Eric Lee / smarc-fsl-linux-kernel

Blame view

kernel/rwsem.c 2.59 KB
edit raw normal view history
c4e05116a   Ingo Molnar   [PATCH] lockdep: ... 
1
2
3
4
5
6
7
8
 
  /* kernel/rwsem.c: R/W semaphores, public implementation
   *
   * Written by David Howells (dhowells@redhat.com).
   * Derived from asm-i386/semaphore.h
   */
  
  #include <linux/types.h>
  #include <linux/kernel.h>
c7af77b58   Livio Soares   sched: mark rwsem... 
9
 
  #include <linux/sched.h>
c4e05116a   Ingo Molnar   [PATCH] lockdep: ... 
10
11
12
13
14
15
16
17
18
 
  #include <linux/module.h>
  #include <linux/rwsem.h>
  
  #include <asm/system.h>
  #include <asm/atomic.h>
  
  /*
   * lock for reading
   */
c7af77b58   Livio Soares   sched: mark rwsem... 
19
 
  void __sched down_read(struct rw_semaphore *sem)
c4e05116a   Ingo Molnar   [PATCH] lockdep: ... 
20
21
22
 
  {
  	might_sleep();
  	rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
4fe87745a   Peter Zijlstra   lockstat: hook in... 
23
 
  	LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
c4e05116a   Ingo Molnar   [PATCH] lockdep: ... 
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
 
  }
  
  EXPORT_SYMBOL(down_read);
  
  /*
   * trylock for reading -- returns 1 if successful, 0 if contention
   */
  int down_read_trylock(struct rw_semaphore *sem)
  {
  	int ret = __down_read_trylock(sem);
  
  	if (ret == 1)
  		rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
  	return ret;
  }
  
  EXPORT_SYMBOL(down_read_trylock);
  
  /*
   * lock for writing
   */
c7af77b58   Livio Soares   sched: mark rwsem... 
45
 
  void __sched down_write(struct rw_semaphore *sem)
c4e05116a   Ingo Molnar   [PATCH] lockdep: ... 
46
47
48
 
  {
  	might_sleep();
  	rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
4fe87745a   Peter Zijlstra   lockstat: hook in... 
49
 
  	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
c4e05116a   Ingo Molnar   [PATCH] lockdep: ... 
50
51
52
53
54
55
56
57
58
59
60
61
 
  }
  
  EXPORT_SYMBOL(down_write);
  
  /*
   * trylock for writing -- returns 1 if successful, 0 if contention
   */
  int down_write_trylock(struct rw_semaphore *sem)
  {
  	int ret = __down_write_trylock(sem);
  
  	if (ret == 1)
428e6ce02   Pavel Emelianov   Lockdep treats do... 
62
 
  		rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_);
c4e05116a   Ingo Molnar   [PATCH] lockdep: ... 
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
 
  	return ret;
  }
  
  EXPORT_SYMBOL(down_write_trylock);
  
  /*
   * release a read lock
   */
  void up_read(struct rw_semaphore *sem)
  {
  	rwsem_release(&sem->dep_map, 1, _RET_IP_);
  
  	__up_read(sem);
  }
  
  EXPORT_SYMBOL(up_read);
  
  /*
   * release a write lock
   */
  void up_write(struct rw_semaphore *sem)
  {
  	rwsem_release(&sem->dep_map, 1, _RET_IP_);
  
  	__up_write(sem);
  }
  
  EXPORT_SYMBOL(up_write);
  
  /*
   * downgrade write lock to read lock
   */
  void downgrade_write(struct rw_semaphore *sem)
  {
  	/*
  	 * lockdep: a downgraded write will live on as a write
  	 * dependency.
  	 */
  	__downgrade_write(sem);
  }
  
  EXPORT_SYMBOL(downgrade_write);
4ea2176df   Ingo Molnar   [PATCH] lockdep: ... 
105
106
107
108
109
110
111
 
  
  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  
  void down_read_nested(struct rw_semaphore *sem, int subclass)
  {
  	might_sleep();
  	rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
4fe87745a   Peter Zijlstra   lockstat: hook in... 
112
 
  	LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
4ea2176df   Ingo Molnar   [PATCH] lockdep: ... 
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
 
  }
  
  EXPORT_SYMBOL(down_read_nested);
  
  void down_read_non_owner(struct rw_semaphore *sem)
  {
  	might_sleep();
  
  	__down_read(sem);
  }
  
  EXPORT_SYMBOL(down_read_non_owner);
  
  void down_write_nested(struct rw_semaphore *sem, int subclass)
  {
  	might_sleep();
  	rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
4fe87745a   Peter Zijlstra   lockstat: hook in... 
130
 
  	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
4ea2176df   Ingo Molnar   [PATCH] lockdep: ... 
131
132
133
134
135
136
137
138
139
140
141
142
 
  }
  
  EXPORT_SYMBOL(down_write_nested);
  
  void up_read_non_owner(struct rw_semaphore *sem)
  {
  	__up_read(sem);
  }
  
  EXPORT_SYMBOL(up_read_non_owner);
  
  #endif