subr_lock.c revision 154485 
1/*-
2 * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the author nor the names of any co-contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30/*
31 * This module holds the global variables and functions used to maintain
32 * lock_object structures.
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: head/sys/kern/subr_lock.c 154485 2006-01-17 16:58:32Z jhb $");
37
38#include "opt_ddb.h"
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/ktr.h>
43#include <sys/linker_set.h>
44#include <sys/lock.h>
45
46#ifdef DDB
47#include <ddb/ddb.h>
48#endif
49
50CTASSERT(LOCK_CLASS_MAX == 15);
51
52#if LOCK_DEBUG > 0 || defined(DDB)
53struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = {
54	&lock_class_mtx_spin,
55	&lock_class_mtx_sleep,
56	&lock_class_sx,
57};
58#endif
59
60void
61lock_init(struct lock_object *lock, struct lock_class *class, const char *name,
62    const char *type, int flags)
63{
64	int i;
65
66	/* Check for double-init and zero object. */
67	KASSERT(!lock_initalized(lock), ("lock \"%s\" %p already initialized",
68	    name, lock));
69
70	/* Look up lock class to find its index. */
71	for (i = 0; i < LOCK_CLASS_MAX; i++)
72		if (lock_classes[i] == class) {
73			lock->lo_flags = i << LO_CLASSSHIFT;
74			break;
75		}
76	KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class));
77
78	/* Initialize the lock object. */
79	lock->lo_name = name;
80	lock->lo_type = type != NULL ? type : name;
81	lock->lo_flags |= flags | LO_INITIALIZED;
82	LOCK_LOG_INIT(lock, 0);
83	WITNESS_INIT(lock);
84}
85
86void
87lock_destroy(struct lock_object *lock)
88{
89
90	KASSERT(lock_initalized(lock), ("lock %p is not initialized", lock));
91	WITNESS_DESTROY(lock);
92	LOCK_LOG_DESTROY(lock, 0);
93	lock->lo_flags &= ~LO_INITIALIZED;
94}
95
96#ifdef DDB
97DB_SHOW_COMMAND(lock, db_show_lock)
98{
99	struct lock_object *lock;
100	struct lock_class *class;
101
102	if (!have_addr)
103		return;
104	lock = (struct lock_object *)addr;
105	if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) {
106		db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock));
107		return;
108	}
109	class = LOCK_CLASS(lock);
110	db_printf(" class: %s\n", class->lc_name);
111	db_printf(" name: %s\n", lock->lo_name);
112	if (lock->lo_type && lock->lo_type != lock->lo_name)
113		db_printf(" type: %s\n", lock->lo_type);
114	class->lc_ddb_show(lock);
115}
116#endif
117