a

kern/sleep.c

@@ -0,0 +1,90 @@
+#include	"u.h"
+#include	"lib.h"
+#include	"dat.h"
+#include	"fns.h"
+#include	"error.h"
+
+void
+sleep(Rendez *r, int (*f)(void*), void *arg)
+{
+	int s;
+
+	s = splhi();
+
+	lock(&r->lk);
+	lock(&up->rlock);
+	if(r->p){
+		print("double sleep %lud %lud\n", r->p->pid, up->pid);
+		dumpstack();
+	}
+
+	/*
+	 *  Wakeup only knows there may be something to do by testing
+	 *  r->p in order to get something to lock on.
+	 *  Flush that information out to memory in case the sleep is
+	 *  committed.
+	 */
+	r->p = up;
+
+	if((*f)(arg) || up->notepending){
+		/*
+		 *  if condition happened or a note is pending
+		 *  never mind
+		 */
+		r->p = nil;
+		unlock(&up->rlock);
+		unlock(&r->lk);
+	} else {
+		/*
+		 *  now we are committed to
+		 *  change state and call scheduler
+		 */
+		up->state = Wakeme;
+		up->r = r;
+
+		/* statistics */
+		/* m->cs++; */
+
+		unlock(&up->rlock);
+		unlock(&r->lk);
+
+		procsleep();
+	}
+
+	if(up->notepending) {
+		up->notepending = 0;
+		splx(s);
+		error(Eintr);
+	}
+
+	splx(s);
+}
+
+Proc*
+wakeup(Rendez *r)
+{
+	Proc *p;
+	int s;
+
+	s = splhi();
+
+	lock(&r->lk);
+	p = r->p;
+
+	if(p != nil){
+		lock(&p->rlock);
+		if(p->state != Wakeme || p->r != r)
+			panic("wakeup: state");
+		r->p = nil;
+		p->r = nil;
+		p->state = Running;
+		procwakeup(p);
+		unlock(&p->rlock);
+	}
+	unlock(&r->lk);
+
+	splx(s);
+
+	return p;
+}
+