bio.c 39.4 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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static 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) {
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		bslab = &bio_slabs[i];
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		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;

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	printk(KERN_INFO "bio: create slab <%s> at %d\n", bslab->name, entry);
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	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;
	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.
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 *
 * Description:
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 *   bio_alloc_bioset will 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.
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 *
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 *   Note that the caller must set ->bi_destructor on successful return
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 *   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
 *
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 *	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.
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 *
 *	RETURNS:
 *	Pointer to new bio on success, NULL on failure.
 */
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struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
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{
	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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/**
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 * bio_kmalloc - allocate a bio for I/O using kmalloc()
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 * @gfp_mask:   the GFP_ mask given to the slab allocator
 * @nr_iovecs:	number of iovecs to pre-allocate
 *
 * Description:
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 *   Allocate a new bio with @nr_iovecs bvecs.  If @gfp_mask contains
 *   %__GFP_WAIT, the allocation is guaranteed to succeed.
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 *
 **/
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struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
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{
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	struct bio *bio;
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	if (nr_iovecs > UIO_MAXIOV)
		return NULL;

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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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	return min_t(unsigned,
		     queue_max_segments(q),
		     queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
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}
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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) {
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			unsigned int prev_bv_len = prev->bv_len;
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			prev->bv_len += len;
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			if (q->merge_bvec_fn) {
				struct bvec_merge_data bvm = {
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					/* prev_bvec is already charged in
					   bi_size, discharge it in order to
					   simulate merging updated prev_bvec
					   as new bvec. */
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					.bi_bdev = bio->bi_bdev,
					.bi_sector = bio->bi_sector,
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					.bi_size = bio->bi_size - prev_bv_len,
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					.bi_rw = bio->bi_rw,
				};

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				if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
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					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_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) {
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		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
		 */
608
		if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
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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 */
617
	if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
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		bio->bi_flags &= ~(1 << BIO_SEG_VALID);

	bio->bi_vcnt++;
	bio->bi_phys_segments++;
622
 done:
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623 624 625 626
	bio->bi_size += len;
	return len;
}

627 628
/**
 *	bio_add_pc_page	-	attempt to add page to bio
J
Jens Axboe 已提交
629
 *	@q: the target queue
630 631 632 633 634 635
 *	@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
636 637 638 639 640
 *	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.
641
 */
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
/**
 *	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
658 659 660
 *	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.
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 */
int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
		 unsigned int offset)
{
665
	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
666
	return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
L
Linus Torvalds 已提交
667
}
668
EXPORT_SYMBOL(bio_add_page);
L
Linus Torvalds 已提交
669 670 671

struct bio_map_data {
	struct bio_vec *iovecs;
672
	struct sg_iovec *sgvecs;
673 674
	int nr_sgvecs;
	int is_our_pages;
L
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675 676
};

677
static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
678 679
			     struct sg_iovec *iov, int iov_count,
			     int is_our_pages)
L
Linus Torvalds 已提交
680 681
{
	memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
682 683
	memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
	bmd->nr_sgvecs = iov_count;
684
	bmd->is_our_pages = is_our_pages;
L
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685 686 687 688 689 690
	bio->bi_private = bmd;
}

static void bio_free_map_data(struct bio_map_data *bmd)
{
	kfree(bmd->iovecs);
691
	kfree(bmd->sgvecs);
L
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692 693 694
	kfree(bmd);
}

695 696
static struct bio_map_data *bio_alloc_map_data(int nr_segs,
					       unsigned int iov_count,
697
					       gfp_t gfp_mask)
L
Linus Torvalds 已提交
698
{
699 700 701 702
	struct bio_map_data *bmd;

	if (iov_count > UIO_MAXIOV)
		return NULL;
L
Linus Torvalds 已提交
703

704
	bmd = kmalloc(sizeof(*bmd), gfp_mask);
L
Linus Torvalds 已提交
705 706 707
	if (!bmd)
		return NULL;

708
	bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
709 710 711 712 713
	if (!bmd->iovecs) {
		kfree(bmd);
		return NULL;
	}

714
	bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
715
	if (bmd->sgvecs)
L
Linus Torvalds 已提交
716 717
		return bmd;

718
	kfree(bmd->iovecs);
L
Linus Torvalds 已提交
719 720 721 722
	kfree(bmd);
	return NULL;
}

723
static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
724 725
			  struct sg_iovec *iov, int iov_count,
			  int to_user, int from_user, int do_free_page)
726 727 728 729 730 731 732 733
{
	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);
734
		unsigned int bv_len = iovecs[i].bv_len;
735 736 737

		while (bv_len && iov_idx < iov_count) {
			unsigned int bytes;
738
			char __user *iov_addr;
739 740 741 742 743 744

			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) {
745
				if (to_user)
746 747 748
					ret = copy_to_user(iov_addr, bv_addr,
							   bytes);

749 750 751 752
				if (from_user)
					ret = copy_from_user(bv_addr, iov_addr,
							     bytes);

753 754 755 756 757 758 759 760 761 762 763 764 765 766 767
				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;
			}
		}

768
		if (do_free_page)
769 770 771 772 773 774
			__free_page(bvec->bv_page);
	}

	return ret;
}

L
Linus Torvalds 已提交
775 776 777 778 779 780 781 782 783 784
/**
 *	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;
785
	int ret = 0;
L
Linus Torvalds 已提交
786

787 788
	if (!bio_flagged(bio, BIO_NULL_MAPPED))
		ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
789 790
				     bmd->nr_sgvecs, bio_data_dir(bio) == READ,
				     0, bmd->is_our_pages);
L
Linus Torvalds 已提交
791 792 793 794
	bio_free_map_data(bmd);
	bio_put(bio);
	return ret;
}
795
EXPORT_SYMBOL(bio_uncopy_user);
L
Linus Torvalds 已提交
796 797

/**
798
 *	bio_copy_user_iov	-	copy user data to bio
L
Linus Torvalds 已提交
799
 *	@q: destination block queue
800
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
801 802
 *	@iov:	the iovec.
 *	@iov_count: number of elements in the iovec
L
Linus Torvalds 已提交
803
 *	@write_to_vm: bool indicating writing to pages or not
804
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
805 806 807 808 809
 *
 *	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.
 */
810 811 812 813
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
814 815 816 817 818 819
{
	struct bio_map_data *bmd;
	struct bio_vec *bvec;
	struct page *page;
	struct bio *bio;
	int i, ret;
820 821
	int nr_pages = 0;
	unsigned int len = 0;
822
	unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
L
Linus Torvalds 已提交
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;

833 834 835 836 837 838
		/*
		 * Overflow, abort
		 */
		if (end < start)
			return ERR_PTR(-EINVAL);

839 840 841 842
		nr_pages += end - start;
		len += iov[i].iov_len;
	}

843 844 845
	if (offset)
		nr_pages++;

846
	bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
L
Linus Torvalds 已提交
847 848 849 850
	if (!bmd)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
851
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
852 853 854
	if (!bio)
		goto out_bmd;

855 856
	if (!write_to_vm)
		bio->bi_rw |= REQ_WRITE;
L
Linus Torvalds 已提交
857 858

	ret = 0;
859 860

	if (map_data) {
861
		nr_pages = 1 << map_data->page_order;
862 863
		i = map_data->offset / PAGE_SIZE;
	}
L
Linus Torvalds 已提交
864
	while (len) {
865
		unsigned int bytes = PAGE_SIZE;
L
Linus Torvalds 已提交
866

867 868
		bytes -= offset;

L
Linus Torvalds 已提交
869 870 871
		if (bytes > len)
			bytes = len;

872
		if (map_data) {
873
			if (i == map_data->nr_entries * nr_pages) {
874 875 876
				ret = -ENOMEM;
				break;
			}
877 878 879 880 881 882

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

			i++;
		} else {
883
			page = alloc_page(q->bounce_gfp | gfp_mask);
884 885 886 887
			if (!page) {
				ret = -ENOMEM;
				break;
			}
L
Linus Torvalds 已提交
888 889
		}

890
		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
L
Linus Torvalds 已提交
891 892 893
			break;

		len -= bytes;
894
		offset = 0;
L
Linus Torvalds 已提交
895 896 897 898 899 900 901 902
	}

	if (ret)
		goto cleanup;

	/*
	 * success
	 */
903 904 905
	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);
906 907
		if (ret)
			goto cleanup;
L
Linus Torvalds 已提交
908 909
	}

910
	bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
L
Linus Torvalds 已提交
911 912
	return bio;
cleanup:
913 914 915
	if (!map_data)
		bio_for_each_segment(bvec, bio, i)
			__free_page(bvec->bv_page);
L
Linus Torvalds 已提交
916 917 918 919 920 921 922

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

923 924 925
/**
 *	bio_copy_user	-	copy user data to bio
 *	@q: destination block queue
926
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
927 928 929
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
930
 *	@gfp_mask: memory allocation flags
931 932 933 934 935
 *
 *	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.
 */
936 937 938
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)
939 940 941 942 943 944
{
	struct sg_iovec iov;

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

945
	return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
946
}
947
EXPORT_SYMBOL(bio_copy_user);
948

949
static struct bio *__bio_map_user_iov(struct request_queue *q,
950 951
				      struct block_device *bdev,
				      struct sg_iovec *iov, int iov_count,
952
				      int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
953
{
954 955
	int i, j;
	int nr_pages = 0;
L
Linus Torvalds 已提交
956 957
	struct page **pages;
	struct bio *bio;
958 959
	int cur_page = 0;
	int ret, offset;
L
Linus Torvalds 已提交
960

961 962 963 964 965 966
	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;

967 968 969 970 971 972
		/*
		 * Overflow, abort
		 */
		if (end < start)
			return ERR_PTR(-EINVAL);

973 974
		nr_pages += end - start;
		/*
975
		 * buffer must be aligned to at least hardsector size for now
976
		 */
977
		if (uaddr & queue_dma_alignment(q))
978 979 980 981
			return ERR_PTR(-EINVAL);
	}

	if (!nr_pages)
L
Linus Torvalds 已提交
982 983
		return ERR_PTR(-EINVAL);

984
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
985 986 987 988
	if (!bio)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
989
	pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
L
Linus Torvalds 已提交
990 991 992
	if (!pages)
		goto out;

993 994 995 996 997 998 999
	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;
1000

N
Nick Piggin 已提交
1001 1002
		ret = get_user_pages_fast(uaddr, local_nr_pages,
				write_to_vm, &pages[cur_page]);
1003 1004
		if (ret < local_nr_pages) {
			ret = -EFAULT;
1005
			goto out_unmap;
1006
		}
1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020

		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...
			 */
1021 1022
			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
					    bytes)
1023 1024 1025 1026 1027
				break;

			len -= bytes;
			offset = 0;
		}
L
Linus Torvalds 已提交
1028

1029
		cur_page = j;
L
Linus Torvalds 已提交
1030
		/*
1031
		 * release the pages we didn't map into the bio, if any
L
Linus Torvalds 已提交
1032
		 */
1033 1034
		while (j < page_limit)
			page_cache_release(pages[j++]);
L
Linus Torvalds 已提交
1035 1036 1037 1038 1039 1040 1041 1042
	}

	kfree(pages);

	/*
	 * set data direction, and check if mapped pages need bouncing
	 */
	if (!write_to_vm)
1043
		bio->bi_rw |= REQ_WRITE;
L
Linus Torvalds 已提交
1044

1045
	bio->bi_bdev = bdev;
L
Linus Torvalds 已提交
1046 1047
	bio->bi_flags |= (1 << BIO_USER_MAPPED);
	return bio;
1048 1049 1050 1051 1052 1053 1054 1055

 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
1056 1057 1058 1059 1060 1061 1062
	kfree(pages);
	bio_put(bio);
	return ERR_PTR(ret);
}

/**
 *	bio_map_user	-	map user address into bio
1063
 *	@q: the struct request_queue for the bio
L
Linus Torvalds 已提交
1064 1065 1066 1067
 *	@bdev: destination block device
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
1068
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
1069 1070 1071 1072
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1073
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1074 1075
			 unsigned long uaddr, unsigned int len, int write_to_vm,
			 gfp_t gfp_mask)
1076 1077 1078
{
	struct sg_iovec iov;

1079
	iov.iov_base = (void __user *)uaddr;
1080 1081
	iov.iov_len = len;

1082
	return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1083
}
1084
EXPORT_SYMBOL(bio_map_user);
1085 1086 1087

/**
 *	bio_map_user_iov - map user sg_iovec table into bio
1088
 *	@q: the struct request_queue for the bio
1089 1090 1091 1092
 *	@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
1093
 *	@gfp_mask: memory allocation flags
1094 1095 1096 1097
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1098
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1099
			     struct sg_iovec *iov, int iov_count,
1100
			     int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
1101 1102 1103
{
	struct bio *bio;

1104 1105
	bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
				 gfp_mask);
L
Linus Torvalds 已提交
1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116
	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);

1117
	return bio;
L
Linus Torvalds 已提交
1118 1119 1120 1121 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
}

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);
}
1152
EXPORT_SYMBOL(bio_unmap_user);
L
Linus Torvalds 已提交
1153

1154
static void bio_map_kern_endio(struct bio *bio, int err)
1155 1156 1157 1158
{
	bio_put(bio);
}

1159
static struct bio *__bio_map_kern(struct request_queue *q, void *data,
A
Al Viro 已提交
1160
				  unsigned int len, gfp_t gfp_mask)
M
Mike Christie 已提交
1161 1162 1163 1164 1165 1166 1167 1168
{
	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;

1169
	bio = bio_kmalloc(gfp_mask, nr_pages);
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1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182
	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;

1183 1184
		if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
				    offset) < bytes)
M
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1185 1186 1187 1188 1189 1190 1191
			break;

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

1192
	bio->bi_end_io = bio_map_kern_endio;
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1193 1194 1195 1196 1197
	return bio;
}

/**
 *	bio_map_kern	-	map kernel address into bio
1198
 *	@q: the struct request_queue for the bio
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1199 1200 1201 1202 1203 1204 1205
 *	@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.
 */
1206
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
A
Al Viro 已提交
1207
			 gfp_t gfp_mask)
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1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223
{
	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);
}
1224
EXPORT_SYMBOL(bio_map_kern);
M
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1225

1226 1227 1228 1229
static void bio_copy_kern_endio(struct bio *bio, int err)
{
	struct bio_vec *bvec;
	const int read = bio_data_dir(bio) == READ;
1230
	struct bio_map_data *bmd = bio->bi_private;
1231
	int i;
1232
	char *p = bmd->sgvecs[0].iov_base;
1233 1234 1235

	__bio_for_each_segment(bvec, bio, i, 0) {
		char *addr = page_address(bvec->bv_page);
1236
		int len = bmd->iovecs[i].bv_len;
1237

1238
		if (read)
1239
			memcpy(p, addr, len);
1240 1241

		__free_page(bvec->bv_page);
1242
		p += len;
1243 1244
	}

1245
	bio_free_map_data(bmd);
1246 1247 1248 1249 1250 1251 1252 1253 1254
	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
1255
 *	@reading: data direction is READ
1256 1257 1258 1259 1260 1261 1262 1263 1264
 *
 *	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;
1265
	int i;
1266

1267 1268 1269
	bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
	if (IS_ERR(bio))
		return bio;
1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282

	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;
1283

1284 1285
	return bio;
}
1286
EXPORT_SYMBOL(bio_copy_kern);
1287

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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);
	}
}

1330
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.
 */

1354
static void bio_dirty_fn(struct work_struct *work);
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Linus Torvalds 已提交
1355

1356
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
 */
1363
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);
	}
}

1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424
#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

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/**
 * bio_endio - end I/O on a bio
 * @bio:	bio
 * @error:	error, if any
 *
 * Description:
1431
 *   bio_endio() will end I/O on the whole bio. bio_endio() is the
N
NeilBrown 已提交
1432 1433 1434
 *   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
1435
 *   something went wrong. No one should call bi_end_io() directly on a
N
NeilBrown 已提交
1436 1437
 *   bio unless they own it and thus know that it has an end_io
 *   function.
L
Linus Torvalds 已提交
1438
 **/
1439
void bio_endio(struct bio *bio, int error)
L
Linus Torvalds 已提交
1440 1441 1442
{
	if (error)
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
N
NeilBrown 已提交
1443 1444
	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
		error = -EIO;
L
Linus Torvalds 已提交
1445

N
NeilBrown 已提交
1446
	if (bio->bi_end_io)
1447
		bio->bi_end_io(bio, error);
L
Linus Torvalds 已提交
1448
}
1449
EXPORT_SYMBOL(bio_endio);
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1450 1451 1452 1453 1454 1455

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

1456
		bio_endio(master, bp->error);
L
Linus Torvalds 已提交
1457 1458 1459
		mempool_free(bp, bp->bio2.bi_private);
	}
}
1460
EXPORT_SYMBOL(bio_pair_release);
L
Linus Torvalds 已提交
1461

1462
static void bio_pair_end_1(struct bio *bi, int err)
L
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1463 1464 1465 1466 1467 1468 1469 1470 1471
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

1472
static void bio_pair_end_2(struct bio *bi, int err)
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Linus Torvalds 已提交
1473 1474 1475 1476 1477 1478 1479 1480 1481 1482
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

/*
1483
 * split a bio - only worry about a bio with a single page in its iovec
L
Linus Torvalds 已提交
1484
 */
D
Denis ChengRq 已提交
1485
struct bio_pair *bio_split(struct bio *bi, int first_sectors)
L
Linus Torvalds 已提交
1486
{
D
Denis ChengRq 已提交
1487
	struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
L
Linus Torvalds 已提交
1488 1489 1490 1491

	if (!bp)
		return bp;

1492
	trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1493 1494
				bi->bi_sector + first_sectors);

L
Linus Torvalds 已提交
1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513
	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;

1514 1515 1516
	bp->bio1.bi_max_vecs = 1;
	bp->bio2.bi_max_vecs = 1;

L
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1517 1518 1519 1520
	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
1521
	bp->bio2.bi_private = bio_split_pool;
L
Linus Torvalds 已提交
1522

1523 1524 1525
	if (bio_integrity(bi))
		bio_integrity_split(bi, bp, first_sectors);

L
Linus Torvalds 已提交
1526 1527
	return bp;
}
1528
EXPORT_SYMBOL(bio_split);
L
Linus Torvalds 已提交
1529

1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542
/**
 *      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)
{
1543
	unsigned int sector_sz;
1544 1545 1546 1547
	struct bio_vec *bv;
	sector_t sectors;
	int i;

1548
	sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566
	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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1567 1568 1569 1570 1571

/*
 * create memory pools for biovec's in a bio_set.
 * use the global biovec slabs created for general use.
 */
1572
static int biovec_create_pools(struct bio_set *bs, int pool_entries)
L
Linus Torvalds 已提交
1573
{
1574
	struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
L
Linus Torvalds 已提交
1575

1576 1577 1578
	bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
	if (!bs->bvec_pool)
		return -ENOMEM;
L
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1579 1580 1581 1582 1583 1584

	return 0;
}

static void biovec_free_pools(struct bio_set *bs)
{
1585
	mempool_destroy(bs->bvec_pool);
L
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1586 1587 1588 1589 1590 1591 1592
}

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

1593
	bioset_integrity_free(bs);
L
Linus Torvalds 已提交
1594
	biovec_free_pools(bs);
1595
	bio_put_slab(bs);
L
Linus Torvalds 已提交
1596 1597 1598

	kfree(bs);
}
1599
EXPORT_SYMBOL(bioset_free);
L
Linus Torvalds 已提交
1600

1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614
/**
 * 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
1615
{
1616
	unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1617
	struct bio_set *bs;
L
Linus Torvalds 已提交
1618

1619
	bs = kzalloc(sizeof(*bs), GFP_KERNEL);
L
Linus Torvalds 已提交
1620 1621 1622
	if (!bs)
		return NULL;

1623
	bs->front_pad = front_pad;
1624

1625
	bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1626 1627 1628 1629 1630 1631
	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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1632 1633 1634
	if (!bs->bio_pool)
		goto bad;

1635
	if (!biovec_create_pools(bs, pool_size))
L
Linus Torvalds 已提交
1636 1637 1638 1639 1640 1641
		return bs;

bad:
	bioset_free(bs);
	return NULL;
}
1642
EXPORT_SYMBOL(bioset_create);
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Linus Torvalds 已提交
1643 1644 1645 1646 1647 1648 1649 1650 1651

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;

1652 1653 1654 1655 1656
		if (bvs->nr_vecs <= BIO_INLINE_VECS) {
			bvs->slab = NULL;
			continue;
		}

L
Linus Torvalds 已提交
1657 1658
		size = bvs->nr_vecs * sizeof(struct bio_vec);
		bvs->slab = kmem_cache_create(bvs->name, size, 0,
1659
                                SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
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1660 1661 1662 1663 1664
	}
}

static int __init init_bio(void)
{
1665 1666 1667 1668 1669
	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
1670

1671
	bio_integrity_init();
L
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1672 1673
	biovec_init_slabs();

1674
	fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
L
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1675 1676 1677
	if (!fs_bio_set)
		panic("bio: can't allocate bios\n");

1678 1679 1680
	if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
		panic("bio: can't create integrity pool\n");

1681 1682
	bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
						     sizeof(struct bio_pair));
L
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1683 1684 1685 1686 1687 1688
	if (!bio_split_pool)
		panic("bio: can't create split pool\n");

	return 0;
}
subsys_initcall(init_bio);