1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
4 * Copyright (C) 2001, 2002 Cluster File Systems, Inc.
6 * This file is part of Lustre, http://www.sf.net/projects/lustre/
8 * Lustre is free software; you can redistribute it and/or
9 * modify it under the terms of version 2 of the GNU General Public
10 * License as published by the Free Software Foundation.
12 * Lustre is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with Lustre; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #include <linux/config.h>
26 #include <linux/kernel.h>
28 #include <linux/string.h>
29 #include <linux/stat.h>
30 #include <linux/errno.h>
31 #include <linux/unistd.h>
32 #include <linux/version.h>
34 #include <asm/system.h>
35 #include <asm/uaccess.h>
38 #include <linux/stat.h>
39 #include <asm/uaccess.h>
40 #include <asm/segment.h>
42 #include <linux/pagemap.h>
43 #include <linux/smp_lock.h>
45 #define DEBUG_SUBSYSTEM S_LDLM
47 #include <linux/obd_class.h>
48 #include <linux/lustre_lib.h>
51 - only the owner of the lock changes l_owner/l_depth
52 - if a non-owner changes or checks the variables a spin lock is taken
55 void l_lock_init(struct lustre_lock *lock)
57 sema_init(&lock->l_sem, 1);
58 spin_lock_init(&lock->l_spin);
61 void l_lock(struct lustre_lock *lock)
64 spin_lock(&lock->l_spin);
65 if (lock->l_owner == current) {
68 spin_unlock(&lock->l_spin);
73 spin_lock(&lock->l_spin);
74 lock->l_owner = current;
76 spin_unlock(&lock->l_spin);
80 void l_unlock(struct lustre_lock *lock)
82 if (lock->l_owner != current)
84 if (lock->l_depth < 0)
87 spin_lock(&lock->l_spin);
88 if (--lock->l_depth < 0) {
90 spin_unlock(&lock->l_spin);
94 spin_unlock(&lock->l_spin);