add code to provide simple wait condition handling.

this will be used to replace the bare sleep_state handling in a
bunch of places, starting with the barriers.

1 files changed, 29 insertions, 1 deletions

diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
index 7fb23449560..ea28288d375 100644
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_synch.c,v 1.142 2017/12/04 09:38:20 mpi Exp $	*/
+/*	$OpenBSD: kern_synch.c,v 1.143 2017/12/14 00:41:58 dlg Exp $	*/
 /*	$NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $	*/
 
 /*
@@ -704,3 +704,31 @@ refcnt_finalize(struct refcnt *r, const char *wmesg)
 		sleep_finish(&sls, refcnt);
 	}
 }
+
+void
+cond_init(struct cond *c)
+{
+	c->c_wait = 1;
+}
+
+void
+cond_signal(struct cond *c)
+{
+	c->c_wait = 0;
+
+	wakeup_one(c);
+}
+
+void
+cond_wait(struct cond *c, const char *wmesg)
+{
+	struct sleep_state sls;
+	int wait;
+
+	wait = c->c_wait;
+	while (wait) {
+		sleep_setup(&sls, c, PWAIT, wmesg);
+		wait = c->c_wait;
+		sleep_finish(&sls, wait);
+	}
+}