migration: Optimization about wait-unplug migration state

qemu_savevm_nr_failover_devices() is originally designed to
get the number of failover devices, but it actually returns
the number of "unplug-pending" failover devices now. Moreover,
what drives migration state to wait-unplug should be the number
of "unplug-pending" failover devices, not all failover devices.

We can also notice that qemu_savevm_state_guest_unplug_pending()
and qemu_savevm_nr_failover_devices() is equivalent almost (from
the code view). So the latter is incorrect semantically and
useless, just delete it.

In the qemu_savevm_state_guest_unplug_pending(), once hit a
unplug-pending failover device, then it can return true right
now to save cpu time.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Tested-by: Jens Freimann <jfreimann@redhat.com>
Reviewed-by: Jens Freimann <jfreimann@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 3 insertions, 21 deletions

diff --git a/migration/savevm.c b/migration/savevm.c
index f19cb9ec7a..1d4220ece8 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1140,36 +1140,18 @@ void qemu_savevm_state_header(QEMUFile *f)
     }
 }
 
-int qemu_savevm_nr_failover_devices(void)
+bool qemu_savevm_state_guest_unplug_pending(void)
 {
     SaveStateEntry *se;
-    int n = 0;
 
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
         if (se->vmsd && se->vmsd->dev_unplug_pending &&
             se->vmsd->dev_unplug_pending(se->opaque)) {
-            n++;
-        }
-    }
-
-    return n;
-}
-
-bool qemu_savevm_state_guest_unplug_pending(void)
-{
-    SaveStateEntry *se;
-    int n = 0;
-
-    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
-        if (!se->vmsd || !se->vmsd->dev_unplug_pending) {
-            continue;
-        }
-        if (se->vmsd->dev_unplug_pending(se->opaque)) {
-            n++;
+            return true;
         }
     }
 
-    return n > 0;
+    return false;
 }
 
 void qemu_savevm_state_setup(QEMUFile *f)