crypto: skcipher - Add skcipher walk interface

This patch adds the skcipher walk interface which replaces both
blkcipher walk and ablkcipher walk.  Just like blkcipher walk it
can also be used for AEAD algorithms.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/crypto/internal/skcipher.h

@@ -15,8 +15,10 @@
 
 #include <crypto/algapi.h>
 #include <crypto/skcipher.h>
+#include <linux/list.h>
 #include <linux/types.h>
 
+struct aead_request;
 struct rtattr;
 
 struct skcipher_instance {
@@ -34,6 +36,40 @@ struct crypto_skcipher_spawn {
 	struct crypto_spawn base;
 };
 
+struct skcipher_walk {
+	union {
+		struct {
+			struct page *page;
+			unsigned long offset;
+		} phys;
+
+		struct {
+			u8 *page;
+			void *addr;
+		} virt;
+	} src, dst;
+
+	struct scatter_walk in;
+	unsigned int nbytes;
+
+	struct scatter_walk out;
+	unsigned int total;
+
+	struct list_head buffers;
+
+	u8 *page;
+	u8 *buffer;
+	u8 *oiv;
+	void *iv;
+
+	unsigned int ivsize;
+
+	int flags;
+	unsigned int blocksize;
+	unsigned int chunksize;
+	unsigned int alignmask;
+};
+
 extern const struct crypto_type crypto_givcipher_type;
 
 static inline struct crypto_instance *skcipher_crypto_instance(
@@ -104,6 +140,17 @@ void crypto_unregister_skciphers(struct skcipher_alg *algs, int count);
 int skcipher_register_instance(struct crypto_template *tmpl,
 			       struct skcipher_instance *inst);
 
+int skcipher_walk_done(struct skcipher_walk *walk, int err);
+int skcipher_walk_virt(struct skcipher_walk *walk,
+		       struct skcipher_request *req,
+		       bool atomic);
+void skcipher_walk_atomise(struct skcipher_walk *walk);
+int skcipher_walk_async(struct skcipher_walk *walk,
+			struct skcipher_request *req);
+int skcipher_walk_aead(struct skcipher_walk *walk, struct aead_request *req,
+		       bool atomic);
+void skcipher_walk_complete(struct skcipher_walk *walk, int err);
+
 static inline void ablkcipher_request_complete(struct ablkcipher_request *req,
 					       int err)
 {