crypto: api - Add cra_type->destroy hook

Add a cra_type->destroy hook so that resources can be freed after
the last user of a registered algorithm is gone.

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

Author: herbertx

crypto/api.c

@@ -707,5 +707,15 @@ void crypto_req_done(void *data, int err)
 }
 EXPORT_SYMBOL_GPL(crypto_req_done);
 
+void crypto_destroy_alg(struct crypto_alg *alg)
+{
+	if (alg->cra_type && alg->cra_type->destroy)
+		alg->cra_type->destroy(alg);
+
+	if (alg->cra_destroy)
+		alg->cra_destroy(alg);
+}
+EXPORT_SYMBOL_GPL(crypto_destroy_alg);
+
 MODULE_DESCRIPTION("Cryptographic core API");
 MODULE_LICENSE("GPL");

crypto/internal.h

@@ -40,6 +40,7 @@ struct crypto_type {
 	void (*show)(struct seq_file *m, struct crypto_alg *alg);
 	int (*report)(struct sk_buff *skb, struct crypto_alg *alg);
 	void (*free)(struct crypto_instance *inst);
+	void (*destroy)(struct crypto_alg *alg);
 
 	unsigned int type;
 	unsigned int maskclear;
@@ -127,6 +128,7 @@ void *crypto_create_tfm_node(struct crypto_alg *alg,
 			const struct crypto_type *frontend, int node);
 void *crypto_clone_tfm(const struct crypto_type *frontend,
 		       struct crypto_tfm *otfm);
+void crypto_destroy_alg(struct crypto_alg *alg);
 
 static inline void *crypto_create_tfm(struct crypto_alg *alg,
 			const struct crypto_type *frontend)
@@ -163,8 +165,8 @@ static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
 
 static inline void crypto_alg_put(struct crypto_alg *alg)
 {
-	if (refcount_dec_and_test(&alg->cra_refcnt) && alg->cra_destroy)
-		alg->cra_destroy(alg);
+	if (refcount_dec_and_test(&alg->cra_refcnt))
+		crypto_destroy_alg(alg);
 }
 
 static inline int crypto_tmpl_get(struct crypto_template *tmpl)