[Qemu-devel] [RFC PATCH v2 1/4] migration: Introduce unregister_savevm_live()

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

Introduce a new function unregister_savevm_live() to unregister the vmstate
handlers registered via register_savevm_live().

register_savevm() allocates SaveVMHandlers while register_savevm_live()
gets passed with SaveVMHandlers. During unregistration, we  want to
free SaveVMHandlers in the former case but not free in the latter case.
Hence this new API is needed to differentiate this.

This new API will be needed by PowerPC to unregister the HTAB savevm
handlers.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 include/migration/vmstate.h |  1 +
 migration/savevm.c          | 17 +++++++++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 8489659..02a1bac 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -79,6 +79,7 @@ int register_savevm_live(DeviceState *dev,
                          void *opaque);
 
 void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque);
+void unregister_savevm_live(DeviceState *dev, const char *idstr, void *opaque);
 
 typedef struct VMStateInfo VMStateInfo;
 typedef struct VMStateDescription VMStateDescription;
diff --git a/migration/savevm.c b/migration/savevm.c
index f5e8194..4ef6fdc 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -630,7 +630,8 @@ int register_savevm(DeviceState *dev,
                                 ops, opaque);
 }
 
-void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
+static void unregister_savevm_common(DeviceState *dev, const char *idstr,
+                                     void *opaque, bool free_savevmhandlers)
 {
     SaveStateEntry *se, *new_se;
     char id[256] = "";
@@ -649,12 +650,24 @@ void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
         if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
             QTAILQ_REMOVE(&savevm_state.handlers, se, entry);
             g_free(se->compat);
-            g_free(se->ops);
+            if (free_savevmhandlers) {
+                g_free(se->ops);
+            }
             g_free(se);
         }
     }
 }
 
+void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
+{
+    unregister_savevm_common(dev, idstr, opaque, true);
+}
+
+void unregister_savevm_live(DeviceState *dev, const char *idstr, void *opaque)
+{
+    unregister_savevm_common(dev, idstr, opaque, false);
+}
+
 int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
                                    const VMStateDescription *vmsd,
                                    void *opaque, int alias_id,
-- 
2.7.4