network/network: use hash_ops with destructor for managing stacked netdevs

Author: yuwata

src/network/networkd-network.c

@@ -44,6 +44,11 @@
 #include "strv.h"
 #include "tclass.h"
 
+DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
+                stacked_netdevs_hash_ops,
+                char, string_hash_func, string_compare_func,
+                NetDev, netdev_unref);
+
 static int network_resolve_netdev_one(Network *network, const char *name, NetDevKind kind, NetDev **ret) {
         const char *kind_string;
         NetDev *netdev;
@@ -105,14 +110,14 @@ static int network_resolve_stacked_netdevs(Network *network) {
                 if (network_resolve_netdev_one(network, name, PTR_TO_INT(kind), &netdev) <= 0)
                         continue;
 
-                r = hashmap_ensure_put(&network->stacked_netdevs, &string_hash_ops, netdev->ifname, netdev);
+                r = hashmap_ensure_put(&network->stacked_netdevs, &stacked_netdevs_hash_ops, netdev->ifname, netdev);
                 if (r == -ENOMEM)
                         return log_oom();
                 if (r < 0)
                         log_warning_errno(r, "%s: Failed to add NetDev '%s' to network, ignoring: %m",
                                           network->filename, (const char *) name);
 
-                netdev = NULL;
+                TAKE_PTR(netdev);
         }
 
         return 0;
@@ -825,7 +830,7 @@ static Network *network_free(Network *network) {
         netdev_unref(network->bridge);
         netdev_unref(network->bond);
         netdev_unref(network->vrf);
-        hashmap_free_with_destructor(network->stacked_netdevs, netdev_unref);
+        hashmap_free(network->stacked_netdevs);
 
         /* static configs */
         set_free_free(network->ipv6_proxy_ndp_addresses);