1 #include <u.h>
2 #include <libc.h>
3 
4 /*
5  * The function pointers are supplied by the thread
6  * library during its initialization.  If there is no thread
7  * library, there is no multithreading.
8  */
9 
10 int	(*_lock)(Lock*, int, ulong);
11 void	(*_unlock)(Lock*, ulong);
12 int	(*_qlock)(QLock*, int, ulong);	/* do not use */
13 void	(*_qunlock)(QLock*, ulong);
14 void	(*_rsleep)(Rendez*, ulong);	/* do not use */
15 int	(*_rwakeup)(Rendez*, int, ulong);
16 int	(*_rlock)(RWLock*, int, ulong);	/* do not use */
17 int	(*_wlock)(RWLock*, int, ulong);
18 void	(*_runlock)(RWLock*, ulong);
19 void	(*_wunlock)(RWLock*, ulong);
20 
21 void
22 lock(Lock *l)
23 {
24 	if(_lock)
25 		(*_lock)(l, 1, getcallerpc(&l));
26 	else
27 		l->held = 1;
28 }
29 
30 int
31 canlock(Lock *l)
32 {
33 	if(_lock)
34 		return (*_lock)(l, 0, getcallerpc(&l));
35 	else{
36 		if(l->held)
37 			return 0;
38 		l->held = 1;
39 		return 1;
40 	}
41 }
42 
43 void
44 unlock(Lock *l)
45 {
46 	if(_unlock)
47 		(*_unlock)(l, getcallerpc(&l));
48 	else
49 		l->held = 0;
50 }
51 
52 void
53 qlock(QLock *l)
54 {
55 	if(_qlock)
56 		(*_qlock)(l, 1, getcallerpc(&l));
57 	else
58 		l->l.held = 1;
59 }
60 
61 int
62 canqlock(QLock *l)
63 {
64 	if(_qlock)
65 		return (*_qlock)(l, 0, getcallerpc(&l));
66 	else{
67 		if(l->l.held)
68 			return 0;
69 		l->l.held = 1;
70 		return 1;
71 	}
72 }
73 
74 void
75 qunlock(QLock *l)
76 {
77 	if(_qunlock)
78 		(*_qunlock)(l, getcallerpc(&l));
79 	else
80 		l->l.held = 0;
81 }
82 
83 void
84 rlock(RWLock *l)
85 {
86 	if(_rlock)
87 		(*_rlock)(l, 1, getcallerpc(&l));
88 	else
89 		l->readers++;
90 }
91 
92 int
93 canrlock(RWLock *l)
94 {
95 	if(_rlock)
96 		return (*_rlock)(l, 0, getcallerpc(&l));
97 	else{
98 		if(l->writer)
99 			return 0;
100 		l->readers++;
101 		return 1;
102 	}
103 }
104 
105 void
106 runlock(RWLock *l)
107 {
108 	if(_runlock)
109 		(*_runlock)(l, getcallerpc(&l));
110 	else
111 		l->readers--;
112 }
113 
114 void
115 wlock(RWLock *l)
116 {
117 	if(_wlock)
118 		(*_wlock)(l, 1, getcallerpc(&l));
119 	else
120 		l->writer = (void*)1;
121 }
122 
123 int
124 canwlock(RWLock *l)
125 {
126 	if(_wlock)
127 		return (*_wlock)(l, 0, getcallerpc(&l));
128 	else{
129 		if(l->writer || l->readers)
130 			return 0;
131 		l->writer = (void*)1;
132 		return 1;
133 	}
134 }
135 
136 void
137 wunlock(RWLock *l)
138 {
139 	if(_wunlock)
140 		(*_wunlock)(l, getcallerpc(&l));
141 	else
142 		l->writer = nil;
143 }
144 
145 void
146 rsleep(Rendez *r)
147 {
148 	if(_rsleep)
149 		(*_rsleep)(r, getcallerpc(&r));
150 }
151 
152 int
153 rwakeup(Rendez *r)
154 {
155 	if(_rwakeup)
156 		return (*_rwakeup)(r, 0, getcallerpc(&r));
157 	return 0;
158 }
159 
160 int
161 rwakeupall(Rendez *r)
162 {
163 	if(_rwakeup)
164 		return (*_rwakeup)(r, 1, getcallerpc(&r));
165 	return 0;
166 }