8 files changed, 123 insertions(+), 185 deletions(-)

M gnot/dat.h
M gnot/devmnt.c
M gnot/proc.c
M gnot/sysproc.c
M port/devmnt.c
M port/proc.c
M port/sysproc.c
M power/dat.h

@@ 325,10 325,6 @@ struct Proc
 	Seg	seg[NSEG];
 	ulong	bssend;			/* initial top of bss seg */
 	ulong	pid;
-	Lock	kidlock;		/* access to kid and sib */
-	Proc	*pop;			/* some ascendant */
-	Proc	*kid;			/* some descendant */
-	Proc	*sib;			/* non-ascendant relatives (circular list) */
 	int	nchild;
 	QLock	wait;			/* exiting children to be waited for */
 	ulong	waitmsg;


@@ 361,7 357,7 @@ struct MMUCache
 	MMU	mmu[NMMU];
 };
 
-#define	NERR	15
+#define	NERR	20
 #define	NNOTE	5
 #define	NFD	100
 struct User

@@ 49,7 49,8 @@ struct Mnthdr
 {
 	Mnthdr	*next;		/* in free list or writers list */
 	Mnthdr	*prev;		/* in writers list only */
-	int	writing;	/* flag: in writers list */
+	short	active;
+	short	flushing;	/* a Tflush has been sent */
 	Fcall	thdr;
 	Fcall	rhdr;
 	Rendez	r;


@@ 122,6 123,7 @@ loop:
 	lock(&mnthdralloc);
 	if(mh = mnthdralloc.free){		/* assign = */
 		mnthdralloc.free = mh->next;
+		mh->flushing = 0;
 		unlock(&mnthdralloc);
 		return mh;
 	}


@@ 138,6 140,9 @@ loop:
 void
 mhfree(Mnthdr *mh)
 {
+	if(mh->flushing)
+		return;
+	mh->active = 0;
 	lock(&mnthdralloc);
 	mh->next = mnthdralloc.free;
 	mnthdralloc.free = mh;


@@ 601,22 606,49 @@ mntwunlink(MntQ *q, Mnthdr *w)		/* queue is locked and w is a writer */
 		if(q->writer)
 			q->writer->prev = 0;
 	}
-	w->writing = 0;
 }
 
+/*
+ * m->q is unlocked.  Send Tflush message to flush omh->tag.
+ * Cut off all errors.   Caller will free omh
+ */
 void
-mnterrdequeue(MntQ *q, Mnthdr *mh)	/* queue is unlocked */
+mntflush(Mnt *m, Mnthdr *omh)	/* queue is unlocked */
+{
+	Mnthdr *mh;
+
+	if(omh->thdr.type == Tflush)
+		return;
+
+	mh = mhalloc();
+	if(waserror()){
+		omh->flushing = 0;
+		mhfree(mh);
+		return;		/* no more errors please */
+	}
+	mh->thdr.type = Tflush;
+	mh->thdr.oldtag = omh->thdr.tag;
+	mntxmit(m, mh);
+	omh->flushing = 0;
+	mhfree(mh);
+	poperror();
+}
+
+void
+mnterrdequeue(Mnt *m, Mnthdr *mh)	/* queue is unlocked */
 {
 	Mnthdr *w;
+	MntQ *q;
 
+	mh->flushing = 1;
+	q = m->q;
 	qlock(q);
 	/* take self from queue if necessary */
 	if(q->reader == u->p){	/* advance a writer to reader */
 		w = q->writer;
 		if(w){
+			mntwunlink(q, w);
 			q->reader = w->p;
-			q->writer = w->next;
-			q->writer->prev = 0;
 			wakeup(&w->r);
 		}else{
 			q->reader = 0;


@@ 625,7 657,7 @@ mnterrdequeue(MntQ *q, Mnthdr *mh)	/* queue is unlocked */
 	}else
 		mntwunlink(q, mh);
 	qunlock(q);
-
+	mntflush(m, mh);
 }
 
 int


@@ 641,11 673,11 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	Mntbuf *mbw, *t;
 	Mnthdr *w, *ow;
 	MntQ *q;
-	int qlocked, tag;
+	int qlocked, tag, written;
 
 	mh->mbr = mballoc();
 	mbw = mballoc();
-	if(waserror()){
+	if(waserror()){			/* 1 */
 		mbfree(mh->mbr);
 		mbfree(mbw);
 		nexterror();


@@ 663,7 695,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		goto Normal;
 
 	incref(q);
-	if(waserror()){
+	if(waserror()){		/* 2 */
 		mqfree(q);
 		nexterror();
 	}


@@ 677,7 709,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	 */
 	n = (*devtab[q->msg->type].read)(q->msg, mh->mbr->buf, BUFSIZE);
 	mqfree(q);
-	poperror();
+	poperror();		/* 2 */
 
 	if(convM2S(mh->mbr->buf, &mh->rhdr, n) == 0){
 		print("format error in mntxmit\n");


@@ 712,7 744,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		memcpy(mh->thdr.data, mh->rhdr.data, mh->rhdr.count);
 	mbfree(mh->mbr);
 	mbfree(mbw);
-	poperror();
+	poperror();		/* 1 */
 	return;
 
     Normal:


@@ 720,13 752,14 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	incref(q);
 	qlock(q);
 	qlocked = 1;
-	if(waserror()){
+	if(waserror()){		/* 2 */
 		if(qlocked)
 			qunlock(q);
 		mqfree(q);
 		nexterror();
 	}
 	mh->readreply = 0;
+	mh->active = 1;
 	if((*devtab[q->msg->type].write)(q->msg, mbw->buf, n) != n){
 		print("short write in mntxmit\n");
 		error(Eshortmsg);


@@ 736,14 769,15 @@ mntxmit(Mnt *m, Mnthdr *mh)
     Read:
 		qunlock(q);
 		qlocked = 0;
-		if(waserror()){
-			mnterrdequeue(q, mh);
+		if(waserror()){		/* 3 */
+			mnterrdequeue(m, mh);
 			nexterror();
 		}
 		n = (*devtab[q->msg->type].read)(q->msg, mh->mbr->buf, BUFSIZE);
-		poperror();
+		poperror();		/* 3 */
 		if(convM2S(mh->mbr->buf, &mh->rhdr, n) == 0){
-			mnterrdequeue(q, mh);
+			print("bad reply message\n");
+			mnterrdequeue(m, mh);
 			error(Ebadmsg);
 		}
 		/*


@@ 755,13 789,12 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		if(tag == mh->thdr.tag){	/* it's mine */
 			q->reader = 0;
 			if(w = q->writer){	/* advance a writer to reader */
+				mntwunlink(q, w);
 				q->reader = w->p;
-				q->writer = w->next;
-				if(q->writer)
-					q->writer->prev = 0;
 				w->readreply = 1;
 				wakeup(&w->r);
 			}
+			mh->active = 0;
 			qunlock(q);
 			qlocked = 0;
 			goto Respond;


@@ 774,10 807,8 @@ mntxmit(Mnt *m, Mnthdr *mh)
 			goto Read;
 		}
 		w = &mnthdralloc.arena[tag];
-		if(!w->writing){
-			print("reply not writing\n");
+		if(w->flushing || !w->active)	/* nothing to do; mntflush will clean up */
 			goto Read;
-		}
 		t = mh->mbr;
 		mh->mbr = w->mbr;
 		w->mbr = t;


@@ 791,14 822,13 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		/* put self in queue */
 		mh->next = q->writer;
 		mh->prev = 0;
-		mh->writing = 1;
 		if(q->writer)
 			q->writer->prev = mh;
 		q->writer = mh;
 		qunlock(q);
 		qlocked = 0;
 		if(waserror()){		/* interrupted sleep */
-			mnterrdequeue(q, mh);
+			mnterrdequeue(m, mh);
 			nexterror();
 		}
 		sleep(&mh->r, mntreadreply, mh);


@@ 807,6 837,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		qlocked = 1;
 		if(q->reader == u->p)	/* i got promoted */
 			goto Read;
+		mh->active = 0;
 		qunlock(q);
 		qlocked = 0;
 		goto Respond;


@@ 814,11 845,14 @@ mntxmit(Mnt *m, Mnthdr *mh)
 
     Respond:
 	mqfree(q);
-	poperror();
+	poperror();		/* 2 */
 	if(mh->rhdr.type == Rerror){
 		if(m->mntpt)
 			errors(mh->rhdr.ename);
 		error(Eshutdown);
+	}else if(mh->rhdr.type != mh->thdr.type+1){
+		print("bad type %d not %d in mntxmit\n", mh->rhdr.type, mh->thdr.type+1);
+		error(Ebadmsg);
 	}
 	/*
 	 * Copy out on read


@@ 830,7 864,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	}
 	mbfree(mh->mbr);
 	mbfree(mbw);
-	poperror();
+	poperror();		/* 1 */
 }
 
 mntdump()

@@ 281,9 281,6 @@ loop:
 		unlock(&procalloc);
 		p->mach = 0;
 		p->qnext = 0;
-		p->kid = 0;
-		p->sib = 0;
-		p->pop = 0;
 		p->nchild = 0;
 		p->child = 0;
 		p->exiting = 0;


@@ 350,7 347,7 @@ sleep1(Rendez *r, int (*f)(void*), void *arg)
 	 */
 	p = u->p;
 	if(r->p)
-		print("double sleep %d %d\n", r->p->pid, p->pid);
+		print("double sleep %lux %d %d\n", r, r->p->pid, p->pid);
 	p->r = r;
 	p->wokeup = 0;
 	p->state = Wakeme;


@@ 567,50 564,7 @@ pexit(char *s, int freemem)
 		close(u->dot);
 	}
 
-	/*
-	 * Rearrange inheritance hierarchy
-	 * 1. my children's pop is now my pop
-	 */
-	lock(&c->kidlock);
-	p = c->pop;
-	if(k = c->kid)		/* assign = */
-		do{
-			k->pop = p;
-			k = k->sib;
-		}while(k != c->kid);
-
-	/*
-	 * 2. cut me from pop's tree
-	 */
-	if(p == 0)	/* init process only; fix pops */
-		goto done;
-	lock(&p->kidlock);
-	k = p->kid;
-	while(k->sib != c)
-		k = k->sib;
-	if(k == c)
-		p->kid = 0;
-	else{
-		if(p->kid == c)
-			p->kid = c->sib;
-		k->sib = c->sib;
-	}
-
-	/*
-	 * 3. pass my children (pop's grandchildren) to pop
-	 */
-	if(k = c->kid){		/* assign = */
-		if(p->kid == 0)
-			p->kid = k;
-		else{
-			l = k->sib;
-			k->sib = p->kid->sib;
-			p->kid->sib = l;
-		}
-	}
-	unlock(&p->kidlock);
     done:
-	unlock(&c->kidlock);
 
 	lock(&procalloc);	/* sched() can't do this */
 	lock(&c->debug);	/* sched() can't do this */

@@ 112,20 112,6 @@ sysfork(ulong *arg)
 		if(c = u->fd[n])	/* assign = */
 			incref(c);
 	/*
-	 * Committed.  Link into hierarchy
-	 */
-	lock(&p->kidlock);
-	lock(&u->p->kidlock);
-	if(u->p->kid == 0){
-		p->sib = p;
-		u->p->kid = p;
-	}else{
-		p->sib = u->p->kid->sib;
-		u->p->kid->sib = p;
-	}
-	unlock(&u->p->kidlock);
-	unlock(&p->kidlock);
-	/*
 	 * Sched
 	 */
 	if(setlabel(&p->sched)){


@@ 133,7 119,6 @@ sysfork(ulong *arg)
 		restore();
 		return 0;
 	}
-	p->pop = u->p;
 	p->parent = u->p;
 	p->parentpid = u->p->pid;
 	p->pgrp = u->p->pgrp;

@@ 49,7 49,8 @@ struct Mnthdr
 {
 	Mnthdr	*next;		/* in free list or writers list */
 	Mnthdr	*prev;		/* in writers list only */
-	int	writing;	/* flag: in writers list */
+	short	active;
+	short	flushing;	/* a Tflush has been sent */
 	Fcall	thdr;
 	Fcall	rhdr;
 	Rendez	r;


@@ 122,6 123,7 @@ loop:
 	lock(&mnthdralloc);
 	if(mh = mnthdralloc.free){		/* assign = */
 		mnthdralloc.free = mh->next;
+		mh->flushing = 0;
 		unlock(&mnthdralloc);
 		return mh;
 	}


@@ 138,6 140,9 @@ loop:
 void
 mhfree(Mnthdr *mh)
 {
+	if(mh->flushing)
+		return;
+	mh->active = 0;
 	lock(&mnthdralloc);
 	mh->next = mnthdralloc.free;
 	mnthdralloc.free = mh;


@@ 601,22 606,49 @@ mntwunlink(MntQ *q, Mnthdr *w)		/* queue is locked and w is a writer */
 		if(q->writer)
 			q->writer->prev = 0;
 	}
-	w->writing = 0;
 }
 
+/*
+ * m->q is unlocked.  Send Tflush message to flush omh->tag.
+ * Cut off all errors.   Caller will free omh
+ */
 void
-mnterrdequeue(MntQ *q, Mnthdr *mh)	/* queue is unlocked */
+mntflush(Mnt *m, Mnthdr *omh)	/* queue is unlocked */
+{
+	Mnthdr *mh;
+
+	if(omh->thdr.type == Tflush)
+		return;
+
+	mh = mhalloc();
+	if(waserror()){
+		omh->flushing = 0;
+		mhfree(mh);
+		return;		/* no more errors please */
+	}
+	mh->thdr.type = Tflush;
+	mh->thdr.oldtag = omh->thdr.tag;
+	mntxmit(m, mh);
+	omh->flushing = 0;
+	mhfree(mh);
+	poperror();
+}
+
+void
+mnterrdequeue(Mnt *m, Mnthdr *mh)	/* queue is unlocked */
 {
 	Mnthdr *w;
+	MntQ *q;
 
+	mh->flushing = 1;
+	q = m->q;
 	qlock(q);
 	/* take self from queue if necessary */
 	if(q->reader == u->p){	/* advance a writer to reader */
 		w = q->writer;
 		if(w){
+			mntwunlink(q, w);
 			q->reader = w->p;
-			q->writer = w->next;
-			q->writer->prev = 0;
 			wakeup(&w->r);
 		}else{
 			q->reader = 0;


@@ 625,7 657,7 @@ mnterrdequeue(MntQ *q, Mnthdr *mh)	/* queue is unlocked */
 	}else
 		mntwunlink(q, mh);
 	qunlock(q);
-
+	mntflush(m, mh);
 }
 
 int


@@ 641,11 673,11 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	Mntbuf *mbw, *t;
 	Mnthdr *w, *ow;
 	MntQ *q;
-	int qlocked, tag;
+	int qlocked, tag, written;
 
 	mh->mbr = mballoc();
 	mbw = mballoc();
-	if(waserror()){
+	if(waserror()){			/* 1 */
 		mbfree(mh->mbr);
 		mbfree(mbw);
 		nexterror();


@@ 663,7 695,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		goto Normal;
 
 	incref(q);
-	if(waserror()){
+	if(waserror()){		/* 2 */
 		mqfree(q);
 		nexterror();
 	}


@@ 677,7 709,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	 */
 	n = (*devtab[q->msg->type].read)(q->msg, mh->mbr->buf, BUFSIZE);
 	mqfree(q);
-	poperror();
+	poperror();		/* 2 */
 
 	if(convM2S(mh->mbr->buf, &mh->rhdr, n) == 0){
 		print("format error in mntxmit\n");


@@ 712,7 744,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		memcpy(mh->thdr.data, mh->rhdr.data, mh->rhdr.count);
 	mbfree(mh->mbr);
 	mbfree(mbw);
-	poperror();
+	poperror();		/* 1 */
 	return;
 
     Normal:


@@ 720,13 752,14 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	incref(q);
 	qlock(q);
 	qlocked = 1;
-	if(waserror()){
+	if(waserror()){		/* 2 */
 		if(qlocked)
 			qunlock(q);
 		mqfree(q);
 		nexterror();
 	}
 	mh->readreply = 0;
+	mh->active = 1;
 	if((*devtab[q->msg->type].write)(q->msg, mbw->buf, n) != n){
 		print("short write in mntxmit\n");
 		error(Eshortmsg);


@@ 736,14 769,15 @@ mntxmit(Mnt *m, Mnthdr *mh)
     Read:
 		qunlock(q);
 		qlocked = 0;
-		if(waserror()){
-			mnterrdequeue(q, mh);
+		if(waserror()){		/* 3 */
+			mnterrdequeue(m, mh);
 			nexterror();
 		}
 		n = (*devtab[q->msg->type].read)(q->msg, mh->mbr->buf, BUFSIZE);
-		poperror();
+		poperror();		/* 3 */
 		if(convM2S(mh->mbr->buf, &mh->rhdr, n) == 0){
-			mnterrdequeue(q, mh);
+			print("bad reply message\n");
+			mnterrdequeue(m, mh);
 			error(Ebadmsg);
 		}
 		/*


@@ 755,13 789,12 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		if(tag == mh->thdr.tag){	/* it's mine */
 			q->reader = 0;
 			if(w = q->writer){	/* advance a writer to reader */
+				mntwunlink(q, w);
 				q->reader = w->p;
-				q->writer = w->next;
-				if(q->writer)
-					q->writer->prev = 0;
 				w->readreply = 1;
 				wakeup(&w->r);
 			}
+			mh->active = 0;
 			qunlock(q);
 			qlocked = 0;
 			goto Respond;


@@ 774,10 807,8 @@ mntxmit(Mnt *m, Mnthdr *mh)
 			goto Read;
 		}
 		w = &mnthdralloc.arena[tag];
-		if(!w->writing){
-			print("reply not writing\n");
+		if(w->flushing || !w->active)	/* nothing to do; mntflush will clean up */
 			goto Read;
-		}
 		t = mh->mbr;
 		mh->mbr = w->mbr;
 		w->mbr = t;


@@ 791,14 822,13 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		/* put self in queue */
 		mh->next = q->writer;
 		mh->prev = 0;
-		mh->writing = 1;
 		if(q->writer)
 			q->writer->prev = mh;
 		q->writer = mh;
 		qunlock(q);
 		qlocked = 0;
 		if(waserror()){		/* interrupted sleep */
-			mnterrdequeue(q, mh);
+			mnterrdequeue(m, mh);
 			nexterror();
 		}
 		sleep(&mh->r, mntreadreply, mh);


@@ 807,6 837,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		qlocked = 1;
 		if(q->reader == u->p)	/* i got promoted */
 			goto Read;
+		mh->active = 0;
 		qunlock(q);
 		qlocked = 0;
 		goto Respond;


@@ 814,11 845,14 @@ mntxmit(Mnt *m, Mnthdr *mh)
 
     Respond:
 	mqfree(q);
-	poperror();
+	poperror();		/* 2 */
 	if(mh->rhdr.type == Rerror){
 		if(m->mntpt)
 			errors(mh->rhdr.ename);
 		error(Eshutdown);
+	}else if(mh->rhdr.type != mh->thdr.type+1){
+		print("bad type %d not %d in mntxmit\n", mh->rhdr.type, mh->thdr.type+1);
+		error(Ebadmsg);
 	}
 	/*
 	 * Copy out on read


@@ 830,7 864,7 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	}
 	mbfree(mh->mbr);
 	mbfree(mbw);
-	poperror();
+	poperror();		/* 1 */
 }
 
 mntdump()

@@ 166,9 166,6 @@ loop:
 		unlock(&procalloc);
 		p->mach = 0;
 		p->qnext = 0;
-		p->kid = 0;
-		p->sib = 0;
-		p->pop = 0;
 		p->nchild = 0;
 		p->child = 0;
 		p->exiting = 0;


@@ 477,50 474,7 @@ pexit(char *s, int freemem)
 		close(u->dot);
 	}
 
-	/*
-	 * Rearrange inheritance hierarchy
-	 * 1. my children's pop is now my pop
-	 */
-	lock(&c->kidlock);
-	p = c->pop;
-	if(k = c->kid)		/* assign = */
-		do{
-			k->pop = p;
-			k = k->sib;
-		}while(k != c->kid);
-
-	/*
-	 * 2. cut me from pop's tree
-	 */
-	if(p == 0)	/* init process only; fix pops */
-		goto done;
-	lock(&p->kidlock);
-	k = p->kid;
-	while(k->sib != c)
-		k = k->sib;
-	if(k == c)
-		p->kid = 0;
-	else{
-		if(p->kid == c)
-			p->kid = c->sib;
-		k->sib = c->sib;
-	}
-
-	/*
-	 * 3. pass my children (pop's grandchildren) to pop
-	 */
-	if(k = c->kid){		/* assign = */
-		if(p->kid == 0)
-			p->kid = k;
-		else{
-			l = k->sib;
-			k->sib = p->kid->sib;
-			p->kid->sib = l;
-		}
-	}
-	unlock(&p->kidlock);
     done:
-	unlock(&c->kidlock);
 
 	lock(&procalloc);	/* sched() can't do this */
 	lock(&c->debug);	/* sched() can't do this */

@@ 111,20 111,6 @@ sysfork(ulong *arg)
 		if(c = u->fd[n])	/* assign = */
 			incref(c);
 	/*
-	 * Committed.  Link into hierarchy
-	 */
-	lock(&p->kidlock);
-	lock(&u->p->kidlock);
-	if(u->p->kid == 0){
-		p->sib = p;
-		u->p->kid = p;
-	}else{
-		p->sib = u->p->kid->sib;
-		u->p->kid->sib = p;
-	}
-	unlock(&u->p->kidlock);
-	unlock(&p->kidlock);
-	/*
 	 * Sched
 	 */
 	if(setlabel(&p->sched)){


@@ 135,7 121,6 @@ sysfork(ulong *arg)
 		spllo();
 		return 0;
 	}
-	p->pop = u->p;
 	p->parent = u->p;
 	p->parentpid = u->p->pid;
 	p->pgrp = u->p->pgrp;

@@ 316,10 316,6 @@ struct Proc
 	Page	*upage;			/* BUG: should be unlinked from page list */
 	Seg	seg[NSEG];
 	ulong	pid;
-	Lock	kidlock;		/* access to kid and sib */
-	Proc	*pop;			/* some ascendant */
-	Proc	*kid;			/* some descendant */
-	Proc	*sib;			/* non-ascendant relatives (circular list) */
 	int	nchild;
 	QLock	wait;			/* exiting children to be waited for */
 	ulong	waitmsg;


@@ 339,7 335,7 @@ struct Proc
 
 };
 
-#define	NERR	15
+#define	NERR	20
 #define	NFD	100
 #define	NNOTE	5
 struct User