migration: unify incoming processing

This is the 2nd patch to unbreak postcopy recovery.

Let's unify the migration_incoming_process() call at a single place
rather than calling it in connection setup codes.  This fixes a problem
that we will go into incoming migration procedure even if we are trying
to recovery from a paused postcopy migration.

Fixes: 36c2f8be2c ("migration: Delay start of migration main routines")
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180627132246.5576-5-peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 16 insertions, 2 deletions

diff --git a/migration/migration.c b/migration/migration.c
index eb3e09e899..0404c53215 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -511,17 +511,31 @@ void migration_fd_process_incoming(QEMUFile *f)
 void migration_ioc_process_incoming(QIOChannel *ioc)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
+    bool start_migration;
 
     if (!mis->from_src_file) {
+        /* The first connection (multifd may have multiple) */
         QEMUFile *f = qemu_fopen_channel_input(ioc);
+
+        /* If it's a recovery, we're done */
         if (postcopy_try_recover(f)) {
             return;
         }
+
         migration_incoming_setup(f);
-        return;
+
+        /*
+         * Common migration only needs one channel, so we can start
+         * right now.  Multifd needs more than one channel, we wait.
+         */
+        start_migration = !migrate_use_multifd();
+    } else {
+        /* Multiple connections */
+        assert(migrate_use_multifd());
+        start_migration = multifd_recv_new_channel(ioc);
     }
 
-    if (multifd_recv_new_channel(ioc)) {
+    if (start_migration) {
         migration_incoming_process();
     }
 }