migration: Cleanup postcopy_preempt_setup()

Since we just dropped the only case where postcopy_preempt_setup() can
return an error, it doesn't need a retval anymore because it never fails.
Move the preempt check to the caller, preparing it to be used elsewhere to
do nothing but as simple as kicking the async connection.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

3 files changed, 4 insertions, 14 deletions

diff --git a/migration/migration.c b/migration/migration.c
index f242d657e8..fb0ecf5649 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -4347,12 +4347,8 @@ void migrate_fd_connect(MigrationState *s, Error *error_in)
     }
 
     /* This needs to be done before resuming a postcopy */
-    if (postcopy_preempt_setup(s, &local_err)) {
-        error_report_err(local_err);
-        migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
-                          MIGRATION_STATUS_FAILED);
-        migrate_fd_cleanup(s);
-        return;
+    if (migrate_postcopy_preempt()) {
+        postcopy_preempt_setup(s);
     }
 
     if (resume) {
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 9a9d0ecf49..de6d4a3fd4 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -1629,16 +1629,10 @@ int postcopy_preempt_wait_channel(MigrationState *s)
     return s->postcopy_qemufile_src ? 0 : -1;
 }
 
-int postcopy_preempt_setup(MigrationState *s, Error **errp)
+void postcopy_preempt_setup(MigrationState *s)
 {
-    if (!migrate_postcopy_preempt()) {
-        return 0;
-    }
-
     /* Kick an async task to connect */
     socket_send_channel_create(postcopy_preempt_send_channel_new, s);
-
-    return 0;
 }
 
 static void postcopy_pause_ram_fast_load(MigrationIncomingState *mis)
diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h
index 25881c4127..d5604cbcf1 100644
--- a/migration/postcopy-ram.h
+++ b/migration/postcopy-ram.h
@@ -191,7 +191,7 @@ enum PostcopyChannels {
 };
 
 void postcopy_preempt_new_channel(MigrationIncomingState *mis, QEMUFile *file);
-int postcopy_preempt_setup(MigrationState *s, Error **errp);
+void postcopy_preempt_setup(MigrationState *s);
 int postcopy_preempt_wait_channel(MigrationState *s);
 
 #endif