[PATCH 15/16] migration: Merge precopy/postcopy on switchover start

[Peter Xu <peterx@redhat.com>]

Now after all the cleanups, finally we can merge the switchover startup
phase into one single function for precopy/postcopy.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/migration.c | 62 ++++++++++++++++++++++---------------------
 1 file changed, 32 insertions(+), 30 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 2a95081b6c..f6694e7e94 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -102,7 +102,7 @@ static MigrationIncomingState *current_incoming;
 static GSList *migration_blockers[MIG_MODE__MAX];
 
 static bool migration_object_check(MigrationState *ms, Error **errp);
-static bool migration_switchover_start(MigrationState *s);
+static bool migration_switchover_start(MigrationState *s, Error **errp);
 static void migrate_fd_cancel(MigrationState *s);
 static bool close_return_path_on_source(MigrationState *s);
 static void migration_completion_end(MigrationState *s);
@@ -2540,21 +2540,10 @@ static int postcopy_start(MigrationState *ms, Error **errp)
         goto fail;
     }
 
-    if (!migration_switchover_start(ms)) {
-        error_setg(errp, "migration_switchover_start() failed");
+    if (!migration_switchover_start(ms, errp)) {
         goto fail;
     }
 
-    if (!migration_block_inactivate()) {
-        error_setg(errp, "%s: Failed in bdrv_inactivate_all()", __func__);
-        goto fail;
-    }
-
-    /* Switchover phase, switch to unlimited */
-    migration_rate_set(RATE_LIMIT_DISABLED);
-
-    precopy_notify_complete();
-
     /*
      * Cause any non-postcopiable, but iterative devices to
      * send out their final data.
@@ -2686,7 +2675,7 @@ fail:
 }
 
 /**
- * @migration_switchover_start: Start VM switchover procedure
+ * @migration_switchover_prepare: Start VM switchover procedure
  *
  * @s: The migration state object pointer
  *
@@ -2701,7 +2690,7 @@ fail:
  *
  * Returns: true on success, false on interruptions.
  */
-static bool migration_switchover_start(MigrationState *s)
+static bool migration_switchover_prepare(MigrationState *s)
 {
     /* Concurrent cancellation?  Quit */
     if (s->state == MIGRATION_STATUS_CANCELLING) {
@@ -2749,21 +2738,13 @@ static bool migration_switchover_start(MigrationState *s)
     return s->state == MIGRATION_STATUS_DEVICE;
 }
 
-static int migration_completion_precopy(MigrationState *s)
+static bool migration_switchover_start(MigrationState *s, Error **errp)
 {
-    int ret;
-
-    bql_lock();
-
-    if (!migrate_mode_is_cpr(s)) {
-        ret = migration_stop_vm(s, RUN_STATE_FINISH_MIGRATE);
-        if (ret < 0) {
-            goto out_unlock;
-        }
-    }
+    ERRP_GUARD();
 
-    if (!migration_switchover_start(s)) {
-        goto out_unlock;
+    if (!migration_switchover_prepare(s)) {
+        error_setg(errp, "Switchover is interrupted");
+        return false;
     }
 
     /* Inactivate disks except in COLO */
@@ -2773,8 +2754,8 @@ static int migration_completion_precopy(MigrationState *s)
          * bdrv_activate_all() on the other end won't fail.
          */
         if (!migration_block_inactivate()) {
-            ret = -EFAULT;
-            goto out_unlock;
+            error_setg(errp, "Block inactivate failed during switchover");
+            return false;
         }
     }
 
@@ -2782,6 +2763,27 @@ static int migration_completion_precopy(MigrationState *s)
 
     precopy_notify_complete();
 
+    return true;
+}
+
+static int migration_completion_precopy(MigrationState *s)
+{
+    int ret;
+
+    bql_lock();
+
+    if (!migrate_mode_is_cpr(s)) {
+        ret = migration_stop_vm(s, RUN_STATE_FINISH_MIGRATE);
+        if (ret < 0) {
+            goto out_unlock;
+        }
+    }
+
+    if (!migration_switchover_start(s, NULL)) {
+        ret = -EFAULT;
+        goto out_unlock;
+    }
+
     ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false);
 out_unlock:
     bql_unlock();
-- 
2.47.0