domain: Add helper to determine presence of memory baloon

src/conf/domain_conf.c

@@ -24316,3 +24316,17 @@ virDomainDefCheckDuplicateDiskInfo(virDomainDefPtr def)
 
     return 0;
 }
+
+
+/**
+ * virDomainDefHasMemballoon:
+ * @def: domain definition
+ *
+ * Returns true if domain has a memory ballooning device configured.
+ */
+bool
+virDomainDefHasMemballoon(const virDomainDef *def)
+{
+    return def->memballoon &&
+           def->memballoon->model != VIR_DOMAIN_MEMBALLOON_MODEL_NONE;
+}

src/conf/domain_conf.h

@@ -3160,4 +3160,6 @@ int virDomainDefGetVcpuPinInfoHelper(virDomainDefPtr def,
                                      virBitmapPtr autoCpuset)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(4) ATTRIBUTE_RETURN_CHECK;
 
+bool virDomainDefHasMemballoon(const virDomainDef *def) ATTRIBUTE_NONNULL(1);
+
 #endif /* __DOMAIN_CONF_H */

src/libvirt_private.syms

@@ -225,6 +225,7 @@ virDomainDefGetVcpuPinInfoHelper;
 virDomainDefGetVcpus;
 virDomainDefGetVcpusMax;
 virDomainDefHasDeviceAddress;
+virDomainDefHasMemballoon;
 virDomainDefHasMemoryHotplug;
 virDomainDefHasVcpusOffline;
 virDomainDefMaybeAddController;

src/qemu/qemu_command.c

@@ -3481,8 +3481,7 @@ qemuBuildMemballoonCommandLine(virCommandPtr cmd,
         virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_S390) && def->memballoon)
         def->memballoon->model = VIR_DOMAIN_MEMBALLOON_MODEL_NONE;
 
-    if (!def->memballoon ||
-        def->memballoon->model == VIR_DOMAIN_MEMBALLOON_MODEL_NONE)
+    if (!virDomainDefHasMemballoon(def))
         return 0;
 
     if (def->memballoon->model != VIR_DOMAIN_MEMBALLOON_MODEL_VIRTIO) {

src/qemu/qemu_domain.c

@@ -4534,8 +4534,7 @@ qemuDomainUpdateCurrentMemorySize(virQEMUDriverPtr driver,
 
     /* if no balloning is available, the current size equals to the current
      * full memory size */
-    if (!vm->def->memballoon ||
-        vm->def->memballoon->model == VIR_DOMAIN_MEMBALLOON_MODEL_NONE) {
+    if (!virDomainDefHasMemballoon(vm->def)) {
         vm->def->mem.cur_balloon = virDomainDefGetMemoryActual(vm->def);
         return 0;
     }

src/qemu/qemu_driver.c

@@ -19099,8 +19099,7 @@ qemuDomainGetStatsBalloon(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
     unsigned long long cur_balloon = 0;
     int err = 0;
 
-    if (dom->def->memballoon &&
-        dom->def->memballoon->model == VIR_DOMAIN_MEMBALLOON_MODEL_NONE) {
+    if (!virDomainDefHasMemballoon(dom->def)) {
         cur_balloon = virDomainDefGetMemoryActual(dom->def);
     } else if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BALLOON_EVENT)) {
         cur_balloon = dom->def->mem.cur_balloon;

src/qemu/qemu_process.c

@@ -2003,8 +2003,7 @@ qemuProcessRefreshBalloonState(virQEMUDriverPtr driver,
 
     /* if no ballooning is available, the current size equals to the current
      * full memory size */
-    if (!vm->def->memballoon ||
-        vm->def->memballoon->model == VIR_DOMAIN_MEMBALLOON_MODEL_NONE) {
+    if (!virDomainDefHasMemballoon(vm->def)) {
         vm->def->mem.cur_balloon = virDomainDefGetMemoryActual(vm->def);
         return 0;
     }
@@ -4456,8 +4455,7 @@ qemuProcessSetupBalloon(virQEMUDriverPtr driver,
     int period;
     int ret = -1;
 
-    if (!vm->def->memballoon ||
-        vm->def->memballoon->model == VIR_DOMAIN_MEMBALLOON_MODEL_NONE)
+    if (!virDomainDefHasMemballoon(vm->def))
         return 0;
 
     period = vm->def->memballoon->period;