virtio: net-tap: bugfix: del net client if net_init_tap_one failed

In net_init_tap_one(), if the net-tap initializes successful
but other actions failed during vhost-net hot-plugging, the
net-tap will remain in the net clients.causing next hot-plug
fails again.

Signed-off-by: Jinhua Cao <caojinhua1@huawei.com>

virtio-net-tap-bugfix-del-net-client-if-net_init_tap.patch

@@ -0,0 +1,76 @@
+From cee545754b44b6283408ec6a43eb0e317c98ebb1 Mon Sep 17 00:00:00 2001
+From: Jinhua Cao <caojinhua1@huawei.com>
+Date: Wed, 9 Feb 2022 20:27:41 +0800
+Subject: [PATCH] virtio: net-tap: bugfix: del net client if net_init_tap_one
+ failed
+
+In net_init_tap_one(), if the net-tap initializes successful
+but other actions failed during vhost-net hot-plugging, the
+net-tap will remain in the net clients.causing next hot-plug
+fails again.
+
+Signed-off-by: Jinhua Cao <caojinhua1@huawei.com>
+---
+ net/tap.c | 16 +++++++++++-----
+ 1 file changed, 11 insertions(+), 5 deletions(-)
+
+diff --git a/net/tap.c b/net/tap.c
+index c5cbeaa7a2..3f79cd06c2 100644
+--- a/net/tap.c
++++ b/net/tap.c
+@@ -684,7 +684,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
+     tap_set_sndbuf(s->fd, tap, &err);
+     if (err) {
+         error_propagate(errp, err);
+-        return;
++        goto fail;
+     }
+ 
+     if (tap->has_fd || tap->has_fds) {
+@@ -726,13 +726,13 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
+                 } else {
+                     warn_report_err(err);
+                 }
+-                return;
++                goto fail;
+             }
+             ret = qemu_try_set_nonblock(vhostfd);
+             if (ret < 0) {
+                 error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
+                                  name, fd);
+-                return;
++                goto fail;
+             }
+         } else {
+             vhostfd = open("/dev/vhost-net", O_RDWR);
+@@ -744,7 +744,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
+                     warn_report("tap: open vhost char device failed: %s",
+                                 strerror(errno));
+                 }
+-                return;
++                goto fail;
+             }
+             qemu_set_nonblock(vhostfd);
+         }
+@@ -758,11 +758,17 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
+             } else {
+                 warn_report(VHOST_NET_INIT_FAILED);
+             }
+-            return;
++            goto fail;
+         }
+     } else if (vhostfdname) {
+         error_setg(errp, "vhostfd(s)= is not valid without vhost");
++        goto fail;
+     }
++
++    return;
++
++fail:
++    qemu_del_net_client(&s->nc);
+ }
+ 
+ static int get_fds(char *str, char *fds[], int max)
+-- 
+2.27.0
+