text:
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/uio.h>
#include <linux/iocontext.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/mempool.h>
#include <linux/workqueue.h>
#include <linux/cgroup.h>
#include <scsi/sg.h>		/* for struct sg_iovec */

#include <trace/events/block.h>

/*
 * 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

static mempool_t *bio_split_pool __read_mostly;

/*
 * 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) }
static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
	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.
 */
struct bio_set *fs_bio_set;
EXPORT_SYMBOL(fs_bio_set);

/*
 * 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, *new_bio_slabs;
	unsigned int new_bio_slab_max;
	unsigned int i, entry = -1;

	mutex_lock(&bio_slab_lock);

	i = 0;
	while (i < bio_slab_nr) {
		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) {
		new_bio_slab_max = bio_slab_max << 1;
		new_bio_slabs = krealloc(bio_slabs,
					 new_bio_slab_max * sizeof(struct bio_slab),
					 GFP_KERNEL);
		if (!new_bio_slabs)
			goto out_unlock;
		bio_slab_max = new_bio_slab_max;
		bio_slabs = new_bio_slabs;
	}
	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(KERN_INFO "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);
}

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

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

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

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

struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
			   mempool_t *pool)
{
	struct bio_vec *bvl;

	/*
	 * 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(pool, gfp_mask);
	} else {
		struct biovec_slab *bvs = bvec_slabs + *idx;
		gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);

		/*
		 * Make this allocation restricted and don't dump info on
		 * allocation failures, since we'll fallback to the mempool
		 * in case of failure.
		 */
		__gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;

		/*
		 * Try a slab allocation. If this fails and __GFP_WAIT
		 * is set, retry with the 1-entry mempool
		 */
		bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
		if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
			*idx = BIOVEC_MAX_IDX;
			goto fallback;
		}
	}

	return bvl;
}

static void __bio_free(struct bio *bio)
{
	bio_disassociate_task(bio);

	if (bio_integrity(bio))
		bio_integrity_free(bio);
}

static void bio_free(struct bio *bio)
{
	struct bio_set *bs = bio->bi_pool;
	void *p;

	__bio_free(bio);

	if (bs) {
		if (bio_flagged(bio, BIO_OWNS_VEC))
			bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));

		/*
		 * If we have front padding, adjust the bio pointer before freeing
		 */
		p = bio;
		p -= bs->front_pad;

		mempool_free(p, bs->bio_pool);
	} else {
		/* Bio was allocated by bio_kmalloc() */
		kfree(bio);
	}
}

void bio_init(struct bio *bio)
{
	memset(bio, 0, sizeof(*bio));
	bio->bi_flags = 1 << BIO_UPTODATE;
	atomic_set(&bio->bi_cnt, 1);
}
EXPORT_SYMBOL(bio_init);

/**
 * 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);

	__bio_free(bio);

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

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);
}

/**
 * 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
 * @bs:		the bio_set to allocate from.
 *
 * Description:
 *   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.
 *
 *   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.
 *
 *   RETURNS:
 *   Pointer to new bio on success, NULL on failure.
 */
struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
{
	gfp_t saved_gfp = gfp_mask;
	unsigned front_pad;
	unsigned inline_vecs;
	unsigned long idx = BIO_POOL_NONE;
	struct bio_vec *bvl = NULL;
	struct bio *bio;
	void *p;

	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 {
		/*
		 * 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;

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

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

	if (unlikely(!p))
		return NULL;

	bio = p + front_pad;
	bio_init(bio);

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

		if (unlikely(!bvl))
			goto err_free;

		bio->bi_flags |= 1 << BIO_OWNS_VEC;
	} else if (nr_iovecs) {
		bvl = bio->bi_inline_vecs;
	}

	bio->bi_pool = bs;
	bio->bi_flags |= idx << BIO_POOL_OFFSET;
	bio->bi_max_vecs = nr_iovecs;
	bio->bi_io_vec = bvl;
	return bio;

err_free:
	mempool_free(p, bs->bio_pool);
	return NULL;
}
EXPORT_SYMBOL(bio_alloc_bioset);

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, bio_get or bio_clone. 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_free(bio);
}
EXPORT_SYMBOL(bio_put);

inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
{
	if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
		blk_recount_segments(q, bio);

	return bio->bi_phys_segments;
}
EXPORT_SYMBOL(bio_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.
 */
void __bio_clone(struct bio *bio, struct bio *bio_src)
{
	memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
		bio_src->bi_max_vecs * sizeof(struct bio_vec));

	/*
	 * most users will be overriding ->bi_bdev with a new target,
	 * so we don't set nor calculate new physical/hw segment counts here
	 */
	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;
	bio->bi_idx = bio_src->bi_idx;
}
EXPORT_SYMBOL(__bio_clone);

/**
 *	bio_clone_bioset -	clone a bio
 *	@bio: bio to clone
 *	@gfp_mask: allocation priority
 *	@bs: bio_set to allocate from
 *
 * 	Like __bio_clone, only also allocates the returned bio
 */
struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask,
			     struct bio_set *bs)
{
	struct bio *b;

	b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs);
	if (!b)
		return NULL;

	__bio_clone(b, bio);

	if (bio_integrity(bio)) {
		int ret;

		ret = bio_integrity_clone(b, bio, gfp_mask);

		if (ret < 0) {
			bio_put(b);
			return NULL;
		}
	}

	return b;
}
EXPORT_SYMBOL(bio_clone_bioset);

/**
 *	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)
{
	struct request_queue *q = bdev_get_queue(bdev);
	int nr_pages;

	nr_pages = min_t(unsigned,
		     queue_max_segments(q),
		     queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);

	return min_t(unsigned, nr_pages, BIO_MAX_PAGES);

}
EXPORT_SYMBOL(bio_get_nr_vecs);

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

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

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

	/*
	 * 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) {
			unsigned int prev_bv_len = prev->bv_len;
			prev->bv_len += len;

			if (q->merge_bvec_fn) {
				struct bvec_merge_data bvm = {
					/* prev_bvec is already charged in
					   bi_size, discharge it in order to
					   simulate merging updated prev_bvec
					   as new bvec. */
					.bi_bdev = bio->bi_bdev,
					.bi_sector = bio->bi_sector,
					.bi_size = bio->bi_size - prev_bv_len,
					.bi_rw = bio->bi_rw,
				};

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

			goto done;
		}
	}

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

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

	while (bio->bi_phys_segments >= queue_max_segments(q)) {

		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) {
		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,
		};

		/*
		 * merge_bvec_fn() returns number of bytes it can accept
		 * at this offset
		 */
		if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
			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 */
	if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
		bio->bi_flags &= ~(1 << BIO_SEG_VALID);

	bio->bi_vcnt++;
	bio->bi_phys_segments++;
 done:
	bio->bi_size += len;
	return len;
}

/**
 *	bio_add_pc_page	-	attempt to add page to bio
 *	@q: the target queue
 *	@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 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.
 */
int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
		    unsigned int len, unsigned int offset)
{
	return __bio_add_page(q, bio, page, len, offset,
			      queue_max_hw_sectors(q));
}
EXPORT_SYMBOL(bio_add_pc_page);

/**
 *	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 up to 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)
{
	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
	return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
}
EXPORT_SYMBOL(bio_add_page);

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);

/**
 * 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);

	bio->bi_sector += bytes >> 9;
	bio->bi_size -= bytes;

	if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
		return;

	while (bytes) {
		if (unlikely(bio->bi_idx >= bio->bi_vcnt)) {
			WARN_ONCE(1, "bio idx %d >= vcnt %d\n",
				  bio->bi_idx, bio->bi_vcnt);
			break;
		}

		if (bytes >= bio_iovec(bio)->bv_len) {
			bytes -= bio_iovec(bio)->bv_len;
			bio->bi_idx++;
		} else {
			bio_iovec(bio)->bv_len -= bytes;
			bio_iovec(bio)->bv_offset += bytes;
			bytes = 0;
		}
	}
}
EXPORT_SYMBOL(bio_advance);

/**
 * 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);

/**
 * 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;

	src_bv = bio_iovec(src);
	dst_bv = bio_iovec(dst);

	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;

				src_bv = bio_iovec(src);
			}

			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;

				dst_bv = bio_iovec(dst);
			}

			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);

		memcpy(dst_p + dst_offset,
		       src_p + src_offset,
		       bytes);

		kunmap_atomic(dst_p);
		kunmap_atomic(src_p);

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

struct bio_map_data {
	struct bio_vec *iovecs;
	struct sg_iovec *sgvecs;
	int nr_sgvecs;
	int is_our_pages;
};

static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
			     struct sg_iovec *iov, int iov_count,
			     int is_our_pages)
{
	memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
	memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
	bmd->nr_sgvecs = iov_count;
	bmd->is_our_pages = is_our_pages;
	bio->bi_private = bmd;
}

static void bio_free_map_data(struct bio_map_data *bmd)
{
	kfree(bmd->iovecs);
	kfree(bmd->sgvecs);
	kfree(bmd);
}

static struct bio_map_data *bio_alloc_map_data(int nr_segs,
					       unsigned int iov_count,
					       gfp_t gfp_mask)
{
	struct bio_map_data *bmd;

	if (iov_count > UIO_MAXIOV)
		return NULL;

	bmd = kmalloc(sizeof(*bmd), gfp_mask);
	if (!bmd)
		return NULL;

	bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
	if (!bmd->iovecs) {
		kfree(bmd);
		return NULL;
	}

	bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
	if (bmd->sgvecs)
		return bmd;

	kfree(bmd->iovecs);
	kfree(bmd);
	return NULL;
}

static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
			  struct sg_iovec *iov, int iov_count,
			  int to_user, int from_user, int do_free_page)
{
	int ret = 0, i;
	struct bio_vec *bvec;
	int iov_idx = 0;
	unsigned int iov_off = 0;

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

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

			bytes = min_t(unsigned int,
				      iov[iov_idx].iov_len - iov_off, bv_len);
			iov_addr = iov[iov_idx].iov_base + iov_off;

			if (!ret) {
				if (to_user)
					ret = copy_to_user(iov_addr, bv_addr,
							   bytes);

				if (from_user)
					ret = copy_from_user(bv_addr, iov_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;
			}
		}

		if (do_free_page)
			__free_page(bvec->bv_page);
	}

	return ret;
}

/**
 *	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;
	struct bio_vec *bvec;
	int ret = 0, i;

	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);
	}
	bio_free_map_data(bmd);
	bio_put(bio);
	return ret;
}
EXPORT_SYMBOL(bio_uncopy_user);

/**
 *	bio_copy_user_iov	-	copy user data to bio
 *	@q: destination block queue
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
 *	@iov:	the iovec.
 *	@iov_count: number of elements in the iovec
 *	@write_to_vm: bool indicating writing to pages or not
 *	@gfp_mask: memory allocation flags
 *
 *	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.
 */
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)
{
	struct bio_map_data *bmd;
	struct bio_vec *bvec;
	struct page *page;
	struct bio *bio;
	int i, ret;
	int nr_pages = 0;
	unsigned int len = 0;
	unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;

	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;

		/*
		 * Overflow, abort
		 */
		if (end < start)
			return ERR_PTR(-EINVAL);

		nr_pages += end - start;
		len += iov[i].iov_len;
	}

	if (offset)
		nr_pages++;

	bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
	if (!bmd)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
	bio = bio_kmalloc(gfp_mask, nr_pages);
	if (!bio)
		goto out_bmd;

	if (!write_to_vm)
		bio->bi_rw |= REQ_WRITE;

	ret = 0;

	if (map_data) {
		nr_pages = 1 << map_data->page_order;
		i = map_data->offset / PAGE_SIZE;
	}
	while (len) {
		unsigned int bytes = PAGE_SIZE;

		bytes -= offset;

		if (bytes > len)
			bytes = len;

		if (map_data) {
			if (i == map_data->nr_entries * nr_pages) {
				ret = -ENOMEM;
				break;
			}

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

			i++;
		} else {
			page = alloc_page(q->bounce_gfp | gfp_mask);
			if (!page) {
				ret = -ENOMEM;
				break;
			}
		}

		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
			break;

		len -= bytes;
		offset = 0;
	}

	if (ret)
		goto cleanup;

	/*
	 * success
	 */
	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);
		if (ret)
			goto cleanup;
	}

	bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
	return bio;
cleanup:
	if (!map_data)
		bio_for_each_segment_all(bvec, bio, i)
			__free_page(bvec->bv_page);

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

/**
 *	bio_copy_user	-	copy user data to bio
 *	@q: destination block queue
 *	@map_data: pointer to the rq_map_data holding pages (if necessary)
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
 *	@gfp_mask: memory allocation flags
 *
 *	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.
 */
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)
{
	struct sg_iovec iov;

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

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

static struct bio *__bio_map_user_iov(struct request_queue *q,
				      struct block_device *bdev,
				      struct sg_iovec *iov, int iov_count,
				      int write_to_vm, gfp_t gfp_mask)
{
	int i, j;
	int nr_pages = 0;
	struct page **pages;
	struct bio *bio;
	int cur_page = 0;
	int ret, offset;

	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;

		/*
		 * Overflow, abort
		 */
		if (end < start)
			return ERR_PTR(-EINVAL);

		nr_pages += end - start;
		/*
		 * buffer must be aligned to at least hardsector size for now
		 */
		if (uaddr & queue_dma_alignment(q))
			return ERR_PTR(-EINVAL);
	}

	if (!nr_pages)
		return ERR_PTR(-EINVAL);

	bio = bio_kmalloc(gfp_mask, nr_pages);
	if (!bio)
		return ERR_PTR(-ENOMEM);

	ret = -ENOMEM;
	pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
	if (!pages)
		goto out;

	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;

		ret = get_user_pages_fast(uaddr, local_nr_pages,
				write_to_vm, &pages[cur_page]);
		if (ret < local_nr_pages) {
			ret = -EFAULT;
			goto out_unmap;
		}

		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...
			 */
			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
					    bytes)
				break;

			len -= bytes;
			offset = 0;
		}

		cur_page = j;
		/*
		 * release the pages we didn't map into the bio, if any
		 */
		while (j < page_limit)
			page_cache_release(pages[j++]);
	}

	kfree(pages);

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

	bio->bi_bdev = bdev;
	bio->bi_flags |= (1 << BIO_USER_MAPPED);
	return bio;

 out_unmap:
	for (i = 0; i < nr_pages; i++) {
		if(!pages[i])
			break;
		page_cache_release(pages[i]);
	}
 out:
	kfree(pages);
	bio_put(bio);
	return ERR_PTR(ret);
}

/**
 *	bio_map_user	-	map user address into bio
 *	@q: the struct request_queue for the bio
 *	@bdev: destination block device
 *	@uaddr: start of user address
 *	@len: length in bytes
 *	@write_to_vm: bool indicating writing to pages or not
 *	@gfp_mask: memory allocation flags
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
			 unsigned long uaddr, unsigned int len, int write_to_vm,
			 gfp_t gfp_mask)
{
	struct sg_iovec iov;

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

	return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
}
EXPORT_SYMBOL(bio_map_user);

/**
 *	bio_map_user_iov - map user sg_iovec table into bio
 *	@q: the struct request_queue for the bio
 *	@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
 *	@gfp_mask: memory allocation flags
 *
 *	Map the user space address into a bio suitable for io to a block
 *	device. Returns an error pointer in case of error.
 */
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
			     struct sg_iovec *iov, int iov_count,
			     int write_to_vm, gfp_t gfp_mask)
{
	struct bio *bio;

	bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
				 gfp_mask);
	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);

	return bio;
}

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_all(bvec, bio, i) {
		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);
}
EXPORT_SYMBOL(bio_unmap_user);

static void bio_map_kern_endio(struct bio *bio, int err)
{
	bio_put(bio);
}

static struct bio *__bio_map_kern(struct request_queue *q, void *data,
				  unsigned int len, gfp_t gfp_mask)
{
	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;

	bio = bio_kmalloc(gfp_mask, nr_pages);
	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;

		if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
				    offset) < bytes)
			break;

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

	bio->bi_end_io = bio_map_kern_endio;
	return bio;
}

/**
 *	bio_map_kern	-	map kernel address into bio
 *	@q: the struct request_queue for the bio
 *	@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.
 */
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
			 gfp_t gfp_mask)
{
	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);
}
EXPORT_SYMBOL(bio_map_kern);

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

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

		if (read)
			memcpy(p, addr, len);

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

	bio_free_map_data(bmd);
	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
 *	@reading: data direction is READ
 *
 *	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;
	int i;

	bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
	if (IS_ERR(bio))
		return bio;

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

		bio_for_each_segment_all(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;

	return bio;
}
EXPORT_SYMBOL(bio_copy_kern);

/*
 * 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, flusher threads) 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;
	int i;

	bio_for_each_segment_all(bvec, bio, i) {
		struct page *page = bvec->bv_page;

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

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

	bio_for_each_segment_all(bvec, bio, i) {
		struct page *page = bvec->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.
 */

static void bio_dirty_fn(struct work_struct *work);

static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
static DEFINE_SPINLOCK(bio_dirty_lock);
static struct bio *bio_dirty_list;

/*
 * This runs in process context
 */
static void bio_dirty_fn(struct work_struct *work)
{
	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;
	int nr_clean_pages = 0;
	int i;

	bio_for_each_segment_all(bvec, bio, i) {
		struct page *page = bvec->bv_page;

		if (PageDirty(page) || PageCompound(page)) {
			page_cache_release(page);
			bvec->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);
	}
}

#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
void bio_flush_dcache_pages(struct bio *bi)
{
	int i;
	struct bio_vec *bvec;

	bio_for_each_segment(bvec, bi, i)
		flush_dcache_page(bvec->bv_page);
}
EXPORT_SYMBOL(bio_flush_dcache_pages);
#endif

/**
 * bio_endio - end I/O on a bio
 * @bio:	bio
 * @error:	error, if any
 *
 * Description:
 *   bio_endio() will end I/O on the whole bio. bio_endio() is the
 *   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. No one should call bi_end_io() directly on a
 *   bio unless they own it and thus know that it has an end_io
 *   function.
 **/
void bio_endio(struct bio *bio, int error)
{
	if (error)
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
		error = -EIO;

	if (bio->bi_end_io)
		bio->bi_end_io(bio, error);
}
EXPORT_SYMBOL(bio_endio);

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

		bio_endio(master, bp->error);
		mempool_free(bp, bp->bio2.bi_private);
	}
}
EXPORT_SYMBOL(bio_pair_release);

static void bio_pair_end_1(struct bio *bi, int err)
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

static void bio_pair_end_2(struct bio *bi, int err)
{
	struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);

	if (err)
		bp->error = err;

	bio_pair_release(bp);
}

/*
 * split a bio - only worry about a bio with a single page in its iovec
 */
struct bio_pair *bio_split(struct bio *bi, int first_sectors)
{
	struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);

	if (!bp)
		return bp;

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

	BUG_ON(bio_segments(bi) > 1);
	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;

	if (bi->bi_vcnt != 0) {
		bp->bv1 = *bio_iovec(bi);
		bp->bv2 = *bio_iovec(bi);

		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;
		}

		bp->bio1.bi_io_vec = &bp->bv1;
		bp->bio2.bi_io_vec = &bp->bv2;

		bp->bio1.bi_max_vecs = 1;
		bp->bio2.bi_max_vecs = 1;
	}

	bp->bio1.bi_end_io = bio_pair_end_1;
	bp->bio2.bi_end_io = bio_pair_end_2;

	bp->bio1.bi_private = bi;
	bp->bio2.bi_private = bio_split_pool;

	if (bio_integrity(bi))
		bio_integrity_split(bi, bp, first_sectors);

	return bp;
}
EXPORT_SYMBOL(bio_split);

/**
 *      bio_sector_offset - Find hardware sector offset in bio
 *      @bio:           bio to inspect
 *      @index:         bio_vec index
 *      @offset:        offset in bv_page
 *
 *      Return the number of hardware sectors between beginning of bio
 *      and an end point indicated by a bio_vec index and an offset
 *      within that vector's page.
 */
sector_t bio_sector_offset(struct bio *bio, unsigned short index,
			   unsigned int offset)
{
	unsigned int sector_sz;
	struct bio_vec *bv;
	sector_t sectors;
	int i;

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

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

	bio_for_each_segment_all(bv, bio, i) {
		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);

/*
 * create memory pools for biovec's in a bio_set.
 * use the global biovec slabs created for general use.
 */
mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries)
{
	struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;

	return mempool_create_slab_pool(pool_entries, bp->slab);
}

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

	if (bs->bio_pool)
		mempool_destroy(bs->bio_pool);

	if (bs->bvec_pool)
		mempool_destroy(bs->bvec_pool);

	bioset_integrity_free(bs);
	bio_put_slab(bs);

	kfree(bs);
}
EXPORT_SYMBOL(bioset_free);

/**
 * 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)
{
	unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
	struct bio_set *bs;

	bs = kzalloc(sizeof(*bs), GFP_KERNEL);
	if (!bs)
		return NULL;

	bs->front_pad = front_pad;

	spin_lock_init(&bs->rescue_lock);
	bio_list_init(&bs->rescue_list);
	INIT_WORK(&bs->rescue_work, bio_alloc_rescue);

	bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
	if (!bs->bio_slab) {
		kfree(bs);
		return NULL;
	}

	bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
	if (!bs->bio_pool)
		goto bad;

	bs->bvec_pool = biovec_create_pool(bs, pool_size);
	if (!bs->bvec_pool)
		goto bad;

	bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
	if (!bs->rescue_workqueue)
		goto bad;

	return bs;
bad:
	bioset_free(bs);
	return NULL;
}
EXPORT_SYMBOL(bioset_create);

#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();
	css = task_subsys_state(current, blkio_subsys_id);
	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 */

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;

		if (bvs->nr_vecs <= BIO_INLINE_VECS) {
			bvs->slab = NULL;
			continue;
		}

		size = bvs->nr_vecs * sizeof(struct bio_vec);
		bvs->slab = kmem_cache_create(bvs->name, size, 0,
                                SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
	}
}

static int __init init_bio(void)
{
	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");

	bio_integrity_init();
	biovec_init_slabs();

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

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

	bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
						     sizeof(struct bio_pair));
	if (!bio_split_pool)
		panic("bio: can't create split pool\n");

	return 0;
}
subsys_initcall(init_bio);

redpajama_set_name: RedPajamaGithub


text:
Kurali è una città dell'India di 23.039 abitanti, situata nel distretto di Sahibzada Ajit Singh Nagar, nello stato federato del Punjab. In base al numero di abitanti la città rientra nella classe III (da 20.000 a 49.999 persone).

Geografia fisica
La città è situata a 30° 49' 59 N e 76° 34' 24 E e ha un'altitudine di 280 .

Società

Evoluzione demografica
Al censimento del 2001 la popolazione di Kurali assommava a 23.039 persone, delle quali 12.304 maschi e 10.735 femmine. I bambini di età inferiore o uguale ai sei anni assommavano a 2.748, dei quali 1.524 maschi e 1.224 femmine. Infine, coloro che erano in grado di saper almeno leggere e scrivere erano 16.774, dei quali 9.371 maschi e 7.403 femmine.

Note

Centri abitati del Punjab

redpajama_set_name: RedPajamaWikipedia


I thought it was about time to share my empties for June and July. All I can say these two months have been crazy and time just flew by. I just did not really have the time to post in June Therefor I just combined the month June and July together. I thought I did not have a lot of empties. But looking at the list below it seems quite a lot. But what the heck, just go through them.
There are definitely products that I would repurchase and recommend.
Garnier Micellair water 400 ml. So yes I might have written that I wasn't blown away in the beginning. However when I stopped using this stuff, I noticed I was having baby breakouts on my chin. So yeah repurchased for sure.
Dr Van der Hoog Yummy Yoghurt mask. Firstly this smells so good! and It leaves your skin so soft and moisturised.
Lush Ro's Argan Body Conditoner. Again this smells great! And its nice to put on your lotion in the shower. It does save time.
Errrg pass on that one!
Sanex dermo moisturising dermo oils 500 ml showergel. I don't hate this one. But this is not a shower gel I would repurchase. I did not really like the formulation and the smell is not my fave.
Super Drug Tea Tree Facial Cleansing Pads. I just did not feel this product was working for me.
So hope you all liked this empties post. I did write it in a different style but hope you liked it. For Mays empties click here. And of course if you enjoyed this post and you want to read more post like these, please like or subscribe to Thumbelinaslifestyle.com or follow me on BlogLoving. See you soon!
The Garnier Micellar Water is one of my favorite products.
I use it in the evening to remove my sunscreen before using my regular cleanser. I have definitely noticed a difference in my skin.


text:
Q: Finding an odd number from int[] array using Stream I created  an array and trying to use streams for finding the first odd number as follows:
int[] arr = new int[]{2, 4, 6, 8, 9, 12};
int oddOne = Stream.of(arr).filter(i -> i % 2 != 0).findFirst().get();
                                   // fails above

Error: |  incompatible types: int[] cannot be converted to int

What am I doing wrong? How do I fix this?

A: You're trying to access int[] and not integer inside your filter. One way to resolve that would be to use IntStream with the help of flatMapToInt as:
int oddOrMin = Stream.of(arr) // Stream<int[]> and not integers
                     .flatMapToInt(Arrays::stream) // IntStream
                     .filter(i -> i % 2 != 0)
                     .findFirst() // OptionalInt
                     .orElse(Integer.MIN_VALUE); //default to some value

A: Simply you can also use IntStream to stream int[]
int[] arr = new int[]{2, 4, 6, 8, 9, 12};
int result = IntStream.of(arr).filter(i->i%2 !=0).findFirst().getAsInt();
System.out.println(result); //9

If you don't have any odd numbers then public int getAsInt() throws NoSuchElementException.

If a value is present in this OptionalInt, returns the value, otherwise throws NoSuchElementException.

So as @nullpointer suggestion always recommended to use orElse(int other)

public int orElse(int other)

A: You need to use Arrays.stream():
Arrays.stream(arr).filter(i -> i % 2 != 0).findFirst().getAsInt();

Which:

Returns a sequential IntStream with the specified array as its source.

As of now you are using the overloaded method Stream.of(T t) which simply:

Returns a sequential Stream containing a single element.

So it will only be a Stream of the single int[]

Also as nullpointer noted, calling get() without ensuring there is in fact an odd number in the Array will cause an error. It is best to use orElse() to return a default value if no odd number is present

A: Varargs are tricky. The signature of Stream.of() is Stream.of(T ...arg).
Where T can be any class. But you are passing an array of native int which does not work. Instead it thinks the whole array is one object.
Problem arises when you use an array of native types.
Your code gives a stream of just one element of type int[].
You could rather use :
Integer[] arr = new Integer[]{2, 4, 6, 8, 9, 12};

You can simply use this or use Arrays.stream(arr) as others have suggested.

redpajama_set_name: RedPajamaStackExchange


Tender steak, served with rice, beans, salad & tortillas.
Steak strips, tomatoes, onions, jalapenos, Ranchero sauce, served with rice, beans & tortillas.
Charbroiled chicken breast, served with rice, beans, salad & tortillas.
Juicy skirt steak, cheese enchilada with Mole sauce, served with rice, beans, salad & tortillas.
Pork simmered in our chile verde sauce, served with rice, beans & tortillas.
black beans, sour cream & tortillas.
Tender chicken thigh with our Mole sauce, served with rice, beans & tortillas.
Shredded pork, served with rice, beans & tortillas.
Two pork enchiladas topped with salsa verde & cheese, served with rice, beans & sour cream.
Two charbroiled chicken kebobs, served with rice, salad & tortillas.
Steak strips, bell peppers, onions, tomatoes, served with rice, sour cream, guacamole & tortillas.
Chicken strips, bell peppers, onions, tomatoes, served with rice, sour cream, guacamole & tortillas.
Shrimp, bell peppers, onions, tomatoes, served with rice, sour cream, guacamole & tortillas.
Shrimp, Steak, Chicken, bell peppers, onions, tomatoes, served with rice, sour cream, guacamole & tortillas.


text:
Veterinary Industry News
2022 Young Dairy Vet Of The Year Announced
22nd September, 2022 11h36
Lora Fryars, veterinary surgeon at Lanes Farm Vets near Preston, Lancashire, is the CREAM Awards' 2022 Young Dairy Vet of the Year. She received the Award, which is sponsored by Krka, during a gala dinner, held at the Crowne Plaza Hotel, Stratford Upon Avon on 8 September. Hannah Kent from Shires Vets in Eccleshall, Staffordshire, was Highly Commended and also received an award. According to the judges, both candidates were excellent role models for veterinary professionals wishing to work more closely with their local farmer community to share learning and build expertise.
Lora Fryars grew up on a dairy farm in Lancashire and graduated from Liverpool University in 2016, where she was awarded the university's farm animal clinical prize for 'the student showing the most aptitude for farm animal work'. She has worked at Lanes Farm Vets since graduating, with disease prevention and health planning forming key elements of her role. With many of her farming customers on supermarket contracts, she works with them to obtain maximum returns through improved performance and high health standards.
Miss Fryars is actively involved in industry-wide initiatives and is a fully-trained Action Johne's Advisor, a role which involves updating colleagues on the latest knowledge about Johne's disease as part of the National Johne's Management Plan. She also led the BVD 'stamp it out' campaign for her practice. Outside work, she has set up a successful agri-business discussion group for the young agricultural community in her locality. Called Ignite Agri-Forum, it meets quarterly with a guest speaker and is facilitated by Miss Fryars. It aims to build and share knowledge and offer an opportunity for socialising within the community.
Commenting on receiving the Award, she said: "The CREAM Awards was a fantastic, high-energy event and I felt totally humbled to receive such a prestigious award. I am lucky to work with some outstanding farmers, who keep me on my toes and I would like to thank them for their support, as well as my brilliant colleagues at Lanes Farm Vets."
Farmer Andy Gibbons from Catterall Farm in St Michaels said: "Lora is an essential part of our team. She has successfully helped with the dramatic reduction in mastitis cases from high cell count, which, as a result, has significantly reduced our antibiotic usage. She has also been proactive in reducing our calving interval from 400+ to 382, and has achieved a better conception rate from 28% to 44%, which has had a large impact on the farm's bottom line."
The runner up, Hannah Kent, also cites infectious disease management and herd health planning as key interest areas and has created a discussion group for her farmer clients called 'Futureproof your farm' to help educate them on these topics. She has also led efforts to strengthen Shires Vets' relationships with its clients. As an example, she uses the practice's social platforms to celebrate successes achieved both by clients and the Shires' veterinary team within the wider community, at the same time, promoting British farming and high welfare practice.
She said: "I really enjoy being able to build on my relationships with clients by discussing their wider herd health and infectious disease management, and using this to increase their productivity either on farm or by organising meetings for our next generation farm clients. I also really enjoy my meetings with the Farming Community Network to see how vets can help support farmers through tough times. I would like to thank Krka for sponsoring the award and the CREAM Awards for a brilliant night."
The Young Dairy Vet of the Year Award, generously supported by Krka UK Ltd, recognises an exceptional farm vet who has been working in the dairy industry for three-five years, and who has contributed significantly to the health and wellbeing of the herds under their care.
Charlotte Read, Key Account Manager – Farm, at Krka, added: "In just a few years, both Lora and Hannah have made an outstanding contribution to their practices, to their farmer clients and to the agricultural community in their regions. Krka is proud to support the UK's dairy sector and the next generation of dairy vets by sponsoring this award and we congratulate both Lora and Hannah on their achievements."
The CREAM Awards are organised by British Dairying Magazine.
Krka UK Ltd is the fastest growing animal health company in the UK (source: Kynetec UK Vet Data November 2021). A subsidiary of Slovenia-based Krka, d. d. Novo Mesto; the animal health product portfolio consists of high-quality generic pharmaceuticals for both companion animal and food producing animals covering parasite control, antibiotics and pain relief. It includes the Milprazon CHEWABLE and Prinocate ranges, for parasite prevention and treatment in cats and dogs, and Tolracol for coccidiosis management in cows and sheep.
Rebecca George, George PR
Tel: 01449 737281/07974 161108
More from KRKA
Krka launches first line antibiotic Cladaxxa® in its companion animal range
Krka Expands Sales Team with new South East Account Manager
Experienced Vet Nurse Joins Krka as Account Manager for the North of England
New Milprazon® CHEWABLE Range Eases Year-round Worming Compliance
Krka Starts 2022 with New Senior Account Manager
Farm Veterinary Surgeon required at Wright and Morten Vets, Holly Tree (Farm)
Congleton, Cheshire. United Kingdom
The RoleAn exciting opportunity has arisen for an enthusiastic new addition to join our proactive and friendly team Wright & Morten farm...
1 week ago 2 months ago
Veterinary Surgeon - Westpoint Farm Vets - Horsham, West Sussex
Horsham, West Sussex. United Kingdom
We are seeking a Vet to join our growing team in a supportive and varied farm practice. Already providing proactive commercial services, we ...
Experienced Farm Vet - LLM Farm Vets - Bakewell, Derbyshire
Bakewell, Derbyshire. United Kingdom
Are you looking for a stimulating, progressive farm veterinary career whilst being part of a fun and innovative team? Due to expansion, we...
Farm Veterinary Surgeon – Calweton Vets – Cornwall/Devon
Callington, Cornwall. United Kingdom
We are seeking a Farm Veterinary Surgeon to join our team at Calweton Vets.Servicing clients from mid-Cornwall to West Devon, you will work ...
Search our news items

redpajama_set_name: RedPajamaCommonCrawl


text:
great white shark diet
Note: Content may be edited for style and length. The study found that based on abundance, the sharks' diet relied mostly on: - Bottom-dwelling fish, such as stargazers, sole or flathead: 17.4%, - Reef fish, such as eastern blue gropers: 5.0%. Great White Shark Diet Is More Than Seals. While they are carnivores, great white sharks feed on other fish and mammals commonly found in our planets oceans. Unfortunately, due to certain media the great white shark has a reputation for being a mindless killing machine, but as scientific research is starting to increase, this image is beginning to fade. They have been known to eat large fish, rays, seals, sea lions, dolphins, and whales. Even the coloring is designed to enhance its predatory success. The scientists also found that larger sharks tended to have a diet that was higher in fat, likely due to their high energy needs for migration. The Great White doesn't chew its food. He did a fairly simple experiment, where he hooked carcasses of a pig, a sheep, and a seal on strong fishing lines and trailed them through waters with Great Whites. It is notable for its size, with larger female individuals growing to 6.1 m (20 ft) in length and 1,905–2,268 kg (4,200–5,000 lb) in weight at maturity. Perhaps we are simply not that tasty to them, or perhaps their preference for fatty meat makes a human a poor substitute for a nice fat seal. Newborn white sharks feed on fishes and other sharks. There are 2 to 10 pups in a litter, and the pups are about 1.5 m (5 ft) long, when they emerge from the womb in spring and summer. Mr Grainger said: "White sharks have a varied diet. Copyright © 2020 Welcome To SharkSider.com!. As they reach adulthood, their prey includes sea turtles, seals, sea lions, porpoises, dolphins, and small whales. The first-ever study to look at the great white shark's diet has surprised scientists. The first-ever detailed study of the diets of great white sharks off the east Australian coast reveals this apex predator spends more time feeding close to the seabed than expected. "Great white shark diet surprises scientists: Understanding how sharks feed is vital for managing human interactions." As the young sharks grow and their jaws get stronger, they start hunting larger prey. The only two fishes that grow larger than Great Whites are the whale shark and the basking shark, both filter feeders that eat plankton. Fully grown, Great White Sharks are at the top of the ocean's food chain. It should be clear by now that the Great White Shark diet is based on fish for the young sharks and marine mammals for the adults. A change in prey: their diet changes from seal pups in the winter at the islands to game fish runs and smaller shark species that use the inshore bays during the summer. University of Sydney On the other hand, the Great White can go without food for up to 2 months after one of these feasts. PUBLISHED October 6, 2012. At birth a baby great white shark is already about 5 feet (1.5 meters) long; as it grows it may reach a length up to four times that. As we all know, Great White Sharks do sometimes attack humans, although they rarely kill and eat human beings. We found that rays were also an important dietary component, including small bottom-dwelling stingrays and electric rays. Mature females can be as long as 6 m (20 ft) and weigh up to 1950 kg (4300 lbs), although the average size of a Great White is closer to 4.5 m (15 ft), which is still a massive size. The scientists compared this with published data elsewhere in the world, mainly South Africa, to establish a nutritional framework for the species. "The stereotype of a shark's dorsal fin above the surface as it hunts is probably not a very accurate picture," he said. This was tested by the researcher Peter Klimley. "Within the sharks' stomachs we found remains from a variety of fish species that typically live on the seafloor or buried in the sand. The diet of adult Great White Sharks consists mostly of marine mammals, like different species of seals and dolphins, but they will also eat sea turtles and otters. Photo by … 2) These super swimmers are the largest predatory fish (fish that eat other fish or animals) on our planet. The great white shark is the world's largest known predatory fish. It is not intended to provide medical or other professional advice. till it runs out of oxygen. Information About Sharks, For Shark Lovers, Sharks Of The World Have Added Some Strange Items To Their Diet, Blue Shark Facts That Will Not Make You Blue, 5 Interesting Locations That Different Types Of Sharks Have Been Found, Lemon Shark Facts That Won't Make Your Face Pucker, Bluntnose Sixgill Shark (Hexanchus griseus), Jacques-Yves Cousteau, The Pioneer (1910 – 1997) Jacques Yves Cousteau, Port Jackson Shark (Heterodontus portusjacksoni), Scientific Nomenclature – The Shark Naming System, Zebra Bullhead Shark (Heterodontus zebra). Great white shark diet surprises scientists. Great White Sharks are ovoviviparous, which means that the eggs hatch inside the mother's womb, where the little sharks feed on the yolk sacs and continue to develop until they are born. The sharks happily feasted on the pig and the seal, but turned up their noses at the sheep, whose meat is not as fatty. The idea of a dorsal fin above the water signifying shark feeding might not be very accurate, says PhD student Richard Grainger, who has found that these predators spend a lot of time feeding at the seafloor. The sharks' diet consisted mostly of mid-water fish like Australian salmon (32.2%), but bottom-dwelling fish like sole made up a significant 17.4% of the stomach contents. Great white sharks are the largest predatory fish in the world. Great white shark diet surprises scientists. The first-ever detailed study of the diets of great white sharks off the east Australian coast reveals this apex predator spends more time feeding close to the seabed than expected. View Images. Great whites are the world's largest predatory fish, according to Discovery. Though massive, the great white is not the biggest shark. This indicates the sharks must spend a good portion of their time foraging just above the seabed," said lead author Richard Grainger, a PhD candidate at the Charles Perkins Centre and School of Life and Environmental Sciences at the University of Sydney. Great white shark diet surprises scientists: Understanding how sharks feed is vital for managing human interactions. It seems that individual sharks have specific food preferences, so some may prefer seals, whereas others really like dolphin meat. ... the government argues, in the Western Cape — show that small shark species comprise at least 30 percent of great whites' diet. Fat is the key for great white sharks diet. Great Whites do get hunted by humans, however, because the jaws and fins can fetch high prices. The diet of adult Great White Sharks consists mostly of marine mammals, like different species of seals and dolphins, but they will also eat sea turtles and otters. The only threats to this powerful shark are killer whales and humans. Like some of us, the great white prefers a fatty meal to one with lots of protein. Or view hourly updated newsfeeds in your RSS reader: Keep up to date with the latest news from ScienceDaily via social networks: Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Dr Vic Peddemors a co-author from the NSW Department of Primary Industries (Fisheries), said: "We discovered that although mid-water fish, especially eastern Australian salmon, were the predominant prey for juvenile white sharks in NSW, stomach contents highlighted that these sharks also feed at or near the seabed. The study, published today on World Oceans Day in the journal Frontiers in Marine Science, is an important contribution towards understanding the sharks' feeding and migratory habits. With shark attacks happening along the coasts of many countries, people believe that these sharks will feed on humans if given the chance. The great white shark is a streamlined swimmer and a ferocious predator with 3,000 teeth at any one time. Great white sharks that occupy the waters off Seal Island, that prey on fur seals, are generally about 3.5 meters (11.5 feet) in length, 4 meters (13 feet) at most. (2020, June 7). Great whites also have powerful jaws filled with lots of long teeth up to 2 1/2 inches long. There is a particularly large concentration of Great Whites around Dyer Island, South Africa, which makes this location a center for research on Great Whites. ScienceDaily shares links with sites in the. Rather it tears the prey into chunks and swallows the chunks whole. Sharks like the Great White are equipped with serrated teeth that allow the seizing and ripping of flesh as well as the ability to chew through the shell of a marine turtle. Its stocky body is most notable for its long, white-tipped, rounded fins.. This is not unlike how predators on land, like the big cats, have adapted to the feast or famine aspect of being hunters. Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. So, in the end, the Great Whites should probably fear us more than we fear them. Have any problems using the site? "The hunting of bigger prey, including other sharks and marine mammals such as dolphin, is not likely to happen until the sharks reach about 2.2 metres in length," Mr Grainger said. 15 June 2020 Recognising how sharks feed vital for managing human interactions. "Great white shark diet surprises scientists: Understanding how sharks feed is vital for managing human interactions." University of Sydney. "Within the sharks' stomachs we found remains from a variety of fish species that typically live on the seafloor or buried in the sand. ScienceDaily. Great white shark diet surprises scientists. If you had to guess what the Great White Shark diet was, after watching Jaws, you might think that it is favorite food group was humans, but that is far from being the case. Great White Sharks live in temperate zones across the globe. Richard Grainger examining the contents of a white shark's stomach at the Sydney Institute of Marine Science. "Eagle rays are also hunted, although this can be difficult for the sharks given how fast the rays can swim.". (2,268 kilograms). Until they reach 10 ft. long, juvenile sharks jaws are not strong enough to prey on large animals. Great article with great facts. Instead, younger sharks feed mostly on large fish. Great white sharks are popularly known to be man-eaters. ScienceDaily. Great white shark diet: The sharks' diet relied mostly on pelagic, or mid-water ocean swimming fish (Image: Getty) "We found that rays were also an … ScienceDaily. University of Sydney. ScienceDaily, 7 June 2020. . Marine mammals, other sharks, squids and cuttlefish also occasionally form part of the diet of a juvenile great white shark, according to the researchers. Content on this website is for information only. Great Whites much prefer prey that has meat high in fat. Batoid fish, such as stingrays: 14.9%. Once they reach 13 ft. in length they transfer to a diet of marine mammals. In addition, the Great White can smell a single drop of blood in 100 liters (25 gallons) of water. The oceanic whitetip shark (Carcharhinus longimanus), also known as Brown Milbert's sand bar shark, brown shark, lesser white shark, nigano shark, oceanic white-tipped whaler, and silvertip shark, is a large pelagic requiem shark inhabiting tropical and warm temperate seas. Although it attacks humans far less frequently than public hysteria might suggest, it is a fearsome predator. The Great White is probably the most feared of all the sharks, and not completely without reason. Jul 1 Great white shark diet surprises scientists My Vet Candy The first-ever detailed study of the diets of great white sharks off the east Australian coast reveals this apex predator spends more time feeding close to the seabed than expected. Great white shark facts. Great white shark diet surprises scientists: Understanding how sharks feed is vital for managing human interactions. Richard Grainger, Victor M. Peddemors, David Raubenheimer, Gabriel E. Machovsky-Capuska. While the shark in Jaws was inspired by a great white shark in New Jersey, the legendary fish is far less fearsome in reality. They will also prey on sea turtles, sea otters, and seabirds. They grow to be about 15 to 20 feet (4.6 to 6.1 meters) or more and can weigh more than 5,000 lbs. This much-feared fish has a torpedo-shaped body, a pointed snout, a crescent-shaped tail, 5 gill slits, no fin spines, an anal fin, and 3 main fins: the dorsal fin … Share. When they attack large mammals like elephant seals, they typically attack from behind, bite the animal's hindquarters and then wait for the seal to bleed to death, before devouring it. As well as east Australian salmon, we found evidence of other bony fish including eels, whiting, mullet and wrasses. The largest predatory fish in the world – capable of eating marine mammals that weigh several hundred pounds – is the great white shark. The only animals that will attack a great white shark are orca whales and other great white sharks. The great white shark (Carcharodon carcharias), also known as the great white, white shark or "white pointer", is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. Reef fish, such as eastern blue gropers: 5.0%. Mr Grainger said that marine mammals, other sharks and cephalopods (squid and cuttlefish) were eaten less frequently. However, humans are not part of the great white shark diet. This legendary shark is way more fearsome in our imaginations that they are in reality. A shark-bitten elephant seal rests on an Año Nuevo State Park Beach. White sharks possibly give birth and mate in the bay during the summer. They prefer coastal waters and hunt near the surface, which explains why they have run-ins with humans from time to time. This classification goes to the whale shark, which is not considered a predatory fish. Great whites have a white underbelly, but are darker on top. 1) Great white sharks can be found throughout the world's oceans, mostly in cool waters close to the coast. Late last year, while on a tour of California's Año Neuvo State Park, I saw a shark attack victim lying on the beach. www.sciencedaily.com/releases/2020/06/200607131646.htm (accessed December 4, 2020). If the mammal prey is smaller, they grab it, drag it down and keep it under water till it stops fighting, i.e. They are most common In the United States, on both coasts, South Africa, Oceania, Chile and Japan, but are also found in the Mediterranean. It will also feast on a giant meal, when it has had a particularly good hunt. But before it grows larger, the pup must avoid predators bigger than it is—including other great white sharks. (2020, June 7). They can be seen patrolling the breakers where the water is particularly rich in oxygen. The pup (which is what a baby shark is called) will live its life at the top of the ocean's food chain. Views expressed here do not necessarily reflect those of ScienceDaily, its staff, its contributors, or its partners. The first-ever detailed study of the diets of great white sharks off the east Australian coast reveals this apex predator spends more time feeding close to the seabed than expected. ", Mr Grainger said: "This evidence matches data we have from tagging white sharks that shows them spending a lot of time many metres below the surface.". Questions? Advertisements The Tiger Shark is known for eating almost anything it encounters. The Great White is a fast and nimble swimmer, reaching speeds up to 24 km/hr (15 mph). The remainder was unidentified fish or less abundant prey. It has 300 teeth, yet does not chew its food. I agree that a great white due to sheer size will win but let's not forget that tigers have got a stronger bite due to a diet consisting of armored prey such as turtles. Tracking of white sharks shows that they migrate seasonally along Australia's east coast from southern Queensland to northern Tasmania, and the range of movement increases with age. Great white shark diet surprises scientists In the first detailed study of what Great White Sharks actually eat, surprising evidence shows they spend more time feeding at the ocean floor than many would expect. Understanding how sharks feed is vital for managing human interactions.NOTE The mouth is also impressive, in that it contains 3000 teeth in rows that rotate into use as needed. 4 Minute Read. 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Rex Had Huge Growth Spurts, but Other Dinos Grew Slow and Steady. The pups mostly eat fish, because until they reach a length of about 3 m (9.8 ft), their jaws are not strong enough to kill and eat larger animals. White sharks like to eat bony fish like lingcod, demersal rockfish and benthic flatfish. This is where their ability to detect even tiny amounts of blood in the water comes in handy, as it allows them to find a dinner all ready for them, without having to hunt and kill it themselves. The Great White is one the largest sharks in the world. It seems that individual sharks have specific food preferences, so some may prefer seals, whereas others really like dolphin meat. They may seem like a creature from outer space, but if these fish disappeared from our waters, our wh… University of Sydney. Protecting this species and safely managing its interactions with humans is a priority for scientists and the NSW Department of Primary Industries. Prey is usually hunted by ambush, where the shark will attempt to rush the animal by surprise and inflict a … The study examined the stomach contents of 40 juvenile white sharks (Carcharodon carcharias) caught in the NSW Shark Meshing Program. Financial support for ScienceDaily comes from advertisements and referral programs, where indicated. Great white shark diet surprises scientists Understanding how sharks feed is vital for managing human interactions. Pop culture often portrays them in films and in novels to be dangerous creatures, always craving for human flesh whenever they see one. A great white shark breaching in False Bay. The grey back blends into the sea when seen from above, and the white belly is difficult to see from below. Sharks rip their prey into mouth-sized pieces which are swallowed whole. It doesnt help that most Hollywood movies out there depict sharks as giant human-killing beasts. Great White Shark Diet Is More Than Seals. White sharks are carnivores that prey upon a number of large animals. University of Sydney. The team found that the species actually spends a large amount of time feeding close to the sea bed. Bottom-dwelling fish, such as stargazers, sole or flathead: 17.4%. but aside for the bite, the great white has speed, weight and sharper teeth which when unleashed on a lightly protected animal like a seal or a shark would be devastating. "Understanding the nutritional goals of these cryptic predators and how these relate to migration patterns will give insights into what drives human-shark conflict and how we can best protect this species," said Dr Gabriel Machovsky-Capuska, an adjunct Senior Research Fellow at the Charles Perkins Centre and a co-author of the study. All together, it is built to hunt and kill efficiently – a natural-born predator. "This study will give us a lot of information to assist in this management process," Dr Peddemors said. The great white shark diet consists of a wide range of food enabling it to eat from smaller animals like tuna, rays and skates and all the way up to larger ones like seals, sea lions and dolphins. Given the habitat of the Great Whites, they could hunt human beings far more than they actually do. In addition to the stellar hunting skills of the Great Whites, they are also skilled at sniffing out fast food, in other words animals that have died and are floating in the sea. "This fits with a lot of other research we've done showing that wild animals, including predators, select diets precisely balanced to meet their nutrient needs," said co-author Professor David Raubenheimer, Chair of Nutritional Ecology in the School of Life and Environmental Sciences. Materials provided by University of Sydney. They start hunting larger prey fishes and other sharks 100 liters ( 25 gallons ) of water strong enough prey. 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