crypto: authencesn - use crypto_grab_ahash() and simplify error paths

Make the authencesn template use the new function crypto_grab_ahash() to
initialize its ahash spawn.

This is needed to make all spawns be initialized in a consistent way.

Also simplify the error handling by taking advantage of crypto_drop_*()
now accepting (as a no-op) spawns that haven't been initialized yet, and
by taking advantage of crypto_grab_*() now handling ERR_PTR() names.

Signed-off-by: Eric Biggers <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

crypto/authencesn.c

···
 	struct crypto_attr_type *algt;
 	u32 mask;
 	struct aead_instance *inst;
+	struct authenc_esn_instance_ctx *ctx;
 	struct hash_alg_common *auth;
 	struct crypto_alg *auth_base;
 	struct skcipher_alg *enc;
-	struct authenc_esn_instance_ctx *ctx;
-	const char *enc_name;
 	int err;
 
 	algt = crypto_get_attr_type(tb);
···
 
 	mask = crypto_requires_sync(algt->type, algt->mask);
 
-	auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
-			      CRYPTO_ALG_TYPE_AHASH_MASK | mask);
-	if (IS_ERR(auth))
-		return PTR_ERR(auth);
-
-	auth_base = &auth->base;
-
-	enc_name = crypto_attr_alg_name(tb[2]);
-	err = PTR_ERR(enc_name);
-	if (IS_ERR(enc_name))
-		goto out_put_auth;
-
 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
-	err = -ENOMEM;
 	if (!inst)
-		goto out_put_auth;
-
+		return -ENOMEM;
 	ctx = aead_instance_ctx(inst);
 
-	err = crypto_init_ahash_spawn(&ctx->auth, auth,
-				      aead_crypto_instance(inst));
+	err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst),
+				crypto_attr_alg_name(tb[1]), 0, mask);
 	if (err)
 		goto err_free_inst;
+	auth = crypto_spawn_ahash_alg(&ctx->auth);
+	auth_base = &auth->base;
 
 	err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
-				   enc_name, 0, mask);
+				   crypto_attr_alg_name(tb[2]), 0, mask);
 	if (err)
-		goto err_drop_auth;
-
+		goto err_free_inst;
 	enc = crypto_spawn_skcipher_alg(&ctx->enc);
 
 	err = -ENAMETOOLONG;
 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 		     "authencesn(%s,%s)", auth_base->cra_name,
 		     enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
-		goto err_drop_enc;
+		goto err_free_inst;
 
 	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 		     "authencesn(%s,%s)", auth_base->cra_driver_name,
 		     enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
-		goto err_drop_enc;
+		goto err_free_inst;
 
 	inst->alg.base.cra_flags = (auth_base->cra_flags |
 				    enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
···
 	inst->free = crypto_authenc_esn_free,
 
 	err = aead_register_instance(tmpl, inst);
-	if (err)
-		goto err_drop_enc;
-
-out:
-	crypto_mod_put(auth_base);
-	return err;
-
-err_drop_enc:
-	crypto_drop_skcipher(&ctx->enc);
-err_drop_auth:
-	crypto_drop_ahash(&ctx->auth);
+	if (err) {
 err_free_inst:
-	kfree(inst);
-out_put_auth:
-	goto out;
+		crypto_authenc_esn_free(inst);
+	}
+	return err;
 }
 
 static struct crypto_template crypto_authenc_esn_tmpl = {