static int
cryptoloop_transfer(struct loop_device *lo, int cmd,
		    struct page *raw_page, unsigned raw_off,
		    struct page *loop_page, unsigned loop_off,
		    int size, sector_t IV)
{
	struct crypto_blkcipher *tfm = lo->key_data;
	struct blkcipher_desc desc = {
		.tfm = tfm,
		.flags = CRYPTO_TFM_REQ_MAY_SLEEP,
	};
	struct scatterlist sg_out;
	struct scatterlist sg_in;

	encdec_cbc_t encdecfunc;
	struct page *in_page, *out_page;
	unsigned in_offs, out_offs;
	int err;

	sg_init_table(&sg_out, 1);
	sg_init_table(&sg_in, 1);

	if (cmd == READ) {
		in_page = raw_page;
		in_offs = raw_off;
		out_page = loop_page;
		out_offs = loop_off;
		encdecfunc = crypto_blkcipher_crt(tfm)->decrypt;
	} else {
		in_page = loop_page;
		in_offs = loop_off;
		out_page = raw_page;
		out_offs = raw_off;
		encdecfunc = crypto_blkcipher_crt(tfm)->encrypt;
	}

	while (size > 0) {
		const int sz = min(size, LOOP_IV_SECTOR_SIZE);
		u32 iv[4] = { 0, };
		iv[0] = cpu_to_le32(IV & 0xffffffff);

		sg_set_page(&sg_in, in_page, sz, in_offs);
		sg_set_page(&sg_out, out_page, sz, out_offs);

		desc.info = iv;
		err = encdecfunc(&desc, &sg_out, &sg_in, sz);
		if (err)
			return err;

		IV++;
		size -= sz;
		in_offs += sz;
		out_offs += sz;
	}

	return 0;
}

static int do_page_crypto(struct inode *inode,
			fscrypt_direction_t rw, pgoff_t index,
			struct page *src_page, struct page *dest_page,
			gfp_t gfp_flags)
{
	struct {
		__le64 index;
		u8 padding[FS_XTS_TWEAK_SIZE - sizeof(__le64)];
	} xts_tweak;
	struct skcipher_request *req = NULL;
	DECLARE_FS_COMPLETION_RESULT(ecr);
	struct scatterlist dst, src;
	struct fscrypt_info *ci = inode->i_crypt_info;
	struct crypto_skcipher *tfm = ci->ci_ctfm;
	int res = 0;

	req = skcipher_request_alloc(tfm, gfp_flags);
	if (!req) {
		printk_ratelimited(KERN_ERR
				"%s: crypto_request_alloc() failed\n",
				__func__);
		return -ENOMEM;
	}

	skcipher_request_set_callback(
		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
		page_crypt_complete, &ecr);

	BUILD_BUG_ON(sizeof(xts_tweak) != FS_XTS_TWEAK_SIZE);
	xts_tweak.index = cpu_to_le64(index);
	memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding));

	sg_init_table(&dst, 1);
	sg_set_page(&dst, dest_page, PAGE_SIZE, 0);
	sg_init_table(&src, 1);
	sg_set_page(&src, src_page, PAGE_SIZE, 0);
	skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE, &xts_tweak);
	if (rw == FS_DECRYPT)
		res = crypto_skcipher_decrypt(req);
	else
		res = crypto_skcipher_encrypt(req);
	if (res == -EINPROGRESS || res == -EBUSY) {
		BUG_ON(req->base.data != &ecr);
		wait_for_completion(&ecr.completion);
		res = ecr.res;
	}
	skcipher_request_free(req);
	if (res) {
		printk_ratelimited(KERN_ERR
			"%s: crypto_skcipher_encrypt() returned %d\n",
			__func__, res);
		return res;
	}
	return 0;
}

/**
 * sgl_map_user_pages() - Pin user pages and put them into a scatter gather list
 * @sgl: Scatter gather list to fill
 * @nr_pages: Number of pages
 * @uaddr: User buffer address
 * @count: Length of user buffer
 * @rw: Direction (0=read from userspace / 1 = write to userspace)
 * @to_user: 1 - transfer is to/from a user-space buffer. 0 - kernel buffer.
 *
 *  This function pins the pages of the userspace buffer and fill in the
 * scatter gather list.
 */
static int sgl_map_user_pages(struct scatterlist *sgl,
			      const unsigned int nr_pages, unsigned long uaddr,
			      size_t length, int rw, int to_user)
{
	int rc;
	int i;
	struct page **pages;

	if ((pages = kmalloc(nr_pages * sizeof(struct page *),
			     GFP_KERNEL)) == NULL)
		return -ENOMEM;

	if (to_user) {
		rc = sgl_fill_user_pages(pages, uaddr, nr_pages, rw);
		if (rc >= 0 && rc < nr_pages) {
			/* Some pages were pinned, release these */
			for (i = 0; i < rc; i++)
				page_cache_release(pages[i]);
			rc = -ENOMEM;
			goto out_free;
		}
	} else {
		rc = sgl_fill_kernel_pages(pages, uaddr, nr_pages, rw);
	}

	if (rc < 0)
		/* We completely failed to get the pages */
		goto out_free;

	/* Populate the scatter/gather list */
	sg_init_table(sgl, nr_pages);

	/* Take a shortcut here when we only have a single page transfer */
	if (nr_pages > 1) {
		unsigned int off = offset_in_page(uaddr);
		unsigned int len = PAGE_SIZE - off;

		sg_set_page (&sgl[0], pages[0], len, off);
		length -= len;

		for (i = 1; i < nr_pages; i++) {
			sg_set_page (&sgl[i], pages[i],
				     (length < PAGE_SIZE) ? length : PAGE_SIZE,
				     0);
			length -= PAGE_SIZE;
		}
	} else
		sg_set_page (&sgl[0], pages[0], length, offset_in_page(uaddr));

out_free:
	/* We do not need the pages array anymore */
	kfree(pages);

	return nr_pages;
}

static int ext4_page_crypto(struct inode *inode,
			    ext4_direction_t rw,
			    pgoff_t index,
			    struct page *src_page,
			    struct page *dest_page)

{
	u8 xts_tweak[EXT4_XTS_TWEAK_SIZE];
	struct ablkcipher_request *req = NULL;
	DECLARE_EXT4_COMPLETION_RESULT(ecr);
	struct scatterlist dst, src;
	struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info;
	struct crypto_ablkcipher *tfm = ci->ci_ctfm;
	int res = 0;

	req = ablkcipher_request_alloc(tfm, GFP_NOFS);
	if (!req) {
		printk_ratelimited(KERN_ERR
				   "%s: crypto_request_alloc() failed\n",
				   __func__);
		return -ENOMEM;
	}
	ablkcipher_request_set_callback(
		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
		ext4_crypt_complete, &ecr);

	BUILD_BUG_ON(EXT4_XTS_TWEAK_SIZE < sizeof(index));
	memcpy(xts_tweak, &index, sizeof(index));
	memset(&xts_tweak[sizeof(index)], 0,
	       EXT4_XTS_TWEAK_SIZE - sizeof(index));

	sg_init_table(&dst, 1);
	sg_set_page(&dst, dest_page, PAGE_CACHE_SIZE, 0);
	sg_init_table(&src, 1);
	sg_set_page(&src, src_page, PAGE_CACHE_SIZE, 0);
	ablkcipher_request_set_crypt(req, &src, &dst, PAGE_CACHE_SIZE,
				     xts_tweak);
	if (rw == EXT4_DECRYPT)
		res = crypto_ablkcipher_decrypt(req);
	else
		res = crypto_ablkcipher_encrypt(req);
	if (res == -EINPROGRESS || res == -EBUSY) {
		wait_for_completion(&ecr.completion);
		res = ecr.res;
	}
	ablkcipher_request_free(req);
	if (res) {
		printk_ratelimited(
			KERN_ERR
			"%s: crypto_ablkcipher_encrypt() returned %d\n",
			__func__, res);
		return res;
	}
	return 0;
}

static int crypt_convert_block(struct crypt_config *cc,
                               struct convert_context *ctx,
                               struct ablkcipher_request *req)
{
    struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
    struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
    struct dm_crypt_request *dmreq;
    u8 *iv;
    int r;

    dmreq = dmreq_of_req(cc, req);
    iv = iv_of_dmreq(cc, dmreq);

    dmreq->iv_sector = ctx->cc_sector;
    dmreq->ctx = ctx;
    sg_init_table(&dmreq->sg_in, 1);
    sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
                bv_in->bv_offset + ctx->offset_in);

    sg_init_table(&dmreq->sg_out, 1);
    sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
                bv_out->bv_offset + ctx->offset_out);

    ctx->offset_in += 1 << SECTOR_SHIFT;
    if (ctx->offset_in >= bv_in->bv_len) {
        ctx->offset_in = 0;
        ctx->idx_in++;
    }

    ctx->offset_out += 1 << SECTOR_SHIFT;
    if (ctx->offset_out >= bv_out->bv_len) {
        ctx->offset_out = 0;
        ctx->idx_out++;
    }

    if (cc->iv_gen_ops) {
        r = cc->iv_gen_ops->generator(cc, iv, dmreq);
        if (r < 0)
            return r;
    }

    ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
                                 1 << SECTOR_SHIFT, iv);

    if (bio_data_dir(ctx->bio_in) == WRITE)
        r = crypto_ablkcipher_encrypt(req);
    else
        r = crypto_ablkcipher_decrypt(req);

    if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
        r = cc->iv_gen_ops->post(cc, iv, dmreq);

    return r;
}

static struct sg_table *
huge_get_pages(struct drm_i915_gem_object *obj)
{
#define GFP (GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY)
	const unsigned long nreal = obj->scratch / PAGE_SIZE;
	const unsigned long npages = obj->base.size / PAGE_SIZE;
	struct scatterlist *sg, *src, *end;
	struct sg_table *pages;
	unsigned long n;

	pages = kmalloc(sizeof(*pages), GFP);
	if (!pages)
		return ERR_PTR(-ENOMEM);

	if (sg_alloc_table(pages, npages, GFP)) {
		kfree(pages);
		return ERR_PTR(-ENOMEM);
	}

	sg = pages->sgl;
	for (n = 0; n < nreal; n++) {
		struct page *page;

		page = alloc_page(GFP | __GFP_HIGHMEM);
		if (!page) {
			sg_mark_end(sg);
			goto err;
		}

		sg_set_page(sg, page, PAGE_SIZE, 0);
		sg = __sg_next(sg);
	}
	if (nreal < npages) {
		for (end = sg, src = pages->sgl; sg; sg = __sg_next(sg)) {
			sg_set_page(sg, sg_page(src), PAGE_SIZE, 0);
			src = __sg_next(src);
			if (src == end)
				src = pages->sgl;
		}
	}

	if (i915_gem_gtt_prepare_pages(obj, pages))
		goto err;

	return pages;

err:
	huge_free_pages(obj, pages);
	return ERR_PTR(-ENOMEM);
#undef GFP
}

/**
 * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer,
 * this takes a list of pages.
 * @sg: scatter/gather list to pack into
 * @start: which segment of the sg_list to start at
 * @pdata: a list of pages to add into sg.
 * @nr_pages: number of pages to pack into the scatter/gather list
 * @data: data to pack into scatter/gather list
 * @count: amount of data to pack into the scatter/gather list
 */
static int
pack_sg_list_p(struct scatterlist *sg, int start, int limit,
	       struct page **pdata, int nr_pages, char *data, int count)
{
	int i = 0, s;
	int data_off;
	int index = start;

	BUG_ON(nr_pages > (limit - start));
	/*
	 * if the first page doesn't start at
	 * page boundary find the offset
	 */
	data_off = offset_in_page(data);
	while (nr_pages) {
		s = rest_of_page(data);
		if (s > count)
			s = count;
		/* Make sure we don't terminate early. */
		sg_unmark_end(&sg[index]);
		sg_set_page(&sg[index++], pdata[i++], s, data_off);
		data_off = 0;
		data += s;
		count -= s;
		nr_pages--;
	}

	if (index-start)
		sg_mark_end(&sg[index - 1]);
	return index - start;
}

/**
 * sg_init_one - Initialize a single entry sg list
 * @sg:		 SG entry
 * @buf:	 Virtual address for IO
 * @buflen:	 IO length
 *
 **/
void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen)
{
  //pr_debug("### %s:%d SG %08x %d\n", __FILE__,__LINE__, buf, buflen);
	sg_init_table(sg, 1);
	sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
	//sg_set_buf(sg, buf, buflen);
}

static int ion_mm_heap_allocate(struct ion_heap *heap,
                                struct ion_buffer *buffer,
                                unsigned long size, unsigned long align,
                                unsigned long flags)
{
    ion_mm_buffer_info* pBufferInfo = NULL;
    int ret;
    unsigned int addr;
    struct sg_table *table;
    struct scatterlist *sg;
    void* pVA;
    ION_FUNC_ENTER;
    pVA = vmalloc_user(size);
    buffer->priv_virt = NULL;
    if (IS_ERR_OR_NULL(pVA))
    {
        printk("[ion_mm_heap_allocate]: Error. Allocate buffer failed.\n");
        ION_FUNC_LEAVE;
        return -ENOMEM;
    }
    pBufferInfo = (ion_mm_buffer_info*) kzalloc(sizeof(ion_mm_buffer_info), GFP_KERNEL);
    if (IS_ERR_OR_NULL(pBufferInfo))
    {
        vfree(pVA);
        printk("[ion_mm_heap_allocate]: Error. Allocate ion_buffer failed.\n");
        ION_FUNC_LEAVE;
        return -ENOMEM;
    }
    table = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
    if (!table)
    {
        vfree(pVA);
        kfree(pBufferInfo);
        ION_FUNC_LEAVE;
        return -ENOMEM;
    }
    ret = sg_alloc_table(table, PAGE_ALIGN(size) / PAGE_SIZE, GFP_KERNEL);
    if (ret)
    {
        vfree(pVA);
        kfree(pBufferInfo);
        kfree(table);
        ION_FUNC_LEAVE;
        return -ENOMEM;
    }
    sg = table->sgl;
    for (addr=(unsigned int)pVA; addr < (unsigned int) pVA + size; addr += PAGE_SIZE)
    {
        struct page *page = vmalloc_to_page((void*)addr);
        sg_set_page(sg, page, PAGE_SIZE, 0);
        sg = sg_next(sg);
    }
    buffer->sg_table = table;

    pBufferInfo->pVA = pVA;
    pBufferInfo->eModuleID = -1;
    buffer->priv_virt = pBufferInfo;
    ION_FUNC_LEAVE;
    return 0;
}

struct scatterlist *ion_system_heap_map_dma(struct ion_heap *heap,
					    struct ion_buffer *buffer)
{
	struct scatterlist *sglist;
	struct page *page;
	int i;
	int npages = PAGE_ALIGN(buffer->size) / PAGE_SIZE;
	void *vaddr = buffer->priv_virt;

	sglist = vmalloc(npages * sizeof(struct scatterlist));
	if (!sglist)
		return ERR_PTR(-ENOMEM);
	memset(sglist, 0, npages * sizeof(struct scatterlist));
	sg_init_table(sglist, npages);
	for (i = 0; i < npages; i++) {
		page = vmalloc_to_page(vaddr);
		if (!page)
			goto end;
		sg_set_page(&sglist[i], page, PAGE_SIZE, 0);
		vaddr += PAGE_SIZE;
	}
	/* XXX do cache maintenance for dma? */
	return sglist;
end:
	vfree(sglist);
	return NULL;
}

static struct sg_table *mock_map_dma_buf(struct dma_buf_attachment *attachment,
					 enum dma_data_direction dir)
{
	struct mock_dmabuf *mock = to_mock(attachment->dmabuf);
	struct sg_table *st;
	struct scatterlist *sg;
	int i, err;

	st = kmalloc(sizeof(*st), GFP_KERNEL);
	if (!st)
		return ERR_PTR(-ENOMEM);

	err = sg_alloc_table(st, mock->npages, GFP_KERNEL);
	if (err)
		goto err_free;

	sg = st->sgl;
	for (i = 0; i < mock->npages; i++) {
		sg_set_page(sg, mock->pages[i], PAGE_SIZE, 0);
		sg = sg_next(sg);
	}

	if (!dma_map_sg(attachment->dev, st->sgl, st->nents, dir)) {
		err = -ENOMEM;
		goto err_st;
	}

	return st;

err_st:
	sg_free_table(st);
err_free:
	kfree(st);
	return ERR_PTR(err);
}

int msm_iommu_map_extra(struct iommu_domain *domain,
				unsigned long start_iova,
				unsigned long size,
				unsigned long page_size,
				int cached)
{
	int ret = 0;
	int i = 0;
	unsigned long phy_addr = ALIGN(virt_to_phys(iommu_dummy), page_size);
	unsigned long temp_iova = start_iova;
	if (page_size == SZ_4K) {
		struct scatterlist *sglist;
		unsigned int nrpages = PFN_ALIGN(size) >> PAGE_SHIFT;
		struct page *dummy_page = phys_to_page(phy_addr);

		sglist = kmalloc(sizeof(*sglist) * nrpages, GFP_KERNEL);
		if (!sglist) {
			ret = -ENOMEM;
			goto out;
		}

		sg_init_table(sglist, nrpages);

		for (i = 0; i < nrpages; i++)
			sg_set_page(&sglist[i], dummy_page, PAGE_SIZE, 0);

		ret = iommu_map_range(domain, temp_iova, sglist, size, cached);
		if (ret) {
			pr_err("%s: could not map extra %lx in domain %p\n",
				__func__, start_iova, domain);
		}

		kfree(sglist);
	} else {

struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len)
{
	struct rds_message *rm;
	unsigned int i;
	int num_sgs = ceil(total_len, PAGE_SIZE);
	int extra_bytes = num_sgs * sizeof(struct scatterlist);

	rm = rds_message_alloc(extra_bytes, GFP_NOWAIT);
	if (!rm)
		return ERR_PTR(-ENOMEM);

	set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
	rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
	rm->data.op_nents = ceil(total_len, PAGE_SIZE);
	rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
	if (!rm->data.op_sg) {
		rds_message_put(rm);
		return ERR_PTR(-ENOMEM);
	}

	for (i = 0; i < rm->data.op_nents; ++i) {
		sg_set_page(&rm->data.op_sg[i],
				virt_to_page(page_addrs[i]),
				PAGE_SIZE, 0);
	}

	return rm;
}

/*
 * Return a scatterlist for some page-aligned vmalloc()'ed memory
 * block (NULL on errors).  Memory for the scatterlist is allocated
 * using kmalloc.  The caller must free the memory.
 */
static struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt,
						  int nr_pages)
{
	struct scatterlist *sglist;
	struct page *pg;
	int i;

	sglist = vmalloc(nr_pages * sizeof(*sglist));
	if (NULL == sglist)
		return NULL;
	memset(sglist, 0, nr_pages * sizeof(*sglist));
	sg_init_table(sglist, nr_pages);
	for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
		pg = vmalloc_to_page(virt);
		if (NULL == pg)
			goto err;
		BUG_ON(PageHighMem(pg));
		sg_set_page(&sglist[i], pg, PAGE_SIZE, 0);
	}
	return sglist;

err:
	vfree(sglist);
	return NULL;
}

static int mmc_test_multi_read_high(struct mmc_test_card *test)
{
	int ret;
	unsigned int size;
	struct scatterlist sg;

	if (test->card->host->max_blk_count == 1)
		return RESULT_UNSUP_HOST;

	size = PAGE_SIZE * 2;
	size = min(size, test->card->host->max_req_size);
	size = min(size, test->card->host->max_seg_size);
	size = min(size, test->card->host->max_blk_count * 512);

	if (size < 1024)
		return RESULT_UNSUP_HOST;

	sg_init_table(&sg, 1);
	sg_set_page(&sg, test->highmem, size, 0);

	ret = mmc_test_transfer(test, &sg, 1, 0, size/512, 512, 0);
	if (ret)
		return ret;

	return 0;
}

static void *ion_page_pool_alloc_pages(struct ion_page_pool *pool)
{
	struct page *page;
	struct scatterlist sg;

	page = alloc_pages(pool->gfp_mask & ~__GFP_ZERO, pool->order);

	if (!page)
		return NULL;

	if (pool->gfp_mask & __GFP_ZERO)
		if (ion_heap_high_order_page_zero(
				page, pool->order, pool->should_invalidate))
			goto error_free_pages;

	sg_init_table(&sg, 1);
	sg_set_page(&sg, page, PAGE_SIZE << pool->order, 0);
	sg_dma_address(&sg) = sg_phys(&sg);
	dma_sync_sg_for_device(NULL, &sg, 1, DMA_BIDIRECTIONAL);

	return page;
error_free_pages:
	__free_pages(page, pool->order);
	return NULL;
}

static struct sg_table *exynos_pages_to_sg(struct page **pages, int nr_pages,
		unsigned int page_size)
{
	struct sg_table *sgt = NULL;
	struct scatterlist *sgl;
	int i, ret;

	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
	if (!sgt)
		goto out;

	ret = sg_alloc_table(sgt, nr_pages, GFP_KERNEL);
	if (ret)
		goto err_free_sgt;

	if (page_size < PAGE_SIZE)
		page_size = PAGE_SIZE;

	for_each_sg(sgt->sgl, sgl, nr_pages, i)
		sg_set_page(sgl, pages[i], page_size, 0);

	return sgt;

err_free_sgt:
	kfree(sgt);
	sgt = NULL;
out:
	return NULL;
}

/*---------------------------------------------------------------------------*/
static inline void xio_sg_set_addr(struct scatterlist *sg, void *addr)
{
	/* keep the length */
#ifdef XIO_DEBUG_SG
	BUG_ON(sg->sg_magic != SG_MAGIC);
#endif
	sg_set_page(sg, virt_to_page(addr), sg->length, offset_in_page(addr));
}

/*---------------------------------------------------------------------------*/
static inline void xio_sg_set_buf(struct scatterlist *sg, const void *buf,
				  uint32_t buflen, void *mr)
{
#ifdef XIO_DEBUG_SG
	BUG_ON(sg->sg_magic != SG_MAGIC);
#endif
	sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
}

static int crypt_convert_block(struct crypt_config *cc,
			       struct convert_context *ctx,
			       struct ablkcipher_request *req)
{
	struct bio_vec bv_in = bio_iter_iovec(ctx->bio_in, ctx->iter_in);
	struct bio_vec bv_out = bio_iter_iovec(ctx->bio_out, ctx->iter_out);
	struct dm_crypt_request *dmreq;
	u8 *iv;
	int r;

	dmreq = dmreq_of_req(cc, req);
	iv = iv_of_dmreq(cc, dmreq);

	dmreq->iv_sector = ctx->cc_sector;
	dmreq->ctx = ctx;
	sg_init_table(&dmreq->sg_in, 1);
	sg_set_page(&dmreq->sg_in, bv_in.bv_page, 1 << SECTOR_SHIFT,
		    bv_in.bv_offset);

	sg_init_table(&dmreq->sg_out, 1);
	sg_set_page(&dmreq->sg_out, bv_out.bv_page, 1 << SECTOR_SHIFT,
		    bv_out.bv_offset);

	bio_advance_iter(ctx->bio_in, &ctx->iter_in, 1 << SECTOR_SHIFT);
	bio_advance_iter(ctx->bio_out, &ctx->iter_out, 1 << SECTOR_SHIFT);

	if (cc->iv_gen_ops) {
		r = cc->iv_gen_ops->generator(cc, iv, dmreq);
		if (r < 0)
			return r;
	}

	ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
				     1 << SECTOR_SHIFT, iv);

	if (bio_data_dir(ctx->bio_in) == WRITE)
		r = crypto_ablkcipher_encrypt(req);
	else
		r = crypto_ablkcipher_decrypt(req);

	if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
		r = cc->iv_gen_ops->post(cc, iv, dmreq);

	return r;
}