[PATCH v2] vhost: use dedicated variable for vhost message result code

[Xia, Chenbo]

> -----Original Message-----
> From: Pei, Andy <andy.pei at intel.com>
> Sent: Friday, September 23, 2022 10:33 AM
> To: dev at dpdk.org
> Cc: Xia, Chenbo <chenbo.xia at intel.com>; maxime.coquelin at redhat.com
> Subject: [PATCH v2] vhost: use dedicated variable for vhost message result
> code
> 
> Currently in function vhost_user_msg_handler, variable ret is used to
> store both vhost msg result code and function call return value.
> After this patch, variable ret is used only to store function call
> return value, a new dedicated variable msg_result is used to
> store vhost msg result. This can improve readability.
> 
> Signed-off-by: Andy Pei <andy.pei at intel.com>
> ---
>  lib/vhost/vhost_user.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
> index 0182090..6d93495 100644
> --- a/lib/vhost/vhost_user.c
> +++ b/lib/vhost/vhost_user.c
> @@ -2954,6 +2954,7 @@ static int is_vring_iotlb(struct virtio_net *dev,
>  	struct vhu_msg_context ctx;
>  	vhost_message_handler_t *msg_handler;
>  	struct rte_vdpa_device *vdpa_dev;
> +	int msg_result = RTE_VHOST_MSG_RESULT_OK;
>  	int ret;
>  	int unlock_required = 0;
>  	bool handled;
> @@ -3046,8 +3047,8 @@ static int is_vring_iotlb(struct virtio_net *dev,
>  	handled = false;
>  	if (dev->extern_ops.pre_msg_handle) {
>  		RTE_BUILD_BUG_ON(offsetof(struct vhu_msg_context, msg) != 0);
> -		ret = (*dev->extern_ops.pre_msg_handle)(dev->vid, &ctx);
> -		switch (ret) {
> +		msg_result = (*dev->extern_ops.pre_msg_handle)(dev->vid, &ctx);
> +		switch (msg_result) {
>  		case RTE_VHOST_MSG_RESULT_REPLY:
>  			send_vhost_reply(dev, fd, &ctx);
>  			/* Fall-through */
> @@ -3065,12 +3066,12 @@ static int is_vring_iotlb(struct virtio_net *dev,
>  		goto skip_to_post_handle;
> 
>  	if (!msg_handler->accepts_fd && validate_msg_fds(dev, &ctx, 0) != 0)
> {
> -		ret = RTE_VHOST_MSG_RESULT_ERR;
> +		msg_result = RTE_VHOST_MSG_RESULT_ERR;
>  	} else {
> -		ret = msg_handler->callback(&dev, &ctx, fd);
> +		msg_result = msg_handler->callback(&dev, &ctx, fd);
>  	}
> 
> -	switch (ret) {
> +	switch (msg_result) {
>  	case RTE_VHOST_MSG_RESULT_ERR:
>  		VHOST_LOG_CONFIG(dev->ifname, ERR,
>  			"processing %s failed.\n",
> @@ -3095,11 +3096,11 @@ static int is_vring_iotlb(struct virtio_net *dev,
>  	}
> 
>  skip_to_post_handle:
> -	if (ret != RTE_VHOST_MSG_RESULT_ERR &&
> +	if (msg_result != RTE_VHOST_MSG_RESULT_ERR &&
>  			dev->extern_ops.post_msg_handle) {
>  		RTE_BUILD_BUG_ON(offsetof(struct vhu_msg_context, msg) != 0);
> -		ret = (*dev->extern_ops.post_msg_handle)(dev->vid, &ctx);
> -		switch (ret) {
> +		msg_result = (*dev->extern_ops.post_msg_handle)(dev->vid,
> &ctx);
> +		switch (msg_result) {
>  		case RTE_VHOST_MSG_RESULT_REPLY:
>  			send_vhost_reply(dev, fd, &ctx);
>  			/* Fall-through */
> @@ -3118,7 +3119,7 @@ static int is_vring_iotlb(struct virtio_net *dev,
>  			"vhost message (req: %d) was not handled.\n",
>  			request);
>  		close_msg_fds(&ctx);
> -		ret = RTE_VHOST_MSG_RESULT_ERR;
> +		msg_result = RTE_VHOST_MSG_RESULT_ERR;
>  	}
> 
>  	/*
> @@ -3127,17 +3128,16 @@ static int is_vring_iotlb(struct virtio_net *dev,
>  	 * VHOST_USER_NEED_REPLY was cleared in send_vhost_reply().
>  	 */
>  	if (ctx.msg.flags & VHOST_USER_NEED_REPLY) {
> -		ctx.msg.payload.u64 = ret == RTE_VHOST_MSG_RESULT_ERR;
> +		ctx.msg.payload.u64 = msg_result == RTE_VHOST_MSG_RESULT_ERR;
>  		ctx.msg.size = sizeof(ctx.msg.payload.u64);
>  		ctx.fd_num = 0;
>  		send_vhost_reply(dev, fd, &ctx);
> -	} else if (ret == RTE_VHOST_MSG_RESULT_ERR) {
> +	} else if (msg_result == RTE_VHOST_MSG_RESULT_ERR) {
>  		VHOST_LOG_CONFIG(dev->ifname, ERR, "vhost message handling
> failed.\n");
>  		ret = -1;
>  		goto unlock;
>  	}
> 
> -	ret = 0;
>  	for (i = 0; i < dev->nr_vring; i++) {
>  		struct vhost_virtqueue *vq = dev->virtqueue[i];
>  		bool cur_ready = vq_is_ready(dev, vq);
> --
> 1.8.3.1

Reviewed-by: Chenbo Xia <chenbo.xia at intel.com>