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, 1 insertions, 1 deletions

diff --git a/migration/migration.c b/migration/migration.c
index 1ca6be2323..8fb68795dc 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -3341,7 +3341,7 @@ static void *migration_thread(void *opaque)
 
     qemu_savevm_state_setup(s->to_dst_file);
 
-    if (qemu_savevm_nr_failover_devices()) {
+    if (qemu_savevm_state_guest_unplug_pending()) {
         migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
                           MIGRATION_STATUS_WAIT_UNPLUG);