migration: put the finish part into a new function

This patch only moved the last part of migration_thread() into a new
function migration_iteration_finish() to make it much shorter.  With
previous works to remove some local variables, now it's fairly easy to
do that.
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

migration/migration.c

@@ -2293,6 +2293,54 @@ static MigIterateState migration_iteration_run(MigrationState *s)
     return MIG_ITERATE_RESUME;
 }
 
+static void migration_iteration_finish(MigrationState *s)
+{
+    /* If we enabled cpu throttling for auto-converge, turn it off. */
+    cpu_throttle_stop();
+
+    qemu_mutex_lock_iothread();
+    switch (s->state) {
+    case MIGRATION_STATUS_COMPLETED:
+        migration_calculate_complete(s);
+        runstate_set(RUN_STATE_POSTMIGRATE);
+        break;
+
+    case MIGRATION_STATUS_ACTIVE:
+        /*
+         * We should really assert here, but since it's during
+         * migration, let's try to reduce the usage of assertions.
+         */
+        if (!migrate_colo_enabled()) {
+            error_report("%s: critical error: calling COLO code without "
+                         "COLO enabled", __func__);
+        }
+        migrate_start_colo_process(s);
+        /*
+         * Fixme: we will run VM in COLO no matter its old running state.
+         * After exited COLO, we will keep running.
+         */
+        s->vm_was_running = true;
+        /* Fallthrough */
+    case MIGRATION_STATUS_FAILED:
+    case MIGRATION_STATUS_CANCELLED:
+        if (s->vm_was_running) {
+            vm_start();
+        } else {
+            if (runstate_check(RUN_STATE_FINISH_MIGRATE)) {
+                runstate_set(RUN_STATE_POSTMIGRATE);
+            }
+        }
+        break;
+
+    default:
+        /* Should not reach here, but if so, forgive the VM. */
+        error_report("%s: Unknown ending state %d", __func__, s->state);
+        break;
+    }
+    qemu_bh_schedule(s->cleanup_bh);
+    qemu_mutex_unlock_iothread();
+}
+
 /*
  * Master migration thread on the source VM.
  * It drives the migration and pumps the data down the outgoing channel.
@@ -2371,51 +2419,7 @@ static void *migration_thread(void *opaque)
     }
 
     trace_migration_thread_after_loop();
-    /* If we enabled cpu throttling for auto-converge, turn it off. */
-    cpu_throttle_stop();
-
-    qemu_mutex_lock_iothread();
-    switch (s->state) {
-    case MIGRATION_STATUS_COMPLETED:
-        migration_calculate_complete(s);
-        runstate_set(RUN_STATE_POSTMIGRATE);
-        break;
-
-    case MIGRATION_STATUS_ACTIVE:
-        /*
-         * We should really assert here, but since it's during
-         * migration, let's try to reduce the usage of assertions.
-         */
-        if (!migrate_colo_enabled()) {
-            error_report("%s: critical error: calling COLO code without "
-                         "COLO enabled", __func__);
-        }
-        migrate_start_colo_process(s);
-        /*
-         * Fixme: we will run VM in COLO no matter its old running state.
-         * After exited COLO, we will keep running.
-         */
-        s->vm_was_running = true;
-        /* Fallthrough */
-    case MIGRATION_STATUS_FAILED:
-    case MIGRATION_STATUS_CANCELLED:
-        if (s->vm_was_running) {
-            vm_start();
-        } else {
-            if (runstate_check(RUN_STATE_FINISH_MIGRATE)) {
-                runstate_set(RUN_STATE_POSTMIGRATE);
-            }
-        }
-        break;
-
-    default:
-        /* Should not reach here, but if so, forgive the VM. */
-        error_report("%s: Unknown ending state %d", __func__, s->state);
-        break;
-    }
-    qemu_bh_schedule(s->cleanup_bh);
-    qemu_mutex_unlock_iothread();
-
+    migration_iteration_finish(s);
     rcu_unregister_thread();
     return NULL;
 }