1 files changed, 76 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/ldlm/l_lock.c b/drivers/staging/lustre/lustre/ldlm/l_lock.c
new file mode 100644
index 000000000000..853409aa945d
--- /dev/null
+++ b/drivers/staging/lustre/lustre/ldlm/l_lock.c
@@ -0,0 +1,76 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2012, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ */
+
+#define DEBUG_SUBSYSTEM S_LDLM
+#include <linux/libcfs/libcfs.h>
+
+#include <lustre_dlm.h>
+#include <lustre_lib.h>
+
+/**
+ * Lock a lock and its resource.
+ *
+ * LDLM locking uses resource to serialize access to locks
+ * but there is a case when we change resource of lock upon
+ * enqueue reply. We rely on lock->l_resource = new_res
+ * being an atomic operation.
+ */
+struct ldlm_resource *lock_res_and_lock(struct ldlm_lock *lock)
+{
+	/* on server-side resource of lock doesn't change */
+	if (!lock->l_ns_srv)
+		spin_lock(&lock->l_lock);
+
+	lock_res(lock->l_resource);
+
+	lock->l_res_locked = 1;
+	return lock->l_resource;
+}
+EXPORT_SYMBOL(lock_res_and_lock);
+
+/**
+ * Unlock a lock and its resource previously locked with lock_res_and_lock
+ */
+void unlock_res_and_lock(struct ldlm_lock *lock)
+{
+	/* on server-side resource of lock doesn't change */
+	lock->l_res_locked = 0;
+
+	unlock_res(lock->l_resource);
+	if (!lock->l_ns_srv)
+		spin_unlock(&lock->l_lock);
+}
+EXPORT_SYMBOL(unlock_res_and_lock);