xref: /freebsd/sys/compat/linuxkpi/common/include/linux/mutex.h (revision 95ee2897e98f5d444f26ed2334cc7c439f9c16c6)
1  /*-
2   * Copyright (c) 2010 Isilon Systems, Inc.
3   * Copyright (c) 2010 iX Systems, Inc.
4   * Copyright (c) 2010 Panasas, Inc.
5   * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
6   * All rights reserved.
7   *
8   * Redistribution and use in source and binary forms, with or without
9   * modification, are permitted provided that the following conditions
10   * are met:
11   * 1. Redistributions of source code must retain the above copyright
12   *    notice unmodified, this list of conditions, and the following
13   *    disclaimer.
14   * 2. Redistributions in binary form must reproduce the above copyright
15   *    notice, this list of conditions and the following disclaimer in the
16   *    documentation and/or other materials provided with the distribution.
17   *
18   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28   */
29  #ifndef	_LINUXKPI_LINUX_MUTEX_H_
30  #define	_LINUXKPI_LINUX_MUTEX_H_
31  
32  #include <sys/param.h>
33  #include <sys/proc.h>
34  #include <sys/lock.h>
35  #include <sys/sx.h>
36  
37  #include <linux/kernel.h>
38  #include <linux/list.h>
39  #include <linux/spinlock.h>
40  #include <asm/atomic.h>
41  
42  typedef struct mutex {
43  	struct sx sx;
44  } mutex_t;
45  
46  /*
47   * By defining CONFIG_NO_MUTEX_SKIP LinuxKPI mutexes and asserts will
48   * not be skipped during panic().
49   */
50  #ifdef CONFIG_NO_MUTEX_SKIP
51  #define	MUTEX_SKIP(void) 0
52  #else
53  #define	MUTEX_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active)
54  #endif
55  
56  #define	mutex_lock(_m) do {			\
57  	if (MUTEX_SKIP())			\
58  		break;				\
59  	sx_xlock(&(_m)->sx);			\
60  } while (0)
61  
62  #define	mutex_lock_nested(_m, _s)	mutex_lock(_m)
63  #define	mutex_lock_nest_lock(_m, _s)	mutex_lock(_m)
64  
65  #define	mutex_lock_interruptible(_m) ({		\
66  	MUTEX_SKIP() ? 0 :			\
67  	linux_mutex_lock_interruptible(_m);	\
68  })
69  
70  #define	mutex_lock_interruptible_nested(m, c)	mutex_lock_interruptible(m)
71  
72  /*
73   * Reuse the interruptable method since the SX
74   * lock handles both signals and interrupts:
75   */
76  #define	mutex_lock_killable(_m) ({		\
77  	MUTEX_SKIP() ? 0 :			\
78  	linux_mutex_lock_interruptible(_m);	\
79  })
80  
81  #define	mutex_lock_killable_nested(_m, _sub)	\
82  	mutex_lock_killable(_m)
83  
84  #define	mutex_unlock(_m) do {			\
85  	if (MUTEX_SKIP())			\
86  		break;				\
87  	sx_xunlock(&(_m)->sx);			\
88  } while (0)
89  
90  #define	mutex_trylock(_m) ({			\
91  	MUTEX_SKIP() ? 1 :			\
92  	!!sx_try_xlock(&(_m)->sx);		\
93  })
94  
95  enum mutex_trylock_recursive_enum {
96  	MUTEX_TRYLOCK_FAILED = 0,
97  	MUTEX_TRYLOCK_SUCCESS = 1,
98  	MUTEX_TRYLOCK_RECURSIVE = 2,
99  };
100  
101  static inline __must_check enum mutex_trylock_recursive_enum
mutex_trylock_recursive(struct mutex * lock)102  mutex_trylock_recursive(struct mutex *lock)
103  {
104  	if (unlikely(sx_xholder(&lock->sx) == curthread))
105  		return (MUTEX_TRYLOCK_RECURSIVE);
106  
107  	return (mutex_trylock(lock));
108  }
109  
110  #define	mutex_init(_m) \
111  	linux_mutex_init(_m, mutex_name(#_m), SX_NOWITNESS)
112  
113  #define	__mutex_init(_m, _n, _l) \
114  	linux_mutex_init(_m, _n, SX_NOWITNESS)
115  
116  #define	mutex_init_witness(_m) \
117  	linux_mutex_init(_m, mutex_name(#_m), SX_DUPOK)
118  
119  #define	mutex_destroy(_m) \
120  	linux_mutex_destroy(_m)
121  
122  static inline bool
mutex_is_locked(mutex_t * m)123  mutex_is_locked(mutex_t *m)
124  {
125  	return ((struct thread *)SX_OWNER(m->sx.sx_lock) != NULL);
126  }
127  
128  static inline bool
mutex_is_owned(mutex_t * m)129  mutex_is_owned(mutex_t *m)
130  {
131  	return (sx_xlocked(&m->sx));
132  }
133  
atomic_dec_and_mutex_lock(atomic_t * cnt,struct mutex * m)134  static inline int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *m)
135  {
136  	if (atomic_dec_and_test(cnt)) {
137  		mutex_lock(m);
138  		return (1);
139  	}
140  
141  	return (0);
142  }
143  
144  #ifdef WITNESS_ALL
145  /* NOTE: the maximum WITNESS name is 64 chars */
146  #define	__mutex_name(name, file, line)		\
147  	(((const char *){file ":" #line "-" name}) +	\
148  	(sizeof(file) > 16 ? sizeof(file) - 16 : 0))
149  #else
150  #define	__mutex_name(name, file, line)	name
151  #endif
152  #define	_mutex_name(...)	__mutex_name(__VA_ARGS__)
153  #define	mutex_name(name)	_mutex_name(name, __FILE__, __LINE__)
154  
155  #define	DEFINE_MUTEX(lock)						\
156  	mutex_t lock;							\
157  	SX_SYSINIT_FLAGS(lock, &(lock).sx, mutex_name(#lock), SX_DUPOK)
158  
159  static inline void
linux_mutex_init(mutex_t * m,const char * name,int flags)160  linux_mutex_init(mutex_t *m, const char *name, int flags)
161  {
162  	memset(m, 0, sizeof(*m));
163  	sx_init_flags(&m->sx, name, flags);
164  }
165  
166  static inline void
linux_mutex_destroy(mutex_t * m)167  linux_mutex_destroy(mutex_t *m)
168  {
169  	if (mutex_is_owned(m))
170  		mutex_unlock(m);
171  	sx_destroy(&m->sx);
172  }
173  
174  extern int linux_mutex_lock_interruptible(mutex_t *m);
175  
176  #endif					/* _LINUXKPI_LINUX_MUTEX_H_ */
177