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  * $FreeBSD$
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 
38 struct ww_class {
39 	const char *mutex_name;
40 };
41 
42 struct ww_acquire_ctx {
43 };
44 
45 struct ww_mutex {
46 	struct mutex base;
47 	struct cv condvar;
48 };
49 
50 #define	DEFINE_WW_CLASS(name)					\
51 	struct ww_class name = {				\
52 		.mutex_name = mutex_name(#name "_mutex")	\
53 	}
54 
55 #define	DEFINE_WW_MUTEX(name, ww_class)					\
56 	struct ww_mutex name;						\
57 	static void name##_init(void *arg)				\
58 	{								\
59 		ww_mutex_init(&name, &ww_class);			\
60 	}								\
61 	SYSINIT(name, SI_SUB_LOCK, SI_ORDER_SECOND, name##_init, NULL)
62 
63 #define	ww_mutex_is_locked(_m) \
64 	sx_xlocked(&(_m)->base.sx)
65 
66 #define	ww_mutex_lock_slow(_m, _x) \
67 	ww_mutex_lock(_m, _x)
68 
69 #define	ww_mutex_lock_slow_interruptible(_m, _x) \
70 	ww_mutex_lock_interruptible(_m, _x)
71 
72 static inline int __must_check
73 ww_mutex_trylock(struct ww_mutex *lock)
74 {
75 	return (mutex_trylock(&lock->base));
76 }
77 
78 extern int linux_ww_mutex_lock_sub(struct ww_mutex *, int catch_signal);
79 
80 static inline int
81 ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
82 {
83 	if (MUTEX_SKIP())
84 		return (0);
85 	else if ((struct thread *)SX_OWNER(lock->base.sx.sx_lock) == curthread)
86 		return (-EALREADY);
87 	else
88 		return (linux_ww_mutex_lock_sub(lock, 0));
89 }
90 
91 static inline int
92 ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
93 {
94 	if (MUTEX_SKIP())
95 		return (0);
96 	else if ((struct thread *)SX_OWNER(lock->base.sx.sx_lock) == curthread)
97 		return (-EALREADY);
98 	else
99 		return (linux_ww_mutex_lock_sub(lock, 1));
100 }
101 
102 extern void linux_ww_mutex_unlock_sub(struct ww_mutex *);
103 
104 static inline void
105 ww_mutex_unlock(struct ww_mutex *lock)
106 {
107 	if (MUTEX_SKIP())
108 		return;
109 	else
110 		linux_ww_mutex_unlock_sub(lock);
111 }
112 
113 static inline void
114 ww_mutex_destroy(struct ww_mutex *lock)
115 {
116 	cv_destroy(&lock->condvar);
117 	mutex_destroy(&lock->base);
118 }
119 
120 static inline void
121 ww_acquire_init(struct ww_acquire_ctx *ctx, struct ww_class *ww_class)
122 {
123 }
124 
125 static inline void
126 ww_mutex_init(struct ww_mutex *lock, struct ww_class *ww_class)
127 {
128 	linux_mutex_init(&lock->base, ww_class->mutex_name, SX_NOWITNESS);
129 	cv_init(&lock->condvar, "lkpi-ww");
130 }
131 
132 static inline void
133 ww_acquire_fini(struct ww_acquire_ctx *ctx)
134 {
135 }
136 
137 static inline void
138 ww_acquire_done(struct ww_acquire_ctx *ctx)
139 {
140 }
141 
142 #endif					/* _LINUX_WW_MUTEX_H_ */
143