1/* $NetBSD: ww_mutex.h,v 1.11 2015/05/21 21:55:55 riastradh Exp $ */
2
3/*-
4 * Copyright (c) 2014 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef _ASM_WW_MUTEX_H_
33#define _ASM_WW_MUTEX_H_
34
35#include <sys/types.h>
36#include <sys/condvar.h>
37#include <sys/mutex.h>
38#include <sys/rbtree.h>
39
40struct ww_class {
41 volatile uint64_t wwc_ticket;
42};
43
44#define DEFINE_WW_CLASS(CLASS) \
45 struct ww_class CLASS = { \
46 .wwc_ticket = 0, \
47 }
48
49struct ww_acquire_ctx {
50 struct ww_class *wwx_class __diagused;
51 struct lwp *wwx_owner __diagused;
52 uint64_t wwx_ticket;
53 unsigned wwx_acquired;
54 bool wwx_acquire_done;
55 struct rb_node wwx_rb_node;
56};
57
58struct ww_mutex {
59 enum ww_mutex_state {
60 WW_UNLOCKED, /* nobody owns it */
61 WW_OWNED, /* owned by a lwp without a context */
62 WW_CTX, /* owned by a context */
63 WW_WANTOWN, /* owned by ctx, waiters w/o ctx waiting */
64 } wwm_state;
65 union {
66 struct lwp *owner;
67 struct ww_acquire_ctx *ctx;
68 } wwm_u;
69 /*
70 * XXX wwm_lock must *not* be first, so that the ww_mutex has a
71 * different address from the kmutex for LOCKDEBUG purposes.
72 */
73 kmutex_t wwm_lock;
74 struct ww_class *wwm_class;
75 struct rb_tree wwm_waiters;
76 kcondvar_t wwm_cv;
77#ifdef LOCKDEBUG
78 bool wwm_debug;
79#endif
80};
81
82/* XXX Make the nm output a little more greppable... */
83#define ww_acquire_done linux_ww_acquire_done
84#define ww_acquire_fini linux_ww_acquire_fini
85#define ww_acquire_init linux_ww_acquire_init
86#define ww_mutex_destroy linux_ww_mutex_destroy
87#define ww_mutex_init linux_ww_mutex_init
88#define ww_mutex_is_locked linux_ww_mutex_is_locked
89#define ww_mutex_lock linux_ww_mutex_lock
90#define ww_mutex_lock_interruptible linux_ww_mutex_lock_interruptible
91#define ww_mutex_lock_slow linux_ww_mutex_lock_slow
92#define ww_mutex_lock_slow_interruptible linux_ww_mutex_lock_slow_interruptible
93#define ww_mutex_trylock linux_ww_mutex_trylock
94#define ww_mutex_unlock linux_ww_mutex_unlock
95
96void ww_acquire_init(struct ww_acquire_ctx *, struct ww_class *);
97void ww_acquire_done(struct ww_acquire_ctx *);
98void ww_acquire_fini(struct ww_acquire_ctx *);
99
100void ww_mutex_init(struct ww_mutex *, struct ww_class *);
101void ww_mutex_destroy(struct ww_mutex *);
102
103/*
104 * WARNING: ww_mutex_is_locked returns true if it is locked by ANYONE.
105 * Does NOT mean `Do I hold this lock?' (answering which really
106 * requires an acquire context).
107 */
108bool ww_mutex_is_locked(struct ww_mutex *);
109
110int ww_mutex_lock(struct ww_mutex *, struct ww_acquire_ctx *);
111int ww_mutex_lock_interruptible(struct ww_mutex *,
112 struct ww_acquire_ctx *);
113void ww_mutex_lock_slow(struct ww_mutex *, struct ww_acquire_ctx *);
114int ww_mutex_lock_slow_interruptible(struct ww_mutex *,
115 struct ww_acquire_ctx *);
116int ww_mutex_trylock(struct ww_mutex *);
117void ww_mutex_unlock(struct ww_mutex *);
118
119#endif /* _ASM_WW_MUTEX_H_ */
120