Rename virCgroupMounted to virCgroupHasController & make it more robust

The virCgroupMounted method is badly named, since a controller can be
mounted, but disabled in the current object. Rename the method to be
virCgroupHasController. Also make it tolerant to a  NULL virCgroupPtr
and out-of-range controller index, to avoid duplication of these
checks in all callers

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

src/libvirt_private.syms

@@ -1117,10 +1117,10 @@ virCgroupGetMemorySoftLimit;
 virCgroupGetMemoryUsage;
 virCgroupGetMemSwapHardLimit;
 virCgroupGetMemSwapUsage;
+virCgroupHasController;
 virCgroupKill;
 virCgroupKillPainfully;
 virCgroupKillRecursive;
-virCgroupMounted;
 virCgroupMoveTask;
 virCgroupPathOfController;
 virCgroupRemove;

src/lxc/lxc_driver.c

@@ -1642,17 +1642,7 @@ cleanup:
 static bool lxcCgroupControllerActive(virLXCDriverPtr driver,
                                       int controller)
 {
-    if (driver->cgroup == NULL)
-        return false;
-    if (controller < 0 || controller >= VIR_CGROUP_CONTROLLER_LAST)
-        return false;
-    if (!virCgroupMounted(driver->cgroup, controller))
-        return false;
-#if 0
-    if (driver->cgroupControllers & (1 << controller))
-        return true;
-#endif
-    return true;
+    return virCgroupHasController(driver->cgroup, controller);
 }
 
 

src/lxc/lxc_process.c

@@ -1053,20 +1053,20 @@ int virLXCProcessStart(virConnectPtr conn,
         return -1;
     }
 
-    if (!virCgroupMounted(lxc_driver->cgroup,
+    if (!virCgroupHasController(lxc_driver->cgroup,
                           VIR_CGROUP_CONTROLLER_CPUACCT)) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("Unable to find 'cpuacct' cgroups controller mount"));
         return -1;
     }
-    if (!virCgroupMounted(lxc_driver->cgroup,
-                          VIR_CGROUP_CONTROLLER_DEVICES)) {
+    if (!virCgroupHasController(lxc_driver->cgroup,
+                                VIR_CGROUP_CONTROLLER_DEVICES)) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("Unable to find 'devices' cgroups controller mount"));
         return -1;
     }
-    if (!virCgroupMounted(lxc_driver->cgroup,
-                          VIR_CGROUP_CONTROLLER_MEMORY)) {
+    if (!virCgroupHasController(lxc_driver->cgroup,
+                                VIR_CGROUP_CONTROLLER_MEMORY)) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("Unable to find 'memory' cgroups controller mount"));
         return -1;

src/qemu/qemu_cgroup.c

@@ -48,19 +48,7 @@ static const char *const defaultDeviceACL[] = {
 bool qemuCgroupControllerActive(virQEMUDriverPtr driver,
                                 int controller)
 {
-    virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
-    bool ret = false;
-
-    if (driver->cgroup == NULL)
-        goto cleanup;
-    if (controller < 0 || controller >= VIR_CGROUP_CONTROLLER_LAST)
-        goto cleanup;
-    if (!virCgroupMounted(driver->cgroup, controller))
-        goto cleanup;
-
-cleanup:
-    virObjectUnref(cfg);
-    return ret;
+    return virCgroupHasController(driver->cgroup, controller);
 }
 
 static int

src/util/vircgroup.c

@@ -94,15 +94,20 @@ void virCgroupFree(virCgroupPtr *group)
 }
 
 /**
- * virCgroupMounted: query whether a cgroup subsystem is mounted or not
+ * virCgroupHasController: query whether a cgroup controller is present
  *
- * @cgroup: The group structure to be queried
+ * @cgroup: The group structure to be queried, or NULL
  * @controller: cgroup subsystem id
  *
- * Returns true if a cgroup is subsystem is mounted.
+ * Returns true if a cgroup controller is mounted and is associated
+ * with this cgroup object.
  */
-bool virCgroupMounted(virCgroupPtr cgroup, int controller)
+bool virCgroupHasController(virCgroupPtr cgroup, int controller)
 {
+    if (!cgroup)
+        return false;
+    if (controller < 0 || controller >= VIR_CGROUP_CONTROLLER_LAST)
+        return false;
     return cgroup->controllers[controller].mountPoint != NULL;
 }
 

src/util/vircgroup.h

@@ -161,7 +161,7 @@ int virCgroupRemoveRecursively(char *grppath);
 int virCgroupRemove(virCgroupPtr group);
 
 void virCgroupFree(virCgroupPtr *group);
-bool virCgroupMounted(virCgroupPtr cgroup, int controller);
+bool virCgroupHasController(virCgroupPtr cgroup, int controller);
 
 int virCgroupKill(virCgroupPtr group, int signum);
 int virCgroupKillRecursive(virCgroupPtr group, int signum);