bio.c 49.3 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>
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#include <linux/uio.h>
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#include <linux/iocontext.h>
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#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/mempool.h>
#include <linux/workqueue.h>
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#include <linux/cgroup.h>
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#include <scsi/sg.h>		/* for struct sg_iovec */
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#include <trace/events/block.h>
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/*
 * Test patch to inline a certain number of bi_io_vec's inside the bio
 * itself, to shrink a bio data allocation from two mempool calls to one
 */
#define BIO_INLINE_VECS		4

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

/*
 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
 * IO code that does not need private memory pools.
 */
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struct bio_set *fs_bio_set;
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EXPORT_SYMBOL(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;
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	struct bio_slab *bslab, *new_bio_slabs;
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	unsigned int new_bio_slab_max;
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	unsigned int i, entry = -1;

	mutex_lock(&bio_slab_lock);

	i = 0;
	while (i < bio_slab_nr) {
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		bslab = &bio_slabs[i];
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		if (!bslab->slab && entry == -1)
			entry = i;
		else if (bslab->slab_size == sz) {
			slab = bslab->slab;
			bslab->slab_ref++;
			break;
		}
		i++;
	}

	if (slab)
		goto out_unlock;

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

	bslab = &bio_slabs[entry];

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

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

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

	mutex_lock(&bio_slab_lock);

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

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

	WARN_ON(!bslab->slab_ref);

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

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

out:
	mutex_unlock(&bio_slab_lock);
}

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

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void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
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{
	BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);

	if (idx == BIOVEC_MAX_IDX)
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		mempool_free(bv, pool);
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	else {
		struct biovec_slab *bvs = bvec_slabs + idx;

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

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struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
			   mempool_t *pool)
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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:
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		bvl = mempool_alloc(pool, gfp_mask);
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	} 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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static void __bio_free(struct bio *bio)
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{
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	bio_disassociate_task(bio);
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	if (bio_integrity(bio))
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		bio_integrity_free(bio);
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}
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static void bio_free(struct bio *bio)
{
	struct bio_set *bs = bio->bi_pool;
	void *p;

	__bio_free(bio);

	if (bs) {
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		if (bio_flagged(bio, BIO_OWNS_VEC))
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			bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
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		/*
		 * If we have front padding, adjust the bio pointer before freeing
		 */
		p = bio;
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		p -= bs->front_pad;

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		mempool_free(p, bs->bio_pool);
	} else {
		/* Bio was allocated by bio_kmalloc() */
		kfree(bio);
	}
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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;
	atomic_set(&bio->bi_cnt, 1);
}
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EXPORT_SYMBOL(bio_init);
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/**
 * bio_reset - reinitialize a bio
 * @bio:	bio to reset
 *
 * Description:
 *   After calling bio_reset(), @bio will be in the same state as a freshly
 *   allocated bio returned bio bio_alloc_bioset() - the only fields that are
 *   preserved are the ones that are initialized by bio_alloc_bioset(). See
 *   comment in struct bio.
 */
void bio_reset(struct bio *bio)
{
	unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);

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	__bio_free(bio);
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	memset(bio, 0, BIO_RESET_BYTES);
	bio->bi_flags = flags|(1 << BIO_UPTODATE);
}
EXPORT_SYMBOL(bio_reset);

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static void bio_alloc_rescue(struct work_struct *work)
{
	struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
	struct bio *bio;

	while (1) {
		spin_lock(&bs->rescue_lock);
		bio = bio_list_pop(&bs->rescue_list);
		spin_unlock(&bs->rescue_lock);

		if (!bio)
			break;

		generic_make_request(bio);
	}
}

static void punt_bios_to_rescuer(struct bio_set *bs)
{
	struct bio_list punt, nopunt;
	struct bio *bio;

	/*
	 * In order to guarantee forward progress we must punt only bios that
	 * were allocated from this bio_set; otherwise, if there was a bio on
	 * there for a stacking driver higher up in the stack, processing it
	 * could require allocating bios from this bio_set, and doing that from
	 * our own rescuer would be bad.
	 *
	 * Since bio lists are singly linked, pop them all instead of trying to
	 * remove from the middle of the list:
	 */

	bio_list_init(&punt);
	bio_list_init(&nopunt);

	while ((bio = bio_list_pop(current->bio_list)))
		bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);

	*current->bio_list = nopunt;

	spin_lock(&bs->rescue_lock);
	bio_list_merge(&bs->rescue_list, &punt);
	spin_unlock(&bs->rescue_lock);

	queue_work(bs->rescue_workqueue, &bs->rescue_work);
}

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/**
 * bio_alloc_bioset - allocate a bio for I/O
 * @gfp_mask:   the GFP_ mask given to the slab allocator
 * @nr_iovecs:	number of iovecs to pre-allocate
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 * @bs:		the bio_set to allocate from.
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 *
 * Description:
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 *   If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
 *   backed by the @bs's mempool.
 *
 *   When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
 *   able to allocate a bio. This is due to the mempool guarantees. To make this
 *   work, callers must never allocate more than 1 bio at a time from this pool.
 *   Callers that need to allocate more than 1 bio must always submit the
 *   previously allocated bio for IO before attempting to allocate a new one.
 *   Failure to do so can cause deadlocks under memory pressure.
 *
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 *   Note that when running under generic_make_request() (i.e. any block
 *   driver), bios are not submitted until after you return - see the code in
 *   generic_make_request() that converts recursion into iteration, to prevent
 *   stack overflows.
 *
 *   This would normally mean allocating multiple bios under
 *   generic_make_request() would be susceptible to deadlocks, but we have
 *   deadlock avoidance code that resubmits any blocked bios from a rescuer
 *   thread.
 *
 *   However, we do not guarantee forward progress for allocations from other
 *   mempools. Doing multiple allocations from the same mempool under
 *   generic_make_request() should be avoided - instead, use bio_set's front_pad
 *   for per bio allocations.
 *
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 *   RETURNS:
 *   Pointer to new bio on success, NULL on failure.
 */
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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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	gfp_t saved_gfp = gfp_mask;
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	unsigned front_pad;
	unsigned inline_vecs;
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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;

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	if (!bs) {
		if (nr_iovecs > UIO_MAXIOV)
			return NULL;

		p = kmalloc(sizeof(struct bio) +
			    nr_iovecs * sizeof(struct bio_vec),
			    gfp_mask);
		front_pad = 0;
		inline_vecs = nr_iovecs;
	} else {
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		/*
		 * generic_make_request() converts recursion to iteration; this
		 * means if we're running beneath it, any bios we allocate and
		 * submit will not be submitted (and thus freed) until after we
		 * return.
		 *
		 * This exposes us to a potential deadlock if we allocate
		 * multiple bios from the same bio_set() while running
		 * underneath generic_make_request(). If we were to allocate
		 * multiple bios (say a stacking block driver that was splitting
		 * bios), we would deadlock if we exhausted the mempool's
		 * reserve.
		 *
		 * We solve this, and guarantee forward progress, with a rescuer
		 * workqueue per bio_set. If we go to allocate and there are
		 * bios on current->bio_list, we first try the allocation
		 * without __GFP_WAIT; if that fails, we punt those bios we
		 * would be blocking to the rescuer workqueue before we retry
		 * with the original gfp_flags.
		 */

		if (current->bio_list && !bio_list_empty(current->bio_list))
			gfp_mask &= ~__GFP_WAIT;

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		p = mempool_alloc(bs->bio_pool, gfp_mask);
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		if (!p && gfp_mask != saved_gfp) {
			punt_bios_to_rescuer(bs);
			gfp_mask = saved_gfp;
			p = mempool_alloc(bs->bio_pool, gfp_mask);
		}

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		front_pad = bs->front_pad;
		inline_vecs = BIO_INLINE_VECS;
	}

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	if (unlikely(!p))
		return NULL;
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	bio = p + front_pad;
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	bio_init(bio);

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	if (nr_iovecs > inline_vecs) {
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		bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
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		if (!bvl && gfp_mask != saved_gfp) {
			punt_bios_to_rescuer(bs);
			gfp_mask = saved_gfp;
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			bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
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		}

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		if (unlikely(!bvl))
			goto err_free;
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		bio->bi_flags |= 1 << BIO_OWNS_VEC;
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	} else if (nr_iovecs) {
		bvl = bio->bi_inline_vecs;
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	}
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	bio->bi_pool = bs;
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	bio->bi_flags |= idx << BIO_POOL_OFFSET;
	bio->bi_max_vecs = nr_iovecs;
	bio->bi_io_vec = bvl;
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	return bio;
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err_free:
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	mempool_free(p, bs->bio_pool);
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	return NULL;
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}
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EXPORT_SYMBOL(bio_alloc_bioset);
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void zero_fill_bio(struct bio *bio)
{
	unsigned long flags;
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	struct bio_vec bv;
	struct bvec_iter iter;
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	bio_for_each_segment(bv, bio, iter) {
		char *data = bvec_kmap_irq(&bv, &flags);
		memset(data, 0, bv.bv_len);
		flush_dcache_page(bv.bv_page);
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		bvec_kunmap_irq(data, &flags);
	}
}
EXPORT_SYMBOL(zero_fill_bio);

/**
 * bio_put - release a reference to a bio
 * @bio:   bio to release reference to
 *
 * Description:
 *   Put a reference to a &struct bio, either one you have gotten with
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 *   bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
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 **/
void bio_put(struct bio *bio)
{
	BIO_BUG_ON(!atomic_read(&bio->bi_cnt));

	/*
	 * last put frees it
	 */
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	if (atomic_dec_and_test(&bio->bi_cnt))
		bio_free(bio);
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}
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EXPORT_SYMBOL(bio_put);
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inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
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{
	if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
		blk_recount_segments(q, bio);

	return bio->bi_phys_segments;
}
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EXPORT_SYMBOL(bio_phys_segments);
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/**
 * 	__bio_clone	-	clone a bio
 * 	@bio: destination bio
 * 	@bio_src: bio to clone
 *
 *	Clone a &bio. Caller will own the returned bio, but not
 *	the actual data it points to. Reference count of returned
 * 	bio will be one.
 */
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void __bio_clone(struct bio *bio, struct bio *bio_src)
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{
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	memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
		bio_src->bi_max_vecs * sizeof(struct bio_vec));
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	/*
	 * most users will be overriding ->bi_bdev with a new target,
	 * so we don't set nor calculate new physical/hw segment counts here
	 */
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	bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
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	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;
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	bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
	bio->bi_iter.bi_idx = bio_src->bi_iter.bi_idx;
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}
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EXPORT_SYMBOL(__bio_clone);
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/**
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 *	bio_clone_bioset -	clone a bio
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 *	@bio: bio to clone
 *	@gfp_mask: allocation priority
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 *	@bs: bio_set to allocate from
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 *
 * 	Like __bio_clone, only also allocates the returned bio
 */
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struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask,
			     struct bio_set *bs)
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{
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	struct bio *b;
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	b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs);
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	if (!b)
		return NULL;

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

	nr_pages = min_t(unsigned,
594 595
		     queue_max_segments(q),
		     queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
596 597 598

	return min_t(unsigned, nr_pages, BIO_MAX_PAGES);

L
Linus Torvalds 已提交
599
}
600
EXPORT_SYMBOL(bio_get_nr_vecs);
L
Linus Torvalds 已提交
601

602
static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
603
			  *page, unsigned int len, unsigned int offset,
604
			  unsigned int max_sectors)
L
Linus Torvalds 已提交
605 606 607 608 609 610 611 612 613 614
{
	int retried_segments = 0;
	struct bio_vec *bvec;

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

615
	if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
L
Linus Torvalds 已提交
616 617
		return 0;

618 619 620 621 622 623 624 625 626 627
	/*
	 * 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) {
628
			unsigned int prev_bv_len = prev->bv_len;
629
			prev->bv_len += len;
630 631 632

			if (q->merge_bvec_fn) {
				struct bvec_merge_data bvm = {
633 634 635 636
					/* prev_bvec is already charged in
					   bi_size, discharge it in order to
					   simulate merging updated prev_bvec
					   as new bvec. */
637
					.bi_bdev = bio->bi_bdev,
638 639 640
					.bi_sector = bio->bi_iter.bi_sector,
					.bi_size = bio->bi_iter.bi_size -
						prev_bv_len,
641 642 643
					.bi_rw = bio->bi_rw,
				};

644
				if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
645 646 647
					prev->bv_len -= len;
					return 0;
				}
648 649 650 651 652 653 654
			}

			goto done;
		}
	}

	if (bio->bi_vcnt >= bio->bi_max_vecs)
L
Linus Torvalds 已提交
655 656 657 658 659 660 661
		return 0;

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

662
	while (bio->bi_phys_segments >= queue_max_segments(q)) {
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Linus Torvalds 已提交
663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685

		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) {
686 687
		struct bvec_merge_data bvm = {
			.bi_bdev = bio->bi_bdev,
688 689
			.bi_sector = bio->bi_iter.bi_sector,
			.bi_size = bio->bi_iter.bi_size,
690 691 692
			.bi_rw = bio->bi_rw,
		};

L
Linus Torvalds 已提交
693 694 695 696
		/*
		 * merge_bvec_fn() returns number of bytes it can accept
		 * at this offset
		 */
697
		if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
L
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			bvec->bv_page = NULL;
			bvec->bv_len = 0;
			bvec->bv_offset = 0;
			return 0;
		}
	}

	/* If we may be able to merge these biovecs, force a recount */
706
	if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
L
Linus Torvalds 已提交
707 708 709 710
		bio->bi_flags &= ~(1 << BIO_SEG_VALID);

	bio->bi_vcnt++;
	bio->bi_phys_segments++;
711
 done:
712
	bio->bi_iter.bi_size += len;
L
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713 714 715
	return len;
}

716 717
/**
 *	bio_add_pc_page	-	attempt to add page to bio
J
Jens Axboe 已提交
718
 *	@q: the target queue
719 720 721 722 723 724
 *	@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
725 726 727 728 729
 *	number of reasons, such as the bio being full or target block device
 *	limitations. The target block device must allow bio's up to PAGE_SIZE,
 *	so it is always possible to add a single page to an empty bio.
 *
 *	This should only be used by REQ_PC bios.
730
 */
731
int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
732 733
		    unsigned int len, unsigned int offset)
{
734 735
	return __bio_add_page(q, bio, page, len, offset,
			      queue_max_hw_sectors(q));
736
}
737
EXPORT_SYMBOL(bio_add_pc_page);
738

L
Linus Torvalds 已提交
739 740 741 742 743 744 745 746
/**
 *	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
747 748 749
 *	number of reasons, such as the bio being full or target block device
 *	limitations. The target block device must allow bio's up to PAGE_SIZE,
 *	so it is always possible to add a single page to an empty bio.
L
Linus Torvalds 已提交
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 */
int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
		 unsigned int offset)
{
754
	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
755
	return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
L
Linus Torvalds 已提交
756
}
757
EXPORT_SYMBOL(bio_add_page);
L
Linus Torvalds 已提交
758

759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794
struct submit_bio_ret {
	struct completion event;
	int error;
};

static void submit_bio_wait_endio(struct bio *bio, int error)
{
	struct submit_bio_ret *ret = bio->bi_private;

	ret->error = error;
	complete(&ret->event);
}

/**
 * submit_bio_wait - submit a bio, and wait until it completes
 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
 * @bio: The &struct bio which describes the I/O
 *
 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
 * bio_endio() on failure.
 */
int submit_bio_wait(int rw, struct bio *bio)
{
	struct submit_bio_ret ret;

	rw |= REQ_SYNC;
	init_completion(&ret.event);
	bio->bi_private = &ret;
	bio->bi_end_io = submit_bio_wait_endio;
	submit_bio(rw, bio);
	wait_for_completion(&ret.event);

	return ret.error;
}
EXPORT_SYMBOL(submit_bio_wait);

K
Kent Overstreet 已提交
795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810
/**
 * bio_advance - increment/complete a bio by some number of bytes
 * @bio:	bio to advance
 * @bytes:	number of bytes to complete
 *
 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
 * be updated on the last bvec as well.
 *
 * @bio will then represent the remaining, uncompleted portion of the io.
 */
void bio_advance(struct bio *bio, unsigned bytes)
{
	if (bio_integrity(bio))
		bio_integrity_advance(bio, bytes);

811 812
	bio->bi_iter.bi_sector += bytes >> 9;
	bio->bi_iter.bi_size -= bytes;
K
Kent Overstreet 已提交
813 814 815 816 817

	if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
		return;

	while (bytes) {
818
		if (unlikely(bio->bi_iter.bi_idx >= bio->bi_vcnt)) {
K
Kent Overstreet 已提交
819
			WARN_ONCE(1, "bio idx %d >= vcnt %d\n",
820
				  bio->bi_iter.bi_idx, bio->bi_vcnt);
K
Kent Overstreet 已提交
821 822 823
			break;
		}

824 825
		if (bytes >= bio_iovec(bio).bv_len) {
			bytes -= bio_iovec(bio).bv_len;
826
			bio->bi_iter.bi_idx++;
K
Kent Overstreet 已提交
827
		} else {
828 829
			bio_iovec(bio).bv_len -= bytes;
			bio_iovec(bio).bv_offset += bytes;
K
Kent Overstreet 已提交
830 831 832 833 834 835
			bytes = 0;
		}
	}
}
EXPORT_SYMBOL(bio_advance);

K
Kent Overstreet 已提交
836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863
/**
 * bio_alloc_pages - allocates a single page for each bvec in a bio
 * @bio: bio to allocate pages for
 * @gfp_mask: flags for allocation
 *
 * Allocates pages up to @bio->bi_vcnt.
 *
 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
 * freed.
 */
int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
{
	int i;
	struct bio_vec *bv;

	bio_for_each_segment_all(bv, bio, i) {
		bv->bv_page = alloc_page(gfp_mask);
		if (!bv->bv_page) {
			while (--bv >= bio->bi_io_vec)
				__free_page(bv->bv_page);
			return -ENOMEM;
		}
	}

	return 0;
}
EXPORT_SYMBOL(bio_alloc_pages);

K
Kent Overstreet 已提交
864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881
/**
 * bio_copy_data - copy contents of data buffers from one chain of bios to
 * another
 * @src: source bio list
 * @dst: destination bio list
 *
 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
 * @src and @dst as linked lists of bios.
 *
 * Stops when it reaches the end of either @src or @dst - that is, copies
 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
 */
void bio_copy_data(struct bio *dst, struct bio *src)
{
	struct bio_vec *src_bv, *dst_bv;
	unsigned src_offset, dst_offset, bytes;
	void *src_p, *dst_p;

882 883
	src_bv = __bio_iovec(src);
	dst_bv = __bio_iovec(dst);
K
Kent Overstreet 已提交
884 885 886 887 888 889 890 891 892 893 894 895

	src_offset = src_bv->bv_offset;
	dst_offset = dst_bv->bv_offset;

	while (1) {
		if (src_offset == src_bv->bv_offset + src_bv->bv_len) {
			src_bv++;
			if (src_bv == bio_iovec_idx(src, src->bi_vcnt)) {
				src = src->bi_next;
				if (!src)
					break;

896
				src_bv = __bio_iovec(src);
K
Kent Overstreet 已提交
897 898 899 900 901 902 903 904 905 906 907 908
			}

			src_offset = src_bv->bv_offset;
		}

		if (dst_offset == dst_bv->bv_offset + dst_bv->bv_len) {
			dst_bv++;
			if (dst_bv == bio_iovec_idx(dst, dst->bi_vcnt)) {
				dst = dst->bi_next;
				if (!dst)
					break;

909
				dst_bv = __bio_iovec(dst);
K
Kent Overstreet 已提交
910 911 912 913 914 915 916 917 918 919 920
			}

			dst_offset = dst_bv->bv_offset;
		}

		bytes = min(dst_bv->bv_offset + dst_bv->bv_len - dst_offset,
			    src_bv->bv_offset + src_bv->bv_len - src_offset);

		src_p = kmap_atomic(src_bv->bv_page);
		dst_p = kmap_atomic(dst_bv->bv_page);

K
Kent Overstreet 已提交
921 922
		memcpy(dst_p + dst_offset,
		       src_p + src_offset,
K
Kent Overstreet 已提交
923 924 925 926 927 928 929 930 931 932 933
		       bytes);

		kunmap_atomic(dst_p);
		kunmap_atomic(src_p);

		src_offset += bytes;
		dst_offset += bytes;
	}
}
EXPORT_SYMBOL(bio_copy_data);

L
Linus Torvalds 已提交
934 935
struct bio_map_data {
	struct bio_vec *iovecs;
936
	struct sg_iovec *sgvecs;
937 938
	int nr_sgvecs;
	int is_our_pages;
L
Linus Torvalds 已提交
939 940
};

941
static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
942 943
			     struct sg_iovec *iov, int iov_count,
			     int is_our_pages)
L
Linus Torvalds 已提交
944 945
{
	memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
946 947
	memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
	bmd->nr_sgvecs = iov_count;
948
	bmd->is_our_pages = is_our_pages;
L
Linus Torvalds 已提交
949 950 951 952 953 954
	bio->bi_private = bmd;
}

static void bio_free_map_data(struct bio_map_data *bmd)
{
	kfree(bmd->iovecs);
955
	kfree(bmd->sgvecs);
L
Linus Torvalds 已提交
956 957 958
	kfree(bmd);
}

959 960
static struct bio_map_data *bio_alloc_map_data(int nr_segs,
					       unsigned int iov_count,
961
					       gfp_t gfp_mask)
L
Linus Torvalds 已提交
962
{
963 964 965 966
	struct bio_map_data *bmd;

	if (iov_count > UIO_MAXIOV)
		return NULL;
L
Linus Torvalds 已提交
967

968
	bmd = kmalloc(sizeof(*bmd), gfp_mask);
L
Linus Torvalds 已提交
969 970 971
	if (!bmd)
		return NULL;

972
	bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
973 974 975 976 977
	if (!bmd->iovecs) {
		kfree(bmd);
		return NULL;
	}

978
	bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
979
	if (bmd->sgvecs)
L
Linus Torvalds 已提交
980 981
		return bmd;

982
	kfree(bmd->iovecs);
L
Linus Torvalds 已提交
983 984 985 986
	kfree(bmd);
	return NULL;
}

987
static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
988 989
			  struct sg_iovec *iov, int iov_count,
			  int to_user, int from_user, int do_free_page)
990 991 992 993 994 995
{
	int ret = 0, i;
	struct bio_vec *bvec;
	int iov_idx = 0;
	unsigned int iov_off = 0;

996
	bio_for_each_segment_all(bvec, bio, i) {
997
		char *bv_addr = page_address(bvec->bv_page);
998
		unsigned int bv_len = iovecs[i].bv_len;
999 1000 1001

		while (bv_len && iov_idx < iov_count) {
			unsigned int bytes;
1002
			char __user *iov_addr;
1003 1004 1005 1006 1007 1008

			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) {
1009
				if (to_user)
1010 1011 1012
					ret = copy_to_user(iov_addr, bv_addr,
							   bytes);

1013 1014 1015 1016
				if (from_user)
					ret = copy_from_user(bv_addr, iov_addr,
							     bytes);

1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031
				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;
			}
		}

1032
		if (do_free_page)
1033 1034 1035 1036 1037 1038
			__free_page(bvec->bv_page);
	}

	return ret;
}

L
Linus Torvalds 已提交
1039 1040 1041 1042 1043 1044 1045 1046 1047 1048
/**
 *	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;
1049 1050
	struct bio_vec *bvec;
	int ret = 0, i;
L
Linus Torvalds 已提交
1051

1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
	if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
		/*
		 * if we're in a workqueue, the request is orphaned, so
		 * don't copy into a random user address space, just free.
		 */
		if (current->mm)
			ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
					     bmd->nr_sgvecs, bio_data_dir(bio) == READ,
					     0, bmd->is_our_pages);
		else if (bmd->is_our_pages)
			bio_for_each_segment_all(bvec, bio, i)
				__free_page(bvec->bv_page);
	}
L
Linus Torvalds 已提交
1065 1066 1067 1068
	bio_free_map_data(bmd);
	bio_put(bio);
	return ret;
}
1069
EXPORT_SYMBOL(bio_uncopy_user);
L
Linus Torvalds 已提交
1070 1071

/**
1072
 *	bio_copy_user_iov	-	copy user data to bio
L
Linus Torvalds 已提交
1073
 *	@q: destination block queue
1074
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
1075 1076
 *	@iov:	the iovec.
 *	@iov_count: number of elements in the iovec
L
Linus Torvalds 已提交
1077
 *	@write_to_vm: bool indicating writing to pages or not
1078
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
1079 1080 1081 1082 1083
 *
 *	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.
 */
1084 1085 1086 1087
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
1088 1089 1090 1091 1092 1093
{
	struct bio_map_data *bmd;
	struct bio_vec *bvec;
	struct page *page;
	struct bio *bio;
	int i, ret;
1094 1095
	int nr_pages = 0;
	unsigned int len = 0;
1096
	unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
L
Linus Torvalds 已提交
1097

1098 1099 1100 1101 1102 1103 1104 1105 1106
	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;

1107 1108 1109 1110 1111 1112
		/*
		 * Overflow, abort
		 */
		if (end < start)
			return ERR_PTR(-EINVAL);

1113 1114 1115 1116
		nr_pages += end - start;
		len += iov[i].iov_len;
	}

1117 1118 1119
	if (offset)
		nr_pages++;

1120
	bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
L
Linus Torvalds 已提交
1121 1122 1123 1124
	if (!bmd)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
1125
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
1126 1127 1128
	if (!bio)
		goto out_bmd;

1129 1130
	if (!write_to_vm)
		bio->bi_rw |= REQ_WRITE;
L
Linus Torvalds 已提交
1131 1132

	ret = 0;
1133 1134

	if (map_data) {
1135
		nr_pages = 1 << map_data->page_order;
1136 1137
		i = map_data->offset / PAGE_SIZE;
	}
L
Linus Torvalds 已提交
1138
	while (len) {
1139
		unsigned int bytes = PAGE_SIZE;
L
Linus Torvalds 已提交
1140

1141 1142
		bytes -= offset;

L
Linus Torvalds 已提交
1143 1144 1145
		if (bytes > len)
			bytes = len;

1146
		if (map_data) {
1147
			if (i == map_data->nr_entries * nr_pages) {
1148 1149 1150
				ret = -ENOMEM;
				break;
			}
1151 1152 1153 1154 1155 1156

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

			i++;
		} else {
1157
			page = alloc_page(q->bounce_gfp | gfp_mask);
1158 1159 1160 1161
			if (!page) {
				ret = -ENOMEM;
				break;
			}
L
Linus Torvalds 已提交
1162 1163
		}

1164
		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
L
Linus Torvalds 已提交
1165 1166 1167
			break;

		len -= bytes;
1168
		offset = 0;
L
Linus Torvalds 已提交
1169 1170 1171 1172 1173 1174 1175 1176
	}

	if (ret)
		goto cleanup;

	/*
	 * success
	 */
1177 1178 1179
	if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
	    (map_data && map_data->from_user)) {
		ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0);
1180 1181
		if (ret)
			goto cleanup;
L
Linus Torvalds 已提交
1182 1183
	}

1184
	bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
L
Linus Torvalds 已提交
1185 1186
	return bio;
cleanup:
1187
	if (!map_data)
1188
		bio_for_each_segment_all(bvec, bio, i)
1189
			__free_page(bvec->bv_page);
L
Linus Torvalds 已提交
1190 1191 1192 1193 1194 1195 1196

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

1197 1198 1199
/**
 *	bio_copy_user	-	copy user data to bio
 *	@q: destination block queue
1200
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
1201 1202 1203
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
1204
 *	@gfp_mask: memory allocation flags
1205 1206 1207 1208 1209
 *
 *	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.
 */
1210 1211 1212
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)
1213 1214 1215 1216 1217 1218
{
	struct sg_iovec iov;

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

1219
	return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
1220
}
1221
EXPORT_SYMBOL(bio_copy_user);
1222

1223
static struct bio *__bio_map_user_iov(struct request_queue *q,
1224 1225
				      struct block_device *bdev,
				      struct sg_iovec *iov, int iov_count,
1226
				      int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
1227
{
1228 1229
	int i, j;
	int nr_pages = 0;
L
Linus Torvalds 已提交
1230 1231
	struct page **pages;
	struct bio *bio;
1232 1233
	int cur_page = 0;
	int ret, offset;
L
Linus Torvalds 已提交
1234

1235 1236 1237 1238 1239 1240
	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;

1241 1242 1243 1244 1245 1246
		/*
		 * Overflow, abort
		 */
		if (end < start)
			return ERR_PTR(-EINVAL);

1247 1248
		nr_pages += end - start;
		/*
1249
		 * buffer must be aligned to at least hardsector size for now
1250
		 */
1251
		if (uaddr & queue_dma_alignment(q))
1252 1253 1254 1255
			return ERR_PTR(-EINVAL);
	}

	if (!nr_pages)
L
Linus Torvalds 已提交
1256 1257
		return ERR_PTR(-EINVAL);

1258
	bio = bio_kmalloc(gfp_mask, nr_pages);
L
Linus Torvalds 已提交
1259 1260 1261 1262
	if (!bio)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
1263
	pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
L
Linus Torvalds 已提交
1264 1265 1266
	if (!pages)
		goto out;

1267 1268 1269 1270 1271 1272 1273
	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;
1274

N
Nick Piggin 已提交
1275 1276
		ret = get_user_pages_fast(uaddr, local_nr_pages,
				write_to_vm, &pages[cur_page]);
1277 1278
		if (ret < local_nr_pages) {
			ret = -EFAULT;
1279
			goto out_unmap;
1280
		}
1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294

		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...
			 */
1295 1296
			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
					    bytes)
1297 1298 1299 1300 1301
				break;

			len -= bytes;
			offset = 0;
		}
L
Linus Torvalds 已提交
1302

1303
		cur_page = j;
L
Linus Torvalds 已提交
1304
		/*
1305
		 * release the pages we didn't map into the bio, if any
L
Linus Torvalds 已提交
1306
		 */
1307 1308
		while (j < page_limit)
			page_cache_release(pages[j++]);
L
Linus Torvalds 已提交
1309 1310 1311 1312 1313 1314 1315 1316
	}

	kfree(pages);

	/*
	 * set data direction, and check if mapped pages need bouncing
	 */
	if (!write_to_vm)
1317
		bio->bi_rw |= REQ_WRITE;
L
Linus Torvalds 已提交
1318

1319
	bio->bi_bdev = bdev;
L
Linus Torvalds 已提交
1320 1321
	bio->bi_flags |= (1 << BIO_USER_MAPPED);
	return bio;
1322 1323 1324 1325 1326 1327 1328 1329

 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
1330 1331 1332 1333 1334 1335 1336
	kfree(pages);
	bio_put(bio);
	return ERR_PTR(ret);
}

/**
 *	bio_map_user	-	map user address into bio
1337
 *	@q: the struct request_queue for the bio
L
Linus Torvalds 已提交
1338 1339 1340 1341
 *	@bdev: destination block device
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
1342
 *	@gfp_mask: memory allocation flags
L
Linus Torvalds 已提交
1343 1344 1345 1346
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1347
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1348 1349
			 unsigned long uaddr, unsigned int len, int write_to_vm,
			 gfp_t gfp_mask)
1350 1351 1352
{
	struct sg_iovec iov;

1353
	iov.iov_base = (void __user *)uaddr;
1354 1355
	iov.iov_len = len;

1356
	return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1357
}
1358
EXPORT_SYMBOL(bio_map_user);
1359 1360 1361

/**
 *	bio_map_user_iov - map user sg_iovec table into bio
1362
 *	@q: the struct request_queue for the bio
1363 1364 1365 1366
 *	@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
1367
 *	@gfp_mask: memory allocation flags
1368 1369 1370 1371
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
1372
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1373
			     struct sg_iovec *iov, int iov_count,
1374
			     int write_to_vm, gfp_t gfp_mask)
L
Linus Torvalds 已提交
1375 1376 1377
{
	struct bio *bio;

1378 1379
	bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
				 gfp_mask);
L
Linus Torvalds 已提交
1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390
	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);

1391
	return bio;
L
Linus Torvalds 已提交
1392 1393 1394 1395 1396 1397 1398 1399 1400 1401
}

static void __bio_unmap_user(struct bio *bio)
{
	struct bio_vec *bvec;
	int i;

	/*
	 * make sure we dirty pages we wrote to
	 */
1402
	bio_for_each_segment_all(bvec, bio, i) {
L
Linus Torvalds 已提交
1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425
		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);
}
1426
EXPORT_SYMBOL(bio_unmap_user);
L
Linus Torvalds 已提交
1427

1428
static void bio_map_kern_endio(struct bio *bio, int err)
1429 1430 1431 1432
{
	bio_put(bio);
}

1433
static struct bio *__bio_map_kern(struct request_queue *q, void *data,
A
Al Viro 已提交
1434
				  unsigned int len, gfp_t gfp_mask)
M
Mike Christie 已提交
1435 1436 1437 1438 1439 1440 1441 1442
{
	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;

1443
	bio = bio_kmalloc(gfp_mask, nr_pages);
M
Mike Christie 已提交
1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456
	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;

1457 1458
		if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
				    offset) < bytes)
M
Mike Christie 已提交
1459 1460 1461 1462 1463 1464 1465
			break;

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

1466
	bio->bi_end_io = bio_map_kern_endio;
M
Mike Christie 已提交
1467 1468 1469 1470 1471
	return bio;
}

/**
 *	bio_map_kern	-	map kernel address into bio
1472
 *	@q: the struct request_queue for the bio
M
Mike Christie 已提交
1473 1474 1475 1476 1477 1478 1479
 *	@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.
 */
1480
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
A
Al Viro 已提交
1481
			 gfp_t gfp_mask)
M
Mike Christie 已提交
1482 1483 1484 1485 1486 1487 1488
{
	struct bio *bio;

	bio = __bio_map_kern(q, data, len, gfp_mask);
	if (IS_ERR(bio))
		return bio;

1489
	if (bio->bi_iter.bi_size == len)
M
Mike Christie 已提交
1490 1491 1492 1493 1494 1495 1496 1497
		return bio;

	/*
	 * Don't support partial mappings.
	 */
	bio_put(bio);
	return ERR_PTR(-EINVAL);
}
1498
EXPORT_SYMBOL(bio_map_kern);
M
Mike Christie 已提交
1499

1500 1501 1502 1503
static void bio_copy_kern_endio(struct bio *bio, int err)
{
	struct bio_vec *bvec;
	const int read = bio_data_dir(bio) == READ;
1504
	struct bio_map_data *bmd = bio->bi_private;
1505
	int i;
1506
	char *p = bmd->sgvecs[0].iov_base;
1507

1508
	bio_for_each_segment_all(bvec, bio, i) {
1509
		char *addr = page_address(bvec->bv_page);
1510
		int len = bmd->iovecs[i].bv_len;
1511

1512
		if (read)
1513
			memcpy(p, addr, len);
1514 1515

		__free_page(bvec->bv_page);
1516
		p += len;
1517 1518
	}

1519
	bio_free_map_data(bmd);
1520 1521 1522 1523 1524 1525 1526 1527 1528
	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
1529
 *	@reading: data direction is READ
1530 1531 1532 1533 1534 1535 1536 1537 1538
 *
 *	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;
1539
	int i;
1540

1541 1542 1543
	bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
	if (IS_ERR(bio))
		return bio;
1544 1545 1546 1547

	if (!reading) {
		void *p = data;

1548
		bio_for_each_segment_all(bvec, bio, i) {
1549 1550 1551 1552 1553 1554 1555 1556
			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;
1557

1558 1559
	return bio;
}
1560
EXPORT_SYMBOL(bio_copy_kern);
1561

L
Linus Torvalds 已提交
1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580
/*
 * 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.
1581
 * But other code (eg, flusher threads) could clean the pages if they are mapped
L
Linus Torvalds 已提交
1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592
 * 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)
{
1593
	struct bio_vec *bvec;
L
Linus Torvalds 已提交
1594 1595
	int i;

1596 1597
	bio_for_each_segment_all(bvec, bio, i) {
		struct page *page = bvec->bv_page;
L
Linus Torvalds 已提交
1598 1599 1600 1601 1602 1603

		if (page && !PageCompound(page))
			set_page_dirty_lock(page);
	}
}

1604
static void bio_release_pages(struct bio *bio)
L
Linus Torvalds 已提交
1605
{
1606
	struct bio_vec *bvec;
L
Linus Torvalds 已提交
1607 1608
	int i;

1609 1610
	bio_for_each_segment_all(bvec, bio, i) {
		struct page *page = bvec->bv_page;
L
Linus Torvalds 已提交
1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627

		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.
 */

1628
static void bio_dirty_fn(struct work_struct *work);
L
Linus Torvalds 已提交
1629

1630
static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
L
Linus Torvalds 已提交
1631 1632 1633 1634 1635 1636
static DEFINE_SPINLOCK(bio_dirty_lock);
static struct bio *bio_dirty_list;

/*
 * This runs in process context
 */
1637
static void bio_dirty_fn(struct work_struct *work)
L
Linus Torvalds 已提交
1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658
{
	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)
{
1659
	struct bio_vec *bvec;
L
Linus Torvalds 已提交
1660 1661 1662
	int nr_clean_pages = 0;
	int i;

1663 1664
	bio_for_each_segment_all(bvec, bio, i) {
		struct page *page = bvec->bv_page;
L
Linus Torvalds 已提交
1665 1666 1667

		if (PageDirty(page) || PageCompound(page)) {
			page_cache_release(page);
1668
			bvec->bv_page = NULL;
L
Linus Torvalds 已提交
1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686
		} 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);
	}
}

1687 1688 1689
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
void bio_flush_dcache_pages(struct bio *bi)
{
1690 1691
	struct bio_vec bvec;
	struct bvec_iter iter;
1692

1693 1694
	bio_for_each_segment(bvec, bi, iter)
		flush_dcache_page(bvec.bv_page);
1695 1696 1697 1698
}
EXPORT_SYMBOL(bio_flush_dcache_pages);
#endif

L
Linus Torvalds 已提交
1699 1700 1701 1702 1703 1704
/**
 * bio_endio - end I/O on a bio
 * @bio:	bio
 * @error:	error, if any
 *
 * Description:
1705
 *   bio_endio() will end I/O on the whole bio. bio_endio() is the
N
NeilBrown 已提交
1706 1707 1708
 *   preferred way to end I/O on a bio, it takes care of clearing
 *   BIO_UPTODATE on error. @error is 0 on success, and and one of the
 *   established -Exxxx (-EIO, for instance) error values in case
L
Lucas De Marchi 已提交
1709
 *   something went wrong. No one should call bi_end_io() directly on a
N
NeilBrown 已提交
1710 1711
 *   bio unless they own it and thus know that it has an end_io
 *   function.
L
Linus Torvalds 已提交
1712
 **/
1713
void bio_endio(struct bio *bio, int error)
L
Linus Torvalds 已提交
1714 1715 1716
{
	if (error)
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
N
NeilBrown 已提交
1717 1718
	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
		error = -EIO;
L
Linus Torvalds 已提交
1719

N
NeilBrown 已提交
1720
	if (bio->bi_end_io)
1721
		bio->bi_end_io(bio, error);
L
Linus Torvalds 已提交
1722
}
1723
EXPORT_SYMBOL(bio_endio);
L
Linus Torvalds 已提交
1724 1725 1726 1727 1728 1729

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

1730
		bio_endio(master, bp->error);
L
Linus Torvalds 已提交
1731 1732 1733
		mempool_free(bp, bp->bio2.bi_private);
	}
}
1734
EXPORT_SYMBOL(bio_pair_release);
L
Linus Torvalds 已提交
1735

1736
static void bio_pair_end_1(struct bio *bi, int err)
L
Linus Torvalds 已提交
1737 1738 1739 1740 1741 1742 1743 1744 1745
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

1746
static void bio_pair_end_2(struct bio *bi, int err)
L
Linus Torvalds 已提交
1747 1748 1749 1750 1751 1752 1753 1754 1755 1756
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

/*
1757
 * split a bio - only worry about a bio with a single page in its iovec
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1758
 */
D
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1759
struct bio_pair *bio_split(struct bio *bi, int first_sectors)
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{
D
Denis ChengRq 已提交
1761
	struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
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1762 1763 1764 1765

	if (!bp)
		return bp;

1766
	trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1767
				bi->bi_iter.bi_sector + first_sectors);
1768

1769
	BUG_ON(bio_segments(bi) > 1);
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Linus Torvalds 已提交
1770 1771 1772 1773
	atomic_set(&bp->cnt, 3);
	bp->error = 0;
	bp->bio1 = *bi;
	bp->bio2 = *bi;
1774 1775 1776
	bp->bio2.bi_iter.bi_sector += first_sectors;
	bp->bio2.bi_iter.bi_size -= first_sectors << 9;
	bp->bio1.bi_iter.bi_size = first_sectors << 9;
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Linus Torvalds 已提交
1777

1778
	if (bi->bi_vcnt != 0) {
1779 1780
		bp->bv1 = bio_iovec(bi);
		bp->bv2 = bio_iovec(bi);
1781

1782 1783 1784 1785 1786
		if (bio_is_rw(bi)) {
			bp->bv2.bv_offset += first_sectors << 9;
			bp->bv2.bv_len -= first_sectors << 9;
			bp->bv1.bv_len = first_sectors << 9;
		}
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1788 1789
		bp->bio1.bi_io_vec = &bp->bv1;
		bp->bio2.bi_io_vec = &bp->bv2;
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1790

1791 1792 1793
		bp->bio1.bi_max_vecs = 1;
		bp->bio2.bi_max_vecs = 1;
	}
1794

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1795 1796 1797 1798
	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
1799
	bp->bio2.bi_private = bio_split_pool;
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1800

1801 1802 1803
	if (bio_integrity(bi))
		bio_integrity_split(bi, bp, first_sectors);

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1804 1805
	return bp;
}
1806
EXPORT_SYMBOL(bio_split);
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1807

1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824
/**
 * bio_trim - trim a bio
 * @bio:	bio to trim
 * @offset:	number of sectors to trim from the front of @bio
 * @size:	size we want to trim @bio to, in sectors
 */
void bio_trim(struct bio *bio, int offset, int size)
{
	/* 'bio' is a cloned bio which we need to trim to match
	 * the given offset and size.
	 * This requires adjusting bi_sector, bi_size, and bi_io_vec
	 */
	int i;
	struct bio_vec *bvec;
	int sofar = 0;

	size <<= 9;
1825
	if (offset == 0 && size == bio->bi_iter.bi_size)
1826 1827 1828 1829 1830 1831
		return;

	clear_bit(BIO_SEG_VALID, &bio->bi_flags);

	bio_advance(bio, offset << 9);

1832
	bio->bi_iter.bi_size = size;
1833 1834

	/* avoid any complications with bi_idx being non-zero*/
1835 1836 1837 1838 1839 1840
	if (bio->bi_iter.bi_idx) {
		memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_iter.bi_idx,
			(bio->bi_vcnt - bio->bi_iter.bi_idx) *
			sizeof(struct bio_vec));
		bio->bi_vcnt -= bio->bi_iter.bi_idx;
		bio->bi_iter.bi_idx = 0;
1841 1842
	}
	/* Make sure vcnt and last bv are not too big */
1843
	bio_for_each_segment_all(bvec, bio, i) {
1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854
		if (sofar + bvec->bv_len > size)
			bvec->bv_len = size - sofar;
		if (bvec->bv_len == 0) {
			bio->bi_vcnt = i;
			break;
		}
		sofar += bvec->bv_len;
	}
}
EXPORT_SYMBOL_GPL(bio_trim);

1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867
/**
 *      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)
{
1868
	unsigned int sector_sz;
1869 1870 1871 1872
	struct bio_vec *bv;
	sector_t sectors;
	int i;

1873
	sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
1874 1875
	sectors = 0;

1876
	if (index >= bio->bi_iter.bi_idx)
1877 1878
		index = bio->bi_vcnt - 1;

1879
	bio_for_each_segment_all(bv, bio, i) {
1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891
		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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/*
 * create memory pools for biovec's in a bio_set.
 * use the global biovec slabs created for general use.
 */
1897
mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries)
L
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1898
{
1899
	struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
L
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1900

1901
	return mempool_create_slab_pool(pool_entries, bp->slab);
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1902 1903 1904 1905
}

void bioset_free(struct bio_set *bs)
{
1906 1907 1908
	if (bs->rescue_workqueue)
		destroy_workqueue(bs->rescue_workqueue);

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1909 1910 1911
	if (bs->bio_pool)
		mempool_destroy(bs->bio_pool);

1912 1913 1914
	if (bs->bvec_pool)
		mempool_destroy(bs->bvec_pool);

1915
	bioset_integrity_free(bs);
1916
	bio_put_slab(bs);
L
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1917 1918 1919

	kfree(bs);
}
1920
EXPORT_SYMBOL(bioset_free);
L
Linus Torvalds 已提交
1921

1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935
/**
 * 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)
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Linus Torvalds 已提交
1936
{
1937
	unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1938
	struct bio_set *bs;
L
Linus Torvalds 已提交
1939

1940
	bs = kzalloc(sizeof(*bs), GFP_KERNEL);
L
Linus Torvalds 已提交
1941 1942 1943
	if (!bs)
		return NULL;

1944
	bs->front_pad = front_pad;
1945

1946 1947 1948 1949
	spin_lock_init(&bs->rescue_lock);
	bio_list_init(&bs->rescue_list);
	INIT_WORK(&bs->rescue_work, bio_alloc_rescue);

1950
	bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1951 1952 1953 1954 1955 1956
	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
1957 1958 1959
	if (!bs->bio_pool)
		goto bad;

1960 1961
	bs->bvec_pool = biovec_create_pool(bs, pool_size);
	if (!bs->bvec_pool)
1962 1963 1964 1965 1966
		goto bad;

	bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
	if (!bs->rescue_workqueue)
		goto bad;
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Linus Torvalds 已提交
1967

1968
	return bs;
L
Linus Torvalds 已提交
1969 1970 1971 1972
bad:
	bioset_free(bs);
	return NULL;
}
1973
EXPORT_SYMBOL(bioset_create);
L
Linus Torvalds 已提交
1974

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
#ifdef CONFIG_BLK_CGROUP
/**
 * bio_associate_current - associate a bio with %current
 * @bio: target bio
 *
 * Associate @bio with %current if it hasn't been associated yet.  Block
 * layer will treat @bio as if it were issued by %current no matter which
 * task actually issues it.
 *
 * This function takes an extra reference of @task's io_context and blkcg
 * which will be put when @bio is released.  The caller must own @bio,
 * ensure %current->io_context exists, and is responsible for synchronizing
 * calls to this function.
 */
int bio_associate_current(struct bio *bio)
{
	struct io_context *ioc;
	struct cgroup_subsys_state *css;

	if (bio->bi_ioc)
		return -EBUSY;

	ioc = current->io_context;
	if (!ioc)
		return -ENOENT;

	/* acquire active ref on @ioc and associate */
	get_io_context_active(ioc);
	bio->bi_ioc = ioc;

	/* associate blkcg if exists */
	rcu_read_lock();
2007
	css = task_css(current, blkio_subsys_id);
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032
	if (css && css_tryget(css))
		bio->bi_css = css;
	rcu_read_unlock();

	return 0;
}

/**
 * bio_disassociate_task - undo bio_associate_current()
 * @bio: target bio
 */
void bio_disassociate_task(struct bio *bio)
{
	if (bio->bi_ioc) {
		put_io_context(bio->bi_ioc);
		bio->bi_ioc = NULL;
	}
	if (bio->bi_css) {
		css_put(bio->bi_css);
		bio->bi_css = NULL;
	}
}

#endif /* CONFIG_BLK_CGROUP */

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2033 2034 2035 2036 2037 2038 2039 2040
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;

2041 2042 2043 2044 2045
		if (bvs->nr_vecs <= BIO_INLINE_VECS) {
			bvs->slab = NULL;
			continue;
		}

L
Linus Torvalds 已提交
2046 2047
		size = bvs->nr_vecs * sizeof(struct bio_vec);
		bvs->slab = kmem_cache_create(bvs->name, size, 0,
2048
                                SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
2049 2050 2051 2052 2053
	}
}

static int __init init_bio(void)
{
2054 2055 2056 2057 2058
	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
2059

2060
	bio_integrity_init();
L
Linus Torvalds 已提交
2061 2062
	biovec_init_slabs();

2063
	fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
L
Linus Torvalds 已提交
2064 2065 2066
	if (!fs_bio_set)
		panic("bio: can't allocate bios\n");

2067 2068 2069
	if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
		panic("bio: can't create integrity pool\n");

2070 2071
	bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
						     sizeof(struct bio_pair));
L
Linus Torvalds 已提交
2072 2073 2074 2075 2076 2077
	if (!bio_split_pool)
		panic("bio: can't create split pool\n");

	return 0;
}
subsys_initcall(init_bio);