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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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;

	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 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.
 */
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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/**
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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, 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;
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	if (nr_pages > queue_max_segments(q))
		nr_pages = queue_max_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) {
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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) < 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) {
600 601 602 603 604 605 606
		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
		 */
611
		if (q->merge_bvec_fn(q, &bvm, bvec) < len) {
L
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612 613 614 615 616 617 618 619
			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 */
620
	if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
L
Linus Torvalds 已提交
621 622 623 624
		bio->bi_flags &= ~(1 << BIO_SEG_VALID);

	bio->bi_vcnt++;
	bio->bi_phys_segments++;
625
 done:
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626 627 628 629
	bio->bi_size += len;
	return len;
}

630 631
/**
 *	bio_add_pc_page	-	attempt to add page to bio
J
Jens Axboe 已提交
632
 *	@q: the target queue
633 634 635 636 637 638 639 640 641 642 643
 *	@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.
 */
644
int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
645 646
		    unsigned int len, unsigned int offset)
{
647 648
	return __bio_add_page(q, bio, page, len, offset,
			      queue_max_hw_sectors(q));
649
}
650
EXPORT_SYMBOL(bio_add_pc_page);
651

L
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652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667
/**
 *	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)
{
668
	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
669
	return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
L
Linus Torvalds 已提交
670
}
671
EXPORT_SYMBOL(bio_add_page);
L
Linus Torvalds 已提交
672 673 674

struct bio_map_data {
	struct bio_vec *iovecs;
675
	struct sg_iovec *sgvecs;
676 677
	int nr_sgvecs;
	int is_our_pages;
L
Linus Torvalds 已提交
678 679
};

680
static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
681 682
			     struct sg_iovec *iov, int iov_count,
			     int is_our_pages)
L
Linus Torvalds 已提交
683 684
{
	memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
685 686
	memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
	bmd->nr_sgvecs = iov_count;
687
	bmd->is_our_pages = is_our_pages;
L
Linus Torvalds 已提交
688 689 690 691 692 693
	bio->bi_private = bmd;
}

static void bio_free_map_data(struct bio_map_data *bmd)
{
	kfree(bmd->iovecs);
694
	kfree(bmd->sgvecs);
L
Linus Torvalds 已提交
695 696 697
	kfree(bmd);
}

698 699
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
700
{
701
	struct bio_map_data *bmd = kmalloc(sizeof(*bmd), gfp_mask);
L
Linus Torvalds 已提交
702 703 704 705

	if (!bmd)
		return NULL;

706
	bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
707 708 709 710 711
	if (!bmd->iovecs) {
		kfree(bmd);
		return NULL;
	}

712
	bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
713
	if (bmd->sgvecs)
L
Linus Torvalds 已提交
714 715
		return bmd;

716
	kfree(bmd->iovecs);
L
Linus Torvalds 已提交
717 718 719 720
	kfree(bmd);
	return NULL;
}

721
static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
722 723
			  struct sg_iovec *iov, int iov_count,
			  int to_user, int from_user, int do_free_page)
724 725 726 727 728 729 730 731
{
	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);
732
		unsigned int bv_len = iovecs[i].bv_len;
733 734 735

		while (bv_len && iov_idx < iov_count) {
			unsigned int bytes;
736
			char __user *iov_addr;
737 738 739 740 741 742

			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) {
743
				if (to_user)
744 745 746
					ret = copy_to_user(iov_addr, bv_addr,
							   bytes);

747 748 749 750
				if (from_user)
					ret = copy_from_user(bv_addr, iov_addr,
							     bytes);

751 752 753 754 755 756 757 758 759 760 761 762 763 764 765
				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;
			}
		}

766
		if (do_free_page)
767 768 769 770 771 772
			__free_page(bvec->bv_page);
	}

	return ret;
}

L
Linus Torvalds 已提交
773 774 775 776 777 778 779 780 781 782
/**
 *	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;
783
	int ret = 0;
L
Linus Torvalds 已提交
784

785 786
	if (!bio_flagged(bio, BIO_NULL_MAPPED))
		ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
787 788
				     bmd->nr_sgvecs, bio_data_dir(bio) == READ,
				     0, bmd->is_our_pages);
L
Linus Torvalds 已提交
789 790 791 792
	bio_free_map_data(bmd);
	bio_put(bio);
	return ret;
}
793
EXPORT_SYMBOL(bio_uncopy_user);
L
Linus Torvalds 已提交
794 795

/**
796
 *	bio_copy_user_iov	-	copy user data to bio
L
Linus Torvalds 已提交
797
 *	@q: destination block queue
798
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
799 800
 *	@iov:	the iovec.
 *	@iov_count: number of elements in the iovec
L
Linus Torvalds 已提交
801
 *	@write_to_vm: bool indicating writing to pages or not
802
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
803 804 805 806 807
 *
 *	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.
 */
808 809 810 811
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
812 813 814 815 816 817
{
	struct bio_map_data *bmd;
	struct bio_vec *bvec;
	struct page *page;
	struct bio *bio;
	int i, ret;
818 819
	int nr_pages = 0;
	unsigned int len = 0;
820
	unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
L
Linus Torvalds 已提交
821

822 823 824 825 826 827 828 829 830 831 832 833 834
	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;
	}

835 836 837
	if (offset)
		nr_pages++;

838
	bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
L
Linus Torvalds 已提交
839 840 841 842
	if (!bmd)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
843
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
844 845 846 847 848 849
	if (!bio)
		goto out_bmd;

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

	ret = 0;
850 851

	if (map_data) {
852
		nr_pages = 1 << map_data->page_order;
853 854
		i = map_data->offset / PAGE_SIZE;
	}
L
Linus Torvalds 已提交
855
	while (len) {
856
		unsigned int bytes = PAGE_SIZE;
L
Linus Torvalds 已提交
857

858 859
		bytes -= offset;

L
Linus Torvalds 已提交
860 861 862
		if (bytes > len)
			bytes = len;

863
		if (map_data) {
864
			if (i == map_data->nr_entries * nr_pages) {
865 866 867
				ret = -ENOMEM;
				break;
			}
868 869 870 871 872 873

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

			i++;
		} else {
874
			page = alloc_page(q->bounce_gfp | gfp_mask);
875 876 877 878
			if (!page) {
				ret = -ENOMEM;
				break;
			}
L
Linus Torvalds 已提交
879 880
		}

881
		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
L
Linus Torvalds 已提交
882 883 884
			break;

		len -= bytes;
885
		offset = 0;
L
Linus Torvalds 已提交
886 887 888 889 890 891 892 893
	}

	if (ret)
		goto cleanup;

	/*
	 * success
	 */
894 895 896
	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);
897 898
		if (ret)
			goto cleanup;
L
Linus Torvalds 已提交
899 900
	}

901
	bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
L
Linus Torvalds 已提交
902 903
	return bio;
cleanup:
904 905 906
	if (!map_data)
		bio_for_each_segment(bvec, bio, i)
			__free_page(bvec->bv_page);
L
Linus Torvalds 已提交
907 908 909 910 911 912 913

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

914 915 916
/**
 *	bio_copy_user	-	copy user data to bio
 *	@q: destination block queue
917
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
918 919 920
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
921
 *	@gfp_mask: memory allocation flags
922 923 924 925 926
 *
 *	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.
 */
927 928 929
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)
930 931 932 933 934 935
{
	struct sg_iovec iov;

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

936
	return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
937
}
938
EXPORT_SYMBOL(bio_copy_user);
939

940
static struct bio *__bio_map_user_iov(struct request_queue *q,
941 942
				      struct block_device *bdev,
				      struct sg_iovec *iov, int iov_count,
943
				      int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
944
{
945 946
	int i, j;
	int nr_pages = 0;
L
Linus Torvalds 已提交
947 948
	struct page **pages;
	struct bio *bio;
949 950
	int cur_page = 0;
	int ret, offset;
L
Linus Torvalds 已提交
951

952 953 954 955 956 957 958 959
	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;
		/*
960
		 * buffer must be aligned to at least hardsector size for now
961
		 */
962
		if (uaddr & queue_dma_alignment(q))
963 964 965 966
			return ERR_PTR(-EINVAL);
	}

	if (!nr_pages)
L
Linus Torvalds 已提交
967 968
		return ERR_PTR(-EINVAL);

969
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
970 971 972 973
	if (!bio)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
974
	pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
L
Linus Torvalds 已提交
975 976 977
	if (!pages)
		goto out;

978 979 980 981 982 983 984 985
	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
986 987
		ret = get_user_pages_fast(uaddr, local_nr_pages,
				write_to_vm, &pages[cur_page]);
988 989
		if (ret < local_nr_pages) {
			ret = -EFAULT;
990
			goto out_unmap;
991
		}
992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005

		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...
			 */
1006 1007
			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
					    bytes)
1008 1009 1010 1011 1012
				break;

			len -= bytes;
			offset = 0;
		}
L
Linus Torvalds 已提交
1013

1014
		cur_page = j;
L
Linus Torvalds 已提交
1015
		/*
1016
		 * release the pages we didn't map into the bio, if any
L
Linus Torvalds 已提交
1017
		 */
1018 1019
		while (j < page_limit)
			page_cache_release(pages[j++]);
L
Linus Torvalds 已提交
1020 1021 1022 1023 1024 1025 1026 1027 1028 1029
	}

	kfree(pages);

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

1030
	bio->bi_bdev = bdev;
L
Linus Torvalds 已提交
1031 1032
	bio->bi_flags |= (1 << BIO_USER_MAPPED);
	return bio;
1033 1034 1035 1036 1037 1038 1039 1040

 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
1041 1042 1043 1044 1045 1046 1047
	kfree(pages);
	bio_put(bio);
	return ERR_PTR(ret);
}

/**
 *	bio_map_user	-	map user address into bio
1048
 *	@q: the struct request_queue for the bio
L
Linus Torvalds 已提交
1049 1050 1051 1052
 *	@bdev: destination block device
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
1053
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
1054 1055 1056 1057
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1058
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1059 1060
			 unsigned long uaddr, unsigned int len, int write_to_vm,
			 gfp_t gfp_mask)
1061 1062 1063
{
	struct sg_iovec iov;

1064
	iov.iov_base = (void __user *)uaddr;
1065 1066
	iov.iov_len = len;

1067
	return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1068
}
1069
EXPORT_SYMBOL(bio_map_user);
1070 1071 1072

/**
 *	bio_map_user_iov - map user sg_iovec table into bio
1073
 *	@q: the struct request_queue for the bio
1074 1075 1076 1077
 *	@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
1078
 *	@gfp_mask: memory allocation flags
1079 1080 1081 1082
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1083
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1084
			     struct sg_iovec *iov, int iov_count,
1085
			     int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
1086 1087 1088
{
	struct bio *bio;

1089 1090
	bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
				 gfp_mask);
L
Linus Torvalds 已提交
1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101
	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);

1102
	return bio;
L
Linus Torvalds 已提交
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 1135 1136
}

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);
}
1137
EXPORT_SYMBOL(bio_unmap_user);
L
Linus Torvalds 已提交
1138

1139
static void bio_map_kern_endio(struct bio *bio, int err)
1140 1141 1142 1143
{
	bio_put(bio);
}

1144
static struct bio *__bio_map_kern(struct request_queue *q, void *data,
A
Al Viro 已提交
1145
				  unsigned int len, gfp_t gfp_mask)
M
Mike Christie 已提交
1146 1147 1148 1149 1150 1151 1152 1153
{
	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;

1154
	bio = bio_kmalloc(gfp_mask, nr_pages);
M
Mike Christie 已提交
1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167
	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;

1168 1169
		if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
				    offset) < bytes)
M
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1170 1171 1172 1173 1174 1175 1176
			break;

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

1177
	bio->bi_end_io = bio_map_kern_endio;
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1178 1179 1180 1181 1182
	return bio;
}

/**
 *	bio_map_kern	-	map kernel address into bio
1183
 *	@q: the struct request_queue for the bio
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1184 1185 1186 1187 1188 1189 1190
 *	@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.
 */
1191
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
A
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1192
			 gfp_t gfp_mask)
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1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208
{
	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);
}
1209
EXPORT_SYMBOL(bio_map_kern);
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1210

1211 1212 1213 1214
static void bio_copy_kern_endio(struct bio *bio, int err)
{
	struct bio_vec *bvec;
	const int read = bio_data_dir(bio) == READ;
1215
	struct bio_map_data *bmd = bio->bi_private;
1216
	int i;
1217
	char *p = bmd->sgvecs[0].iov_base;
1218 1219 1220

	__bio_for_each_segment(bvec, bio, i, 0) {
		char *addr = page_address(bvec->bv_page);
1221
		int len = bmd->iovecs[i].bv_len;
1222

1223
		if (read)
1224
			memcpy(p, addr, len);
1225 1226

		__free_page(bvec->bv_page);
1227
		p += len;
1228 1229
	}

1230
	bio_free_map_data(bmd);
1231 1232 1233 1234 1235 1236 1237 1238 1239
	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
1240
 *	@reading: data direction is READ
1241 1242 1243 1244 1245 1246 1247 1248 1249
 *
 *	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;
1250
	int i;
1251

1252 1253 1254
	bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
	if (IS_ERR(bio))
		return bio;
1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267

	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;
1268

1269 1270
	return bio;
}
1271
EXPORT_SYMBOL(bio_copy_kern);
1272

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1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314
/*
 * 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);
	}
}

1315
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.
 */

1339
static void bio_dirty_fn(struct work_struct *work);
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Linus Torvalds 已提交
1340

1341
static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
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1342 1343 1344 1345 1346 1347
static DEFINE_SPINLOCK(bio_dirty_lock);
static struct bio *bio_dirty_list;

/*
 * This runs in process context
 */
1348
static void bio_dirty_fn(struct work_struct *work)
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1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397
{
	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);
	}
}

1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409
#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:
1416
 *   bio_endio() will end I/O on the whole bio. bio_endio() is the
N
NeilBrown 已提交
1417 1418 1419 1420 1421 1422
 *   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
Linus Torvalds 已提交
1423
 **/
1424
void bio_endio(struct bio *bio, int error)
L
Linus Torvalds 已提交
1425 1426 1427
{
	if (error)
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
N
NeilBrown 已提交
1428 1429
	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
		error = -EIO;
L
Linus Torvalds 已提交
1430

N
NeilBrown 已提交
1431
	if (bio->bi_end_io)
1432
		bio->bi_end_io(bio, error);
L
Linus Torvalds 已提交
1433
}
1434
EXPORT_SYMBOL(bio_endio);
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1435 1436 1437 1438 1439 1440

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

1441
		bio_endio(master, bp->error);
L
Linus Torvalds 已提交
1442 1443 1444
		mempool_free(bp, bp->bio2.bi_private);
	}
}
1445
EXPORT_SYMBOL(bio_pair_release);
L
Linus Torvalds 已提交
1446

1447
static void bio_pair_end_1(struct bio *bi, int err)
L
Linus Torvalds 已提交
1448 1449 1450 1451 1452 1453 1454 1455 1456
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

1457
static void bio_pair_end_2(struct bio *bi, int err)
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1458 1459 1460 1461 1462 1463 1464 1465 1466 1467
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

/*
1468
 * split a bio - only worry about a bio with a single page in its iovec
L
Linus Torvalds 已提交
1469
 */
D
Denis ChengRq 已提交
1470
struct bio_pair *bio_split(struct bio *bi, int first_sectors)
L
Linus Torvalds 已提交
1471
{
D
Denis ChengRq 已提交
1472
	struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
L
Linus Torvalds 已提交
1473 1474 1475 1476

	if (!bp)
		return bp;

1477
	trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1478 1479
				bi->bi_sector + first_sectors);

L
Linus Torvalds 已提交
1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498
	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;

1499 1500 1501
	bp->bio1.bi_max_vecs = 1;
	bp->bio2.bi_max_vecs = 1;

L
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1502 1503 1504 1505
	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
1506
	bp->bio2.bi_private = bio_split_pool;
L
Linus Torvalds 已提交
1507

1508 1509 1510
	if (bio_integrity(bi))
		bio_integrity_split(bi, bp, first_sectors);

L
Linus Torvalds 已提交
1511 1512
	return bp;
}
1513
EXPORT_SYMBOL(bio_split);
L
Linus Torvalds 已提交
1514

1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527
/**
 *      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)
{
1528
	unsigned int sector_sz;
1529 1530 1531 1532
	struct bio_vec *bv;
	sector_t sectors;
	int i;

1533
	sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551
	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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1552 1553 1554 1555 1556

/*
 * create memory pools for biovec's in a bio_set.
 * use the global biovec slabs created for general use.
 */
1557
static int biovec_create_pools(struct bio_set *bs, int pool_entries)
L
Linus Torvalds 已提交
1558
{
1559
	struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
L
Linus Torvalds 已提交
1560

1561 1562 1563
	bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
	if (!bs->bvec_pool)
		return -ENOMEM;
L
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1564 1565 1566 1567 1568 1569

	return 0;
}

static void biovec_free_pools(struct bio_set *bs)
{
1570
	mempool_destroy(bs->bvec_pool);
L
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1571 1572 1573 1574 1575 1576 1577
}

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

1578
	bioset_integrity_free(bs);
L
Linus Torvalds 已提交
1579
	biovec_free_pools(bs);
1580
	bio_put_slab(bs);
L
Linus Torvalds 已提交
1581 1582 1583

	kfree(bs);
}
1584
EXPORT_SYMBOL(bioset_free);
L
Linus Torvalds 已提交
1585

1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599
/**
 * 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
1600
{
1601
	unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1602
	struct bio_set *bs;
L
Linus Torvalds 已提交
1603

1604
	bs = kzalloc(sizeof(*bs), GFP_KERNEL);
L
Linus Torvalds 已提交
1605 1606 1607
	if (!bs)
		return NULL;

1608
	bs->front_pad = front_pad;
1609

1610
	bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1611 1612 1613 1614 1615 1616
	if (!bs->bio_slab) {
		kfree(bs);
		return NULL;
	}

	bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
L
Linus Torvalds 已提交
1617 1618 1619
	if (!bs->bio_pool)
		goto bad;

1620 1621 1622
	if (bioset_integrity_create(bs, pool_size))
		goto bad;

1623
	if (!biovec_create_pools(bs, pool_size))
L
Linus Torvalds 已提交
1624 1625 1626 1627 1628 1629
		return bs;

bad:
	bioset_free(bs);
	return NULL;
}
1630
EXPORT_SYMBOL(bioset_create);
L
Linus Torvalds 已提交
1631 1632 1633 1634 1635 1636 1637 1638 1639

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;

1640 1641 1642 1643 1644 1645 1646
#ifndef CONFIG_BLK_DEV_INTEGRITY
		if (bvs->nr_vecs <= BIO_INLINE_VECS) {
			bvs->slab = NULL;
			continue;
		}
#endif

L
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1647 1648
		size = bvs->nr_vecs * sizeof(struct bio_vec);
		bvs->slab = kmem_cache_create(bvs->name, size, 0,
1649
                                SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
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1650 1651 1652 1653 1654
	}
}

static int __init init_bio(void)
{
1655 1656 1657 1658 1659
	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
1660

1661
	bio_integrity_init();
L
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1662 1663
	biovec_init_slabs();

1664
	fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
L
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1665 1666 1667
	if (!fs_bio_set)
		panic("bio: can't allocate bios\n");

1668 1669
	bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
						     sizeof(struct bio_pair));
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1670 1671 1672 1673 1674 1675
	if (!bio_split_pool)
		panic("bio: can't create split pool\n");

	return 0;
}
subsys_initcall(init_bio);