From: Juan Quintela <quintela@redhat.com>

RDMA was having trouble because
migrate_multifd_flush_after_each_section() can only be true or false,
but we don't want to send any flush when we are not in multifd
migration.

CC: Fabiano Rosas <farosas@suse.de
Fixes: 294e5a4034e81 ("multifd: Only flush once each full round of memory")

Reported-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011205548.10571-2-quintela@redhat.com>
(cherry picked from commit d4f34485ca8a077c98fc2303451e9bece9200dd7)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/migration/ram.c b/migration/ram.c
index 9040d66e61..6e1514f69f 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1399,7 +1399,8 @@ static int find_dirty_block(RAMState *rs, PageSearchStatus *pss)
         pss->page = 0;
         pss->block = QLIST_NEXT_RCU(pss->block, next);
         if (!pss->block) {
-            if (!migrate_multifd_flush_after_each_section()) {
+            if (migrate_multifd() &&
+                !migrate_multifd_flush_after_each_section()) {
                 QEMUFile *f = rs->pss[RAM_CHANNEL_PRECOPY].pss_channel;
                 int ret = multifd_send_sync_main(f);
                 if (ret < 0) {
@@ -3076,7 +3077,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
         return ret;
     }
 
-    if (!migrate_multifd_flush_after_each_section()) {
+    if (migrate_multifd() && !migrate_multifd_flush_after_each_section()) {
         qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH);
     }
 
@@ -3188,7 +3189,7 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
 out:
     if (ret >= 0
         && migration_is_setup_or_active(migrate_get_current()->state)) {
-        if (migrate_multifd_flush_after_each_section()) {
+        if (migrate_multifd() && migrate_multifd_flush_after_each_section()) {
             ret = multifd_send_sync_main(rs->pss[RAM_CHANNEL_PRECOPY].pss_channel);
             if (ret < 0) {
                 return ret;
@@ -3265,7 +3266,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
         return ret;
     }
 
-    if (!migrate_multifd_flush_after_each_section()) {
+    if (migrate_multifd() && !migrate_multifd_flush_after_each_section()) {
         qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH);
     }
     qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
@@ -3774,7 +3775,8 @@ int ram_load_postcopy(QEMUFile *f, int channel)
             break;
         case RAM_SAVE_FLAG_EOS:
             /* normal exit */
-            if (migrate_multifd_flush_after_each_section()) {
+            if (migrate_multifd() &&
+                migrate_multifd_flush_after_each_section()) {
                 multifd_recv_sync_main();
             }
             break;
@@ -4052,7 +4054,8 @@ static int ram_load_precopy(QEMUFile *f)
             break;
         case RAM_SAVE_FLAG_EOS:
             /* normal exit */
-            if (migrate_multifd_flush_after_each_section()) {
+            if (migrate_multifd() &&
+                migrate_multifd_flush_after_each_section()) {
                 multifd_recv_sync_main();
             }
             break;
-- 
2.39.2