crypto: virtio - Replace GFP_ATOMIC with GFP_KERNEL in __virtio_crypto_ablkcipher_do_req()

__virtio_crypto_ablkcipher_do_req() is never called in atomic context.

__virtio_crypto_ablkcipher_do_req() is only called by
virtio_crypto_ablkcipher_crypt_req(), which is only called by
virtcrypto_find_vqs() that is never called in atomic context.

__virtio_crypto_ablkcipher_do_req() calls kzalloc_node() with GFP_ATOMIC,
which is not necessary.
GFP_ATOMIC can be replaced with GFP_KERNEL.

This is found by a static analysis tool named DCNS written by myself.
I also manually check the kernel code before reporting it.
Signed-off-by: NJia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/virtio/virtio_crypto_algs.c

@@ -383,12 +383,12 @@ __virtio_crypto_ablkcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,
 
 	/* Why 3?  outhdr + iv + inhdr */
 	sg_total = src_nents + dst_nents + 3;
-	sgs = kcalloc_node(sg_total, sizeof(*sgs), GFP_ATOMIC,
+	sgs = kcalloc_node(sg_total, sizeof(*sgs), GFP_KERNEL,
 				dev_to_node(&vcrypto->vdev->dev));
 	if (!sgs)
 		return -ENOMEM;
 
-	req_data = kzalloc_node(sizeof(*req_data), GFP_ATOMIC,
+	req_data = kzalloc_node(sizeof(*req_data), GFP_KERNEL,
 				dev_to_node(&vcrypto->vdev->dev));
 	if (!req_data) {
 		kfree(sgs);