crypto: virtio - Less function calls in __virtio_crypto_akcipher_do_req() after error detection

The kfree() function was called in up to two cases by the
__virtio_crypto_akcipher_do_req() function during error handling
even if the passed variable contained a null pointer.
This issue was detected by using the Coccinelle software.

* Adjust jump targets.

* Delete two initialisations which became unnecessary
  with this refactoring.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Author: elfring

drivers/crypto/virtio/virtio_crypto_akcipher_algs.c

@@ -224,11 +224,11 @@ static int __virtio_crypto_akcipher_do_req(struct virtio_crypto_akcipher_request
 	struct virtio_crypto *vcrypto = ctx->vcrypto;
 	struct virtio_crypto_op_data_req *req_data = vc_req->req_data;
 	struct scatterlist *sgs[4], outhdr_sg, inhdr_sg, srcdata_sg, dstdata_sg;
-	void *src_buf = NULL, *dst_buf = NULL;
+	void *src_buf, *dst_buf = NULL;
 	unsigned int num_out = 0, num_in = 0;
 	int node = dev_to_node(&vcrypto->vdev->dev);
 	unsigned long flags;
-	int ret = -ENOMEM;
+	int ret;
 	bool verify = vc_akcipher_req->opcode == VIRTIO_CRYPTO_AKCIPHER_VERIFY;
 	unsigned int src_len = verify ? req->src_len + req->dst_len : req->src_len;
 
@@ -239,7 +239,7 @@ static int __virtio_crypto_akcipher_do_req(struct virtio_crypto_akcipher_request
 	/* src data */
 	src_buf = kcalloc_node(src_len, 1, GFP_KERNEL, node);
 	if (!src_buf)
-		goto err;
+		return -ENOMEM;
 
 	if (verify) {
 		/* for verify operation, both src and dst data work as OUT direction */
@@ -254,7 +254,7 @@ static int __virtio_crypto_akcipher_do_req(struct virtio_crypto_akcipher_request
 		/* dst data */
 		dst_buf = kcalloc_node(req->dst_len, 1, GFP_KERNEL, node);
 		if (!dst_buf)
-			goto err;
+			goto free_src;
 
 		sg_init_one(&dstdata_sg, dst_buf, req->dst_len);
 		sgs[num_out + num_in++] = &dstdata_sg;
@@ -277,9 +277,9 @@ static int __virtio_crypto_akcipher_do_req(struct virtio_crypto_akcipher_request
 	return 0;
 
 err:
-	kfree(src_buf);
 	kfree(dst_buf);
-
+free_src:
+	kfree(src_buf);
 	return -ENOMEM;
 }