Continue the track to avoid dependency on @tap in net_tap_setup(),
no move the vhost fd initialization to net_tap_new(). So in
net_tap_setup() we simply check, do we have and vhostfd at this
point or not.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 net/tap.c | 90 ++++++++++++++++++++++++++++++-------------------------
 1 file changed, 50 insertions(+), 40 deletions(-)

diff --git a/net/tap.c b/net/tap.c
index 877564405a..dbd1eb3a17 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -83,11 +83,11 @@ typedef struct TAPState {
 
     bool sndbuf_required;
     int sndbuf;
+    int vhostfd;
+    uint32_t vhost_busyloop_timeout;
 } TAPState;
 
-static bool net_tap_setup(TAPState *s, const NetdevTapOptions *tap,
-                          const char *vhostfdname,
-                          int fd, int vnet_hdr, Error **errp);
+static bool net_tap_setup(TAPState *s, int fd, int vnet_hdr, Error **errp);
 
 static void launch_script(const char *setup_script, const char *ifname,
                           int fd, Error **errp);
@@ -351,6 +351,11 @@ static void tap_cleanup(NetClientState *nc)
     tap_write_poll(s, false);
     close(s->fd);
     s->fd = -1;
+
+    if (s->vhostfd != -1) {
+        close(s->vhostfd);
+        s->vhostfd = -1;
+    }
 }
 
 static void tap_poll(NetClientState *nc, bool enable)
@@ -409,12 +414,14 @@ static NetClientInfo net_tap_info = {
 };
 
 static TAPState *net_tap_new(NetClientState *peer, const char *model,
-                             const char *name, const NetdevTapOptions *tap)
+                             const char *name, const NetdevTapOptions *tap,
+                             const char *vhostfdname, Error **errp)
 {
     NetClientState *nc = qemu_new_net_client(&net_tap_info, peer, model, name);
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 
     s->fd = -1;
+    s->vhostfd = -1;
 
     if (!tap) {
         return s;
@@ -424,7 +431,36 @@ static TAPState *net_tap_new(NetClientState *peer, const char *model,
     s->sndbuf =
         (tap->has_sndbuf && tap->sndbuf) ? MIN(tap->sndbuf, INT_MAX) : INT_MAX;
 
+    if (tap->has_vhost ? tap->vhost :
+        vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
+        if (vhostfdname) {
+            s->vhostfd = monitor_fd_param(monitor_cur(), vhostfdname, errp);
+            if (s->vhostfd == -1) {
+                goto failed;
+            }
+            if (!qemu_set_blocking(s->vhostfd, false, errp)) {
+                goto failed;
+            }
+        } else {
+            s->vhostfd = open("/dev/vhost-net", O_RDWR);
+            if (s->vhostfd < 0) {
+                error_setg_errno(errp, errno,
+                                 "tap: open vhost char device failed");
+                goto failed;
+            }
+            if (!qemu_set_blocking(s->vhostfd, false, errp)) {
+                goto failed;
+            }
+        }
+
+        s->vhost_busyloop_timeout = tap->has_poll_us ? tap->poll_us : 0;
+    }
+
     return s;
+
+failed:
+    qemu_del_net_client(&s->nc);
+    return NULL;
 }
 
 static bool net_tap_set_fd(TAPState *s, int fd, int vnet_hdr, Error **errp)
@@ -671,7 +707,7 @@ int net_init_bridge(const Netdev *netdev, const char *name,
         return -1;
     }
 
-    s = net_tap_new(peer, "bridge", name, NULL);
+    s = net_tap_new(peer, "bridge", name, NULL, NULL, &error_abort);
     net_tap_set_fd(s, fd, vnet_hdr, &error_abort);
 
     qemu_set_info_str(&s->nc, "helper=%s,br=%s", helper, br);
@@ -712,7 +748,10 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
                              const char *downscript, const char *vhostfdname,
                              int vnet_hdr, int fd, Error **errp)
 {
-    TAPState *s = net_tap_new(peer, model, name, tap);
+    TAPState *s = net_tap_new(peer, model, name, tap, vhostfdname, errp);
+    if (!s) {
+        return;
+    }
 
     if (tap->fd || tap->fds) {
         qemu_set_info_str(&s->nc, "fd=%d", fd);
@@ -731,53 +770,24 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
         }
     }
 
-    if (!net_tap_setup(s, tap, vhostfdname, fd, vnet_hdr, errp)) {
+    if (!net_tap_setup(s, 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)
+static bool net_tap_setup(TAPState *s, 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)) {
+    if (s->vhostfd != -1) {
         VhostNetOptions options;
 
         options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
         options.net_backend = &s->nc;
-        if (tap->has_poll_us) {
-            options.busyloop_timeout = tap->poll_us;
-        } else {
-            options.busyloop_timeout = 0;
-        }
-
-        if (vhostfdname) {
-            vhostfd = monitor_fd_param(monitor_cur(), vhostfdname, errp);
-            if (vhostfd == -1) {
-                return false;
-            }
-            if (!qemu_set_blocking(vhostfd, false, errp)) {
-                return false;
-            }
-        } else {
-            vhostfd = open("/dev/vhost-net", O_RDWR);
-            if (vhostfd < 0) {
-                error_setg_errno(errp, errno,
-                                 "tap: open vhost char device failed");
-                return false;
-            }
-            if (!qemu_set_blocking(vhostfd, false, errp)) {
-                return false;
-            }
-        }
-        options.opaque = (void *)(uintptr_t)vhostfd;
+        options.busyloop_timeout = s->vhost_busyloop_timeout;
+        options.opaque = (void *)(uintptr_t)s->vhostfd;
         options.nvqs = 2;
         options.feature_bits = kernel_feature_bits;
         options.get_acked_features = NULL;
-- 
2.48.1