crypto: hash - Export shash through hash

This patch allows shash algorithms to be used through the old hash
interface.  This is a transitional measure so we can convert the
underlying algorithms to shash before converting the users across.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/ahash.c b/crypto/ahash.c
index 7d4e33d..9f98956 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -112,6 +112,22 @@
 }
 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 
+int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
+				  struct crypto_hash_walk *walk,
+				  struct scatterlist *sg, unsigned int len)
+{
+	walk->total = len;
+
+	if (!walk->total)
+		return 0;
+
+	walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
+	walk->sg = sg;
+	walk->flags = hdesc->flags;
+
+	return hash_walk_new_entry(walk);
+}
+
 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 				unsigned int keylen)
 {