struct blkcipher_walk {
	union {
		struct {
			struct page *page;
			unsigned long offset;
		} phys;

		struct {
			u8 *page;
			u8 *addr;
		} virt;
	} src, dst;

	struct scatter_walk in;
	unsigned int nbytes;

	struct scatter_walk out;
	unsigned int total;

	void *page;
	u8 *buffer;
	u8 *iv;
	unsigned int ivsize;

	int flags;
	unsigned int walk_blocksize;
	unsigned int cipher_blocksize;
	unsigned int alignmask;
};

struct scatter_walk {
	struct scatterlist *sg;
	unsigned int offset;
};

static inline void blkcipher_walk_init(struct blkcipher_walk *walk,
				       struct scatterlist *dst,
				       struct scatterlist *src,
				       unsigned int nbytes)
{
	walk->in.sg = src;
	walk->out.sg = dst;
	walk->total = nbytes;
}