crypto: aead - Add type-safe init/exit functions

As it stands the only non-type safe functions left in the new
AEAD interface are the cra_init/cra_exit functions.  It means
exposing the ugly __crypto_aead_cast to every AEAD implementor.

This patch adds type-safe init/exit functions to AEAD.  Existing
algorithms are unaffected while new implementations can simply
fill in these two instead of cra_init/cra_exit.

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

crypto/aead.c

@@ -174,6 +174,14 @@ static int crypto_old_aead_init_tfm(struct crypto_tfm *tfm)
 	return 0;
 }
 
+static void crypto_aead_exit_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_aead *aead = __crypto_aead_cast(tfm);
+	struct aead_alg *alg = crypto_aead_alg(aead);
+
+	alg->exit(aead);
+}
+
 static int crypto_aead_init_tfm(struct crypto_tfm *tfm)
 {
 	struct crypto_aead *aead = __crypto_aead_cast(tfm);
@@ -189,6 +197,12 @@ static int crypto_aead_init_tfm(struct crypto_tfm *tfm)
 	aead->child = __crypto_aead_cast(tfm);
 	aead->authsize = alg->maxauthsize;
 
+	if (alg->exit)
+		aead->base.exit = crypto_aead_exit_tfm;
+
+	if (alg->init)
+		return alg->init(aead);
+
 	return 0;
 }
 

include/crypto/aead.h

@@ -109,6 +109,17 @@ struct aead_givcrypt_request {
  * @decrypt: see struct ablkcipher_alg
  * @geniv: see struct ablkcipher_alg
  * @ivsize: see struct ablkcipher_alg
+ * @init: Initialize the cryptographic transformation object. This function
+ *	  is used to initialize the cryptographic transformation object.
+ *	  This function is called only once at the instantiation time, right
+ *	  after the transformation context was allocated. In case the
+ *	  cryptographic hardware has some special requirements which need to
+ *	  be handled by software, this function shall check for the precise
+ *	  requirement of the transformation and put any software fallbacks
+ *	  in place.
+ * @exit: Deinitialize the cryptographic transformation object. This is a
+ *	  counterpart to @init, used to remove various changes set in
+ *	  @init.
  *
  * All fields except @ivsize is mandatory and must be filled.
  */
@@ -118,6 +129,8 @@ struct aead_alg {
 	int (*setauthsize)(struct crypto_aead *tfm, unsigned int authsize);
 	int (*encrypt)(struct aead_request *req);
 	int (*decrypt)(struct aead_request *req);
+	int (*init)(struct crypto_aead *tfm);
+	void (*exit)(struct crypto_aead *tfm);
 
 	const char *geniv;