vhost: rework message handling as a callback array

Introduce vhost_message_handlers, which maps the message request
type to the message handler. Then replace the switch construct
with a map and call.

Failing vhost_user_set_features is fatal and all processing should
stop immediately and propagate the error to the upper layers. Change
the code accordingly to reflect that.

Signed-off-by: Nikolay Nikolaev <nicknickolaev@gmail.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index e1b705f..7ef3fb4 100644 (file)
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1477,6 +1477,35 @@ vhost_user_iotlb_msg(struct virtio_net **pdev, struct VhostUserMsg *msg)
        return VH_RESULT_OK;
 }
 
+typedef int (*vhost_message_handler_t)(struct virtio_net **pdev,
+                                       struct VhostUserMsg *msg);
+static vhost_message_handler_t 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,
+};
+
+
 /* return bytes# of read on success or negative val on failure. */
 static int
 read_vhost_message(int sockfd, struct VhostUserMsg *msg)
@@ -1630,6 +1659,7 @@ vhost_user_msg_handler(int vid, int fd)
        int ret;
        int unlock_required = 0;
        uint32_t skip_master = 0;
+       int request;
 
        dev = get_device(vid);
        if (dev == NULL)
@@ -1722,100 +1752,34 @@ 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);
-               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);
-               if (ret)
-                       goto skip_to_reply;
-               /* it needs a reply */
-               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;
-
-       case VHOST_USER_GET_VRING_BASE:
-               ret = vhost_user_get_vring_base(&dev, &msg);
-               if (ret)
-                       goto skip_to_reply;
-               send_vhost_reply(fd, &msg);
-               break;
-
-       case VHOST_USER_SET_VRING_KICK:
-               ret = vhost_user_set_vring_kick(&dev, &msg);
-               break;
-       case VHOST_USER_SET_VRING_CALL:
-               ret = vhost_user_set_vring_call(&dev, &msg);
-               break;
-
-       case VHOST_USER_SET_VRING_ERR:
-               ret = vhost_user_set_vring_err(&dev, &msg);
-               break;
-
-       case VHOST_USER_GET_QUEUE_NUM:
-               ret = vhost_user_get_queue_num(&dev, &msg);
-               send_vhost_reply(fd, &msg);
-               break;
-
-       case VHOST_USER_SET_VRING_ENABLE:
-               ret = vhost_user_set_vring_enable(&dev, &msg);
-               break;
-       case VHOST_USER_SEND_RARP:
-               ret = vhost_user_send_rarp(&dev, &msg);
-               break;
-
-       case VHOST_USER_NET_SET_MTU:
-               ret = vhost_user_net_set_mtu(&dev, &msg);
-               break;
-
-       case VHOST_USER_SET_SLAVE_REQ_FD:
-               ret = vhost_user_set_req_fd(&dev, &msg);
-               break;
-
-       case VHOST_USER_IOTLB_MSG:
-               ret = vhost_user_iotlb_msg(&dev, &msg);
-               break;
+       request = msg.request.master;
+       if (request > VHOST_USER_NONE && request < VHOST_USER_MAX) {
+               if (!vhost_message_handlers[request])
+                       goto skip_to_post_handle;
+               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]);
+                       break;
+               case VH_RESULT_OK:
+                       RTE_LOG(DEBUG, VHOST_CONFIG,
+                               "Processing %s succeeded.\n",
+                               vhost_message_str[request]);
+                       break;
+               case VH_RESULT_REPLY:
+                       RTE_LOG(DEBUG, 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);
+               ret = VH_RESULT_ERR;
        }
 
 skip_to_post_handle: