netdev: Correctly maintain netdev refcounts even if errors occur.

If an error occured while opening a netdev it would decrement the
refcount, even though it was never incremented.  Depending on
the timing this could result in either an error message or an
assertion failure.  This workaround simply always increments
the refcount before openning a device.  A more complete fix
already exists in the netdev overhaul in the 'next' branch.

NIC-59

diff --git a/lib/netdev.c b/lib/netdev.c
index 804050f..f1eb29b 100644 (file)
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -235,6 +235,7 @@ netdev_open(const char *name, int ethertype, struct netdev **netdevp)
 
     netdev_obj = shash_find_data(&netdev_obj_shash, name);
     if (netdev_obj) {
+        netdev_obj->ref_cnt++;
         error = netdev_obj->netdev_class->open(name, ethertype, &netdev);
     } else {
         /* Default to "system". */
@@ -249,16 +250,14 @@ netdev_open(const char *name, int ethertype, struct netdev **netdevp)
                  * closes its handle. */
                 error = class->create(name, "system", &empty_args, false);
                 if (!error) {
-                    error = class->open(name, ethertype, &netdev);
                     netdev_obj = shash_find_data(&netdev_obj_shash, name);
+                    netdev_obj->ref_cnt++;
+                    error = class->open(name, ethertype, &netdev);
                 }
                 break;
             }
         }
     }
-    if (!error) {
-        netdev_obj->ref_cnt++;
-    }
 
     *netdevp = error ? NULL : netdev;
     return error;