[libvirt] [PATCH 1/2] network: only clear bandwidth if it has been set

[Laine Stump]

libvirt was unconditionally calling virNetDevBandwidthClear() for
every interface (and network bridge) of a type that supported
bandwidth, whether it actually had anything set or not. This doesn't
hurt anything (unless ifname == NULL!), but is wasteful.

This patch makes sure that all calls to virNetDevBandwidthClear() are
qualified by checking that ifname != NULL and that it really had some
bandwidth setup done.

(NB: an sa_assert(detach->ifname) was added in
lxcDomainDetachDeviceNetLive() because the preceding new check of
detach->ifname before calling virNetDevBandwidthClear() caused
Coverity to complain about a possible null dereference.)
---
 src/conf/netdev_bandwidth_conf.c | 6 ++++--
 src/lxc/lxc_driver.c             | 7 ++++++-
 src/network/bridge_driver.c      | 6 ++++--
 src/qemu/qemu_hotplug.c          | 4 +++-
 4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/conf/netdev_bandwidth_conf.c b/src/conf/netdev_bandwidth_conf.c
index c3e0f9f..42d42d6 100644
--- a/src/conf/netdev_bandwidth_conf.c
+++ b/src/conf/netdev_bandwidth_conf.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009-2014 Red Hat, Inc.
+ * Copyright (C) 2009-2015 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -285,7 +285,9 @@ virDomainClearNetBandwidth(virDomainObjPtr vm)
 
     for (i = 0; i < vm->def->nnets; i++) {
         type = virDomainNetGetActualType(vm->def->nets[i]);
-        if (virNetDevSupportBandwidth(type))
+        if (vm->def->nets[i]->ifname &&
+            virDomainNetGetActualBandwidth(vm->def->nets[i]) &&
+            virNetDevSupportBandwidth(type))
             virNetDevBandwidthClear(vm->def->nets[i]->ifname);
     }
 }
diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
index 3adb21d..87fcd98 100644
--- a/src/lxc/lxc_driver.c
+++ b/src/lxc/lxc_driver.c
@@ -4650,13 +4650,18 @@ lxcDomainDetachDeviceNetLive(virDomainObjPtr vm,
     actualType = virDomainNetGetActualType(detach);
 
     /* clear network bandwidth */
-    if (virNetDevSupportBandwidth(actualType) &&
+    if (detach->ifname &&
+        virDomainNetGetActualBandwidth(detach) &&
+        virNetDevSupportBandwidth(actualType) &&
         virNetDevBandwidthClear(detach->ifname))
         goto cleanup;
 
     switch (actualType) {
     case VIR_DOMAIN_NET_TYPE_BRIDGE:
     case VIR_DOMAIN_NET_TYPE_NETWORK:
+        /* make sure Coverity knows that detach->ifname is valid */
+        sa_assert(detach->ifname);
+
         if (virNetDevVethDelete(detach->ifname) < 0) {
             virDomainAuditNet(vm, detach, NULL, "detach", false);
             goto cleanup;
diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index f240d3b..1209609 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -2096,7 +2096,8 @@ networkStartNetworkVirtual(virNetworkObjPtr network)
     return 0;
 
  err5:
-    virNetDevBandwidthClear(network->def->bridge);
+    if (network->def->bandwidth)
+       virNetDevBandwidthClear(network->def->bridge);
 
  err4:
     if (!save_err)
@@ -2142,7 +2143,8 @@ networkStartNetworkVirtual(virNetworkObjPtr network)
 
 static int networkShutdownNetworkVirtual(virNetworkObjPtr network)
 {
-    virNetDevBandwidthClear(network->def->bridge);
+    if (network->def->bandwidth)
+        virNetDevBandwidthClear(network->def->bridge);
 
     if (network->radvdPid > 0) {
         char *radvdpidbase;
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 8691c7e..9518abd 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -3750,7 +3750,9 @@ qemuDomainDetachNetDevice(virQEMUDriverPtr driver,
             goto cleanup;
     }
 
-    if (virNetDevSupportBandwidth(virDomainNetGetActualType(detach)) &&
+    if (detach->ifname &&
+        virDomainNetGetActualBandwidth(detach) &&
+        virNetDevSupportBandwidth(virDomainNetGetActualType(detach)) &&
         virNetDevBandwidthClear(detach->ifname) < 0)
         VIR_WARN("cannot clear bandwidth setting for device : %s",
                  detach->ifname);
-- 
2.1.0