crypto: allow blkcipher walks over AEAD data

This adds the function blkcipher_aead_walk_virt_block, which allows the caller
to use the blkcipher walk API to handle the input and output scatterlists.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index d9d14a0..016c2f1 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -195,6 +195,10 @@
 int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
 			      struct blkcipher_walk *walk,
 			      unsigned int blocksize);
+int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc,
+				   struct blkcipher_walk *walk,
+				   struct crypto_aead *tfm,
+				   unsigned int blocksize);
 
 int ablkcipher_walk_done(struct ablkcipher_request *req,
 			 struct ablkcipher_walk *walk, int err);