sys/kern/kern_condvar.c

   1 #include <sys/condvar.h>
   2 #include <sys/spinlock2.h>
   3 #include <sys/systm.h>
   4 #include <sys/lock.h>
   5
   6 void
   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);
  12 }
  13
  14 void
  15 cv_destroy(struct cv *c)
  16 {
  17         spin_uninit(&c->cv_lock);
  18 }
  19
  20 int
  21 _cv_timedwait(struct cv *c, struct lock *l, int timo, int wakesig)
  22 {
  23         int flags = wakesig ? PCATCH : 0;
  24         int error;
  25
  26         spin_lock(&c->cv_lock);
  27         tsleep_interlock(c, flags);
  28         c->cv_waiters++;
  29         spin_unlock(&c->cv_lock);
  30         if (l != NULL)
  31                 lockmgr(l, LK_RELEASE);
  32         error = tsleep(c, flags, c->cv_desc, timo);
  33         if (l != NULL)
  34                 lockmgr(l, LK_EXCLUSIVE);
  35
  36         return (error);
  37 }
  38
  39 void
  40 _cv_signal(struct cv *c, int broadcast)
  41 {
  42         spin_lock(&c->cv_lock);
  43         if (c->cv_waiters == 0)
  44                 goto out;
  45
  46         if (broadcast) {
  47                 c->cv_waiters = 0;
  48                 wakeup(c);
  49         } else {
  50                 c->cv_waiters--;
  51                 wakeup_one(c);
  52         }
  53
  54 out:
  55         spin_unlock(&c->cv_lock);
  56 }
  57
  58 int
  59 cv_has_waiters(const struct cv *c)
  60 {
  61         return (c->cv_waiters);
  62 }