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	_LINUXKPI_LINUX_WW_MUTEX_H_
29 #define	_LINUXKPI_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 	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 
73 static inline int __must_check
74 ww_mutex_trylock(struct ww_mutex *lock)
75 {
76 	return (mutex_trylock(&lock->base));
77 }
78 
79 extern int linux_ww_mutex_lock_sub(struct ww_mutex *,
80     struct ww_acquire_ctx *, int catch_signal);
81 
82 static inline int
83 ww_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 
93 static inline int
94 ww_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 
104 extern void linux_ww_mutex_unlock_sub(struct ww_mutex *);
105 
106 static inline void
107 ww_mutex_unlock(struct ww_mutex *lock)
108 {
109 	if (MUTEX_SKIP())
110 		return;
111 	else
112 		linux_ww_mutex_unlock_sub(lock);
113 }
114 
115 static inline void
116 ww_mutex_destroy(struct ww_mutex *lock)
117 {
118 	cv_destroy(&lock->condvar);
119 	mutex_destroy(&lock->base);
120 }
121 
122 static inline void
123 ww_acquire_init(struct ww_acquire_ctx *ctx, struct ww_class *ww_class)
124 {
125 }
126 
127 static inline void
128 ww_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 
134 static inline void
135 ww_acquire_fini(struct ww_acquire_ctx *ctx)
136 {
137 }
138 
139 static inline void
140 ww_acquire_done(struct ww_acquire_ctx *ctx)
141 {
142 }
143 
144 #endif					/* _LINUXKPI_LINUX_WW_MUTEX_H_ */
145