crypto: hash - Add import/export interface

It is often useful to save the partial state of a hash function
so that it can be used as a base for two or more computations.

The most prominent example is HMAC where all hashes start from
a base determined by the key.  Having an import/export interface
means that we only have to compute that base once rather than
for each message.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 44c72f0f9b05..77a1f3d9416d 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -221,6 +221,7 @@ struct ablkcipher_alg {
 
 struct ahash_alg {
         int (*init)(struct ahash_request *req);
+        int (*reinit)(struct ahash_request *req);
         int (*update)(struct ahash_request *req);
         int (*final)(struct ahash_request *req);
         int (*digest)(struct ahash_request *req);