[Qemu-devel] [RFC v2 8/8] migration: add incoming mgmt lock

[Peter Xu <peterx@redhat.com>]

Now at least migrate_incoming can be run in parallel.  Let's provide a
migration lock to protect it.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/migration.c | 6 ++++++
 migration/migration.h | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/migration/migration.c b/migration/migration.c
index c3fe0ed..32058f7 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -145,6 +145,7 @@ MigrationIncomingState *migration_incoming_get_current(void)
         mis_current.state = MIGRATION_STATUS_NONE;
         memset(&mis_current, 0, sizeof(MigrationIncomingState));
         qemu_mutex_init(&mis_current.rp_mutex);
+        qemu_mutex_init(&mis_current.mgmt_mutex);
         qemu_event_init(&mis_current.main_thread_load_event, false);
         once = true;
     }
@@ -1171,6 +1172,7 @@ void qmp_migrate_incoming(const char *uri, Error **errp)
 {
     Error *local_err = NULL;
     static bool once = true;
+    MigrationIncomingState *mis = migration_incoming_get_current();
 
     if (!deferred_incoming) {
         error_setg(errp, "For use with '-incoming defer'");
@@ -1180,8 +1182,12 @@ void qmp_migrate_incoming(const char *uri, Error **errp)
         error_setg(errp, "The incoming migration has already been started");
     }
 
+    qemu_mutex_lock(&mis->mgmt_mutex);
+
     qemu_start_incoming_migration(uri, &local_err);
 
+    qemu_mutex_unlock(&mis->mgmt_mutex);
+
     if (local_err) {
         error_propagate(errp, local_err);
         return;
diff --git a/migration/migration.h b/migration/migration.h
index 148c9fa..95f077b 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -58,6 +58,9 @@ struct MigrationIncomingState {
     /* The coroutine we should enter (back) after failover */
     Coroutine *migration_incoming_co;
     QemuSemaphore colo_incoming_sem;
+
+    /* Migration incoming management lock */
+    QemuMutex mgmt_mutex;
 };
 
 MigrationIncomingState *migration_incoming_get_current(void);
-- 
2.7.4