lib/vhost: add flag for async connection in client mode

This patch introduces a new flag RTE_VHOST_USER_ASYNC_CONNECT,
which in combination with the flag RTE_VHOST_USER_CLIENT makes
rte_vhost_driver_start connect asynchronously to the vhost server.

Signed-off-by: Daniil Ushkov <daniil.ushkov@yandex.ru>
Signed-off-by: 0-day Robot <robot@bytheb.org>

lib/vhost/rte_vhost.h

@@ -41,6 +41,7 @@ extern "C" {
 #define RTE_VHOST_USER_ASYNC_COPY	(1ULL << 7)
 #define RTE_VHOST_USER_NET_COMPLIANT_OL_FLAGS	(1ULL << 8)
 #define RTE_VHOST_USER_NET_STATS_ENABLE	(1ULL << 9)
+#define RTE_VHOST_USER_ASYNC_CONNECT	(1ULL << 10)
 
 /* Features. */
 #ifndef VIRTIO_NET_F_GUEST_ANNOUNCE

lib/vhost/socket.c

@@ -45,6 +45,7 @@ struct vhost_user_socket {
 	bool async_copy;
 	bool net_compliant_ol_flags;
 	bool stats_enabled;
+	bool async_connect;
 
 	/*
 	 * The "supported_features" indicates the feature bits the
@@ -533,21 +534,23 @@ vhost_user_start_client(struct vhost_user_socket *vsocket)
 	const char *path = vsocket->path;
 	struct vhost_user_reconnect *reconn;
 
-	ret = vhost_user_connect_nonblock(vsocket->path, fd, (struct sockaddr *)&vsocket->un,
-					  sizeof(vsocket->un));
-	if (ret == 0) {
-		vhost_user_add_connection(fd, vsocket);
-		return 0;
-	}
+	if (!vsocket->async_connect || !vsocket->reconnect) {
+		ret = vhost_user_connect_nonblock(vsocket->path, fd,
+			(struct sockaddr *)&vsocket->un, sizeof(vsocket->un));
+		if (ret == 0) {
+			vhost_user_add_connection(fd, vsocket);
+			return 0;
+		}
 
-	VHOST_CONFIG_LOG(path, WARNING, "failed to connect: %s", strerror(errno));
+		VHOST_CONFIG_LOG(path, WARNING, "failed to connect: %s", strerror(errno));
 
-	if (ret == -2 || !vsocket->reconnect) {
-		close(fd);
-		return -1;
-	}
+		if (ret == -2 || !vsocket->reconnect) {
+			close(fd);
+			return -1;
+		}
 
-	VHOST_CONFIG_LOG(path, INFO, "reconnecting...");
+		VHOST_CONFIG_LOG(path, INFO, "reconnecting...");
+	}
 	reconn = malloc(sizeof(*reconn));
 	if (reconn == NULL) {
 		VHOST_CONFIG_LOG(path, ERR, "failed to allocate memory for reconnect");
@@ -930,6 +933,7 @@ rte_vhost_driver_register(const char *path, uint64_t flags)
 	vsocket->async_copy = flags & RTE_VHOST_USER_ASYNC_COPY;
 	vsocket->net_compliant_ol_flags = flags & RTE_VHOST_USER_NET_COMPLIANT_OL_FLAGS;
 	vsocket->stats_enabled = flags & RTE_VHOST_USER_NET_STATS_ENABLE;
+	vsocket->async_connect = flags & RTE_VHOST_USER_ASYNC_CONNECT;
 	if (vsocket->is_vduse)
 		vsocket->iommu_support = true;
 	else