23 files changed, 348 insertions(+), 186 deletions(-)

M gnot/chan.c
M gnot/clock.c
M gnot/devcons.c
M gnot/devdk.c
M gnot/devincon.c
M gnot/fns.h
M gnot/main.c
M gnot/pgrp.c
M gnot/proc.c
M gnot/screen.c
M gnot/stream.c
M gnot/sturp.c
M gnot/trap.c
M port/chan.c
M port/devcons.c
M port/devdk.c
M port/pgrp.c
M port/stream.c
M port/sturp.c
M port/sysfile.c
M power/devbit.c
M power/fns.h
M power/main.c

@@ 149,7 149,7 @@ mount(Chan *new, Chan *old, int flag)
 	Mtab *mt, *mz;
 	Mount *mnt, *omnt, *nmnt, *pmnt;
 	Pgrp *pg;
-	int isnew;
+	int islast;
 
 	if(CHDIR & (old->qid^new->qid))
 		error(0, Emount);


@@ 157,10 157,15 @@ mount(Chan *new, Chan *old, int flag)
 		error(0, Emount);
 
 	mz = 0;
-	isnew = 0;
+	islast = 0;
+	mnt = 0;
 	pg = u->p->pgrp;
 	lock(pg);
 	if(waserror()){
+		if(mnt){
+			mnt->c = 0;	/* caller will close new */
+			closemount(mnt);
+		}
 		unlock(pg);
 		nexterror();
 	}


@@ 171,18 176,18 @@ mount(Chan *new, Chan *old, int flag)
 	for(i=0; i<pg->nmtab; i++,mt++){
 		if(mt->c==0 && mz==0)
 			mz = mt;
-		else if(eqchan(mt->c, old, CHDIR|QPATH))
+		else if(eqchan(mt->c, old, CHDIR|QPATH)){
+			mz = 0;
 			goto Found;
+		}
 	}
-	isnew = 1;
 	if(mz == 0){
 		if(i == conf.nmtab)
 			error(0, Enomount);
 		mz = &pg->mtab[i];
-		pg->nmtab++;
+		islast++;
 	}
 	mz->mnt = 0;
-	mz->c = old;
 	mt = mz;
 
     Found:


@@ 244,8 249,12 @@ mount(Chan *new, Chan *old, int flag)
 	}
 
 	incref(new);
-	if(isnew)
+	if(mz){
+		mz->c = old;
 		incref(old);
+	}
+	if(islast)
+		pg->nmtab++;
 	unlock(pg);
 	poperror();
 	return mnt->mountid;


@@ 286,7 295,7 @@ domount(Chan *c)
     Found:
 	lock(pg);
 	if(!eqchan(mt->c, c, CHDIR|QPATH)){	/* table changed underfoot */
-		print("domount: changed underfoot?\n");
+		pprint("domount: changed underfoot?\n");
 		unlock(pg);
 		return c;
 	}


@@ 333,7 342,7 @@ walk(Chan *ac, char *name, int domnt)
 			goto Notfound;
 		}
 		if(c->mountid != mnt->mountid){
-			print("walk: changed underfoot?\n");
+			pprint("walk: changed underfoot?\n");
 			unlock(pg);
 			goto Notfound;
 		}


@@ 353,6 362,7 @@ walk(Chan *ac, char *name, int domnt)
 		if(!first)
 			close(c);
 		nc->mnt = mnt;
+		nc->mountid = mnt->mountid;
 		c = nc;
 		first = 0;
 		goto Again;


@@ 391,7 401,7 @@ createdir(Chan *c)
 	}
 	mnt = c->mnt;
 	if(c->mountid != mnt->mountid){
-		print("createdir: changed underfoot?\n");
+		pprint("createdir: changed underfoot?\n");
 		error(0, Enocreate);
 	}
 	do{

@@ 117,9 117,10 @@ clock(Ureg *ur)
 		}
 		unlock(&m->alarmlock);
 	}
+	kbdclock();
 	if((ur->sr&SPL(7)) == 0){
 		spllo();
 		if(p && p->state==Running)
-			sched();
+			checksched();
 	}
 }

@@ 30,9 30,15 @@ struct IOQ{
 	Rendez	r;
 };
 
-IOQ	kbdq;		/* qlock to getc; interrupt putc's */
 IOQ	lineq;		/* lock to getc; interrupt putc's */
 
+struct{
+	IOQ;		/* qlock to getc; interrupt putc's */
+	int	c;
+	int	repeat;
+	int	count;
+}kbdq;
+
 void
 printinit(void)
 {


@@ 142,17 148,18 @@ pprint(char *fmt, ...)
 
 	c = u->fd[2];
 	if(c==0 || (c->mode!=OWRITE && c->mode!=ORDWR))
-		return;
+		return 0;
 	n = sprint(buf, "%s %d: ", u->p->text, u->p->pid);
 	n = donprint(buf+n, buf+sizeof(buf), fmt, (&fmt+1)) - buf;
 	qlock(c);
 	if(waserror()){
 		qunlock(c);
-		return;
+		return 0;
 	}
 	(*devtab[c->type].write)(c, buf, n);
 	c->offset += n;
 	qunlock(c);
+	poperror();
 	return n;
 }
 


@@ 185,9 192,15 @@ echo(int c)
  * Put character into read queue at interrupt time.
  * Always called splhi from proc 0.
  */
+
 void
 kbdchar(int c)
 {
+	if(kbdq.repeat == 1){
+		kbdq.c = c;
+		kbdq.count = 0;
+		kbdq.repeat = 2;
+	}
 	if(c == '\r')
 		c = '\n';
 	echo(c);


@@ 198,6 211,22 @@ kbdchar(int c)
 		wakeup(&kbdq.r);
 }
 
+void
+kbdrepeat(int rep)
+{
+	if(rep)
+		kbdq.repeat = 1;
+	else
+		kbdq.repeat = 0;
+}
+
+void
+kbdclock(void)
+{
+	if(kbdq.repeat==2 && (++kbdq.count&1))
+		kbdchar(kbdq.c);
+}
+
 int
 consactive(void)
 {

@@ 538,6 538,8 @@ Dirtab dksubdir[]={
 void
 dkreset(void)
 {
+	newqinfo(&dkmuxinfo);
+	newqinfo(&urpinfo);
 }
 
 /*

@@ 23,8 23,9 @@ enum {
 	Minstation=	2,	/* lowest station # to poll */
 	Maxstation=	15,	/* highest station # to poll */
 	Nincon=		1,	/* number of incons */
-	Nin=		16,	/* Blocks in the input ring */
+	Nin=		64,	/* Blocks in the input ring */
 	Bsize=		128,	/* size of an input ring block */
+	Mfifo=		0xff	/* a mask, must be 2^n-1, must be > Nin */
 };
 
 /*


@@ 631,7 632,7 @@ inconkproc(void *arg)
 }
 
 /*
- *  drop an input packet on the floor
+ *  drop a single packet
  */
 static void
 droppacket(Device *dev)


@@ 639,17 640,24 @@ droppacket(Device *dev)
 	int i;
 	int c;
 
-	screenputc('!');
-	while(!(dev->status & RCV_EMPTY)){
-		for(i = 0; i < 17; i++){
-			c = dev->data_cntl;
-			if(c==0)
-				break;
-		}
+	for(i = 0; i < 17; i++){
+		c = dev->data_cntl;
+		if(c==0)
+			break;
 	}
 }
 
 /*
+ *  flush the input fifo
+ */
+static void
+flushfifo(Device *dev)
+{
+	while(!(dev->status & RCV_EMPTY))
+		droppacket(dev);
+}
+
+/*
  *  advance the queue. if we've run out of staged input blocks,
  *  drop the packet and return 0.  otherwise return the next input
  *  block to fill.


@@ 657,19 665,20 @@ droppacket(Device *dev)
 static Block *
 nextin(Incon *ip, unsigned int c)
 {
-	Block *bp = ip->inb[ip->wi];
+	Block *bp;
 	int next;
 
-	next = (ip->wi+1)%Nin;
-	if(next == ip->ri){
-		bp->wptr = bp->base+3;
-		droppacket(ip->dev);
-		return 0;
-	}
+	bp = ip->inb[ip->wi];
 	bp->base[0] = ip->chan;
 	bp->base[1] = ip->chan>>8;
 	bp->base[2] = c;
-	ip->wi = next;
+
+	next = (ip->wi+3)%Nin;
+	if(next == ip->ri){
+		bp->wptr = bp->base+3;
+		return bp;
+	}
+	ip->wi = (ip->wi+1)%Nin;
 
 	return ip->inb[ip->wi];
 }


@@ 690,8 699,8 @@ rdpackets(Incon *ip)
 	dev = ip->dev;
 	bp = ip->inb[ip->wi];
 	if(bp==0){
-		droppacket(ip->dev);
-		goto done;
+		flushfifo(ip->dev);
+		return;
 	}
 	p = bp->wptr;
 	while(!(dev->status & RCV_EMPTY)){


@@ 699,12 708,14 @@ rdpackets(Incon *ip)
 		 *  get channel number
 		 */
 		c = (dev->data_cntl)>>8;
+		if(c == 0){
+			droppacket(dev);
+			continue;
+		}
 		if(ip->chan != c){
 			if(p - bp->rptr > 3){
 				bp->wptr = p;
 				bp = nextin(ip, 0);
-				if(bp == 0)
-					goto done;
 				p = bp->wptr;
 			}
 			ip->chan = c;


@@ 725,8 736,6 @@ rdpackets(Incon *ip)
 				 */
 				bp->wptr = p;
 				bp = nextin(ip, c);
-				if(bp == 0)
-					goto done;
 				p = bp->wptr;
 			} else {
 				/* end of packet */


@@ 741,14 750,11 @@ rdpackets(Incon *ip)
 		if(p + 16 > bp->lim){
 			bp->wptr = p;
 			bp = nextin(ip, 0);
-			if(bp == 0)
-				goto done;
 			p = bp->wptr;
 		}
 	}	
 	bp->wptr = p;
 
-done:
 	if(first != ip->wi)/**/
 		wakeup(&ip->kr);
 }

@@ 8,6 8,7 @@ int	canqlock(QLock*);
 void	chaninit(void);
 void	chandevreset(void);
 void	chandevinit(void);
+void	checksched(void);
 void	clock(Ureg*);
 Chan	*clone(Chan*, Chan*);
 void	close(Chan*);


@@ 58,6 59,8 @@ int	incref(Ref*);
 void	insert(List**, List*, List*);
 void	isdir(Chan*);
 void	kbdchar(int);
+void	kbdrepeat(int);
+void	kbdclock(void);
 void	kproc(char*, void(*)(void*), void*);
 void	lock(Lock*);
 void	lockinit(void);


@@ 76,6 79,7 @@ Orig	*neworig(ulong, ulong, int, Chan*);
 Page	*newpage(int, Orig*, ulong);
 Pgrp	*newpgrp(void);
 Proc	*newproc(void);
+void	newqinfo(Qinfo*);
 char	*nextelem(char*, char*);
 void	nullput(Queue*, Block*);
 int	openmode(ulong);

@@ 240,10 240,10 @@ confinit(void)
 	conf.nmod = 50;
 	conf.nalarm = 1000;
 	conf.norig = 50;
-	conf.nchan = 100;
-	conf.nenv = 50;
-	conf.nenvchar = 4000;
-	conf.npgenv = 100;
+	conf.nchan = 200;
+	conf.nenv = 100;
+	conf.nenvchar = 8000;
+	conf.npgenv = 200;
 	conf.nmtab = 50;
 	conf.nmount = 100;
 	conf.nmntdev = 5;


@@ 251,6 251,6 @@ confinit(void)
 	conf.nmnthdr = 10;
 	conf.nstream = 64;
 	conf.nqueue = 5 * conf.nstream;
-	conf.nblock = 16 * conf.nstream;
+	conf.nblock = 32 * conf.nstream;
 	conf.nsrv = 32;
 }

@@ 122,7 122,8 @@ closemount(Mount *m)
 {
 	lock(m);
 	if(m->ref == 1){
-		close(m->c);
+		if(m->c)
+			close(m->c);
 		if(m->next)
 			closemount(m->next);
 		unlock(m);

@@ 117,6 117,13 @@ ready(Proc *p)
 	splx(s);
 }
 
+void
+checksched(void)		/* just for efficiency; don't sched if no need */
+{
+	if(runq.head)
+		sched();
+}
+
 /*
  * Always called spllo
  */

@@ 161,11 161,15 @@ duartintr(void)
 		c = duart->data;
 		if(status & (FRM_ERR|OVR_ERR|PAR_ERR))
 			duart->cmnd = RESET_ERR;
-		if(c == 0x7F)
-			c = 0xFF;	/* VIEW key (bizarre) */
-		if(c & 0x80)
-			c = keymap[c&0x7F];
-		kbdchar(c);
+		if(status & PAR_ERR) /* control word: caps lock (0x4) or repeat (0x10) */
+			kbdrepeat((c&0x10) == 0);
+		else{
+			if(c == 0x7F)
+				c = 0xFF;	/* VIEW key (bizarre) */
+			if(c & 0x80)
+				c = keymap[c&0x7F];
+			kbdchar(c);
+		}
 	}
 	/*
 	 * Is it 2?

@@ 7,6 7,11 @@
 #include	"errno.h"
 #include	"devtab.h"
 
+enum {
+	Nclass=4,	/* number of block classes */
+	Nlds=32,	/* max number of pushable line disciplines */
+};
+
 /*
  *  process end line discipline
  */


@@ 15,21 20,21 @@ Qinfo procinfo = { stputq, nullput, 0, 0, "process" };
 
 /*
  *  line disciplines that can be pushed
- *
- *  WARNING: this table should be the result of configuration
- */
-extern Qinfo noetherinfo;
-extern Qinfo dkmuxinfo;
-extern Qinfo urpinfo;
-static Qinfo *lds[] = {
-	&dkmuxinfo,
-	&urpinfo,
-	0
-};
+ */
+static Qinfo *lds[Nlds+1];
 
-enum {
-	Nclass=4,
-};
+void
+newqinfo(Qinfo *qi)
+{
+	int i;
+
+	for(i=0; i<Nlds && lds[i]; i++)
+		if(lds[i] == qi)
+			return;
+	if(i == Nlds)
+		panic("pushable");
+	lds[i] = qi;
+}
 
 /*
  *  All stream structures are ialloc'd at boot time


@@ 51,8 56,8 @@ typedef struct {
 } Bclass;
 Bclass bclass[Nclass]={
 	{ 0 },
-	{ 64 },
-	{ 512 },
+	{ 68 },
+	{ 260 },
 	{ 4096 },
 };
 


@@ 88,7 93,6 @@ streaminit(void)
 	}
 }
 
-
 /*
  *  allocate a block
  */


@@ 169,7 173,8 @@ freeb(Block *bp)
 	}
 	bcp->last = bp;
 	unlock(bcp);
-	wakeup(&bcp->r);
+	if(bcp->r.p)
+		wakeup(&bcp->r);
 }
 
 /*


@@ 716,30 721,37 @@ streamclose(Chan *c)
 void
 stputq(Queue *q, Block *bp)
 {
-	int i;
+	int delim;
 
 	if(bp->type == M_HANGUP){
 		freeb(bp);
 		q->flag |= QHUNGUP;
 		q->other->flag |= QHUNGUP;
 		wakeup(&q->other->r);
+		delim = 1;
 	} else {
+		delim = 0;
 		lock(q);
 		if(q->first)
 			q->last->next = bp;
 		else
 			q->first = bp;
 		q->len += BLEN(bp);
+		delim = bp->flags & S_DELIM;
 		while(bp->next) {
 			bp = bp->next;
 			q->len += BLEN(bp);
+			delim |= bp->flags & S_DELIM;
 		}
 		q->last = bp;
-		if(q->len >= Streamhi)
+		if(q->len >= Streamhi){
 			q->flag |= QHIWAT;
+			delim = 1;
+		}
 		unlock(q);
 	}
-	wakeup(&q->r);
+	if(delim)
+		wakeup(&q->r);
 }
 
 /*

@@ 39,12 39,13 @@ struct Urp {
 	Rendez	r;		/* process waiting for close */
 
 	/* input */
-
+	QLock	ack;		/* ack lock */
 	Queue	*rq;		/* input queue */
 	uchar	iseq;		/* last good input sequence number */
 	uchar	lastecho;	/* last echo/rej sent */
 	uchar	trbuf[3];	/* trailer being collected */
 	short	trx;		/* # bytes in trailer being collected */
+	int	blocks;
 
 	/* output */
 


@@ 110,6 111,8 @@ static void	sendblock(Urp*, int);
 static void	rcvack(Urp*, int);
 static void	flushinput(Urp*);
 static void	sendctl(Urp*, int);
+static void	sendack(Urp*);
+static void	sendrej(Urp*);
 static void	initoutput(Urp*, int);
 static void	initinput(Urp*, int);
 static void	urpkproc(void *arg);


@@ 305,10 308,12 @@ urpciput(Queue *q, Block *bp)
 
 	case SEQ+0: case SEQ+1: case SEQ+2: case SEQ+3:
 	case SEQ+4: case SEQ+5: case SEQ+6: case SEQ+7:
+		qlock(&up->ack);
 		i = ctl & Nmask;
 		if(q->next->len < Streamhi)
 			sendctl(up, up->lastecho = ECHO+i);
 		up->iseq = i;
+		qunlock(&up->ack);
 		break;
 	}
 }


@@ 377,7 382,8 @@ urpiput(Queue *q, Block *bp)
 	case 0:
 		break;
 	case ENQ:
-		DPRINT("rENQ %uo %uo\n", up->lastecho, ACK+up->iseq);
+		DPRINT("rENQ %d %uo %uo\n", up->blocks, up->lastecho, ACK+up->iseq);
+		up->blocks = 0;
 		urpstat.enqsr++;
 		sendctl(up, up->lastecho);
 		sendctl(up, ACK+up->iseq);


@@ 440,25 446,15 @@ urpiput(Queue *q, Block *bp)
 		i = ctl & Nmask;
 		if(up->trx != 3){
 			urpstat.rjtrs++;
-			flushinput(up);
-			DPRINT("sREJ1 %d\n", up->iseq);
-			if((up->lastecho&~7)==ECHO)
-				sendctl(up, up->lastecho = REJ+up->iseq);/**/
+			sendrej(up);
 			break;
 		} else if(q->len != up->trbuf[1] + (up->trbuf[2]<<8)){
 			urpstat.rjpks++;
-			DPRINT("sREJ2 %d %d %d\n", up->iseq, q->len,
-				up->trbuf[1] + (up->trbuf[2]<<8));
-			flushinput(up);
-			if((up->lastecho&~7)==ECHO)
-				sendctl(up, up->lastecho = REJ+up->iseq);/**/
+			sendrej(up);
 			break;
 		} else if(i != ((up->iseq+1)&Nmask)) {
 			urpstat.rjseq++;
-			flushinput(up);
-			DPRINT("sREJ3 %d %d\n", i, up->iseq);
-			if((up->lastecho&~7)==ECHO)
-				sendctl(up, up->lastecho = REJ+up->iseq);/**/
+			sendrej(up);
 			break;
 		}
 


@@ 480,11 476,11 @@ urpiput(Queue *q, Block *bp)
 		/*
 		 *  acknowledge receipt
 		 */
-		if(q->next->len < Streamhi){
-			sendctl(up, up->lastecho = ECHO+i);
-			wakeup(&up->rq->r);
-		}
+		qlock(&up->ack);
 		up->iseq = i;
+		if(q->next->len < Streamhi)
+			sendctl(up, up->lastecho = ECHO|i);
+		qunlock(&up->ack);
 		break;
 	}
 }


@@ 636,6 632,53 @@ sendctl(Urp *up, int ctl)
 }
 
 /*
+ *  send a reject
+ */
+static void
+sendrej(Urp *up)
+{
+	flushinput(up);
+	qlock(&up->ack);
+	if((up->lastecho&~Nmask) == ECHO){
+		DPRINT("REJ %d\n", up->iseq);
+		sendctl(up, up->lastecho = REJ|up->iseq);
+	}
+	qunlock(&up->ack);
+}
+
+/*
+ *  send an acknowledge
+ */
+static void
+sendack(Urp *up)
+{
+	Block *bp;
+
+	/*
+	 *  check the precondition for acking
+	 */
+	if(up->rq->next->len>=Streamhi || (up->lastecho&Nmask)==up->iseq)
+		return;
+
+	if(!canqlock(&up->ack))
+		return;
+
+	/*
+	 *  check again now that we've locked
+	 */
+	if(up->rq->next->len>=Streamhi || (up->lastecho&Nmask)==up->iseq){
+		qunlock(&up->ack);
+		return;
+	}
+
+	/*
+	 *  send the ack
+	 */
+	sendctl(up, up->lastecho = ECHO|up->iseq);
+	qunlock(&up->ack);
+}
+
+/*
  *  send a block.
  */
 static void


@@ 801,6 844,7 @@ initinput(Urp *up, int window)
 	/*
 	 *  restart all sequence parameters
 	 */
+	up->blocks = 0;
 	up->trx = 0;
 	up->iseq = 0;
 	up->lastecho = ECHO+0;


@@ 832,8 876,7 @@ urpkproc(void *arg)
 			if(up->state & HUNGUP)
 				break;
 		}
-		if((up->lastecho&Nmask)!=up->iseq && up->rq->next->len<Streamhi)
-			sendctl(up, up->lastecho = ECHO+up->iseq);
+		sendack(up);
 		output(up);
 		tsleep(&up->rq->r, todo, up, MSrexmit/2);
 	}

@@ 270,6 270,7 @@ syscall(Ureg *aur)
 	ret = -1;
 	if(!waserror())
 		ret = (*systab[r0])((ulong*)(sp+BY2WD));
+else print("syscall %d err %d %d\n", r0, u->error.type, u->error.code);
 	u->nerrlab = 0;
 	u->p->insyscall = 0;
 	if(r0 == NOTED)	/* ugly hack */

@@ 149,7 149,7 @@ mount(Chan *new, Chan *old, int flag)
 	Mtab *mt, *mz;
 	Mount *mnt, *omnt, *nmnt, *pmnt;
 	Pgrp *pg;
-	int isnew;
+	int islast;
 
 	if(CHDIR & (old->qid^new->qid))
 		error(0, Emount);


@@ 157,10 157,15 @@ mount(Chan *new, Chan *old, int flag)
 		error(0, Emount);
 
 	mz = 0;
-	isnew = 0;
+	islast = 0;
+	mnt = 0;
 	pg = u->p->pgrp;
 	lock(pg);
 	if(waserror()){
+		if(mnt){
+			mnt->c = 0;	/* caller will close new */
+			closemount(mnt);
+		}
 		unlock(pg);
 		nexterror();
 	}


@@ 171,18 176,18 @@ mount(Chan *new, Chan *old, int flag)
 	for(i=0; i<pg->nmtab; i++,mt++){
 		if(mt->c==0 && mz==0)
 			mz = mt;
-		else if(eqchan(mt->c, old, CHDIR|QPATH))
+		else if(eqchan(mt->c, old, CHDIR|QPATH)){
+			mz = 0;
 			goto Found;
+		}
 	}
-	isnew = 1;
 	if(mz == 0){
 		if(i == conf.nmtab)
 			error(0, Enomount);
 		mz = &pg->mtab[i];
-		pg->nmtab++;
+		islast++;
 	}
 	mz->mnt = 0;
-	mz->c = old;
 	mt = mz;
 
     Found:


@@ 244,8 249,12 @@ mount(Chan *new, Chan *old, int flag)
 	}
 
 	incref(new);
-	if(isnew)
+	if(mz){
+		mz->c = old;
 		incref(old);
+	}
+	if(islast)
+		pg->nmtab++;
 	unlock(pg);
 	poperror();
 	return mnt->mountid;


@@ 286,7 295,7 @@ domount(Chan *c)
     Found:
 	lock(pg);
 	if(!eqchan(mt->c, c, CHDIR|QPATH)){	/* table changed underfoot */
-		print("domount: changed underfoot?\n");
+		pprint("domount: changed underfoot?\n");
 		unlock(pg);
 		return c;
 	}


@@ 333,7 342,7 @@ walk(Chan *ac, char *name, int domnt)
 			goto Notfound;
 		}
 		if(c->mountid != mnt->mountid){
-			print("walk: changed underfoot?\n");
+			pprint("walk: changed underfoot?\n");
 			unlock(pg);
 			goto Notfound;
 		}


@@ 353,6 362,7 @@ walk(Chan *ac, char *name, int domnt)
 		if(!first)
 			close(c);
 		nc->mnt = mnt;
+		nc->mountid = mnt->mountid;
 		c = nc;
 		first = 0;
 		goto Again;


@@ 391,7 401,7 @@ createdir(Chan *c)
 	}
 	mnt = c->mnt;
 	if(c->mountid != mnt->mountid){
-		print("createdir: changed underfoot?\n");
+		pprint("createdir: changed underfoot?\n");
 		error(0, Enocreate);
 	}
 	do{

@@ 180,17 180,18 @@ pprint(char *fmt, ...)
 
 	c = u->fd[2];
 	if(c==0 || (c->mode!=OWRITE && c->mode!=ORDWR))
-		return;
+		return 0;
 	n = sprint(buf, "%s %d: ", u->p->text, u->p->pid);
 	n = donprint(buf+n, buf+sizeof(buf), fmt, (&fmt+1)) - buf;
 	qlock(c);
 	if(waserror()){
 		qunlock(c);
-		return;
+		return 0;
 	}
 	(*devtab[c->type].write)(c, buf, n);
 	c->offset += n;
 	qunlock(c);
+	poperror();
 	return n;
 }
 

@@ 538,6 538,8 @@ Dirtab dksubdir[]={
 void
 dkreset(void)
 {
+	newqinfo(&dkmuxinfo);
+	newqinfo(&urpinfo);
 }
 
 /*

@@ 122,7 122,8 @@ closemount(Mount *m)
 {
 	lock(m);
 	if(m->ref == 1){
-		close(m->c);
+		if(m->c)
+			close(m->c);
 		if(m->next)
 			closemount(m->next);
 		unlock(m);

@@ 7,6 7,11 @@
 #include	"errno.h"
 #include	"devtab.h"
 
+enum {
+	Nclass=4,	/* number of block classes */
+	Nlds=32,	/* max number of pushable line disciplines */
+};
+
 /*
  *  process end line discipline
  */


@@ 15,22 20,21 @@ Qinfo procinfo = { stputq, nullput, 0, 0, "process" };
 
 /*
  *  line disciplines that can be pushed
- *
- *  WARNING: this table should be the result of configuration
- */
-extern Qinfo noetherinfo;
-extern Qinfo dkmuxinfo;
-extern Qinfo urpinfo;
-static Qinfo *lds[] = {
-	&noetherinfo,
-	&dkmuxinfo,
-	&urpinfo,
-	0
-};
+ */
+static Qinfo *lds[Nlds+1];
 
-enum {
-	Nclass=4,
-};
+void
+newqinfo(Qinfo *qi)
+{
+	int i;
+
+	for(i=0; i<Nlds && lds[i]; i++)
+		if(lds[i] == qi)
+			return;
+	if(i == Nlds)
+		panic("pushable");
+	lds[i] = qi;
+}
 
 /*
  *  All stream structures are ialloc'd at boot time


@@ 52,8 56,8 @@ typedef struct {
 } Bclass;
 Bclass bclass[Nclass]={
 	{ 0 },
-	{ 64 },
-	{ 512 },
+	{ 68 },
+	{ 260 },
 	{ 4096 },
 };
 


@@ 89,7 93,6 @@ streaminit(void)
 	}
 }
 
-
 /*
  *  allocate a block
  */


@@ 170,7 173,8 @@ freeb(Block *bp)
 	}
 	bcp->last = bp;
 	unlock(bcp);
-	wakeup(&bcp->r);
+	if(bcp->r.p)
+		wakeup(&bcp->r);
 }
 
 /*


@@ 717,30 721,37 @@ streamclose(Chan *c)
 void
 stputq(Queue *q, Block *bp)
 {
-	int i;
+	int delim;
 
 	if(bp->type == M_HANGUP){
 		freeb(bp);
 		q->flag |= QHUNGUP;
 		q->other->flag |= QHUNGUP;
 		wakeup(&q->other->r);
+		delim = 1;
 	} else {
+		delim = 0;
 		lock(q);
 		if(q->first)
 			q->last->next = bp;
 		else
 			q->first = bp;
 		q->len += BLEN(bp);
+		delim = bp->flags & S_DELIM;
 		while(bp->next) {
 			bp = bp->next;
 			q->len += BLEN(bp);
+			delim |= bp->flags & S_DELIM;
 		}
 		q->last = bp;
-		if(q->len >= Streamhi)
+		if(q->len >= Streamhi){
 			q->flag |= QHIWAT;
+			delim = 1;
+		}
 		unlock(q);
 	}
-	wakeup(&q->r);
+	if(delim)
+		wakeup(&q->r);
 }
 
 /*

@@ 39,12 39,13 @@ struct Urp {
 	Rendez	r;		/* process waiting for close */
 
 	/* input */
-
+	QLock	ack;		/* ack lock */
 	Queue	*rq;		/* input queue */
 	uchar	iseq;		/* last good input sequence number */
 	uchar	lastecho;	/* last echo/rej sent */
 	uchar	trbuf[3];	/* trailer being collected */
 	short	trx;		/* # bytes in trailer being collected */
+	int	blocks;
 
 	/* output */
 


@@ 110,6 111,8 @@ static void	sendblock(Urp*, int);
 static void	rcvack(Urp*, int);
 static void	flushinput(Urp*);
 static void	sendctl(Urp*, int);
+static void	sendack(Urp*);
+static void	sendrej(Urp*);
 static void	initoutput(Urp*, int);
 static void	initinput(Urp*, int);
 static void	urpkproc(void *arg);


@@ 123,8 126,6 @@ urpopen(Queue *q, Stream *s)
 	int i;
 	char name[128];
 
-	DPRINT("urpopen\n");
-
 	/*
 	 *  find a free urp structure
 	 */


@@ 200,13 201,11 @@ urpclose(Queue *q)
 		i = 7;
 	rcvack(up, ECHO+i);
 	qunlock(&up->xmit);
-	DPRINT("urpclose(%ux)\n", up);
 
 	/*
 	 *  kill off the kernel process
 	 */
 	wakeup(&up->rq->r);
-	DPRINT("urpclosed(%ux)\n", up);
 }
 
 /*


@@ 309,10 308,12 @@ urpciput(Queue *q, Block *bp)
 
 	case SEQ+0: case SEQ+1: case SEQ+2: case SEQ+3:
 	case SEQ+4: case SEQ+5: case SEQ+6: case SEQ+7:
+		qlock(&up->ack);
 		i = ctl & Nmask;
 		if(q->next->len < Streamhi)
 			sendctl(up, up->lastecho = ECHO+i);
 		up->iseq = i;
+		qunlock(&up->ack);
 		break;
 	}
 }


@@ 381,7 382,8 @@ urpiput(Queue *q, Block *bp)
 	case 0:
 		break;
 	case ENQ:
-		print("rENQ %uo %uo\n", up->lastecho, ACK+up->iseq);
+		DPRINT("rENQ %d %uo %uo\n", up->blocks, up->lastecho, ACK+up->iseq);
+		up->blocks = 0;
 		urpstat.enqsr++;
 		sendctl(up, up->lastecho);
 		sendctl(up, ACK+up->iseq);


@@ 422,7 424,7 @@ urpiput(Queue *q, Block *bp)
 
 	case REJ+0: case REJ+1: case REJ+2: case REJ+3:
 	case REJ+4: case REJ+5: case REJ+6: case REJ+7:
-		print("rREJ\n");
+		DPRINT("rREJ\n");
 		rcvack(up, ctl);
 		break;
 	


@@ 444,21 446,15 @@ urpiput(Queue *q, Block *bp)
 		i = ctl & Nmask;
 		if(up->trx != 3){
 			urpstat.rjtrs++;
-			flushinput(up);
-			print("sREJ1 %d\n", up->iseq);
-			sendctl(up, up->lastecho = REJ+up->iseq);
+			sendrej(up);
 			break;
 		} else if(q->len != up->trbuf[1] + (up->trbuf[2]<<8)){
 			urpstat.rjpks++;
-			flushinput(up);
-			print("sREJ2 %d\n", up->iseq);
-			sendctl(up, up->lastecho = REJ+up->iseq);
+			sendrej(up);
 			break;
 		} else if(i != ((up->iseq+1)&Nmask)) {
 			urpstat.rjseq++;
-			flushinput(up);
-			print("sREJ3 %d %d\n", i, up->iseq);
-			sendctl(up, up->lastecho = REJ+up->iseq);
+			sendrej(up);
 			break;
 		}
 


@@ 480,12 476,11 @@ urpiput(Queue *q, Block *bp)
 		/*
 		 *  acknowledge receipt
 		 */
-		if(q->next->len < Streamhi){
-			sendctl(up, ECHO+i);
-			up->lastecho = ECHO+i;
-			wakeup(&up->rq->r);
-		}
+		qlock(&up->ack);
 		up->iseq = i;
+		if(q->next->len < Streamhi)
+			sendctl(up, up->lastecho = ECHO|i);
+		qunlock(&up->ack);
 		break;
 	}
 }


@@ 510,7 505,6 @@ urpctloput(Urp *up, Queue *q, Block *bp)
 				outwin = strtoul(fields[0], 0, 0);
 			}
 /*			initinput(up, inwin); */
-			DPRINT("initoutput %d\n", outwin);
 			initoutput(up, outwin);
 			freeb(bp);
 			return;


@@ 596,7 590,7 @@ output(Urp *up)
 	 *  if a retransmit time has elapsed since a transmit, send an ENQ
 	 */
 	if(up->unechoed != up->next && NOW > up->timer){
-		print("sENQ\n");
+		DPRINT("sENQ\n");
 		up->timer = NOW + MSrexmit;
 		up->state &= ~REJECTING;
 		sendctl(up, ENQ);


@@ 638,6 632,53 @@ sendctl(Urp *up, int ctl)
 }
 
 /*
+ *  send a reject
+ */
+static void
+sendrej(Urp *up)
+{
+	flushinput(up);
+	qlock(&up->ack);
+	if((up->lastecho&~Nmask) == ECHO){
+		DPRINT("REJ %d\n", up->iseq);
+		sendctl(up, up->lastecho = REJ|up->iseq);
+	}
+	qunlock(&up->ack);
+}
+
+/*
+ *  send an acknowledge
+ */
+static void
+sendack(Urp *up)
+{
+	Block *bp;
+
+	/*
+	 *  check the precondition for acking
+	 */
+	if(up->rq->next->len>=Streamhi || (up->lastecho&Nmask)==up->iseq)
+		return;
+
+	if(!canqlock(&up->ack))
+		return;
+
+	/*
+	 *  check again now that we've locked
+	 */
+	if(up->rq->next->len>=Streamhi || (up->lastecho&Nmask)==up->iseq){
+		qunlock(&up->ack);
+		return;
+	}
+
+	/*
+	 *  send the ack
+	 */
+	sendctl(up, up->lastecho = ECHO|up->iseq);
+	qunlock(&up->ack);
+}
+
+/*
  *  send a block.
  */
 static void


@@ 803,6 844,7 @@ initinput(Urp *up, int window)
 	/*
 	 *  restart all sequence parameters
 	 */
+	up->blocks = 0;
 	up->trx = 0;
 	up->iseq = 0;
 	up->lastecho = ECHO+0;


@@ 826,7 868,6 @@ urpkproc(void *arg)
 	Urp *up;
 
 	up = (Urp *)arg;
-	DPRINT("urpkproc started\n");
 
 	for(;;){
 		if(up->state & (HUNGUP|CLOSING)){


@@ 835,12 876,10 @@ urpkproc(void *arg)
 			if(up->state & HUNGUP)
 				break;
 		}
-		if((up->lastecho&Nmask)!=up->iseq && up->rq->next->len<Streamhi)
-			sendctl(up, up->lastecho = ECHO+up->iseq);
+		sendack(up);
 		output(up);
 		tsleep(&up->rq->r, todo, up, MSrexmit/2);
 	}
-	DPRINT("urpkproc exiting %ux\n", up);
 	up->kstarted = 0;
 	up->state = 0;
 }

@@ 126,7 126,7 @@ unionread(Chan *c, void *va, long n)
 	mnt = c->mnt;
 	lock(pg);
 	if(c->mountid != mnt->mountid){
-		print("unionread: changed underfoot?\n");
+		pprint("unionread: changed underfoot?\n");
 		unlock(pg);
 		return 0;
 	}

@@ 26,21 26,17 @@ enum
 	WRITE,
 };
 
-long	hold, wait, hang;
-
 void
 bitsend(Bitmsg *bp, ulong cmd, void *addr, ulong count)
 {
-	do wait++; while(*BITADDR);
+	do; while(*BITADDR);
 	bp->cmd = cmd;
 	bp->addr = (ulong)addr;
 	bp->count = count;
-/* print("%d %lux %d ", cmd, addr, count); /**/
 	*BITADDR = bp;
 	wbflush();
-	do hold++; while(*BITHOLD);
+	do; while(*BITHOLD);
 	*BITINTR = 0x20;
-/* print("done\n");  /**/
 }
 
 void


@@ 153,21 149,11 @@ bitread(Chan *c, void *buf, long n)
 			docpy = 1;
 		}
 		qunlock(&bit);
-		do{
+		do
 			n = bp->rcount;
-			hang++;
-		}while(n == 0);
+		while(n == 0);
 		if(docpy)
 			memcpy(buf, bit.buf, n);
-if(0 && n > 512){
-	int i;
-	char *cp=buf;
-	for(i=9; i<n; i++)
-		if(cp[i] != cp[i-1]){
-			print("r %d %x %x\n", i, cp[i-1], cp[i]);
-			break;
-		}
-}
 		return n;
 	}
 	error(0, Egreg);


@@ 184,15 170,6 @@ bitwrite(Chan *c, void *buf, long n)
 	case 1:
 		if(n > sizeof bit.buf)
 			error(0, Egreg);
-if(0 && n > 512){
-	int i;
-	char *cp=buf;
-	for(i=15; i<n; i++)
-		if(cp[i] != cp[i-1]){
-			print("w %d %x %x\n", i, cp[i-1], cp[i]);
-			break;
-		}
-}
 		qlock(&bit);
 		if((((ulong)buf)&(KSEGM|3)) == KSEG0)
 			bitsend(bp, WRITE, buf, n);

@@ 97,6 97,7 @@ Orig	*neworig(ulong, ulong, int, Chan*);
 Page	*newpage(int, Orig*, ulong);
 Pgrp	*newpgrp(void);
 Proc	*newproc(void);
+void	newqinfo(Qinfo*);
 char	*nextelem(char*, char*);
 void	newstart(void);
 int	newtlbpid(Proc*);

@@ 375,9 375,9 @@ confinit(void)
 	conf.nalarm = 1000;
 	conf.norig = 500;
 	conf.nchan = 500;
-	conf.nenv = 200;
-	conf.nenvchar = 10000;
-	conf.npgenv = 200;
+	conf.nenv = 400;
+	conf.nenvchar = 20000;
+	conf.npgenv = 400;
 	conf.nmtab = 100;
 	conf.nmount = 500;
 	conf.nmntdev = 30;