crypto: eliminate fallback proxy overhead while disabled

@@ -476,28 +482,39 @@ static ssize_t fallback_enabled_store(struct device *dev,
 		for (i = 0; i < fallback->num_groups; i++)
 			WRITE_ONCE(fallback->groups[i].threshold.value,
 				   fallback->groups[i].value);
+
+		if (!fallback->enabled) {
+			err = fallback_register_algs(fallback);
+			if (err) {
+				for (i = 0; i < fallback->num_groups; i++)
+					WRITE_ONCE(fallback->groups[i].threshold.value,
+						   0);
+				goto out_unlock;
+			}
+		}
 	} else {
+		WRITE_ONCE(fallback->enabled, false);
 		for (i = 0; i < fallback->num_groups; i++)
 			WRITE_ONCE(fallback->groups[i].threshold.value, 0);
+		fallback_unregister_algs(fallback);
 	}
 	WRITE_ONCE(fallback->enabled, enabled);
 
 out_unlock:
 	mutex_unlock(&fallback->lock);
 
-	return count;
+	return err ?: count;
 }

+static void fallback_alg_destroy(struct fallback_alg *alg)
+{
+	struct crypto_fallback *fallback = alg->fallback;
+	unsigned long flags;
+	bool release = false;
+
+	spin_lock_irqsave(&fallback->alg_lock, flags);
+	alg->dead = true;
+	alg->registered = false;
+	if (alg->registration_complete) {
+		list_del_init(&alg->list);
+		release = true;
+	}
+	spin_unlock_irqrestore(&fallback->alg_lock, flags);
+
+	if (release)
+		kref_put(&alg->refcount, fallback_alg_release);
+}
+
+static void fallback_skcipher_destroy(struct crypto_alg *base)
+{
+	struct skcipher_alg *alg;
+
+	alg = container_of(base, struct skcipher_alg, base);
+	fallback_alg_destroy(container_of(alg, struct fallback_alg,
+					  alg.skcipher));
+}

+			alg = kzalloc_obj(*alg, GFP_KERNEL);
+			if (!alg) {
+				err = -ENOMEM;
+				goto err_unregister_algs;
+			}
+
+			INIT_LIST_HEAD(&alg->list);
+			kref_init(&alg->refcount);
+			alg->fallback = fallback;
+			alg->threshold = &fallback->groups[i].threshold;
+			alg->type = group->benchmark.type;
+			if (strscpy(alg->driver_name, group->algs[j],
+				    sizeof(alg->driver_name)) < 0) {
+				kfree(alg);
+				err = -ENAMETOOLONG;
+				goto err_unregister_algs;
+			}
+
+			kref_get(&fallback->refcount);
+			spin_lock_irqsave(&fallback->alg_lock, flags);
+			list_add_tail(&alg->list, &fallback->algs);
+			spin_unlock_irqrestore(&fallback->alg_lock, flags);
+
+			err = fallback_register_alg(alg, fallback->owner);
+			err = fallback_alg_complete_registration(alg, err);