Follow common recommendations to avoid error propagation.

Probably, it would also be good to use bool as a return type
(switching to true/false as success/failure instead of 0/-1). But
seems almost all functions (including a lot of them with errp
argument) have 0/-1 semantics in net/, so making exclusions doesn't
seem good. If we want such a switch, we should update the whole
net/ directory.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Tested-by: Lei Yang <leiyang@redhat.com>
---
 net/tap-linux.c | 5 ++++-
 net/tap.c       | 4 +---
 net/tap_int.h   | 2 +-
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/net/tap-linux.c b/net/tap-linux.c
index 786f339c13..ce09d2816b 100644
--- a/net/tap-linux.c
+++ b/net/tap-linux.c
@@ -146,7 +146,7 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
  */
 #define TAP_DEFAULT_SNDBUF 0
 
-void tap_set_sndbuf(int fd, const NetdevTapOptions *tap, Error **errp)
+int tap_set_sndbuf(int fd, const NetdevTapOptions *tap, Error **errp)
 {
     int sndbuf;
 
@@ -160,7 +160,10 @@ void tap_set_sndbuf(int fd, const NetdevTapOptions *tap, Error **errp)
 
     if (ioctl(fd, TUNSETSNDBUF, &sndbuf) == -1 && tap->has_sndbuf) {
         error_setg_errno(errp, errno, "TUNSETSNDBUF ioctl failed");
+        return -1;
     }
+
+    return 0;
 }
 
 int tap_probe_vnet_hdr(int fd, Error **errp)
diff --git a/net/tap.c b/net/tap.c
index 89feb01756..9793c7ab40 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -689,9 +689,7 @@ static int net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
     TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
     int vhostfd;
 
-    tap_set_sndbuf(s->fd, tap, &err);
-    if (err) {
-        error_propagate(errp, err);
+    if (tap_set_sndbuf(s->fd, tap, errp) < 0) {
         goto failed;
     }
 
diff --git a/net/tap_int.h b/net/tap_int.h
index 8857ff299d..d21acf8486 100644
--- a/net/tap_int.h
+++ b/net/tap_int.h
@@ -33,7 +33,7 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
 
 ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen);
 
-void tap_set_sndbuf(int fd, const NetdevTapOptions *tap, Error **errp);
+int tap_set_sndbuf(int fd, const NetdevTapOptions *tap, Error **errp);
 int tap_probe_vnet_hdr(int fd, Error **errp);
 int tap_probe_has_ufo(int fd);
 int tap_probe_has_uso(int fd);
-- 
2.48.1