[Qemu-devel] [RFC 5/6] migration: store listen task tag

[Peter Xu <peterx@redhat.com>]

Store the task tag for migration types: tcp/unix/fd/exec in current
MigrationIncomingState struct.

For defered migration, no need to store task tag since there is no task
running in the main loop at all. For RDMA, let's mark it as todo.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/migration.c | 22 ++++++++++++++++++----
 migration/migration.h |  2 ++
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index c9b7085..daf356b 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -171,6 +171,7 @@ void migration_incoming_state_destroy(void)
         mis->from_src_file = NULL;
     }
 
+    mis->listen_task_tag = 0;
     qemu_event_destroy(&mis->main_thread_load_event);
 }
 
@@ -265,25 +266,31 @@ int migrate_send_rp_req_pages(MigrationIncomingState *mis, const char *rbname,
 void qemu_start_incoming_migration(const char *uri, Error **errp)
 {
     const char *p;
+    guint task_tag = 0;
+    MigrationIncomingState *mis = migration_incoming_get_current();
 
     qapi_event_send_migration(MIGRATION_STATUS_SETUP, &error_abort);
     if (!strcmp(uri, "defer")) {
         deferred_incoming_migration(errp);
     } else if (strstart(uri, "tcp:", &p)) {
-        tcp_start_incoming_migration(p, errp);
+        task_tag = tcp_start_incoming_migration(p, errp);
 #ifdef CONFIG_RDMA
     } else if (strstart(uri, "rdma:", &p)) {
+        /* TODO: store task tag for RDMA migrations */
         rdma_start_incoming_migration(p, errp);
 #endif
     } else if (strstart(uri, "exec:", &p)) {
-        exec_start_incoming_migration(p, errp);
+        task_tag = exec_start_incoming_migration(p, errp);
     } else if (strstart(uri, "unix:", &p)) {
-        unix_start_incoming_migration(p, errp);
+        task_tag = unix_start_incoming_migration(p, errp);
     } else if (strstart(uri, "fd:", &p)) {
-        fd_start_incoming_migration(p, errp);
+        task_tag = fd_start_incoming_migration(p, errp);
     } else {
         error_setg(errp, "unknown migration protocol: %s", uri);
+        return;
     }
+
+    mis->listen_task_tag = task_tag;
 }
 
 static void process_incoming_migration_bh(void *opaque)
@@ -422,6 +429,13 @@ void migration_fd_process_incoming(QEMUFile *f)
         co = qemu_coroutine_create(process_incoming_migration_co, f);
         qemu_coroutine_enter(co);
     }
+
+    /*
+     * When reach here, we should not need the listening port any
+     * more. We'll detach the listening task soon, let's reset the
+     * listen task tag.
+     */
+    mis->listen_task_tag = 0;
 }
 
 /*
diff --git a/migration/migration.h b/migration/migration.h
index d041369..1f4faef 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -26,6 +26,8 @@
 /* State for the incoming migration */
 struct MigrationIncomingState {
     QEMUFile *from_src_file;
+    /* Task tag for incoming listen port. Valid when >0. */
+    guint listen_task_tag;
 
     /*
      * Free at the start of the main state load, set as the main thread finishes
-- 
2.7.4