bio.c 39.0 KB
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/*
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 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
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 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 *
 */
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mempool.h>
#include <linux/workqueue.h>
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#include <scsi/sg.h>		/* for struct sg_iovec */
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#include <trace/events/block.h>
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/*
 * Test patch to inline a certain number of bi_io_vec's inside the bio
 * itself, to shrink a bio data allocation from two mempool calls to one
 */
#define BIO_INLINE_VECS		4

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

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

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

	mutex_lock(&bio_slab_lock);

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

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

	if (slab)
		goto out_unlock;

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

	bslab = &bio_slabs[entry];

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

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

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

	mutex_lock(&bio_slab_lock);

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

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

	WARN_ON(!bslab->slab_ref);

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

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

out:
	mutex_unlock(&bio_slab_lock);
}

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

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

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

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

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

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

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

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

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	return bvl;
}

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void bio_free(struct bio *bio, struct bio_set *bs)
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{
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	void *p;
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	if (bio_has_allocated_vec(bio))
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		bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
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	if (bio_integrity(bio))
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		bio_integrity_free(bio, bs);
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	/*
	 * If we have front padding, adjust the bio pointer before freeing
	 */
	p = bio;
	if (bs->front_pad)
		p -= bs->front_pad;

	mempool_free(p, bs->bio_pool);
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}

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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))
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		bio_integrity_free(bio, fs_bio_set);
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	kfree(bio);
}

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

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

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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, 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;
}

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

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	nr_pages = ((queue_max_sectors(q) << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
	if (nr_pages > queue_max_phys_segments(q))
		nr_pages = queue_max_phys_segments(q);
	if (nr_pages > queue_max_hw_segments(q))
		nr_pages = queue_max_hw_segments(q);
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	return nr_pages;
}

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

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

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

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

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

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

			goto done;
		}
	}

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

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

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	while (bio->bi_phys_segments >= queue_max_phys_segments(q)
	       || bio->bi_phys_segments >= queue_max_hw_segments(q)) {
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		if (retried_segments)
			return 0;

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

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

	/*
	 * if queue has other restrictions (eg varying max sector size
	 * depending on offset), it can specify a merge_bvec_fn in the
	 * queue to get further control
	 */
	if (q->merge_bvec_fn) {
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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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Linus Torvalds 已提交
609 610 611 612
		bio->bi_flags &= ~(1 << BIO_SEG_VALID);

	bio->bi_vcnt++;
	bio->bi_phys_segments++;
613
 done:
L
Linus Torvalds 已提交
614 615 616 617
	bio->bi_size += len;
	return len;
}

618 619
/**
 *	bio_add_pc_page	-	attempt to add page to bio
J
Jens Axboe 已提交
620
 *	@q: the target queue
621 622 623 624 625 626 627 628 629 630 631
 *	@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.
 */
632
int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
633 634
		    unsigned int len, unsigned int offset)
{
635 636
	return __bio_add_page(q, bio, page, len, offset,
			      queue_max_hw_sectors(q));
637 638
}

L
Linus Torvalds 已提交
639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654
/**
 *	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)
{
655
	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
656
	return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
L
Linus Torvalds 已提交
657 658 659 660
}

struct bio_map_data {
	struct bio_vec *iovecs;
661
	struct sg_iovec *sgvecs;
662 663
	int nr_sgvecs;
	int is_our_pages;
L
Linus Torvalds 已提交
664 665
};

666
static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
667 668
			     struct sg_iovec *iov, int iov_count,
			     int is_our_pages)
L
Linus Torvalds 已提交
669 670
{
	memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
671 672
	memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
	bmd->nr_sgvecs = iov_count;
673
	bmd->is_our_pages = is_our_pages;
L
Linus Torvalds 已提交
674 675 676 677 678 679
	bio->bi_private = bmd;
}

static void bio_free_map_data(struct bio_map_data *bmd)
{
	kfree(bmd->iovecs);
680
	kfree(bmd->sgvecs);
L
Linus Torvalds 已提交
681 682 683
	kfree(bmd);
}

684 685
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
686
{
687
	struct bio_map_data *bmd = kmalloc(sizeof(*bmd), gfp_mask);
L
Linus Torvalds 已提交
688 689 690 691

	if (!bmd)
		return NULL;

692
	bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
693 694 695 696 697
	if (!bmd->iovecs) {
		kfree(bmd);
		return NULL;
	}

698
	bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
699
	if (bmd->sgvecs)
L
Linus Torvalds 已提交
700 701
		return bmd;

702
	kfree(bmd->iovecs);
L
Linus Torvalds 已提交
703 704 705 706
	kfree(bmd);
	return NULL;
}

707
static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
708 709
			  struct sg_iovec *iov, int iov_count, int uncopy,
			  int do_free_page)
710 711 712 713 714 715 716 717 718
{
	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);
719
		unsigned int bv_len = iovecs[i].bv_len;
720 721 722

		while (bv_len && iov_idx < iov_count) {
			unsigned int bytes;
723
			char __user *iov_addr;
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

			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;
			}
		}

752
		if (do_free_page)
753 754 755 756 757 758
			__free_page(bvec->bv_page);
	}

	return ret;
}

L
Linus Torvalds 已提交
759 760 761 762 763 764 765 766 767 768
/**
 *	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;
769
	int ret = 0;
L
Linus Torvalds 已提交
770

771 772 773
	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
774 775 776 777 778 779
	bio_free_map_data(bmd);
	bio_put(bio);
	return ret;
}

/**
780
 *	bio_copy_user_iov	-	copy user data to bio
L
Linus Torvalds 已提交
781
 *	@q: destination block queue
782
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
783 784
 *	@iov:	the iovec.
 *	@iov_count: number of elements in the iovec
L
Linus Torvalds 已提交
785
 *	@write_to_vm: bool indicating writing to pages or not
786
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
787 788 789 790 791
 *
 *	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.
 */
792 793 794 795
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
796 797 798 799 800 801
{
	struct bio_map_data *bmd;
	struct bio_vec *bvec;
	struct page *page;
	struct bio *bio;
	int i, ret;
802 803
	int nr_pages = 0;
	unsigned int len = 0;
804
	unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
L
Linus Torvalds 已提交
805

806 807 808 809 810 811 812 813 814 815 816 817 818
	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;
	}

819 820 821
	if (offset)
		nr_pages++;

822
	bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
L
Linus Torvalds 已提交
823 824 825 826
	if (!bmd)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
827
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
828 829 830 831 832 833
	if (!bio)
		goto out_bmd;

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

	ret = 0;
834 835

	if (map_data) {
836
		nr_pages = 1 << map_data->page_order;
837 838
		i = map_data->offset / PAGE_SIZE;
	}
L
Linus Torvalds 已提交
839
	while (len) {
840
		unsigned int bytes = PAGE_SIZE;
L
Linus Torvalds 已提交
841

842 843
		bytes -= offset;

L
Linus Torvalds 已提交
844 845 846
		if (bytes > len)
			bytes = len;

847
		if (map_data) {
848
			if (i == map_data->nr_entries * nr_pages) {
849 850 851
				ret = -ENOMEM;
				break;
			}
852 853 854 855 856 857

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

			i++;
		} else {
858
			page = alloc_page(q->bounce_gfp | gfp_mask);
859 860 861 862
			if (!page) {
				ret = -ENOMEM;
				break;
			}
L
Linus Torvalds 已提交
863 864
		}

865
		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
L
Linus Torvalds 已提交
866 867 868
			break;

		len -= bytes;
869
		offset = 0;
L
Linus Torvalds 已提交
870 871 872 873 874 875 876 877
	}

	if (ret)
		goto cleanup;

	/*
	 * success
	 */
878
	if (!write_to_vm && (!map_data || !map_data->null_mapped)) {
879
		ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 0);
880 881
		if (ret)
			goto cleanup;
L
Linus Torvalds 已提交
882 883
	}

884
	bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
L
Linus Torvalds 已提交
885 886
	return bio;
cleanup:
887 888 889
	if (!map_data)
		bio_for_each_segment(bvec, bio, i)
			__free_page(bvec->bv_page);
L
Linus Torvalds 已提交
890 891 892 893 894 895 896

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

897 898 899
/**
 *	bio_copy_user	-	copy user data to bio
 *	@q: destination block queue
900
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
901 902 903
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
904
 *	@gfp_mask: memory allocation flags
905 906 907 908 909
 *
 *	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.
 */
910 911 912
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)
913 914 915 916 917 918
{
	struct sg_iovec iov;

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

919
	return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
920 921
}

922
static struct bio *__bio_map_user_iov(struct request_queue *q,
923 924
				      struct block_device *bdev,
				      struct sg_iovec *iov, int iov_count,
925
				      int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
926
{
927 928
	int i, j;
	int nr_pages = 0;
L
Linus Torvalds 已提交
929 930
	struct page **pages;
	struct bio *bio;
931 932
	int cur_page = 0;
	int ret, offset;
L
Linus Torvalds 已提交
933

934 935 936 937 938 939 940 941
	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;
		/*
942
		 * buffer must be aligned to at least hardsector size for now
943
		 */
944
		if (uaddr & queue_dma_alignment(q))
945 946 947 948
			return ERR_PTR(-EINVAL);
	}

	if (!nr_pages)
L
Linus Torvalds 已提交
949 950
		return ERR_PTR(-EINVAL);

951
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
952 953 954 955
	if (!bio)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
956
	pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
L
Linus Torvalds 已提交
957 958 959
	if (!pages)
		goto out;

960 961 962 963 964 965 966 967
	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
968 969
		ret = get_user_pages_fast(uaddr, local_nr_pages,
				write_to_vm, &pages[cur_page]);
970 971
		if (ret < local_nr_pages) {
			ret = -EFAULT;
972
			goto out_unmap;
973
		}
974 975 976 977 978 979 980 981 982 983 984 985 986 987

		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...
			 */
988 989
			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
					    bytes)
990 991 992 993 994
				break;

			len -= bytes;
			offset = 0;
		}
L
Linus Torvalds 已提交
995

996
		cur_page = j;
L
Linus Torvalds 已提交
997
		/*
998
		 * release the pages we didn't map into the bio, if any
L
Linus Torvalds 已提交
999
		 */
1000 1001
		while (j < page_limit)
			page_cache_release(pages[j++]);
L
Linus Torvalds 已提交
1002 1003 1004 1005 1006 1007 1008 1009 1010 1011
	}

	kfree(pages);

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

1012
	bio->bi_bdev = bdev;
L
Linus Torvalds 已提交
1013 1014
	bio->bi_flags |= (1 << BIO_USER_MAPPED);
	return bio;
1015 1016 1017 1018 1019 1020 1021 1022

 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
1023 1024 1025 1026 1027 1028 1029
	kfree(pages);
	bio_put(bio);
	return ERR_PTR(ret);
}

/**
 *	bio_map_user	-	map user address into bio
1030
 *	@q: the struct request_queue for the bio
L
Linus Torvalds 已提交
1031 1032 1033 1034
 *	@bdev: destination block device
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
1035
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
1036 1037 1038 1039
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1040
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1041 1042
			 unsigned long uaddr, unsigned int len, int write_to_vm,
			 gfp_t gfp_mask)
1043 1044 1045
{
	struct sg_iovec iov;

1046
	iov.iov_base = (void __user *)uaddr;
1047 1048
	iov.iov_len = len;

1049
	return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1050 1051 1052 1053
}

/**
 *	bio_map_user_iov - map user sg_iovec table into bio
1054
 *	@q: the struct request_queue for the bio
1055 1056 1057 1058
 *	@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
1059
 *	@gfp_mask: memory allocation flags
1060 1061 1062 1063
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1064
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1065
			     struct sg_iovec *iov, int iov_count,
1066
			     int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
1067 1068 1069
{
	struct bio *bio;

1070 1071
	bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
				 gfp_mask);
L
Linus Torvalds 已提交
1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082
	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);

1083
	return bio;
L
Linus Torvalds 已提交
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 1117 1118
}

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);
}

1119
static void bio_map_kern_endio(struct bio *bio, int err)
1120 1121 1122 1123 1124
{
	bio_put(bio);
}


1125
static struct bio *__bio_map_kern(struct request_queue *q, void *data,
A
Al Viro 已提交
1126
				  unsigned int len, gfp_t gfp_mask)
M
Mike Christie 已提交
1127 1128 1129 1130 1131 1132 1133 1134
{
	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;

1135
	bio = bio_kmalloc(gfp_mask, nr_pages);
M
Mike Christie 已提交
1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148
	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;

1149 1150
		if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
				    offset) < bytes)
M
Mike Christie 已提交
1151 1152 1153 1154 1155 1156 1157
			break;

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

1158
	bio->bi_end_io = bio_map_kern_endio;
M
Mike Christie 已提交
1159 1160 1161 1162 1163
	return bio;
}

/**
 *	bio_map_kern	-	map kernel address into bio
1164
 *	@q: the struct request_queue for the bio
M
Mike Christie 已提交
1165 1166 1167 1168 1169 1170 1171
 *	@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.
 */
1172
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
A
Al Viro 已提交
1173
			 gfp_t gfp_mask)
M
Mike Christie 已提交
1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190
{
	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);
}

1191 1192 1193 1194
static void bio_copy_kern_endio(struct bio *bio, int err)
{
	struct bio_vec *bvec;
	const int read = bio_data_dir(bio) == READ;
1195
	struct bio_map_data *bmd = bio->bi_private;
1196
	int i;
1197
	char *p = bmd->sgvecs[0].iov_base;
1198 1199 1200

	__bio_for_each_segment(bvec, bio, i, 0) {
		char *addr = page_address(bvec->bv_page);
1201
		int len = bmd->iovecs[i].bv_len;
1202

1203
		if (read)
1204
			memcpy(p, addr, len);
1205 1206

		__free_page(bvec->bv_page);
1207
		p += len;
1208 1209
	}

1210
	bio_free_map_data(bmd);
1211 1212 1213 1214 1215 1216 1217 1218 1219
	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
1220
 *	@reading: data direction is READ
1221 1222 1223 1224 1225 1226 1227 1228 1229
 *
 *	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;
1230
	int i;
1231

1232 1233 1234
	bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
	if (IS_ERR(bio))
		return bio;
1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247

	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;
1248

1249 1250 1251
	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);
	}
}

1294
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.
 */

1318
static void bio_dirty_fn(struct work_struct *work);
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1320
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
 */
1327
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:
1383
 *   bio_endio() will end I/O on the whole bio. bio_endio() is the
N
NeilBrown 已提交
1384 1385 1386 1387 1388 1389
 *   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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 **/
1391
void bio_endio(struct bio *bio, int error)
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1392 1393 1394
{
	if (error)
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
N
NeilBrown 已提交
1395 1396
	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
		error = -EIO;
L
Linus Torvalds 已提交
1397

N
NeilBrown 已提交
1398
	if (bio->bi_end_io)
1399
		bio->bi_end_io(bio, error);
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1400 1401 1402 1403 1404 1405 1406
}

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

1407
		bio_endio(master, bp->error);
L
Linus Torvalds 已提交
1408 1409 1410 1411
		mempool_free(bp, bp->bio2.bi_private);
	}
}

1412
static void bio_pair_end_1(struct bio *bi, int err)
L
Linus Torvalds 已提交
1413 1414 1415 1416 1417 1418 1419 1420 1421
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

1422
static void bio_pair_end_2(struct bio *bi, int err)
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Linus Torvalds 已提交
1423 1424 1425 1426 1427 1428 1429 1430 1431 1432
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

/*
1433
 * split a bio - only worry about a bio with a single page in its iovec
L
Linus Torvalds 已提交
1434
 */
D
Denis ChengRq 已提交
1435
struct bio_pair *bio_split(struct bio *bi, int first_sectors)
L
Linus Torvalds 已提交
1436
{
D
Denis ChengRq 已提交
1437
	struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
L
Linus Torvalds 已提交
1438 1439 1440 1441

	if (!bp)
		return bp;

1442
	trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1443 1444
				bi->bi_sector + first_sectors);

L
Linus Torvalds 已提交
1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463
	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;

1464 1465 1466
	bp->bio1.bi_max_vecs = 1;
	bp->bio2.bi_max_vecs = 1;

L
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1467 1468 1469 1470
	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
1471
	bp->bio2.bi_private = bio_split_pool;
L
Linus Torvalds 已提交
1472

1473 1474 1475
	if (bio_integrity(bi))
		bio_integrity_split(bi, bp, first_sectors);

L
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1476 1477 1478
	return bp;
}

1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491
/**
 *      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)
{
1492
	unsigned int sector_sz;
1493 1494 1495 1496
	struct bio_vec *bv;
	sector_t sectors;
	int i;

1497
	sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515
	sectors = 0;

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

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

		sectors += bv->bv_len / sector_sz;
	}

	return sectors;
}
EXPORT_SYMBOL(bio_sector_offset);
L
Linus Torvalds 已提交
1516 1517 1518 1519 1520

/*
 * create memory pools for biovec's in a bio_set.
 * use the global biovec slabs created for general use.
 */
1521
static int biovec_create_pools(struct bio_set *bs, int pool_entries)
L
Linus Torvalds 已提交
1522
{
1523
	struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
L
Linus Torvalds 已提交
1524

1525 1526 1527
	bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
	if (!bs->bvec_pool)
		return -ENOMEM;
L
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1528 1529 1530 1531 1532 1533

	return 0;
}

static void biovec_free_pools(struct bio_set *bs)
{
1534
	mempool_destroy(bs->bvec_pool);
L
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1535 1536 1537 1538 1539 1540 1541
}

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

1542
	bioset_integrity_free(bs);
L
Linus Torvalds 已提交
1543
	biovec_free_pools(bs);
1544
	bio_put_slab(bs);
L
Linus Torvalds 已提交
1545 1546 1547 1548

	kfree(bs);
}

1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562
/**
 * 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
1563
{
1564
	unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1565
	struct bio_set *bs;
L
Linus Torvalds 已提交
1566

1567
	bs = kzalloc(sizeof(*bs), GFP_KERNEL);
L
Linus Torvalds 已提交
1568 1569 1570
	if (!bs)
		return NULL;

1571
	bs->front_pad = front_pad;
1572

1573
	bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1574 1575 1576 1577 1578 1579
	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
1580 1581 1582
	if (!bs->bio_pool)
		goto bad;

1583 1584 1585
	if (bioset_integrity_create(bs, pool_size))
		goto bad;

1586
	if (!biovec_create_pools(bs, pool_size))
L
Linus Torvalds 已提交
1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601
		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;

1602 1603 1604 1605 1606 1607 1608
#ifndef CONFIG_BLK_DEV_INTEGRITY
		if (bvs->nr_vecs <= BIO_INLINE_VECS) {
			bvs->slab = NULL;
			continue;
		}
#endif

L
Linus Torvalds 已提交
1609 1610
		size = bvs->nr_vecs * sizeof(struct bio_vec);
		bvs->slab = kmem_cache_create(bvs->name, size, 0,
1611
                                SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
1612 1613 1614 1615 1616
	}
}

static int __init init_bio(void)
{
1617 1618 1619 1620 1621
	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
1622

1623
	bio_integrity_init();
L
Linus Torvalds 已提交
1624 1625
	biovec_init_slabs();

1626
	fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
L
Linus Torvalds 已提交
1627 1628 1629
	if (!fs_bio_set)
		panic("bio: can't allocate bios\n");

1630 1631
	bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
						     sizeof(struct bio_pair));
L
Linus Torvalds 已提交
1632 1633 1634 1635 1636 1637 1638 1639 1640
	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
1641
EXPORT_SYMBOL(bio_kmalloc);
L
Linus Torvalds 已提交
1642
EXPORT_SYMBOL(bio_put);
P
Peter Osterlund 已提交
1643
EXPORT_SYMBOL(bio_free);
L
Linus Torvalds 已提交
1644 1645 1646 1647 1648 1649
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);
1650
EXPORT_SYMBOL(bio_add_pc_page);
L
Linus Torvalds 已提交
1651
EXPORT_SYMBOL(bio_get_nr_vecs);
J
Jens Axboe 已提交
1652 1653
EXPORT_SYMBOL(bio_map_user);
EXPORT_SYMBOL(bio_unmap_user);
M
Mike Christie 已提交
1654
EXPORT_SYMBOL(bio_map_kern);
1655
EXPORT_SYMBOL(bio_copy_kern);
L
Linus Torvalds 已提交
1656 1657 1658 1659 1660 1661 1662
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);