From 2dbff7551b815536e88352d0af6836ce32831c55 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 20 Feb 1997 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1997-02-20

---
 carrera/fns.h  |  1 +
 pc/fns.h       |  1 +
 port/devmnt.c  | 16 +++-------------
 port/portdat.h |  1 -
 port/portfns.h |  2 +-
 port/proc.c    | 14 +++++++++++---
 port/taslock.c |  2 ++
 power/fns.h    |  1 +
 8 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/carrera/fns.h b/carrera/fns.h
index 556fbc2b7738ef5cb471e474e52d72d3a7c4d99e..361e3d233db4ab3e084c71d141d9d76d4088d247 100644
--- a/carrera/fns.h
+++ b/carrera/fns.h
@@ -142,3 +142,4 @@ void*	ifroute(ulong);
 ulong	ifunroute(ulong);
 void	parseip(char*, char*);
 void	mpegintr(void);
+#define coherence()
diff --git a/pc/fns.h b/pc/fns.h
index 4816e6f483f420e027a747e713ed1dab608a6f5b..fff67dd96eca7426c946c436ab830b60bbdc827e 100644
--- a/pc/fns.h
+++ b/pc/fns.h
@@ -129,3 +129,4 @@ ulong	ifunroute(ulong);
 void	parseip(char*, char*);
 
 #define	dcflush(a, b)
+#define coherence()
diff --git a/port/devmnt.c b/port/devmnt.c
index 68892cee08f886f4e47670734da1b9ac596ce2c3..efc2e479d2b13d72ec1d0c0e0ecf577cbe3271c2 100644
--- a/port/devmnt.c
+++ b/port/devmnt.c
@@ -768,19 +768,9 @@ mntgate(Mnt *m)
 	lock(m);
 	m->rip = 0;
 	for(q = m->queue; q; q = q->list) {
-		if(q->done == 0) {
-			x = splhi();	/* because sleep also does */
-			lock(&q->r);
-			if(q->r.p) {
-				unlock(&q->r);
-				splx(x);
-				unlock(m);
-				wakeup(&q->r);
-				return;
-			}
-			unlock(&q->r);
-			splx(x);
-		}
+		if(q->done == 0)
+		if(wakeup(&q->r))
+			break;
 	}
 	unlock(m);
 }
diff --git a/port/portdat.h b/port/portdat.h
index f6d3ce9c5b073c2acc16e2f4aa3de7f12f30c981..7c1eb0c3ddec98c593094234c310b801beb64925 100644
--- a/port/portdat.h
+++ b/port/portdat.h
@@ -50,7 +50,6 @@ struct Ref
 
 struct Rendez
 {
-	Lock;
 	Proc	*p;
 };
 
diff --git a/port/portfns.h b/port/portfns.h
index 2e80d3e3bcb4c0f2da701ff096276910e0b5bd69..1f0cdea78da3de35deff6500e59e4120305a04e3 100644
--- a/port/portfns.h
+++ b/port/portfns.h
@@ -286,7 +286,7 @@ long		userwrite(char*, int);
 void		validaddr(ulong, ulong, int);
 void		vcacheinval(Page*, ulong);
 void*		vmemchr(void*, int, int);
-void		wakeup(Rendez*);
+int		wakeup(Rendez*);
 Chan*		walk(Chan*, char*, int);
 void		wlock(RWlock*);
 void		wunlock(RWlock*);
diff --git a/port/proc.c b/port/proc.c
index 6f90ce1645ff1fb12ff90e7bb7d52f830c392de3..3acc99cf703af1d69e8de303205435230ec776b4 100644
--- a/port/proc.c
+++ b/port/proc.c
@@ -390,6 +390,8 @@ sleep1(Rendez *r, int (*f)(void*), void *arg)
 	}
 	r->p = up;
 
+	coherence();	/* force memory state to reflect processor state */
+
 	/*
 	 * if condition happened, never mind
 	 */
@@ -477,15 +479,18 @@ tsleep(Rendez *r, int (*fn)(void*), void *arg, int ms)
 /*
  * Expects that only one process can call wakeup for any given Rendez
  */
-void
+int
 wakeup(Rendez *r)
 {
 	Proc *p;
-	int s;
+	int s, rv;
 
+	coherence();	/* force memory state to reflect processor state */
+
+	rv = 0;
 	p = r->p;
 	if(p == 0)
-		return;
+		return rv;
 
 	s = splhi();
 	lock(&p->rlock);
@@ -496,10 +501,13 @@ wakeup(Rendez *r)
 			panic("wakeup: state");
 		p->r = 0;
 		ready(p);
+		rv = 1;
 	}
 
 	unlock(&p->rlock);
 	splx(s);
+
+	return rv;
 }
 
 int
diff --git a/port/taslock.c b/port/taslock.c
index dc2b8b6836b171fdcbef2f4c77984450d3d47547..3277c2ffd9bc61afcab54ac36daedde205bd050b 100644
--- a/port/taslock.c
+++ b/port/taslock.c
@@ -96,6 +96,7 @@ unlock(Lock *l)
 {
 	l->key = 0;
 	l->pc = 0;
+	coherence();
 }
 
 void
@@ -107,4 +108,5 @@ iunlock(Lock *l)
 	l->key = 0;
 	l->pc = 0;
 	splx(sr);
+	coherence();
 }
diff --git a/power/fns.h b/power/fns.h
index 62b1e65c4e4a67c63b9cc450f4409a16c06de3f9..d8ff6abdfe7a7cf4827e3e09702ed6c3a5892ce7 100644
--- a/power/fns.h
+++ b/power/fns.h
@@ -84,3 +84,4 @@ void	wbflush(void);
 Page*	lkpage(Segment*, ulong);
 void	lkpgfree(Page*);
 #define vcacheinval(s)
+#define coherence()