C++ sg_init_table函数代码示例

/*
 * Key Derivation, from RFC 3078, RFC 3079.
 * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
 */
static void get_new_key_from_sha(struct ppp_mppe_state * state)
{
	struct hash_desc desc;
	struct scatterlist sg[4];
	unsigned int nbytes;

	sg_init_table(sg, 4);

	nbytes = setup_sg(&sg[0], state->master_key, state->keylen);
	nbytes += setup_sg(&sg[1], sha_pad->sha_pad1,
			   sizeof(sha_pad->sha_pad1));
	nbytes += setup_sg(&sg[2], state->session_key, state->keylen);
	nbytes += setup_sg(&sg[3], sha_pad->sha_pad2,
			   sizeof(sha_pad->sha_pad2));

	desc.tfm = state->sha1;
	desc.flags = 0;

	crypto_hash_digest(&desc, sg, nbytes, state->sha1_digest);
}

struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
				     struct scatterlist *src,
				     unsigned int len)
{
	for (;;) {
		if (!len)
			return src;

		if (src->length > len)
			break;

		len -= src->length;
		src = sg_next(src);
	}

	sg_init_table(dst, 2);
	sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
	scatterwalk_crypto_chain(dst, sg_next(src), 0, 2);

	return dst;
}

static int cx23885_alsa_dma_init(struct cx23885_audio_dev *chip, int nr_pages)
{
	struct cx23885_audio_buffer *buf = chip->buf;
	struct page *pg;
	int i;

	buf->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT);
	if (NULL == buf->vaddr) {
		dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
		return -ENOMEM;
	}

	dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
				(unsigned long)buf->vaddr,
				nr_pages << PAGE_SHIFT);

	memset(buf->vaddr, 0, nr_pages << PAGE_SHIFT);
	buf->nr_pages = nr_pages;

	buf->sglist = vzalloc(buf->nr_pages * sizeof(*buf->sglist));
	if (NULL == buf->sglist)
		goto vzalloc_err;

	sg_init_table(buf->sglist, buf->nr_pages);
	for (i = 0; i < buf->nr_pages; i++) {
		pg = vmalloc_to_page(buf->vaddr + i * PAGE_SIZE);
		if (NULL == pg)
			goto vmalloc_to_page_err;
		sg_set_page(&buf->sglist[i], pg, PAGE_SIZE, 0);
	}
	return 0;

vmalloc_to_page_err:
	vfree(buf->sglist);
	buf->sglist = NULL;
vzalloc_err:
	vfree(buf->vaddr);
	buf->vaddr = NULL;
	return -ENOMEM;
}

static int samsung_dmadev_prepare(unsigned ch,
			struct samsung_dma_prep_info *info)
{
	struct scatterlist sg;
	struct dma_chan *chan = (struct dma_chan *)ch;
	struct dma_async_tx_descriptor *desc;

	switch (info->cap) {
	case DMA_SLAVE:
		sg_init_table(&sg, 1);
		sg_dma_len(&sg) = info->len;
		sg_set_page(&sg, pfn_to_page(PFN_DOWN(info->buf)),
			    info->len, offset_in_page(info->buf));
		sg_dma_address(&sg) = info->buf;

		desc = chan->device->device_prep_slave_sg(chan,
			&sg, 1, info->direction, DMA_PREP_INTERRUPT);
		break;
	case DMA_CYCLIC:
		desc = chan->device->device_prep_dma_cyclic(chan,
			info->buf, info->len, info->period, info->direction);
		break;
	default:
		dev_err(&chan->dev->device, "unsupported format\n");
		return -EFAULT;
	}

	if (!desc) {
		dev_err(&chan->dev->device, "cannot prepare cyclic dma\n");
		return -EFAULT;
	}

	desc->callback = info->fp;
	desc->callback_param = info->fp_param;

	dmaengine_submit((struct dma_async_tx_descriptor *)desc);

	return 0;
}

/*
 * Return a scatterlist for a an array of userpages (NULL on errors).
 * Memory for the scatterlist is allocated using kmalloc.  The caller
 * must free the memory.
 */
static struct scatterlist *videobuf_pages_to_sg(struct page **pages,
					int nr_pages, int offset, size_t size)
{
	struct scatterlist *sglist;
	int i;

	if (NULL == pages[0])
		return NULL;
	sglist = vmalloc(nr_pages * sizeof(*sglist));
	if (NULL == sglist)
		return NULL;
	sg_init_table(sglist, nr_pages);

	if (PageHighMem(pages[0]))
		/* DMA to highmem pages might not work */
		goto highmem;
	sg_set_page(&sglist[0], pages[0],
			min_t(size_t, PAGE_SIZE - offset, size), offset);
	size -= min_t(size_t, PAGE_SIZE - offset, size);
	for (i = 1; i < nr_pages; i++) {
		if (NULL == pages[i])
			goto nopage;
		if (PageHighMem(pages[i]))
			goto highmem;
		sg_set_page(&sglist[i], pages[i], min_t(size_t, PAGE_SIZE, size), 0);
		size -= min_t(size_t, PAGE_SIZE, size);
	}
	return sglist;

nopage:
	dprintk(2, "sgl: oops - no page\n");
	vfree(sglist);
	return NULL;

highmem:
	dprintk(2, "sgl: oops - highmem page\n");
	vfree(sglist);
	return NULL;
}

static void digest_data(struct hash_desc *hash, struct iscsi_cmnd *cmnd,
			struct tio *tio, u32 offset, u8 *crc)
{
	struct scatterlist *sg = cmnd->conn->hash_sg;
	u32 size, length;
	int i, idx, count;
	unsigned int nbytes;

	size = cmnd->pdu.datasize;
	nbytes = size = (size + 3) & ~3;

	offset += tio->offset;
	idx = offset >> PAGE_CACHE_SHIFT;
	offset &= ~PAGE_CACHE_MASK;
	count = get_pgcnt(size, offset);
	assert(idx + count <= tio->pg_cnt);

	assert(count <= ISCSI_CONN_IOV_MAX);

	sg_init_table(sg, ARRAY_SIZE(cmnd->conn->hash_sg));
	crypto_hash_init(hash);

	for (i = 0; size; i++) {
		if (offset + size > PAGE_CACHE_SIZE)
			length = PAGE_CACHE_SIZE - offset;
		else
			length = size;

		sg_set_page(&sg[i], tio->pvec[idx + i], length, offset);
		size -= length;
		offset = 0;
	}

	sg_mark_end(&sg[i - 1]);

	crypto_hash_update(hash, sg, nbytes);
	crypto_hash_final(hash, crc);
}

struct scatterlist*
videobuf_pages_to_sg(struct page **pages, int nr_pages, int offset)
{
	struct scatterlist *sglist;
	int i = 0;

	if (NULL == pages[0])
		return NULL;
	sglist = kcalloc(nr_pages, sizeof(*sglist), GFP_KERNEL);
	if (NULL == sglist)
		return NULL;
	sg_init_table(sglist, nr_pages);

	if (NULL == pages[0])
		goto nopage;
	if (PageHighMem(pages[0]))
		/* DMA to highmem pages might not work */
		goto highmem;
	sg_set_page(&sglist[0], pages[0], PAGE_SIZE - offset, offset);
	for (i = 1; i < nr_pages; i++) {
		if (NULL == pages[i])
			goto nopage;
		if (PageHighMem(pages[i]))
			goto highmem;
		sg_set_page(&sglist[i], pages[i], PAGE_SIZE, 0);
	}
	return sglist;

 nopage:
	dprintk(2,"sgl: oops - no page\n");
	kfree(sglist);
	return NULL;

 highmem:
	dprintk(2,"sgl: oops - highmem page\n");
	kfree(sglist);
	return NULL;
}

int msm_iommu_map_extra(struct iommu_domain *domain,
				unsigned long start_iova,
				phys_addr_t phy_addr,
				unsigned long size,
				unsigned long page_size,
				int prot)
{
	int ret = 0;
	int i = 0;
	unsigned long temp_iova = start_iova;
	/* the extra "padding" should never be written to. map it
	 * read-only. */
	prot &= ~IOMMU_WRITE;

	if (msm_iommu_page_size_is_supported(page_size)) {
		struct scatterlist *sglist;
		unsigned int nrpages = PFN_ALIGN(size) >> PAGE_SHIFT;
		struct page *dummy_page = phys_to_page(phy_addr);

		sglist = vmalloc(sizeof(*sglist) * nrpages);
		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, prot);
		if (ret) {
			pr_err("%s: could not map extra %lx in domain %p\n",
				__func__, start_iova, domain);
		}

		vfree(sglist);
	} else {

static int omap_crypto_copy_sg_lists(int total, int bs,
				     struct scatterlist **sg,
				     struct scatterlist *new_sg, u16 flags)
{
	int n = sg_nents(*sg);
	struct scatterlist *tmp;

	if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY)) {
		new_sg = kmalloc_array(n, sizeof(*sg), GFP_KERNEL);
		if (!new_sg)
			return -ENOMEM;

		sg_init_table(new_sg, n);
	}

	tmp = new_sg;

	while (*sg && total) {
		int len = (*sg)->length;

		if (total < len)
			len = total;

		if (len > 0) {
			total -= len;
			sg_set_page(tmp, sg_page(*sg), len, (*sg)->offset);
			if (total <= 0)
				sg_mark_end(tmp);
			tmp = sg_next(tmp);
		}

		*sg = sg_next(*sg);
	}

	*sg = new_sg;

	return 0;
}

/* this is videobuf_vmalloc_to_sg() from videobuf-dma-sg.c
   make sure virt has been allocated with vmalloc_32(), otherwise the BUG()
   may be triggered on highmem machines */
static struct scatterlist* vmalloc_to_sg(unsigned char *virt, int nr_pages)
{
    struct scatterlist *sglist;
    struct page *pg;
    int i;

    sglist = kcalloc(nr_pages, sizeof(struct scatterlist), GFP_KERNEL);
    if (NULL == sglist)
        return NULL;
    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:
    kfree(sglist);
    return NULL;
}

void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
			       u8 *data, size_t data_len, u8 *mic)
{
	struct scatterlist assoc, pt, ct[2];
	struct {
		struct aead_request	req;
		u8			priv[crypto_aead_reqsize(tfm)];
	} aead_req;

	memset(&aead_req, 0, sizeof(aead_req));

	sg_init_one(&pt, data, data_len);
	sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
	sg_init_table(ct, 2);
	sg_set_buf(&ct[0], data, data_len);
	sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);

	aead_request_set_tfm(&aead_req.req, tfm);
	aead_request_set_assoc(&aead_req.req, &assoc, assoc.length);
	aead_request_set_crypt(&aead_req.req, &pt, ct, data_len, b_0);

	crypto_aead_encrypt(&aead_req.req);
}

void ieee80211_aes_gcm_encrypt(struct crypto_aead *tfm, u8 *j_0, u8 *aad,
			       u8 *data, size_t data_len, u8 *mic)
{
	struct scatterlist sg[3];

	char aead_req_data[sizeof(struct aead_request) +
			   crypto_aead_reqsize(tfm)]
		__aligned(__alignof__(struct aead_request));
	struct aead_request *aead_req = (void *)aead_req_data;

	memset(aead_req, 0, sizeof(aead_req_data));

	sg_init_table(sg, 3);
	sg_set_buf(&sg[0], &aad[2], be16_to_cpup((__be16 *)aad));
	sg_set_buf(&sg[1], data, data_len);
	sg_set_buf(&sg[2], mic, IEEE80211_GCMP_MIC_LEN);

	aead_request_set_tfm(aead_req, tfm);
	aead_request_set_crypt(aead_req, sg, sg, data_len, j_0);
	aead_request_set_ad(aead_req, sg[0].length);

	crypto_aead_encrypt(aead_req);
}

int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
			      u8 *data, size_t data_len, u8 *mic)
{
	struct scatterlist assoc, pt, ct[2];
	char aead_req_data[sizeof(struct aead_request) +
				crypto_aead_reqsize(tfm)]
				__aligned(__alignof__(struct aead_request));
	struct aead_request *aead_req = (void *) aead_req_data;
	memset(aead_req, 0, sizeof(aead_req_data));

	sg_init_one(&pt, data, data_len);
	sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
	sg_init_table(ct, 2);
	sg_set_buf(&ct[0], data, data_len);
	sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);

	aead_request_set_tfm(aead_req, tfm);
	aead_request_set_assoc(aead_req, &assoc, assoc.length);
	aead_request_set_crypt(aead_req, ct, &pt,
			       data_len + IEEE80211_CCMP_MIC_LEN, b_0);

	return crypto_aead_decrypt(aead_req);
}

void mars_digest(unsigned char *digest, void *data, int len)
{
	struct hash_desc desc = {
		.tfm = mars_tfm,
		.flags = 0,
	};
	struct scatterlist sg;

	memset(digest, 0, mars_digest_size);

	// TODO: use per-thread instance, omit locking
	down(&tfm_sem);

	crypto_hash_init(&desc);
	sg_init_table(&sg, 1);
	sg_set_buf(&sg, data, len);
	crypto_hash_update(&desc, &sg, sg.length);
	crypto_hash_final(&desc, digest);
	up(&tfm_sem);
}
EXPORT_SYMBOL_GPL(mars_digest);

void mref_checksum(struct mref_object *mref)
{
	unsigned char checksum[mars_digest_size];
	int len;

	if (mref->ref_cs_mode <= 0 || !mref->ref_data)
		return;

	mars_digest(checksum, mref->ref_data, mref->ref_len);

	len = sizeof(mref->ref_checksum);
	if (len > mars_digest_size)
		len = mars_digest_size;
	memcpy(&mref->ref_checksum, checksum, len);
}

static struct sg_table *omap_gem_map_dma_buf(
		struct dma_buf_attachment *attachment,
		enum dma_data_direction dir)
{
	struct drm_gem_object *obj = attachment->dmabuf->priv;
	struct sg_table *sg;
	dma_addr_t dma_addr;
	int ret;

	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
	if (!sg)
		return ERR_PTR(-ENOMEM);

	/* camera, etc, need physically contiguous.. but we need a
	 * better way to know this..
	 */
	ret = omap_gem_pin(obj, &dma_addr);
	if (ret)
		goto out;

	ret = sg_alloc_table(sg, 1, GFP_KERNEL);
	if (ret)
		goto out;

	sg_init_table(sg->sgl, 1);
	sg_dma_len(sg->sgl) = obj->size;
	sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(dma_addr)), obj->size, 0);
	sg_dma_address(sg->sgl) = dma_addr;

	/* this must be after omap_gem_pin() to ensure we have pages attached */
	omap_gem_dma_sync_buffer(obj, dir);

	return sg;
out:
	kfree(sg);
	return ERR_PTR(ret);
}