bio.c 39.1 KB
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/*
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 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
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 *
 * 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>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mempool.h>
#include <linux/workqueue.h>
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#include <scsi/sg.h>		/* for struct sg_iovec */
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#include <trace/events/block.h>
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/*
 * 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

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static mempool_t *bio_split_pool __read_mostly;
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/*
 * 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) }
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struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
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	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.
 */
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struct bio_set *fs_bio_set;
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/*
 * 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;
	struct bio_slab *bslab;
	unsigned int i, entry = -1;

	mutex_lock(&bio_slab_lock);

	i = 0;
	while (i < bio_slab_nr) {
		struct bio_slab *bslab = &bio_slabs[i];

		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;
		bio_slabs = krealloc(bio_slabs,
				     bio_slab_max * sizeof(struct bio_slab),
				     GFP_KERNEL);
		if (!bio_slabs)
			goto out_unlock;
	}
	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;

	printk("bio: create slab <%s> at %d\n", bslab->name, entry);
	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);
}

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unsigned int bvec_nr_vecs(unsigned short idx)
{
	return bvec_slabs[idx].nr_vecs;
}

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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);
	}
}

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struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
			      struct bio_set *bs)
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{
	struct bio_vec *bvl;

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	/*
	 * 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);

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		/*
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		 * Make this allocation restricted and don't dump info on
		 * allocation failures, since we'll fallback to the mempool
		 * in case of failure.
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		 */
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		__gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
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		/*
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		 * Try a slab allocation. If this fails and __GFP_WAIT
		 * is set, retry with the 1-entry mempool
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		 */
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		bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
		if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
			*idx = BIOVEC_MAX_IDX;
			goto fallback;
		}
	}

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	return bvl;
}

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void bio_free(struct bio *bio, struct bio_set *bs)
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{
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	void *p;
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	if (bio_has_allocated_vec(bio))
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		bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
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	if (bio_integrity(bio))
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		bio_integrity_free(bio, bs);
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	/*
	 * 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);
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}
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EXPORT_SYMBOL(bio_free);
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void bio_init(struct bio *bio)
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{
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	memset(bio, 0, sizeof(*bio));
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	bio->bi_flags = 1 << BIO_UPTODATE;
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	bio->bi_comp_cpu = -1;
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	atomic_set(&bio->bi_cnt, 1);
}
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EXPORT_SYMBOL(bio_init);
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/**
 * 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
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 * @bs:		the bio_set to allocate from. If %NULL, just use kmalloc
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 *
 * Description:
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 *   bio_alloc_bioset will first try its own mempool to satisfy the allocation.
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 *   If %__GFP_WAIT is set then we will block on the internal pool waiting
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 *   for a &struct bio to become free. If a %NULL @bs is passed in, we will
 *   fall back to just using @kmalloc to allocate the required memory.
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 *
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 *   Note that the caller must set ->bi_destructor on succesful return
 *   of a bio, to do the appropriate freeing of the bio once the reference
 *   count drops to zero.
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 **/
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struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
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{
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	unsigned long idx = BIO_POOL_NONE;
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	struct bio_vec *bvl = NULL;
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	struct bio *bio;
	void *p;

	p = mempool_alloc(bs->bio_pool, gfp_mask);
	if (unlikely(!p))
		return NULL;
	bio = p + bs->front_pad;
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	bio_init(bio);

	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);
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	}
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out_set:
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	bio->bi_flags |= idx << BIO_POOL_OFFSET;
	bio->bi_max_vecs = nr_iovecs;
	bio->bi_io_vec = bvl;
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	return bio;
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err_free:
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	mempool_free(p, bs->bio_pool);
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	return NULL;
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}
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EXPORT_SYMBOL(bio_alloc_bioset);
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static void bio_fs_destructor(struct bio *bio)
{
	bio_free(bio, fs_bio_set);
}

/**
 *	bio_alloc - allocate a new bio, memory pool backed
 *	@gfp_mask: allocation mask to use
 *	@nr_iovecs: number of iovecs
 *
 *	Allocate a new bio with @nr_iovecs bvecs.  If @gfp_mask
 *	contains __GFP_WAIT, the allocation is guaranteed to succeed.
 *
 *	RETURNS:
 *	Pointer to new bio on success, NULL on failure.
 */
struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
{
	struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);

	if (bio)
		bio->bi_destructor = bio_fs_destructor;

	return bio;
}
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EXPORT_SYMBOL(bio_alloc);
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static void bio_kmalloc_destructor(struct bio *bio)
{
	if (bio_integrity(bio))
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		bio_integrity_free(bio, fs_bio_set);
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	kfree(bio);
}

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/**
 * bio_alloc - allocate a bio for I/O
 * @gfp_mask:   the GFP_ mask given to the slab allocator
 * @nr_iovecs:	number of iovecs to pre-allocate
 *
 * Description:
 *   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.
 *
 *   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
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 *   must never allocate more than 1 bio at a time from this pool. Callers
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 *   that need to allocate more than 1 bio must always submit the previously
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 *   allocated bio for IO before attempting to allocate a new one. Failure to
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 *   do so can cause livelocks under memory pressure.
 *
 **/
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struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs)
{
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	struct bio *bio;
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	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;
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	return bio;
}
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EXPORT_SYMBOL(bio_kmalloc);
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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
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 *   bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
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 **/
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)) {
		bio->bi_next = NULL;
		bio->bi_destructor(bio);
	}
}
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EXPORT_SYMBOL(bio_put);
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inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
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{
	if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
		blk_recount_segments(q, bio);

	return bio->bi_phys_segments;
}
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EXPORT_SYMBOL(bio_phys_segments);
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/**
 * 	__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.
 */
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void __bio_clone(struct bio *bio, struct bio *bio_src)
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{
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	memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
		bio_src->bi_max_vecs * sizeof(struct bio_vec));
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	/*
	 * most users will be overriding ->bi_bdev with a new target,
	 * so we don't set nor calculate new physical/hw segment counts here
	 */
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	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;
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	bio->bi_idx = bio_src->bi_idx;
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}
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EXPORT_SYMBOL(__bio_clone);
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/**
 *	bio_clone	-	clone a bio
 *	@bio: bio to clone
 *	@gfp_mask: allocation priority
 *
 * 	Like __bio_clone, only also allocates the returned bio
 */
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struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
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{
	struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);

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	if (!b)
		return NULL;

	b->bi_destructor = bio_fs_destructor;
	__bio_clone(b, bio);

	if (bio_integrity(bio)) {
		int ret;

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		ret = bio_integrity_clone(b, bio, gfp_mask, fs_bio_set);
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		if (ret < 0) {
			bio_put(b);
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			return NULL;
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		}
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	}
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	return b;
}
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EXPORT_SYMBOL(bio_clone);
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/**
 *	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)
{
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	struct request_queue *q = bdev_get_queue(bdev);
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	int nr_pages;

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	nr_pages = ((queue_max_sectors(q) << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
	if (nr_pages > queue_max_phys_segments(q))
		nr_pages = queue_max_phys_segments(q);
	if (nr_pages > queue_max_hw_segments(q))
		nr_pages = queue_max_hw_segments(q);
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	return nr_pages;
}
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EXPORT_SYMBOL(bio_get_nr_vecs);
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static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
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			  *page, unsigned int len, unsigned int offset,
			  unsigned short max_sectors)
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{
	int retried_segments = 0;
	struct bio_vec *bvec;

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

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	if (((bio->bi_size + len) >> 9) > max_sectors)
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		return 0;

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	/*
	 * 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) {
			prev->bv_len += len;
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			if (q->merge_bvec_fn) {
				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,
				};

				if (q->merge_bvec_fn(q, &bvm, prev) < len) {
					prev->bv_len -= len;
					return 0;
				}
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			}

			goto done;
		}
	}

	if (bio->bi_vcnt >= bio->bi_max_vecs)
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		return 0;

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

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	while (bio->bi_phys_segments >= queue_max_phys_segments(q)
	       || bio->bi_phys_segments >= queue_max_hw_segments(q)) {
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		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) {
598 599 600 601 602 603 604
		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,
		};

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		/*
		 * merge_bvec_fn() returns number of bytes it can accept
		 * at this offset
		 */
609
		if (q->merge_bvec_fn(q, &bvm, bvec) < len) {
L
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			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 */
618
	if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
L
Linus Torvalds 已提交
619 620 621 622
		bio->bi_flags &= ~(1 << BIO_SEG_VALID);

	bio->bi_vcnt++;
	bio->bi_phys_segments++;
623
 done:
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Linus Torvalds 已提交
624 625 626 627
	bio->bi_size += len;
	return len;
}

628 629
/**
 *	bio_add_pc_page	-	attempt to add page to bio
J
Jens Axboe 已提交
630
 *	@q: the target queue
631 632 633 634 635 636 637 638 639 640 641
 *	@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
 *	number of reasons, such as the bio being full or target block
 *	device limitations. The target block device must allow bio's
 *      smaller than 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.
 */
642
int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
643 644
		    unsigned int len, unsigned int offset)
{
645 646
	return __bio_add_page(q, bio, page, len, offset,
			      queue_max_hw_sectors(q));
647
}
648
EXPORT_SYMBOL(bio_add_pc_page);
649

L
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650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665
/**
 *	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
 *	number of reasons, such as the bio being full or target block
 *	device limitations. The target block device must allow bio's
 *      smaller than PAGE_SIZE, so it is always possible to add a single
 *      page to an empty bio.
 */
int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
		 unsigned int offset)
{
666
	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
667
	return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
L
Linus Torvalds 已提交
668
}
669
EXPORT_SYMBOL(bio_add_page);
L
Linus Torvalds 已提交
670 671 672

struct bio_map_data {
	struct bio_vec *iovecs;
673
	struct sg_iovec *sgvecs;
674 675
	int nr_sgvecs;
	int is_our_pages;
L
Linus Torvalds 已提交
676 677
};

678
static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
679 680
			     struct sg_iovec *iov, int iov_count,
			     int is_our_pages)
L
Linus Torvalds 已提交
681 682
{
	memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
683 684
	memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
	bmd->nr_sgvecs = iov_count;
685
	bmd->is_our_pages = is_our_pages;
L
Linus Torvalds 已提交
686 687 688 689 690 691
	bio->bi_private = bmd;
}

static void bio_free_map_data(struct bio_map_data *bmd)
{
	kfree(bmd->iovecs);
692
	kfree(bmd->sgvecs);
L
Linus Torvalds 已提交
693 694 695
	kfree(bmd);
}

696 697
static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count,
					       gfp_t gfp_mask)
L
Linus Torvalds 已提交
698
{
699
	struct bio_map_data *bmd = kmalloc(sizeof(*bmd), gfp_mask);
L
Linus Torvalds 已提交
700 701 702 703

	if (!bmd)
		return NULL;

704
	bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
705 706 707 708 709
	if (!bmd->iovecs) {
		kfree(bmd);
		return NULL;
	}

710
	bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
711
	if (bmd->sgvecs)
L
Linus Torvalds 已提交
712 713
		return bmd;

714
	kfree(bmd->iovecs);
L
Linus Torvalds 已提交
715 716 717 718
	kfree(bmd);
	return NULL;
}

719
static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
720 721
			  struct sg_iovec *iov, int iov_count,
			  int to_user, int from_user, int do_free_page)
722 723 724 725 726 727 728 729
{
	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);
730
		unsigned int bv_len = iovecs[i].bv_len;
731 732 733

		while (bv_len && iov_idx < iov_count) {
			unsigned int bytes;
734
			char __user *iov_addr;
735 736 737 738 739 740

			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) {
741
				if (to_user)
742 743 744
					ret = copy_to_user(iov_addr, bv_addr,
							   bytes);

745 746 747 748
				if (from_user)
					ret = copy_from_user(bv_addr, iov_addr,
							     bytes);

749 750 751 752 753 754 755 756 757 758 759 760 761 762 763
				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;
			}
		}

764
		if (do_free_page)
765 766 767 768 769 770
			__free_page(bvec->bv_page);
	}

	return ret;
}

L
Linus Torvalds 已提交
771 772 773 774 775 776 777 778 779 780
/**
 *	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;
781
	int ret = 0;
L
Linus Torvalds 已提交
782

783 784
	if (!bio_flagged(bio, BIO_NULL_MAPPED))
		ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
785 786
				     bmd->nr_sgvecs, bio_data_dir(bio) == READ,
				     0, bmd->is_our_pages);
L
Linus Torvalds 已提交
787 788 789 790
	bio_free_map_data(bmd);
	bio_put(bio);
	return ret;
}
791
EXPORT_SYMBOL(bio_uncopy_user);
L
Linus Torvalds 已提交
792 793

/**
794
 *	bio_copy_user_iov	-	copy user data to bio
L
Linus Torvalds 已提交
795
 *	@q: destination block queue
796
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
797 798
 *	@iov:	the iovec.
 *	@iov_count: number of elements in the iovec
L
Linus Torvalds 已提交
799
 *	@write_to_vm: bool indicating writing to pages or not
800
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
801 802 803 804 805
 *
 *	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.
 */
806 807 808 809
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
810 811 812 813 814 815
{
	struct bio_map_data *bmd;
	struct bio_vec *bvec;
	struct page *page;
	struct bio *bio;
	int i, ret;
816 817
	int nr_pages = 0;
	unsigned int len = 0;
818
	unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
L
Linus Torvalds 已提交
819

820 821 822 823 824 825 826 827 828 829 830 831 832
	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;

		nr_pages += end - start;
		len += iov[i].iov_len;
	}

833 834 835
	if (offset)
		nr_pages++;

836
	bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
L
Linus Torvalds 已提交
837 838 839 840
	if (!bmd)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
841
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
842 843 844 845 846 847
	if (!bio)
		goto out_bmd;

	bio->bi_rw |= (!write_to_vm << BIO_RW);

	ret = 0;
848 849

	if (map_data) {
850
		nr_pages = 1 << map_data->page_order;
851 852
		i = map_data->offset / PAGE_SIZE;
	}
L
Linus Torvalds 已提交
853
	while (len) {
854
		unsigned int bytes = PAGE_SIZE;
L
Linus Torvalds 已提交
855

856 857
		bytes -= offset;

L
Linus Torvalds 已提交
858 859 860
		if (bytes > len)
			bytes = len;

861
		if (map_data) {
862
			if (i == map_data->nr_entries * nr_pages) {
863 864 865
				ret = -ENOMEM;
				break;
			}
866 867 868 869 870 871

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

			i++;
		} else {
872
			page = alloc_page(q->bounce_gfp | gfp_mask);
873 874 875 876
			if (!page) {
				ret = -ENOMEM;
				break;
			}
L
Linus Torvalds 已提交
877 878
		}

879
		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
L
Linus Torvalds 已提交
880 881 882
			break;

		len -= bytes;
883
		offset = 0;
L
Linus Torvalds 已提交
884 885 886 887 888 889 890 891
	}

	if (ret)
		goto cleanup;

	/*
	 * success
	 */
892 893 894
	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);
895 896
		if (ret)
			goto cleanup;
L
Linus Torvalds 已提交
897 898
	}

899
	bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
L
Linus Torvalds 已提交
900 901
	return bio;
cleanup:
902 903 904
	if (!map_data)
		bio_for_each_segment(bvec, bio, i)
			__free_page(bvec->bv_page);
L
Linus Torvalds 已提交
905 906 907 908 909 910 911

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

912 913 914
/**
 *	bio_copy_user	-	copy user data to bio
 *	@q: destination block queue
915
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
916 917 918
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
919
 *	@gfp_mask: memory allocation flags
920 921 922 923 924
 *
 *	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.
 */
925 926 927
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)
928 929 930 931 932 933
{
	struct sg_iovec iov;

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

934
	return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
935
}
936
EXPORT_SYMBOL(bio_copy_user);
937

938
static struct bio *__bio_map_user_iov(struct request_queue *q,
939 940
				      struct block_device *bdev,
				      struct sg_iovec *iov, int iov_count,
941
				      int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
942
{
943 944
	int i, j;
	int nr_pages = 0;
L
Linus Torvalds 已提交
945 946
	struct page **pages;
	struct bio *bio;
947 948
	int cur_page = 0;
	int ret, offset;
L
Linus Torvalds 已提交
949

950 951 952 953 954 955 956 957
	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;

		nr_pages += end - start;
		/*
958
		 * buffer must be aligned to at least hardsector size for now
959
		 */
960
		if (uaddr & queue_dma_alignment(q))
961 962 963 964
			return ERR_PTR(-EINVAL);
	}

	if (!nr_pages)
L
Linus Torvalds 已提交
965 966
		return ERR_PTR(-EINVAL);

967
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
968 969 970 971
	if (!bio)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
972
	pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
L
Linus Torvalds 已提交
973 974 975
	if (!pages)
		goto out;

976 977 978 979 980 981 982 983
	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;
		
N
Nick Piggin 已提交
984 985
		ret = get_user_pages_fast(uaddr, local_nr_pages,
				write_to_vm, &pages[cur_page]);
986 987
		if (ret < local_nr_pages) {
			ret = -EFAULT;
988
			goto out_unmap;
989
		}
990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003

		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...
			 */
1004 1005
			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
					    bytes)
1006 1007 1008 1009 1010
				break;

			len -= bytes;
			offset = 0;
		}
L
Linus Torvalds 已提交
1011

1012
		cur_page = j;
L
Linus Torvalds 已提交
1013
		/*
1014
		 * release the pages we didn't map into the bio, if any
L
Linus Torvalds 已提交
1015
		 */
1016 1017
		while (j < page_limit)
			page_cache_release(pages[j++]);
L
Linus Torvalds 已提交
1018 1019 1020 1021 1022 1023 1024 1025 1026 1027
	}

	kfree(pages);

	/*
	 * set data direction, and check if mapped pages need bouncing
	 */
	if (!write_to_vm)
		bio->bi_rw |= (1 << BIO_RW);

1028
	bio->bi_bdev = bdev;
L
Linus Torvalds 已提交
1029 1030
	bio->bi_flags |= (1 << BIO_USER_MAPPED);
	return bio;
1031 1032 1033 1034 1035 1036 1037 1038

 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
1039 1040 1041 1042 1043 1044 1045
	kfree(pages);
	bio_put(bio);
	return ERR_PTR(ret);
}

/**
 *	bio_map_user	-	map user address into bio
1046
 *	@q: the struct request_queue for the bio
L
Linus Torvalds 已提交
1047 1048 1049 1050
 *	@bdev: destination block device
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
1051
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
1052 1053 1054 1055
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1056
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1057 1058
			 unsigned long uaddr, unsigned int len, int write_to_vm,
			 gfp_t gfp_mask)
1059 1060 1061
{
	struct sg_iovec iov;

1062
	iov.iov_base = (void __user *)uaddr;
1063 1064
	iov.iov_len = len;

1065
	return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1066
}
1067
EXPORT_SYMBOL(bio_map_user);
1068 1069 1070

/**
 *	bio_map_user_iov - map user sg_iovec table into bio
1071
 *	@q: the struct request_queue for the bio
1072 1073 1074 1075
 *	@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
1076
 *	@gfp_mask: memory allocation flags
1077 1078 1079 1080
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1081
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1082
			     struct sg_iovec *iov, int iov_count,
1083
			     int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
1084 1085 1086
{
	struct bio *bio;

1087 1088
	bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
				 gfp_mask);
L
Linus Torvalds 已提交
1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
	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);

1100
	return bio;
L
Linus Torvalds 已提交
1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134
}

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);
}
1135
EXPORT_SYMBOL(bio_unmap_user);
L
Linus Torvalds 已提交
1136

1137
static void bio_map_kern_endio(struct bio *bio, int err)
1138 1139 1140 1141
{
	bio_put(bio);
}

1142
static struct bio *__bio_map_kern(struct request_queue *q, void *data,
A
Al Viro 已提交
1143
				  unsigned int len, gfp_t gfp_mask)
M
Mike Christie 已提交
1144 1145 1146 1147 1148 1149 1150 1151
{
	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;

1152
	bio = bio_kmalloc(gfp_mask, nr_pages);
M
Mike Christie 已提交
1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165
	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;

1166 1167
		if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
				    offset) < bytes)
M
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1168 1169 1170 1171 1172 1173 1174
			break;

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

1175
	bio->bi_end_io = bio_map_kern_endio;
M
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1176 1177 1178 1179 1180
	return bio;
}

/**
 *	bio_map_kern	-	map kernel address into bio
1181
 *	@q: the struct request_queue for the bio
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1182 1183 1184 1185 1186 1187 1188
 *	@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.
 */
1189
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
A
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1190
			 gfp_t gfp_mask)
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{
	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);
}
1207
EXPORT_SYMBOL(bio_map_kern);
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1209 1210 1211 1212
static void bio_copy_kern_endio(struct bio *bio, int err)
{
	struct bio_vec *bvec;
	const int read = bio_data_dir(bio) == READ;
1213
	struct bio_map_data *bmd = bio->bi_private;
1214
	int i;
1215
	char *p = bmd->sgvecs[0].iov_base;
1216 1217 1218

	__bio_for_each_segment(bvec, bio, i, 0) {
		char *addr = page_address(bvec->bv_page);
1219
		int len = bmd->iovecs[i].bv_len;
1220

1221
		if (read)
1222
			memcpy(p, addr, len);
1223 1224

		__free_page(bvec->bv_page);
1225
		p += len;
1226 1227
	}

1228
	bio_free_map_data(bmd);
1229 1230 1231 1232 1233 1234 1235 1236 1237
	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
1238
 *	@reading: data direction is READ
1239 1240 1241 1242 1243 1244 1245 1246 1247
 *
 *	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;
1248
	int i;
1249

1250 1251 1252
	bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
	if (IS_ERR(bio))
		return bio;
1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265

	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;
1266

1267 1268
	return bio;
}
1269
EXPORT_SYMBOL(bio_copy_kern);
1270

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/*
 * 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.
 * But other code (eg, pdflush) could clean the pages if they are mapped
 * 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);
	}
}

1313
static void bio_release_pages(struct bio *bio)
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{
	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.
 */

1337
static void bio_dirty_fn(struct work_struct *work);
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1339
static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
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static DEFINE_SPINLOCK(bio_dirty_lock);
static struct bio *bio_dirty_list;

/*
 * This runs in process context
 */
1346
static void bio_dirty_fn(struct work_struct *work)
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{
	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);
	}
}

/**
 * bio_endio - end I/O on a bio
 * @bio:	bio
 * @error:	error, if any
 *
 * Description:
1402
 *   bio_endio() will end I/O on the whole bio. bio_endio() is the
N
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 *   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
 *   something went wrong. Noone should call bi_end_io() directly on a
 *   bio unless they own it and thus know that it has an end_io
 *   function.
L
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 **/
1410
void bio_endio(struct bio *bio, int error)
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1411 1412 1413
{
	if (error)
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
N
NeilBrown 已提交
1414 1415
	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
		error = -EIO;
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1416

N
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1417
	if (bio->bi_end_io)
1418
		bio->bi_end_io(bio, error);
L
Linus Torvalds 已提交
1419
}
1420
EXPORT_SYMBOL(bio_endio);
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1421 1422 1423 1424 1425 1426

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

1427
		bio_endio(master, bp->error);
L
Linus Torvalds 已提交
1428 1429 1430
		mempool_free(bp, bp->bio2.bi_private);
	}
}
1431
EXPORT_SYMBOL(bio_pair_release);
L
Linus Torvalds 已提交
1432

1433
static void bio_pair_end_1(struct bio *bi, int err)
L
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1434 1435 1436 1437 1438 1439 1440 1441 1442
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

1443
static void bio_pair_end_2(struct bio *bi, int err)
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1444 1445 1446 1447 1448 1449 1450 1451 1452 1453
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

/*
1454
 * split a bio - only worry about a bio with a single page in its iovec
L
Linus Torvalds 已提交
1455
 */
D
Denis ChengRq 已提交
1456
struct bio_pair *bio_split(struct bio *bi, int first_sectors)
L
Linus Torvalds 已提交
1457
{
D
Denis ChengRq 已提交
1458
	struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
L
Linus Torvalds 已提交
1459 1460 1461 1462

	if (!bp)
		return bp;

1463
	trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1464 1465
				bi->bi_sector + first_sectors);

L
Linus Torvalds 已提交
1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484
	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;

1485 1486 1487
	bp->bio1.bi_max_vecs = 1;
	bp->bio2.bi_max_vecs = 1;

L
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1488 1489 1490 1491
	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
1492
	bp->bio2.bi_private = bio_split_pool;
L
Linus Torvalds 已提交
1493

1494 1495 1496
	if (bio_integrity(bi))
		bio_integrity_split(bi, bp, first_sectors);

L
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1497 1498
	return bp;
}
1499
EXPORT_SYMBOL(bio_split);
L
Linus Torvalds 已提交
1500

1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513
/**
 *      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)
{
1514
	unsigned int sector_sz;
1515 1516 1517 1518
	struct bio_vec *bv;
	sector_t sectors;
	int i;

1519
	sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537
	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);
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1538 1539 1540 1541 1542

/*
 * create memory pools for biovec's in a bio_set.
 * use the global biovec slabs created for general use.
 */
1543
static int biovec_create_pools(struct bio_set *bs, int pool_entries)
L
Linus Torvalds 已提交
1544
{
1545
	struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
L
Linus Torvalds 已提交
1546

1547 1548 1549
	bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
	if (!bs->bvec_pool)
		return -ENOMEM;
L
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1550 1551 1552 1553 1554 1555

	return 0;
}

static void biovec_free_pools(struct bio_set *bs)
{
1556
	mempool_destroy(bs->bvec_pool);
L
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1557 1558 1559 1560 1561 1562 1563
}

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

1564
	bioset_integrity_free(bs);
L
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1565
	biovec_free_pools(bs);
1566
	bio_put_slab(bs);
L
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1567 1568 1569

	kfree(bs);
}
1570
EXPORT_SYMBOL(bioset_free);
L
Linus Torvalds 已提交
1571

1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585
/**
 * 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
1586
{
1587
	unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1588
	struct bio_set *bs;
L
Linus Torvalds 已提交
1589

1590
	bs = kzalloc(sizeof(*bs), GFP_KERNEL);
L
Linus Torvalds 已提交
1591 1592 1593
	if (!bs)
		return NULL;

1594
	bs->front_pad = front_pad;
1595

1596
	bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1597 1598 1599 1600 1601 1602
	if (!bs->bio_slab) {
		kfree(bs);
		return NULL;
	}

	bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
L
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1603 1604 1605
	if (!bs->bio_pool)
		goto bad;

1606 1607 1608
	if (bioset_integrity_create(bs, pool_size))
		goto bad;

1609
	if (!biovec_create_pools(bs, pool_size))
L
Linus Torvalds 已提交
1610 1611 1612 1613 1614 1615
		return bs;

bad:
	bioset_free(bs);
	return NULL;
}
1616
EXPORT_SYMBOL(bioset_create);
L
Linus Torvalds 已提交
1617 1618 1619 1620 1621 1622 1623 1624 1625

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;

1626 1627 1628 1629 1630 1631 1632
#ifndef CONFIG_BLK_DEV_INTEGRITY
		if (bvs->nr_vecs <= BIO_INLINE_VECS) {
			bvs->slab = NULL;
			continue;
		}
#endif

L
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1633 1634
		size = bvs->nr_vecs * sizeof(struct bio_vec);
		bvs->slab = kmem_cache_create(bvs->name, size, 0,
1635
                                SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
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1636 1637 1638 1639 1640
	}
}

static int __init init_bio(void)
{
1641 1642 1643 1644 1645
	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
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1646

1647
	bio_integrity_init();
L
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1648 1649
	biovec_init_slabs();

1650
	fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
L
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1651 1652 1653
	if (!fs_bio_set)
		panic("bio: can't allocate bios\n");

1654 1655
	bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
						     sizeof(struct bio_pair));
L
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1656 1657 1658 1659 1660 1661
	if (!bio_split_pool)
		panic("bio: can't create split pool\n");

	return 0;
}
subsys_initcall(init_bio);