1/*-
2 * Copyright (c) 2017 Mellanox Technologies, Ltd.
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 unmodified, this list of conditions, and the following
10 *    disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 * $FreeBSD: stable/11/sys/compat/linuxkpi/common/include/linux/ww_mutex.h 366879 2020-10-20 08:23:24Z hselasky $
27 */
28#ifndef	_LINUX_WW_MUTEX_H_
29#define	_LINUX_WW_MUTEX_H_
30
31#include <sys/param.h>
32#include <sys/proc.h>
33#include <sys/condvar.h>
34#include <sys/kernel.h>
35
36#include <linux/mutex.h>
37
38struct ww_class {
39	const char *mutex_name;
40};
41
42struct ww_acquire_ctx {
43};
44
45struct ww_mutex {
46	struct mutex base;
47	struct cv condvar;
48	struct ww_acquire_ctx *ctx;
49};
50
51#define	DEFINE_WW_CLASS(name)					\
52	struct ww_class name = {				\
53		.mutex_name = mutex_name(#name "_mutex")	\
54	}
55
56#define	DEFINE_WW_MUTEX(name, ww_class)					\
57	struct ww_mutex name;						\
58	static void name##_init(void *arg)				\
59	{								\
60		ww_mutex_init(&name, &ww_class);			\
61	}								\
62	SYSINIT(name, SI_SUB_LOCK, SI_ORDER_SECOND, name##_init, NULL)
63
64#define	ww_mutex_is_locked(_m) \
65	sx_xlocked(&(_m)->base.sx)
66
67#define	ww_mutex_lock_slow(_m, _x) \
68	ww_mutex_lock(_m, _x)
69
70#define	ww_mutex_lock_slow_interruptible(_m, _x) \
71	ww_mutex_lock_interruptible(_m, _x)
72
73static inline int __must_check
74ww_mutex_trylock(struct ww_mutex *lock)
75{
76	return (mutex_trylock(&lock->base));
77}
78
79extern int linux_ww_mutex_lock_sub(struct ww_mutex *,
80    struct ww_acquire_ctx *, int catch_signal);
81
82static inline int
83ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
84{
85	if (MUTEX_SKIP())
86		return (0);
87	else if ((struct thread *)SX_OWNER(lock->base.sx.sx_lock) == curthread)
88		return (-EALREADY);
89	else
90		return (linux_ww_mutex_lock_sub(lock, ctx, 0));
91}
92
93static inline int
94ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
95{
96	if (MUTEX_SKIP())
97		return (0);
98	else if ((struct thread *)SX_OWNER(lock->base.sx.sx_lock) == curthread)
99		return (-EALREADY);
100	else
101		return (linux_ww_mutex_lock_sub(lock, ctx, 1));
102}
103
104extern void linux_ww_mutex_unlock_sub(struct ww_mutex *);
105
106static inline void
107ww_mutex_unlock(struct ww_mutex *lock)
108{
109	if (MUTEX_SKIP())
110		return;
111	else
112		linux_ww_mutex_unlock_sub(lock);
113}
114
115static inline void
116ww_mutex_destroy(struct ww_mutex *lock)
117{
118	cv_destroy(&lock->condvar);
119	mutex_destroy(&lock->base);
120}
121
122static inline void
123ww_acquire_init(struct ww_acquire_ctx *ctx, struct ww_class *ww_class)
124{
125}
126
127static inline void
128ww_mutex_init(struct ww_mutex *lock, struct ww_class *ww_class)
129{
130	linux_mutex_init(&lock->base, ww_class->mutex_name, SX_NOWITNESS);
131	cv_init(&lock->condvar, "lkpi-ww");
132}
133
134static inline void
135ww_acquire_fini(struct ww_acquire_ctx *ctx)
136{
137}
138
139static inline void
140ww_acquire_done(struct ww_acquire_ctx *ctx)
141{
142}
143
144#endif					/* _LINUX_WW_MUTEX_H_ */
145