct bio *bio)
{
	struct io_context *ioc;
	struct cgroup_subsys_state *css;

	if (bio->bi_ioc)
		return -EBUSY;

	ioc = current->io_context;
	if (!ioc)
		return -ENOENT;

	/* acquire active ref on @ioc and associate */
	get_io_context_active(ioc);
	bio->bi_ioc = ioc;

	/* associate blkcg if exists */
	rcu_read_lock();
	css = task_subsys_state(current, blkio_subsys_id);
	if (css && css_tryget(css))
		bio->bi_css = css;
	rcu_read_unlock();

	return 0;
}

/**
 * bio_disassociate_task - undo bio_associate_current()
 * @bio: target bio
 */
void bio_disassociate_task(struct bio *bio)
{
	if (bio->bi_ioc) {
		put_io_context(bio->bi_ioc);
		bio->bi_ioc = NULL;
	}
	if (bio->bi_css) {
		css_put(bio->bi_css);
		bio->bi_css = NULL;
	}
}

#endif /* CONFIG_BLK_CGROUP */

L
Linus Torvalds 已提交
1706 1707 1708 1709 1710 1711 1712 1713
static void __init biovec_init_slabs(void)
{
	int i;

	for (i = 0; i < BIOVEC_NR_POOLS; i++) {
		int size;
		struct biovec_slab *bvs = bvec_slabs + i;

1714 1715 1716 1717 1718
		if (bvs->nr_vecs <= BIO_INLINE_VECS) {
			bvs->slab = NULL;
			continue;
		}

L
Linus Torvalds 已提交
1719 1720
		size = bvs->nr_vecs * sizeof(struct bio_vec);
		bvs->slab = kmem_cache_create(bvs->name, size, 0,
1721
                                SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
1722 1723 1724 1725 1726
	}
}

static int __init init_bio(void)
{
1727 1728 1729 1730 1731
	bio_slab_max = 2;
	bio_slab_nr = 0;
	bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
	if (!bio_slabs)
		panic("bio: can't allocate bios\n");
L
Linus Torvalds 已提交
1732

1733
	bio_integrity_init();
L
Linus Torvalds 已提交
1734 1735
	biovec_init_slabs();

1736
	fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
L
Linus Torvalds 已提交
1737 1738 1739
	if (!fs_bio_set)
		panic("bio: can't allocate bios\n");

1740 1741 1742
	if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
		panic("bio: can't create integrity pool\n");

1743 1744
	bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
						     sizeof(struct bio_pair));
L
Linus Torvalds 已提交
1745 1746 1747 1748 1749 1750
	if (!bio_split_pool)
		panic("bio: can't create split pool\n");

	return 0;
}
subsys_initcall(init_bio);