[RFC V1 2/6] tap: common return label

[Steve Sistare]

Modify net_init_tap so every return branches to a common label, for
common cleanup in a subsequent patch.  No functional change.

Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
---
 net/tap.c | 54 ++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 36 insertions(+), 18 deletions(-)

diff --git a/net/tap.c b/net/tap.c
index 51f7aec..8deabcb 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -774,7 +774,8 @@ int net_init_tap(const Netdev *netdev, const char *name,
      * For -netdev, peer is always NULL. */
     if (peer && (tap->has_queues || tap->fds || tap->vhostfds)) {
         error_setg(errp, "Multiqueue tap cannot be used with hubs");
-        return -1;
+        ret = -1;
+        goto out;
     }
 
     if (tap->fd) {
@@ -784,25 +785,29 @@ int net_init_tap(const Netdev *netdev, const char *name,
             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
                        "helper=, queues=, fds=, and vhostfds= "
                        "are invalid with fd=");
-            return -1;
+            ret = -1;
+            goto out;
         }
 
         fd = monitor_fd_param(monitor_cur(), tap->fd, errp);
         if (fd == -1) {
-            return -1;
+            ret = -1;
+            goto out;
         }
 
         if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
             error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
                              name, fd);
             close(fd);
-            return -1;
+            ret = -1;
+            goto out;
         }
 
         vnet_hdr = tap_probe_vnet_hdr(fd, errp);
         if (vnet_hdr < 0) {
             close(fd);
-            return -1;
+            ret = -1;
+            goto out;
         }
 
         net_init_tap_one(tap, peer, "tap", name, NULL,
@@ -811,7 +816,8 @@ int net_init_tap(const Netdev *netdev, const char *name,
         if (err) {
             error_propagate(errp, err);
             close(fd);
-            return -1;
+            ret = -1;
+            goto out;
         }
     } else if (tap->fds) {
         char **fds;
@@ -824,7 +830,8 @@ int net_init_tap(const Netdev *netdev, const char *name,
             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
                        "helper=, queues=, and vhostfd= "
                        "are invalid with fds=");
-            return -1;
+            ret = -1;
+            goto out;
         }
 
         fds = g_new0(char *, MAX_TAP_QUEUES);
@@ -888,30 +895,35 @@ free_fail:
         }
         g_free(fds);
         g_free(vhost_fds);
-        return ret;
+        goto out;
+
     } else if (tap->helper) {
         if (tap->ifname || tap->script || tap->downscript ||
             tap->has_vnet_hdr || tap->has_queues || tap->vhostfds) {
             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
                        "queues=, and vhostfds= are invalid with helper=");
-            return -1;
+            ret = -1;
+            goto out;
         }
 
         fd = net_bridge_run_helper(tap->helper,
                                    tap->br ?: DEFAULT_BRIDGE_INTERFACE,
                                    errp);
         if (fd == -1) {
-            return -1;
+            ret = -1;
+            goto out;
         }
 
         if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
             error_setg_errno(errp, errno, "Failed to set FD nonblocking");
-            return -1;
+            ret = -1;
+            goto out;
         }
         vnet_hdr = tap_probe_vnet_hdr(fd, errp);
         if (vnet_hdr < 0) {
             close(fd);
-            return -1;
+            ret = -1;
+            goto out;
         }
 
         net_init_tap_one(tap, peer, "bridge", name, ifname,
@@ -920,14 +932,16 @@ free_fail:
         if (err) {
             error_propagate(errp, err);
             close(fd);
-            return -1;
+            ret = -1;
+            goto out;
         }
     } else {
         g_autofree char *default_script = NULL;
         g_autofree char *default_downscript = NULL;
         if (tap->vhostfds) {
             error_setg(errp, "vhostfds= is invalid if fds= wasn't specified");
-            return -1;
+            ret = -1;
+            goto out;
         }
 
         if (!script) {
@@ -948,14 +962,16 @@ free_fail:
             fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
                               ifname, sizeof ifname, queues > 1, errp);
             if (fd == -1) {
-                return -1;
+                ret = -1;
+                goto out;
             }
 
             if (queues > 1 && i == 0 && !tap->ifname) {
                 if (tap_fd_get_ifname(fd, ifname)) {
                     error_setg(errp, "Fail to get ifname");
                     close(fd);
-                    return -1;
+                    ret = -1;
+                    goto out;
                 }
             }
 
@@ -966,12 +982,14 @@ free_fail:
             if (err) {
                 error_propagate(errp, err);
                 close(fd);
-                return -1;
+                ret = -1;
+                goto out;
             }
         }
     }
 
-    return 0;
+out:
+    return ret;
 }
 
 VHostNetState *tap_get_vhost_net(NetClientState *nc)
-- 
1.8.3.1