1 #include <sys/condvar.h>
2 #include <sys/spinlock2.h>
3 #include <sys/systm.h>
4 #include <sys/lock.h>
5
6 void
cv_init(struct cv * c,const char * desc)7 cv_init(struct cv *c, const char *desc)
8 {
9 c->cv_desc = desc;
10 c->cv_waiters = 0;
11 spin_init(&c->cv_lock, "cvinit");
12 }
13
14 void
cv_destroy(struct cv * c)15 cv_destroy(struct cv *c)
16 {
17 spin_uninit(&c->cv_lock);
18 }
19
20 int
_cv_timedwait(struct cv * c,struct lock * lk,int timo,int wakesig)21 _cv_timedwait(struct cv *c, struct lock *lk, int timo, int wakesig)
22 {
23 int flags = wakesig ? PCATCH : 0;
24 int error;
25
26 /*
27 * Can interlock without critical section/spinlock as long
28 * as we don't block before calling *sleep(). PINTERLOCKED
29 * must be passed to the *sleep() to use the manual interlock
30 * (else a new one is created which opens a timing race).
31 */
32 tsleep_interlock(c, flags);
33
34 spin_lock(&c->cv_lock);
35 c->cv_waiters++;
36 spin_unlock(&c->cv_lock);
37
38 if (lk)
39 error = lksleep(c, lk, flags | PINTERLOCKED, c->cv_desc, timo);
40 else
41 error = tsleep(c, flags | PINTERLOCKED, c->cv_desc, timo);
42
43 return (error);
44 }
45
46 /*
47 * _cv_timedwait() implementation using mtx.
48 */
49 int
_cv_mtx_timedwait(struct cv * c,struct mtx * mtx,int timo,int wakesig)50 _cv_mtx_timedwait(struct cv *c, struct mtx *mtx, int timo, int wakesig)
51 {
52 int flags = wakesig ? PCATCH : 0;
53 int error;
54
55 /*
56 * Can interlock without critical section/spinlock as long
57 * as we don't block before calling *sleep(). PINTERLOCKED
58 * must be passed to the *sleep() to use the manual interlock
59 * (else a new one is created which opens a timing race).
60 */
61 tsleep_interlock(c, flags);
62
63 spin_lock(&c->cv_lock);
64 c->cv_waiters++;
65 spin_unlock(&c->cv_lock);
66
67 if (mtx)
68 error = mtxsleep(c, mtx, flags | PINTERLOCKED, c->cv_desc, timo);
69 else
70 error = tsleep(c, flags | PINTERLOCKED, c->cv_desc, timo);
71
72 return (error);
73 }
74
75 void
_cv_signal(struct cv * c,int broadcast)76 _cv_signal(struct cv *c, int broadcast)
77 {
78 spin_lock(&c->cv_lock);
79 if (c->cv_waiters == 0) {
80 spin_unlock(&c->cv_lock);
81 } else if (broadcast) {
82 c->cv_waiters = 0;
83 spin_unlock(&c->cv_lock); /* must unlock first */
84 wakeup(c);
85 } else {
86 c->cv_waiters--;
87 spin_unlock(&c->cv_lock); /* must unlock first */
88 wakeup_one(c);
89 }
90 }
91
92 int
cv_has_waiters(const struct cv * c)93 cv_has_waiters(const struct cv *c)
94 {
95 return (c->cv_waiters);
96 }
97