bio.c 38.8 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 <linux/blktrace_api.h>
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#include <trace/block.h>
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#include <scsi/sg.h>		/* for struct sg_iovec */
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DEFINE_TRACE(block_split);

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

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static mempool_t *bio_split_pool __read_mostly;
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/*
 * if you change this list, also change bvec_alloc or things will
 * break badly! cannot be bigger than what you can fit into an
 * unsigned short
 */
#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
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struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
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	BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
};
#undef BV

/*
 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
 * IO code that does not need private memory pools.
 */
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struct bio_set *fs_bio_set;
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/*
 * Our slab pool management
 */
struct bio_slab {
	struct kmem_cache *slab;
	unsigned int slab_ref;
	unsigned int slab_size;
	char name[8];
};
static DEFINE_MUTEX(bio_slab_lock);
static struct bio_slab *bio_slabs;
static unsigned int bio_slab_nr, bio_slab_max;

static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
{
	unsigned int sz = sizeof(struct bio) + extra_size;
	struct kmem_cache *slab = NULL;
	struct bio_slab *bslab;
	unsigned int i, entry = -1;

	mutex_lock(&bio_slab_lock);

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

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

	if (slab)
		goto out_unlock;

	if (bio_slab_nr == bio_slab_max && entry == -1) {
		bio_slab_max <<= 1;
		bio_slabs = krealloc(bio_slabs,
				     bio_slab_max * sizeof(struct bio_slab),
				     GFP_KERNEL);
		if (!bio_slabs)
			goto out_unlock;
	}
	if (entry == -1)
		entry = bio_slab_nr++;

	bslab = &bio_slabs[entry];

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

	printk("bio: create slab <%s> at %d\n", bslab->name, entry);
	bslab->slab = slab;
	bslab->slab_ref = 1;
	bslab->slab_size = sz;
out_unlock:
	mutex_unlock(&bio_slab_lock);
	return slab;
}

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

	mutex_lock(&bio_slab_lock);

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

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

	WARN_ON(!bslab->slab_ref);

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

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

out:
	mutex_unlock(&bio_slab_lock);
}

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

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void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
{
	BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);

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

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

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

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	/*
	 * see comment near bvec_array define!
	 */
	switch (nr) {
	case 1:
		*idx = 0;
		break;
	case 2 ... 4:
		*idx = 1;
		break;
	case 5 ... 16:
		*idx = 2;
		break;
	case 17 ... 64:
		*idx = 3;
		break;
	case 65 ... 128:
		*idx = 4;
		break;
	case 129 ... BIO_MAX_PAGES:
		*idx = 5;
		break;
	default:
		return NULL;
	}

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

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

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	return bvl;
}

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void bio_free(struct bio *bio, struct bio_set *bs)
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{
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	void *p;
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	if (bio_has_allocated_vec(bio))
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		bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
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	if (bio_integrity(bio))
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		bio_integrity_free(bio);
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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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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);
}

/**
 * bio_alloc_bioset - allocate a bio for I/O
 * @gfp_mask:   the GFP_ mask given to the slab allocator
 * @nr_iovecs:	number of iovecs to pre-allocate
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 * @bs:		the bio_set to allocate from. If %NULL, just use kmalloc
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 *
 * Description:
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 *   bio_alloc_bioset will first try its own mempool to satisfy the allocation.
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 *   If %__GFP_WAIT is set then we will block on the internal pool waiting
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 *   for a &struct bio to become free. If a %NULL @bs is passed in, we will
 *   fall back to just using @kmalloc to allocate the required memory.
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 *
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 *   Note that the caller must set ->bi_destructor on succesful return
 *   of a bio, to do the appropriate freeing of the bio once the reference
 *   count drops to zero.
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 **/
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struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
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{
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	unsigned long idx = BIO_POOL_NONE;
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	struct bio_vec *bvl = NULL;
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	struct bio *bio;
	void *p;

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

	if (unlikely(!nr_iovecs))
		goto out_set;

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

		nr_iovecs = bvec_nr_vecs(idx);
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	}
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out_set:
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	bio->bi_flags |= idx << BIO_POOL_OFFSET;
	bio->bi_max_vecs = nr_iovecs;
	bio->bi_io_vec = bvl;
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	return bio;
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err_free:
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	mempool_free(p, bs->bio_pool);
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	return NULL;
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}

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static void bio_fs_destructor(struct bio *bio)
{
	bio_free(bio, fs_bio_set);
}

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

	if (bio)
		bio->bi_destructor = bio_fs_destructor;

	return bio;
}

static void bio_kmalloc_destructor(struct bio *bio)
{
	if (bio_integrity(bio))
		bio_integrity_free(bio);
	kfree(bio);
}

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/**
 * bio_alloc - allocate a bio for I/O
 * @gfp_mask:   the GFP_ mask given to the slab allocator
 * @nr_iovecs:	number of iovecs to pre-allocate
 *
 * Description:
 *   bio_alloc will allocate a bio and associated bio_vec array that can hold
 *   at least @nr_iovecs entries. Allocations will be done from the
 *   fs_bio_set. Also see @bio_alloc_bioset.
 *
 *   If %__GFP_WAIT is set, then bio_alloc will always be able to allocate
 *   a bio. This is due to the mempool guarantees. To make this work, callers
 *   must never allocate more than 1 bio at the time from this pool. Callers
 *   that need to allocate more than 1 bio must always submit the previously
 *   allocate bio for IO before attempting to allocate a new one. Failure to
 *   do so can cause livelocks under memory pressure.
 *
 **/
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struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs)
{
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	struct bio *bio;
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	bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec),
		      gfp_mask);
	if (unlikely(!bio))
		return NULL;

	bio_init(bio);
	bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
	bio->bi_max_vecs = nr_iovecs;
	bio->bi_io_vec = bio->bi_inline_vecs;
	bio->bi_destructor = bio_kmalloc_destructor;
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	return bio;
}

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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
 *   bio_alloc or bio_get. The last put of a bio will free it.
 **/
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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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;
}

/**
 * 	__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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}

/**
 *	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);
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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;
}

/**
 *	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;

	nr_pages = ((q->max_sectors << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
	if (nr_pages > q->max_phys_segments)
		nr_pages = q->max_phys_segments;
	if (nr_pages > q->max_hw_segments)
		nr_pages = q->max_hw_segments;

	return nr_pages;
}

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static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
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			  *page, unsigned int len, unsigned int offset,
			  unsigned short max_sectors)
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{
	int retried_segments = 0;
	struct bio_vec *bvec;

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

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

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

		if (page == prev->bv_page &&
		    offset == prev->bv_offset + prev->bv_len) {
			prev->bv_len += len;
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			if (q->merge_bvec_fn) {
				struct bvec_merge_data bvm = {
					.bi_bdev = bio->bi_bdev,
					.bi_sector = bio->bi_sector,
					.bi_size = bio->bi_size,
					.bi_rw = bio->bi_rw,
				};

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

			goto done;
		}
	}

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

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

	while (bio->bi_phys_segments >= q->max_phys_segments
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	       || bio->bi_phys_segments >= q->max_hw_segments) {
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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
		 */
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		if (q->merge_bvec_fn(q, &bvm, bvec) < 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 */
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	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++;
615
 done:
L
Linus Torvalds 已提交
616 617 618 619
	bio->bi_size += len;
	return len;
}

620 621
/**
 *	bio_add_pc_page	-	attempt to add page to bio
J
Jens Axboe 已提交
622
 *	@q: the target queue
623 624 625 626 627 628 629 630 631 632 633
 *	@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.
 */
634
int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
635 636
		    unsigned int len, unsigned int offset)
{
637
	return __bio_add_page(q, bio, page, len, offset, q->max_hw_sectors);
638 639
}

L
Linus Torvalds 已提交
640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655
/**
 *	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)
{
656 657
	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
	return __bio_add_page(q, bio, page, len, offset, q->max_sectors);
L
Linus Torvalds 已提交
658 659 660 661
}

struct bio_map_data {
	struct bio_vec *iovecs;
662
	struct sg_iovec *sgvecs;
663 664
	int nr_sgvecs;
	int is_our_pages;
L
Linus Torvalds 已提交
665 666
};

667
static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
668 669
			     struct sg_iovec *iov, int iov_count,
			     int is_our_pages)
L
Linus Torvalds 已提交
670 671
{
	memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
672 673
	memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
	bmd->nr_sgvecs = iov_count;
674
	bmd->is_our_pages = is_our_pages;
L
Linus Torvalds 已提交
675 676 677 678 679 680
	bio->bi_private = bmd;
}

static void bio_free_map_data(struct bio_map_data *bmd)
{
	kfree(bmd->iovecs);
681
	kfree(bmd->sgvecs);
L
Linus Torvalds 已提交
682 683 684
	kfree(bmd);
}

685 686
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
687
{
688
	struct bio_map_data *bmd = kmalloc(sizeof(*bmd), gfp_mask);
L
Linus Torvalds 已提交
689 690 691 692

	if (!bmd)
		return NULL;

693
	bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
694 695 696 697 698
	if (!bmd->iovecs) {
		kfree(bmd);
		return NULL;
	}

699
	bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
700
	if (bmd->sgvecs)
L
Linus Torvalds 已提交
701 702
		return bmd;

703
	kfree(bmd->iovecs);
L
Linus Torvalds 已提交
704 705 706 707
	kfree(bmd);
	return NULL;
}

708
static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
709 710
			  struct sg_iovec *iov, int iov_count, int uncopy,
			  int do_free_page)
711 712 713 714 715 716 717 718 719
{
	int ret = 0, i;
	struct bio_vec *bvec;
	int iov_idx = 0;
	unsigned int iov_off = 0;
	int read = bio_data_dir(bio) == READ;

	__bio_for_each_segment(bvec, bio, i, 0) {
		char *bv_addr = page_address(bvec->bv_page);
720
		unsigned int bv_len = iovecs[i].bv_len;
721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752

		while (bv_len && iov_idx < iov_count) {
			unsigned int bytes;
			char *iov_addr;

			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) {
				if (!read && !uncopy)
					ret = copy_from_user(bv_addr, iov_addr,
							     bytes);
				if (read && uncopy)
					ret = copy_to_user(iov_addr, bv_addr,
							   bytes);

				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;
			}
		}

753
		if (do_free_page)
754 755 756 757 758 759
			__free_page(bvec->bv_page);
	}

	return ret;
}

L
Linus Torvalds 已提交
760 761 762 763 764 765 766 767 768 769
/**
 *	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;
770
	int ret = 0;
L
Linus Torvalds 已提交
771

772 773 774
	if (!bio_flagged(bio, BIO_NULL_MAPPED))
		ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
				     bmd->nr_sgvecs, 1, bmd->is_our_pages);
L
Linus Torvalds 已提交
775 776 777 778 779 780
	bio_free_map_data(bmd);
	bio_put(bio);
	return ret;
}

/**
781
 *	bio_copy_user_iov	-	copy user data to bio
L
Linus Torvalds 已提交
782
 *	@q: destination block queue
783
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
784 785
 *	@iov:	the iovec.
 *	@iov_count: number of elements in the iovec
L
Linus Torvalds 已提交
786
 *	@write_to_vm: bool indicating writing to pages or not
787
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
788 789 790 791 792
 *
 *	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.
 */
793 794 795 796
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
797 798 799 800 801 802
{
	struct bio_map_data *bmd;
	struct bio_vec *bvec;
	struct page *page;
	struct bio *bio;
	int i, ret;
803 804
	int nr_pages = 0;
	unsigned int len = 0;
805
	unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
L
Linus Torvalds 已提交
806

807 808 809 810 811 812 813 814 815 816 817 818 819
	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;
	}

820
	bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
L
Linus Torvalds 已提交
821 822 823 824
	if (!bmd)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
825
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
826 827 828 829 830 831
	if (!bio)
		goto out_bmd;

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

	ret = 0;
832 833

	if (map_data) {
834
		nr_pages = 1 << map_data->page_order;
835 836
		i = map_data->offset / PAGE_SIZE;
	}
L
Linus Torvalds 已提交
837
	while (len) {
838
		unsigned int bytes = PAGE_SIZE;
L
Linus Torvalds 已提交
839

840 841
		bytes -= offset;

L
Linus Torvalds 已提交
842 843 844
		if (bytes > len)
			bytes = len;

845
		if (map_data) {
846
			if (i == map_data->nr_entries * nr_pages) {
847 848 849
				ret = -ENOMEM;
				break;
			}
850 851 852 853 854 855

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

			i++;
		} else {
856
			page = alloc_page(q->bounce_gfp | gfp_mask);
857 858 859 860
			if (!page) {
				ret = -ENOMEM;
				break;
			}
L
Linus Torvalds 已提交
861 862
		}

863
		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
L
Linus Torvalds 已提交
864 865 866
			break;

		len -= bytes;
867
		offset = 0;
L
Linus Torvalds 已提交
868 869 870 871 872 873 874 875
	}

	if (ret)
		goto cleanup;

	/*
	 * success
	 */
876
	if (!write_to_vm && (!map_data || !map_data->null_mapped)) {
877
		ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 0);
878 879
		if (ret)
			goto cleanup;
L
Linus Torvalds 已提交
880 881
	}

882
	bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
L
Linus Torvalds 已提交
883 884
	return bio;
cleanup:
885 886 887
	if (!map_data)
		bio_for_each_segment(bvec, bio, i)
			__free_page(bvec->bv_page);
L
Linus Torvalds 已提交
888 889 890 891 892 893 894

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

895 896 897
/**
 *	bio_copy_user	-	copy user data to bio
 *	@q: destination block queue
898
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
899 900 901
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
902
 *	@gfp_mask: memory allocation flags
903 904 905 906 907
 *
 *	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.
 */
908 909 910
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)
911 912 913 914 915 916
{
	struct sg_iovec iov;

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

917
	return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
918 919
}

920
static struct bio *__bio_map_user_iov(struct request_queue *q,
921 922
				      struct block_device *bdev,
				      struct sg_iovec *iov, int iov_count,
923
				      int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
924
{
925 926
	int i, j;
	int nr_pages = 0;
L
Linus Torvalds 已提交
927 928
	struct page **pages;
	struct bio *bio;
929 930
	int cur_page = 0;
	int ret, offset;
L
Linus Torvalds 已提交
931

932 933 934 935 936 937 938 939
	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;
		/*
940
		 * buffer must be aligned to at least hardsector size for now
941
		 */
942
		if (uaddr & queue_dma_alignment(q))
943 944 945 946
			return ERR_PTR(-EINVAL);
	}

	if (!nr_pages)
L
Linus Torvalds 已提交
947 948
		return ERR_PTR(-EINVAL);

949
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
950 951 952 953
	if (!bio)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
954
	pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
L
Linus Torvalds 已提交
955 956 957
	if (!pages)
		goto out;

958 959 960 961 962 963 964 965
	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
966 967
		ret = get_user_pages_fast(uaddr, local_nr_pages,
				write_to_vm, &pages[cur_page]);
968 969
		if (ret < local_nr_pages) {
			ret = -EFAULT;
970
			goto out_unmap;
971
		}
972 973 974 975 976 977 978 979 980 981 982 983 984 985

		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...
			 */
986 987
			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
					    bytes)
988 989 990 991 992
				break;

			len -= bytes;
			offset = 0;
		}
L
Linus Torvalds 已提交
993

994
		cur_page = j;
L
Linus Torvalds 已提交
995
		/*
996
		 * release the pages we didn't map into the bio, if any
L
Linus Torvalds 已提交
997
		 */
998 999
		while (j < page_limit)
			page_cache_release(pages[j++]);
L
Linus Torvalds 已提交
1000 1001 1002 1003 1004 1005 1006 1007 1008 1009
	}

	kfree(pages);

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

1010
	bio->bi_bdev = bdev;
L
Linus Torvalds 已提交
1011 1012
	bio->bi_flags |= (1 << BIO_USER_MAPPED);
	return bio;
1013 1014 1015 1016 1017 1018 1019 1020

 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
1021 1022 1023 1024 1025 1026 1027
	kfree(pages);
	bio_put(bio);
	return ERR_PTR(ret);
}

/**
 *	bio_map_user	-	map user address into bio
1028
 *	@q: the struct request_queue for the bio
L
Linus Torvalds 已提交
1029 1030 1031 1032
 *	@bdev: destination block device
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
1033
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
1034 1035 1036 1037
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1038
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1039 1040
			 unsigned long uaddr, unsigned int len, int write_to_vm,
			 gfp_t gfp_mask)
1041 1042 1043
{
	struct sg_iovec iov;

1044
	iov.iov_base = (void __user *)uaddr;
1045 1046
	iov.iov_len = len;

1047
	return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1048 1049 1050 1051
}

/**
 *	bio_map_user_iov - map user sg_iovec table into bio
1052
 *	@q: the struct request_queue for the bio
1053 1054 1055 1056
 *	@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
1057
 *	@gfp_mask: memory allocation flags
1058 1059 1060 1061
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1062
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1063
			     struct sg_iovec *iov, int iov_count,
1064
			     int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
1065 1066 1067
{
	struct bio *bio;

1068 1069
	bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
				 gfp_mask);
L
Linus Torvalds 已提交
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
	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);

1081
	return bio;
L
Linus Torvalds 已提交
1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116
}

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);
}

1117
static void bio_map_kern_endio(struct bio *bio, int err)
1118 1119 1120 1121 1122
{
	bio_put(bio);
}


1123
static struct bio *__bio_map_kern(struct request_queue *q, void *data,
A
Al Viro 已提交
1124
				  unsigned int len, gfp_t gfp_mask)
M
Mike Christie 已提交
1125 1126 1127 1128 1129 1130 1131 1132
{
	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;

1133
	bio = bio_kmalloc(gfp_mask, nr_pages);
M
Mike Christie 已提交
1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146
	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;

1147 1148
		if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
				    offset) < bytes)
M
Mike Christie 已提交
1149 1150 1151 1152 1153 1154 1155
			break;

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

1156
	bio->bi_end_io = bio_map_kern_endio;
M
Mike Christie 已提交
1157 1158 1159 1160 1161
	return bio;
}

/**
 *	bio_map_kern	-	map kernel address into bio
1162
 *	@q: the struct request_queue for the bio
M
Mike Christie 已提交
1163 1164 1165 1166 1167 1168 1169
 *	@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.
 */
1170
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
A
Al Viro 已提交
1171
			 gfp_t gfp_mask)
M
Mike Christie 已提交
1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188
{
	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);
}

1189 1190 1191 1192
static void bio_copy_kern_endio(struct bio *bio, int err)
{
	struct bio_vec *bvec;
	const int read = bio_data_dir(bio) == READ;
1193
	struct bio_map_data *bmd = bio->bi_private;
1194
	int i;
1195
	char *p = bmd->sgvecs[0].iov_base;
1196 1197 1198

	__bio_for_each_segment(bvec, bio, i, 0) {
		char *addr = page_address(bvec->bv_page);
1199
		int len = bmd->iovecs[i].bv_len;
1200

1201
		if (read)
1202
			memcpy(p, addr, len);
1203 1204

		__free_page(bvec->bv_page);
1205
		p += len;
1206 1207
	}

1208
	bio_free_map_data(bmd);
1209 1210 1211 1212 1213 1214 1215 1216 1217
	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
1218
 *	@reading: data direction is READ
1219 1220 1221 1222 1223 1224 1225 1226 1227
 *
 *	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;
1228
	int i;
1229

1230 1231 1232
	bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
	if (IS_ERR(bio))
		return bio;
1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245

	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;
1246

1247 1248 1249
	return bio;
}

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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);
	}
}

1292
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.
 */

1316
static void bio_dirty_fn(struct work_struct *work);
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1318
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
 */
1325
static void bio_dirty_fn(struct work_struct *work)
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{
	unsigned long flags;
	struct bio *bio;

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

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

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

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

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

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

	if (nr_clean_pages) {
		unsigned long flags;

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

/**
 * bio_endio - end I/O on a bio
 * @bio:	bio
 * @error:	error, if any
 *
 * Description:
1381
 *   bio_endio() will end I/O on the whole bio. bio_endio() is the
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 *   preferred way to end I/O on a bio, it takes care of clearing
 *   BIO_UPTODATE on error. @error is 0 on success, and and one of the
 *   established -Exxxx (-EIO, for instance) error values in case
 *   something went wrong. Noone should call bi_end_io() directly on a
 *   bio unless they own it and thus know that it has an end_io
 *   function.
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 **/
1389
void bio_endio(struct bio *bio, int error)
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1390 1391 1392
{
	if (error)
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
N
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	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
		error = -EIO;
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N
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1396
	if (bio->bi_end_io)
1397
		bio->bi_end_io(bio, error);
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}

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

1405
		bio_endio(master, bp->error);
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Linus Torvalds 已提交
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		mempool_free(bp, bp->bio2.bi_private);
	}
}

1410
static void bio_pair_end_1(struct bio *bi, int err)
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Linus Torvalds 已提交
1411 1412 1413 1414 1415 1416 1417 1418 1419
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

1420
static void bio_pair_end_2(struct bio *bi, int err)
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1421 1422 1423 1424 1425 1426 1427 1428 1429 1430
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

/*
1431
 * split a bio - only worry about a bio with a single page in its iovec
L
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1432
 */
D
Denis ChengRq 已提交
1433
struct bio_pair *bio_split(struct bio *bi, int first_sectors)
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Linus Torvalds 已提交
1434
{
D
Denis ChengRq 已提交
1435
	struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
L
Linus Torvalds 已提交
1436 1437 1438 1439

	if (!bp)
		return bp;

1440
	trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1441 1442
				bi->bi_sector + first_sectors);

L
Linus Torvalds 已提交
1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461
	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;

1462 1463 1464
	bp->bio1.bi_max_vecs = 1;
	bp->bio2.bi_max_vecs = 1;

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	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
1469
	bp->bio2.bi_private = bio_split_pool;
L
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1470

1471 1472 1473
	if (bio_integrity(bi))
		bio_integrity_split(bi, bp, first_sectors);

L
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1474 1475 1476
	return bp;
}

1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512
/**
 *      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)
{
	unsigned int sector_sz = queue_hardsect_size(bio->bi_bdev->bd_disk->queue);
	struct bio_vec *bv;
	sector_t sectors;
	int i;

	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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1513 1514 1515 1516 1517

/*
 * create memory pools for biovec's in a bio_set.
 * use the global biovec slabs created for general use.
 */
1518
static int biovec_create_pools(struct bio_set *bs, int pool_entries)
L
Linus Torvalds 已提交
1519
{
1520
	struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
L
Linus Torvalds 已提交
1521

1522 1523 1524
	bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
	if (!bs->bvec_pool)
		return -ENOMEM;
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1525 1526 1527 1528 1529 1530

	return 0;
}

static void biovec_free_pools(struct bio_set *bs)
{
1531
	mempool_destroy(bs->bvec_pool);
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1532 1533 1534 1535 1536 1537 1538 1539
}

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

	biovec_free_pools(bs);
1540
	bio_put_slab(bs);
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1541 1542 1543 1544

	kfree(bs);
}

1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558
/**
 * 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
1559
{
1560
	unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1561
	struct bio_set *bs;
L
Linus Torvalds 已提交
1562

1563
	bs = kzalloc(sizeof(*bs), GFP_KERNEL);
L
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1564 1565 1566
	if (!bs)
		return NULL;

1567
	bs->front_pad = front_pad;
1568

1569
	bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1570 1571 1572 1573 1574 1575
	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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1576 1577 1578
	if (!bs->bio_pool)
		goto bad;

1579
	if (!biovec_create_pools(bs, pool_size))
L
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1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594
		return bs;

bad:
	bioset_free(bs);
	return NULL;
}

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;

1595 1596 1597 1598 1599 1600 1601
#ifndef CONFIG_BLK_DEV_INTEGRITY
		if (bvs->nr_vecs <= BIO_INLINE_VECS) {
			bvs->slab = NULL;
			continue;
		}
#endif

L
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1602 1603
		size = bvs->nr_vecs * sizeof(struct bio_vec);
		bvs->slab = kmem_cache_create(bvs->name, size, 0,
1604
                                SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
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1605 1606 1607 1608 1609
	}
}

static int __init init_bio(void)
{
1610 1611 1612 1613 1614
	bio_slab_max = 2;
	bio_slab_nr = 0;
	bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
	if (!bio_slabs)
		panic("bio: can't allocate bios\n");
L
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1615 1616 1617

	biovec_init_slabs();

1618
	fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
L
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1619 1620 1621
	if (!fs_bio_set)
		panic("bio: can't allocate bios\n");

1622 1623
	bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
						     sizeof(struct bio_pair));
L
Linus Torvalds 已提交
1624 1625 1626 1627 1628 1629 1630 1631 1632
	if (!bio_split_pool)
		panic("bio: can't create split pool\n");

	return 0;
}

subsys_initcall(init_bio);

EXPORT_SYMBOL(bio_alloc);
J
Jens Axboe 已提交
1633
EXPORT_SYMBOL(bio_kmalloc);
L
Linus Torvalds 已提交
1634
EXPORT_SYMBOL(bio_put);
P
Peter Osterlund 已提交
1635
EXPORT_SYMBOL(bio_free);
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1636 1637 1638 1639 1640 1641
EXPORT_SYMBOL(bio_endio);
EXPORT_SYMBOL(bio_init);
EXPORT_SYMBOL(__bio_clone);
EXPORT_SYMBOL(bio_clone);
EXPORT_SYMBOL(bio_phys_segments);
EXPORT_SYMBOL(bio_add_page);
1642
EXPORT_SYMBOL(bio_add_pc_page);
L
Linus Torvalds 已提交
1643
EXPORT_SYMBOL(bio_get_nr_vecs);
J
Jens Axboe 已提交
1644 1645
EXPORT_SYMBOL(bio_map_user);
EXPORT_SYMBOL(bio_unmap_user);
M
Mike Christie 已提交
1646
EXPORT_SYMBOL(bio_map_kern);
1647
EXPORT_SYMBOL(bio_copy_kern);
L
Linus Torvalds 已提交
1648 1649 1650 1651 1652 1653 1654
EXPORT_SYMBOL(bio_pair_release);
EXPORT_SYMBOL(bio_split);
EXPORT_SYMBOL(bio_copy_user);
EXPORT_SYMBOL(bio_uncopy_user);
EXPORT_SYMBOL(bioset_create);
EXPORT_SYMBOL(bioset_free);
EXPORT_SYMBOL(bio_alloc_bioset);