To avoid error propagation, let's follow common recommendations
in include/qapi/error.h and use return boolean value together with
errp.

Why do we prefer errp-based functions with return value?
In short with additional return value we get:

- less code to handle error
- don't create and set Error object when it's not required
  (when passed errp=NULL)

More details in commit message of e3fe3988d7851cac3
"error: Document Error API usage rules"

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 net/tap.c | 43 +++++++++++++++++--------------------------
 1 file changed, 17 insertions(+), 26 deletions(-)

diff --git a/net/tap.c b/net/tap.c
index f7df702f97..e023c5f67f 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -680,7 +680,7 @@ static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
 
 #define MAX_TAP_QUEUES 1024
 
-static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
+static bool net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
                              const char *model, const char *name,
                              const char *ifname, const char *script,
                              const char *downscript, const char *vhostfdname,
@@ -765,10 +765,11 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
         goto failed;
     }
 
-    return;
+    return true;
 
 failed:
     qemu_del_net_client(&s->nc);
+    return false;
 }
 
 static int get_fds(char *str, char *fds[], int max)
@@ -805,7 +806,6 @@ int net_init_tap(const Netdev *netdev, const char *name,
     /* for the no-fd, no-helper case */
     const char *script;
     const char *downscript;
-    Error *err = NULL;
     const char *vhostfdname;
     char ifname[128];
     int ret = 0;
@@ -852,12 +852,9 @@ int net_init_tap(const Netdev *netdev, const char *name,
             return -1;
         }
 
-        net_init_tap_one(tap, peer, "tap", name, NULL,
-                         script, downscript,
-                         vhostfdname, vnet_hdr, fd, &err);
-        if (err) {
-            error_propagate(errp, err);
-            close(fd);
+        if (!net_init_tap_one(tap, peer, "tap", name, NULL,
+                              script, downscript,
+                              vhostfdname, vnet_hdr, fd, errp)) {
             return -1;
         }
     } else if (tap->fds) {
@@ -915,12 +912,10 @@ int net_init_tap(const Netdev *netdev, const char *name,
                 goto free_fail;
             }
 
-            net_init_tap_one(tap, peer, "tap", name, ifname,
-                             script, downscript,
-                             tap->vhostfds ? vhost_fds[i] : NULL,
-                             vnet_hdr, fd, &err);
-            if (err) {
-                error_propagate(errp, err);
+            if (!net_init_tap_one(tap, peer, "tap", name, ifname,
+                                  script, downscript,
+                                  tap->vhostfds ? vhost_fds[i] : NULL,
+                                  vnet_hdr, fd, errp)) {
                 ret = -1;
                 goto free_fail;
             }
@@ -961,11 +956,9 @@ free_fail:
             return -1;
         }
 
-        net_init_tap_one(tap, peer, "bridge", name, ifname,
-                         script, downscript, vhostfdname,
-                         vnet_hdr, fd, &err);
-        if (err) {
-            error_propagate(errp, err);
+        if (!net_init_tap_one(tap, peer, "bridge", name, ifname,
+                              script, downscript, vhostfdname,
+                              vnet_hdr, fd, errp)) {
             close(fd);
             return -1;
         }
@@ -1006,12 +999,10 @@ free_fail:
                 }
             }
 
-            net_init_tap_one(tap, peer, "tap", name, ifname,
-                             i >= 1 ? "no" : script,
-                             i >= 1 ? "no" : downscript,
-                             vhostfdname, vnet_hdr, fd, &err);
-            if (err) {
-                error_propagate(errp, err);
+            if (!net_init_tap_one(tap, peer, "tap", name, ifname,
+                                  i >= 1 ? "no" : script,
+                                  i >= 1 ? "no" : downscript,
+                                  vhostfdname, vnet_hdr, fd, errp)) {
                 close(fd);
                 return -1;
             }
-- 
2.48.1