hostmem: use host_memory_backend_mr_inited() where proper

Use the new interface to boost readability.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1489151370-15453-3-git-send-email-peterx@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
diff --git a/backends/hostmem.c b/backends/hostmem.c
index d8faab4..4606b73 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -45,7 +45,7 @@
     Error *local_err = NULL;
     uint64_t value;
 
-    if (memory_region_size(&backend->mr)) {
+    if (host_memory_backend_mr_inited(backend)) {
         error_setg(&local_err, "cannot change property value");
         goto out;
     }
@@ -146,7 +146,7 @@
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 
-    if (!memory_region_size(&backend->mr)) {
+    if (!host_memory_backend_mr_inited(backend)) {
         backend->merge = value;
         return;
     }
@@ -172,7 +172,7 @@
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 
-    if (!memory_region_size(&backend->mr)) {
+    if (!host_memory_backend_mr_inited(backend)) {
         backend->dump = value;
         return;
     }
@@ -208,7 +208,7 @@
         }
     }
 
-    if (!memory_region_size(&backend->mr)) {
+    if (!host_memory_backend_mr_inited(backend)) {
         backend->prealloc = value;
         return;
     }
@@ -249,7 +249,7 @@
 MemoryRegion *
 host_memory_backend_get_memory(HostMemoryBackend *backend, Error **errp)
 {
-    return memory_region_size(&backend->mr) ? &backend->mr : NULL;
+    return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
 }
 
 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)