Move most of net_init_tap_one() to net_tap_setup() - future pair
for net_tap_new(), for postponed setup.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 net/tap.c | 43 +++++++++++++++++++++++++++----------------
 1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/net/tap.c b/net/tap.c
index 87d851203b..b4682d7400 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -85,6 +85,10 @@ typedef struct TAPState {
     int sndbuf;
 } TAPState;
 
+static bool net_tap_setup(TAPState *s, const NetdevTapOptions *tap,
+                          const char *vhostfdname,
+                          int fd, int vnet_hdr, Error **errp);
+
 static void launch_script(const char *setup_script, const char *ifname,
                           int fd, Error **errp);
 
@@ -697,11 +701,6 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
                              int vnet_hdr, int fd, Error **errp)
 {
     TAPState *s = net_tap_new(peer, model, name, tap);
-    int vhostfd;
-
-    if (!net_tap_set_fd(s, fd, vnet_hdr, errp)) {
-        goto failed;
-    }
 
     if (tap->fd || tap->fds) {
         qemu_set_info_str(&s->nc, "fd=%d", fd);
@@ -720,6 +719,21 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
         }
     }
 
+    if (!net_tap_setup(s, tap, vhostfdname, fd, vnet_hdr, errp)) {
+        qemu_del_net_client(&s->nc);
+    }
+}
+
+static bool net_tap_setup(TAPState *s, const NetdevTapOptions *tap,
+                          const char *vhostfdname,
+                          int fd, int vnet_hdr, Error **errp)
+{
+    int vhostfd;
+
+    if (!net_tap_set_fd(s, fd, vnet_hdr, errp)) {
+        return false;
+    }
+
     if (tap->has_vhost ? tap->vhost :
         vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
         VhostNetOptions options;
@@ -735,23 +749,23 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
         if (vhostfdname) {
             vhostfd = monitor_fd_param(monitor_cur(), vhostfdname, errp);
             if (vhostfd == -1) {
-                goto failed;
+                return false;
             }
             if (!g_unix_set_fd_nonblocking(vhostfd, true, NULL)) {
-                error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
-                                 name, fd);
-                goto failed;
+                error_setg_errno(errp, errno, "Can't use file descriptor %d",
+                                 fd);
+                return false;
             }
         } else {
             vhostfd = open("/dev/vhost-net", O_RDWR);
             if (vhostfd < 0) {
                 error_setg_errno(errp, errno,
                                  "tap: open vhost char device failed");
-                goto failed;
+                return false;
             }
             if (!g_unix_set_fd_nonblocking(vhostfd, true, NULL)) {
                 error_setg_errno(errp, errno, "Failed to set FD nonblocking");
-                goto failed;
+                return false;
             }
         }
         options.opaque = (void *)(uintptr_t)vhostfd;
@@ -766,14 +780,11 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
         if (!s->vhost_net) {
             error_setg(errp,
                        "vhost-net requested but could not be initialized");
-            goto failed;
+            return false;
         }
     }
 
-    return;
-
-failed:
-    qemu_del_net_client(&s->nc);
+    return true;
 }
 
 static int get_fds(char *str, char *fds[], int max)
-- 
2.48.1