migration: Move the yank unregister of channel_close out

It's efficient, but hackish to call yank unregister calls in channel_close(),
especially it'll be hard to debug when qemu crashed with some yank function
leaked.

Remove that hack, but instead explicitly unregister yank functions at the
places where needed, they are:

  (on src)
  - migrate_fd_cleanup
  - postcopy_pause

  (on dst)
  - migration_incoming_state_destroy
  - postcopy_pause_incoming

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20210722175841.938739-6-peterx@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/migration/yank_functions.c b/migration/yank_functions.c
index 23697173ae..8c08aef14a 100644
--- a/migration/yank_functions.c
+++ b/migration/yank_functions.c
@@ -14,6 +14,7 @@
 #include "qemu/yank.h"
 #include "io/channel-socket.h"
 #include "io/channel-tls.h"
+#include "qemu-file.h"
 
 void migration_yank_iochannel(void *opaque)
 {
@@ -46,3 +47,16 @@ void migration_ioc_unregister_yank(QIOChannel *ioc)
                                  QIO_CHANNEL(ioc));
     }
 }
+
+void migration_ioc_unregister_yank_from_file(QEMUFile *file)
+{
+    QIOChannel *ioc = qemu_file_get_ioc(file);
+
+    if (ioc) {
+        /*
+         * For migration qemufiles, we'll always reach here.  Though we'll skip
+         * calls from e.g. savevm/loadvm as they don't use yank.
+         */
+        migration_ioc_unregister_yank(ioc);
+    }
+}