From 97af757c6c385916f7f4dc4c086016e9a9eb98cd Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Mon, 21 Dec 1992 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1992-12-21

---
 port/devip.c    | 21 +++++++++++++++++++++
 port/devscsi.c  |  2 +-
 port/ipdat.h    |  3 +++
 port/tcpinput.c |  5 +++++
 4 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/port/devip.c b/port/devip.c
index de6430da9aa299c0f73d99a638879bc33648eb5d..4829492cbff712a0a37d98eef26dcb4dbbf9e1d2 100644
--- a/port/devip.c
+++ b/port/devip.c
@@ -604,6 +604,11 @@ tcpstiput(Queue *q, Block *bp)
 	PUTNEXT(q, bp);
 }
 
+tcproominq(void *a)
+{
+	return !((Tcpctl *)a)->sndfull;
+}
+
 void
 tcpstoput(Queue *q, Block *bp)
 {
@@ -637,6 +642,20 @@ tcpstoput(Queue *q, Block *bp)
 	case Syn_received:
 	case Established:
 	case Close_wait:
+		/*
+		 * Process flow control
+	 	 */
+		if(tcb->sndfull){
+			qlock(&tcb->sndrlock);
+			if(waserror()) {
+				qunlock(&tcb->sndrlock);
+				nexterror();
+			}
+			sleep(&tcb->sndr, tcproominq, tcb);
+			poperror();
+			qunlock(&tcb->sndrlock);
+		}
+
 		/*
 		 * Push data
 		 */
@@ -646,6 +665,8 @@ tcpstoput(Queue *q, Block *bp)
 			nexterror();
 		}
 		tcb->sndcnt += blen(bp);
+		if(tcb->sndcnt > Streamhi)
+			tcb->sndfull = 1;
 		if(tcb->sndq == 0)
 			tcb->sndq = bp;
 		else {
diff --git a/port/devscsi.c b/port/devscsi.c
index 82fa18c1969b009013229bd3c7c6d4137f290251..d6f0a83c28f7a0cc2a0a6b63bc97d02df551cf9d 100644
--- a/port/devscsi.c
+++ b/port/devscsi.c
@@ -8,7 +8,7 @@
 
 #define	DPRINT	if(debug)kprint
 
-#define DATASIZE	(32*512)
+#define DATASIZE	(64*512)
 
 static Scsi	staticcmd;	/* BUG: should be one per scsi device */
 
diff --git a/port/ipdat.h b/port/ipdat.h
index a22155e2af9b6d6494f0c7981d2476977efb5d22..7ec2de425198ef4de2c7cedec6bfb581dc43d37b 100644
--- a/port/ipdat.h
+++ b/port/ipdat.h
@@ -240,6 +240,9 @@ struct Tctl
 
 	Block	*sndq;			/* List of data going out */
 	ulong	sndcnt;			/* Amount of data in send queue */
+	Rendez	sndr;			/* process flow control */
+	QLock	sndrlock;
+	int	sndfull;
 
 	Reseq	*reseq;			/* Resequencing queue */
 	Timer	timer;			/* Activity timer */
diff --git a/port/tcpinput.c b/port/tcpinput.c
index 9abfe04ab0e5bd43e77f16c7957a67f8ba13550a..8ccfa69af86ca86b932659cfb93b697a6a9b3036 100644
--- a/port/tcpinput.c
+++ b/port/tcpinput.c
@@ -559,6 +559,11 @@ update(Ipconv *s, Tcp *seg)
 
 	tcb->flags &= ~RETRAN;
 	tcb->backoff = 0;
+
+	if(tcb->sndfull && tcb->sndcnt < Streamhi/2){
+		wakeup(&tcb->sndr);
+		tcb->sndfull = 0;
+	}
 }
 
 int