crypto: api - Introduce notifier for new crypto algorithms

Introduce a facility that can be used to receive a notification
callback when a new algorithm becomes available. This can be used by
existing crypto registrations to trigger a switch from a software-only
algorithm to a hardware-accelerated version.

A new CRYPTO_MSG_ALG_LOADED state is introduced to the existing crypto
notification chain, and the register/unregister functions are exported
so they can be called by subsystems outside of crypto.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/algapi.c

@@ -372,6 +372,8 @@ static void crypto_wait_for_test(struct crypto_larval *larval)
 
 	err = wait_for_completion_killable(&larval->completion);
 	WARN_ON(err);
+	if (!err)
+		crypto_probing_notify(CRYPTO_MSG_ALG_LOADED, larval);
 
 out:
 	crypto_larval_kill(&larval->alg);

crypto/algboss.c

@@ -274,6 +274,8 @@ static int cryptomgr_notify(struct notifier_block *this, unsigned long msg,
 		return cryptomgr_schedule_probe(data);
 	case CRYPTO_MSG_ALG_REGISTER:
 		return cryptomgr_schedule_test(data);
+	case CRYPTO_MSG_ALG_LOADED:
+		break;
 	}
 
 	return NOTIFY_DONE;

crypto/internal.h

@@ -26,12 +26,6 @@
 #include <linux/rwsem.h>
 #include <linux/slab.h>
 
-/* Crypto notification events. */
-enum {
-	CRYPTO_MSG_ALG_REQUEST,
-	CRYPTO_MSG_ALG_REGISTER,
-};
-
 struct crypto_instance;
 struct crypto_template;
 
@@ -90,8 +84,6 @@ struct crypto_alg *crypto_find_alg(const char *alg_name,
 void *crypto_alloc_tfm(const char *alg_name,
 		       const struct crypto_type *frontend, u32 type, u32 mask);
 
-int crypto_register_notifier(struct notifier_block *nb);
-int crypto_unregister_notifier(struct notifier_block *nb);
 int crypto_probing_notify(unsigned long val, void *v);
 
 unsigned int crypto_alg_extsize(struct crypto_alg *alg);

include/crypto/algapi.h

@@ -427,4 +427,14 @@ static inline void crypto_yield(u32 flags)
 #endif
 }
 
+int crypto_register_notifier(struct notifier_block *nb);
+int crypto_unregister_notifier(struct notifier_block *nb);
+
+/* Crypto notification events. */
+enum {
+	CRYPTO_MSG_ALG_REQUEST,
+	CRYPTO_MSG_ALG_REGISTER,
+	CRYPTO_MSG_ALG_LOADED,
+};
+
 #endif	/* _CRYPTO_ALGAPI_H */