Re: [dpdk-dev] [PATCH v1 5/5] vhost: message handling implemented as a callback array

[Tiwei Bie <tiwei.bie@intel.com>]

On Tue, Jun 26, 2018 at 07:19:38PM +0300, Nikolay Nikolaev wrote:
> Introduce vhost_message_handlers, which maps the message request
> type to the message handler. Then replace the switch construct
> with a map and call.
> 
> Signed-off-by: Nikolay Nikolaev <nicknickolaev@gmail.com>
> ---
>  lib/librte_vhost/vhost_user.c |  144 ++++++++++++++++-------------------------
>  1 file changed, 55 insertions(+), 89 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index dd47d84c7..e62164d63 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -1379,6 +1379,36 @@ vhost_user_iotlb_msg(struct virtio_net **pdev, VhostUserMsg *msg)
>  	return VH_RESULT_OK;
>  }
>  
> +typedef int (*message_handler)(struct virtio_net **pdev, VhostUserMsg * msg);

s/message_handler/vhost_message_handler_t/

> +static message_handler vhost_message_handlers[VHOST_USER_MAX] = {
> +	[VHOST_USER_NONE] = NULL,
> +	[VHOST_USER_GET_FEATURES] = vhost_user_get_features,
> +	[VHOST_USER_SET_FEATURES] = vhost_user_set_features,
> +	[VHOST_USER_SET_OWNER] = vhost_user_set_owner,
> +	[VHOST_USER_RESET_OWNER] = vhost_user_reset_owner,
> +	[VHOST_USER_SET_MEM_TABLE] = vhost_user_set_mem_table,
> +	[VHOST_USER_SET_LOG_BASE] = vhost_user_set_log_base,
> +	[VHOST_USER_SET_LOG_FD] = vhost_user_set_log_fd,
> +	[VHOST_USER_SET_VRING_NUM] = vhost_user_set_vring_num,
> +	[VHOST_USER_SET_VRING_ADDR] = vhost_user_set_vring_addr,
> +	[VHOST_USER_SET_VRING_BASE] = vhost_user_set_vring_base,
> +	[VHOST_USER_GET_VRING_BASE] = vhost_user_get_vring_base,
> +	[VHOST_USER_SET_VRING_KICK] = vhost_user_set_vring_kick,
> +	[VHOST_USER_SET_VRING_CALL] = vhost_user_set_vring_call,
> +	[VHOST_USER_SET_VRING_ERR]  = vhost_user_set_vring_err,
> +	[VHOST_USER_GET_PROTOCOL_FEATURES]  = vhost_user_get_protocol_features,
> +	[VHOST_USER_SET_PROTOCOL_FEATURES]  = vhost_user_set_protocol_features,
> +	[VHOST_USER_GET_QUEUE_NUM]  = vhost_user_get_queue_num,
> +	[VHOST_USER_SET_VRING_ENABLE]  = vhost_user_set_vring_enable,
> +	[VHOST_USER_SEND_RARP]  = vhost_user_send_rarp,
> +	[VHOST_USER_NET_SET_MTU]  = vhost_user_net_set_mtu,
> +	[VHOST_USER_SET_SLAVE_REQ_FD]  = vhost_user_set_req_fd,
> +	[VHOST_USER_IOTLB_MSG]  = vhost_user_iotlb_msg,

Please keep using one space between "]" and "=".

> +	[VHOST_USER_CRYPTO_CREATE_SESS] = NULL,
> +	[VHOST_USER_CRYPTO_CLOSE_SESS] = NULL,

There is no need to zero above two explicitly.

> +};
> +
> +
>  /* return bytes# of read on success or negative val on failure. */
>  static int
>  read_vhost_message(int sockfd, VhostUserMsg *msg)
> @@ -1623,97 +1653,33 @@ vhost_user_msg_handler(int vid, int fd)
>  			goto skip_to_post_handle;
>  	}
>  
> -	switch (msg.request.master) {
> -	case VHOST_USER_GET_FEATURES:
> -		ret = vhost_user_get_features(&dev, &msg);
> -		send_vhost_reply(fd, &msg);
> -		break;
> -	case VHOST_USER_SET_FEATURES:
> -		ret = vhost_user_set_features(&dev, &msg);
> -		if (ret)
> -			return -1;
> -		break;
> -
> -	case VHOST_USER_GET_PROTOCOL_FEATURES:
> -		ret = vhost_user_get_protocol_features(&dev, &msg);
> -		send_vhost_reply(fd, &msg);
> -		break;
> -	case VHOST_USER_SET_PROTOCOL_FEATURES:
> -		ret = vhost_user_set_protocol_features(&dev, &msg);
> -		break;
> -
> -	case VHOST_USER_SET_OWNER:
> -		ret = vhost_user_set_owner(&dev, &msg);
> -		break;
> -	case VHOST_USER_RESET_OWNER:
> -		ret = vhost_user_reset_owner(&dev, &msg);
> -		break;
> -
> -	case VHOST_USER_SET_MEM_TABLE:
> -		ret = vhost_user_set_mem_table(&dev, &msg);
> -		break;
> -
> -	case VHOST_USER_SET_LOG_BASE:
> -		ret = vhost_user_set_log_base(&dev, &msg);
> -		send_vhost_reply(fd, &msg);
> -		break;
> -	case VHOST_USER_SET_LOG_FD:
> -		ret = vhost_user_set_log_fd(&dev, &msg);
> -		break;
> -
> -	case VHOST_USER_SET_VRING_NUM:
> -		ret = vhost_user_set_vring_num(&dev, &msg);
> -		break;
> -	case VHOST_USER_SET_VRING_ADDR:
> -		ret = vhost_user_set_vring_addr(&dev, &msg);
> -		break;
> -	case VHOST_USER_SET_VRING_BASE:
> -		ret = vhost_user_set_vring_base(&dev, &msg);
> -		break;
>  

Please also remove above blank line.

> -	case VHOST_USER_GET_VRING_BASE:
> -		ret = vhost_user_get_vring_base(&dev, &msg);
> -		send_vhost_reply(fd, &msg);
> -		break;
> +	int request = msg.request.master;

Please define variable at the beginning of the function.

> +	if (vhost_message_handlers[request]) {

The `request` needs to be checked with VHOST_USER_MAX first.

> +		ret = vhost_message_handlers[request](&dev, &msg);
>  
[...]
> -
> -	default:
> -		ret = -1;
> -		break;
> +		switch (ret) {
> +		case VH_RESULT_ERR:
> +			RTE_LOG(ERR, VHOST_CONFIG,
> +				"Processing %s failed.\n",
> +				vhost_message_str[request]);
> +			return -1;

Queue pairs need to be unlocked when necessary.

> +		case VH_RESULT_OK:
> +			RTE_LOG(DEBUG, VHOST_CONFIG,
> +				"Processing %s succeeded.\n",
> +				vhost_message_str[request]);
> +			break;
> +		case VH_RESULT_REPLY:
> +			RTE_LOG(INFO, VHOST_CONFIG,
> +				"Processing %s succeeded and needs reply.\n",
> +				vhost_message_str[request]);
> +			send_vhost_reply(fd, &msg);
> +			break;
> +		}
> +	} else {
> +		RTE_LOG(ERR, VHOST_CONFIG,
> +			"Requested invalid message type %d.\n", request);
> +		return -1;

The old behaviour is changed, VHOST_USER_CRYPTO_CREATE_SESS
and VHOST_USER_CRYPTO_CLOSE_SESS will be broken.

>  	}
>  
>  skip_to_post_handle:
>