[PATCH v4 09/33] migration: postcopy_ram_listen_thread() needs to take BQL for some calls

[Maciej S. Szmigiero]

From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com>

postcopy_ram_listen_thread() is a free running thread, so it needs to
take BQL around function calls to migration methods requiring BQL.

qemu_loadvm_state_main() needs BQL held since it ultimately calls
"load_state" SaveVMHandlers.

migration_incoming_state_destroy() needs BQL held since it ultimately calls
"load_cleanup" SaveVMHandlers.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com>
---
 migration/savevm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/migration/savevm.c b/migration/savevm.c
index b0b74140daea..0ceea9638cc1 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2013,7 +2013,9 @@ static void *postcopy_ram_listen_thread(void *opaque)
      * in qemu_file, and thus we must be blocking now.
      */
     qemu_file_set_blocking(f, true);
+    bql_lock();
     load_res = qemu_loadvm_state_main(f, mis);
+    bql_unlock();
 
     /*
      * This is tricky, but, mis->from_src_file can change after it
@@ -2073,7 +2075,9 @@ static void *postcopy_ram_listen_thread(void *opaque)
      * (If something broke then qemu will have to exit anyway since it's
      * got a bad migration state).
      */
+    bql_lock();
     migration_incoming_state_destroy();
+    bql_unlock();
 
     rcu_unregister_thread();
     mis->have_listen_thread = false;