[PATCH V1 10/26] migration: vmstate_unregister_named

[Steve Sistare]

Define an accessor to find vmstate state handler by name and id and
unregister it.  This is needed to unregister a specific instance of an
object that is not an Object, since it lacks the VMStateIf get_id hook.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 include/migration/vmstate.h |  9 +++++++++
 migration/savevm.c          | 27 +++++++++++++++++++++++++++
 migration/trace-events      |  1 +
 stubs/vmstate.c             |  6 ++++++
 4 files changed, 43 insertions(+)

diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 22aa3c6..3d71b34 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -1299,6 +1299,15 @@ static inline int vmstate_register_named(const char 
*instance_name,
 void vmstate_unregister(VMStateIf *obj, const VMStateDescription *vmsd,
                         void *opaque);
 
+/**
+ * Delete the VMSD handler for the object with name "vmsd_name/instance_name"
+ * and matching instance_id.  If instance_id is VMSTATE_INSTANCE_ID_ANY,
+ * delete all instances matching name.
+ */
+void vmstate_unregister_named(const char *vmsd_name,
+                              const char *instance_name,
+                              int instance_id);
+
 void vmstate_register_ram(struct MemoryRegion *memory, DeviceState *dev);
 void vmstate_unregister_ram(struct MemoryRegion *memory, DeviceState *dev);
 void vmstate_register_ram_global(struct MemoryRegion *memory);
diff --git a/migration/savevm.c b/migration/savevm.c
index 86b4c87..cd2eabe 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -964,6 +964,8 @@ void vmstate_unregister(VMStateIf *obj, const 
VMStateDescription *vmsd,
 
     SAVEVM_FOREACH_SAFE_ALL(se, entry, new_se) {
         if (se->vmsd == vmsd && se->opaque == opaque) {
+            trace_vmstate_unregister(se->idstr, se->instance_id, (void *)vmsd,
+                                     opaque);
             savevm_state_handler_remove(se);
             g_free(se->compat);
             g_free(se);
@@ -971,6 +973,31 @@ void vmstate_unregister(VMStateIf *obj, const 
VMStateDescription *vmsd,
     }
 }
 
+void vmstate_unregister_named(const char *vmsd_name,
+                              const char *instance_name,
+                              int instance_id)
+{
+    SaveStateEntry *se, *new_se;
+    VMStateId idstr;
+
+    snprintf(idstr, sizeof(idstr), "%s/%s", vmsd_name, instance_name);
+
+    SAVEVM_FOREACH_SAFE_ALL(se, entry, new_se) {
+        if (!strcmp(se->idstr, idstr) &&
+            (instance_id == VMSTATE_INSTANCE_ID_ANY ||
+             se->instance_id == instance_id)) {
+            trace_vmstate_unregister(idstr, se->instance_id, (void *)se->vmsd,
+                                     se->opaque);
+            savevm_state_handler_remove(se);
+            g_free(se->compat);
+            g_free(se);
+            if (instance_id != VMSTATE_INSTANCE_ID_ANY) {
+                return;
+            }
+        }
+    }
+}
+
 static int vmstate_load(QEMUFile *f, SaveStateEntry *se)
 {
     trace_vmstate_load(se->idstr, se->vmsd ? se->vmsd->name : "(old)");
diff --git a/migration/trace-events b/migration/trace-events
index 8647147..1e23238 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -54,6 +54,7 @@ postcopy_pause_incoming(void) ""
 postcopy_pause_incoming_continued(void) ""
 postcopy_page_req_sync(void *host_addr) "sync page req %p"
 vmstate_register(const char *idstr, int id, void *vmsd, void *opaque) "%s, %d, 
vmsd %p, opaque %p"
+vmstate_unregister(const char *idstr, int id, void *vmsd, void *opaque) "%s, 
%d, vmsd %p, opaque %p"
 
 # vmstate.c
 vmstate_load_field_error(const char *field, int ret) "field \"%s\" load 
failed, ret = %d"
diff --git a/stubs/vmstate.c b/stubs/vmstate.c
index d67506e..eff8be4 100644
--- a/stubs/vmstate.c
+++ b/stubs/vmstate.c
@@ -18,6 +18,12 @@ void vmstate_unregister(VMStateIf *obj,
 {
 }
 
+void vmstate_unregister_named(const char *vmsd_name,
+                              const char *instance_name,
+                              int instance_id)
+{
+}
+
 bool vmstate_check_only_migratable(const VMStateDescription *vmsd)
 {
     return true;
-- 
1.8.3.1