--- /dev/null
+/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
+ * vim:expandtab:shiftwidth=8:tabstop=8:
+ *
+ * Copyright (C) 2001, 2002 Cluster File Systems, Inc.
+ *
+ * This file is part of Lustre, http://www.sf.net/projects/lustre/
+ *
+ * Lustre is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * Lustre 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Lustre; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/locks.h>
+#include <linux/unistd.h>
+#include <linux/version.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <asm/uaccess.h>
+#include <asm/segment.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/smp_lock.h>
+
+#define DEBUG_SUBSYSTEM S_LDLM
+
+#include <linux/obd_class.h>
+#include <linux/lustre_lib.h>
+
+/* invariants:
+ - only the owner of the lock changes l_owner/l_depth
+ - if a non-owner changes or checks the variables a spin lock is taken
+*/
+
+void l_lock_init(struct lustre_lock *lock)
+{
+ sema_init(&lock->l_sem, 1);
+ spin_lock_init(&lock->l_spin);
+}
+
+void l_lock(struct lustre_lock *lock)
+{
+ int owner = 0;
+ spin_lock(&lock->l_spin);
+ if (lock->l_owner == current) {
+ owner = 1;
+ }
+ spin_unlock(&lock->l_spin);
+ if (owner)
+ ++lock->l_depth;
+ else {
+ down(&lock->l_sem);
+ spin_lock(&lock->l_spin);
+ lock->l_owner = current;
+ lock->l_depth = 0;
+ spin_unlock(&lock->l_spin);
+ }
+}
+
+void l_unlock(struct lustre_lock *lock)
+{
+ if (lock->l_owner != current)
+ LBUG();
+ if (lock->l_depth < 0)
+ LBUG();
+
+ spin_lock(&lock->l_spin);
+ if (--lock->l_depth < 0) {
+ lock->l_owner = NULL;
+ spin_unlock(&lock->l_spin);
+ up(&lock->l_sem);
+ return ;
+ }
+ spin_unlock(&lock->l_spin);
+}