From 3f85b6589809fc7d9f674dd73f26bbf641d90ef2 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Fri, 15 Jan 1999 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1999-01-15

---
 port/qio.c  | 45 +++++++++++++++++++++++++++++----------------
 port/swap.c | 18 ++++++++++++++++++
 2 files changed, 47 insertions(+), 16 deletions(-)

diff --git a/port/qio.c b/port/qio.c
index 4d7162f47b469acc98fef50c8517e6a4c773b3b5..3b6b72b7b4db85b11fbbabd6c042b50d86dd7aa8 100644
--- a/port/qio.c
+++ b/port/qio.c
@@ -590,6 +590,7 @@ qconsume(Queue *q, void *vp, int len)
 	Block *b;
 	int n, dowakeup;
 	uchar *p = vp;
+	Block *tofree = nil;
 
 	/* sync with qwrite */
 	ilock(q);
@@ -608,7 +609,10 @@ qconsume(Queue *q, void *vp, int len)
 			break;
 		q->bfirst = b->next;
 		q->len -= BALLOC(b);
-		freeb(b);
+
+		/* remember to free this */
+		b->next = tofree;
+		tofree = b;
 	};
 
 	if(n < len)
@@ -620,6 +624,17 @@ qconsume(Queue *q, void *vp, int len)
 	b->rp += len;
 	q->dlen -= len;
 
+	/* discard the block if we're done with it */
+	if((q->state & Qmsg) || len == n){
+		b->next = 0;
+		q->len -= BALLOC(b);
+		q->dlen -= BLEN(b);
+
+		/* remember to free this */
+		b->next = tofree;
+		tofree = b;
+	}
+
 	/* if writer flow controlled, restart */
 	if((q->state & Qflow) && q->len < q->limit/2){
 		q->state &= ~Qflow;
@@ -632,14 +647,9 @@ qconsume(Queue *q, void *vp, int len)
 	if(dowakeup)
 		wakeup(&q->wr);
 
-	QDEBUG checkb(b, "qconsume 2");
-	/* discard the block if we're done with it */
-	if((q->state & Qmsg) || len == n){
-		b->next = 0;
-		q->len -= BALLOC(b);
-		q->dlen -= BLEN(b);
-		freeb(b);
-	}
+	if(tofree != nil)
+		freeblist(tofree);
+
 	return len;
 }
 
@@ -798,6 +808,9 @@ qproduce(Queue *q, void *vp, int len)
 		q->state &= ~Qstarve;
 		dowakeup = 1;
 	}
+
+	if(q->len >= q->limit)
+		q->state |= Qflow;
 	iunlock(q);
 
 	if(dowakeup)
@@ -938,13 +951,6 @@ qbread(Queue *q, int len)
 	q->len -= BALLOC(b);
 	QDEBUG checkb(b, "qbread 1");
 
-	/* if writer flow controlled, restart */
-	if((q->state & Qflow) && q->len < q->limit/2){
-		q->state &= ~Qflow;
-		dowakeup = 1;
-	} else
-		dowakeup = 0;
-
 	/* split block if it's too big and this is not a message-oriented queue */
 	nb = b;
 	if(n > len){
@@ -967,6 +973,13 @@ qbread(Queue *q, int len)
 		nb->wp = nb->rp + len;
 	}
 
+	/* if writer flow controlled, restart */
+	if((q->state & Qflow) && q->len < q->limit/2){
+		q->state &= ~Qflow;
+		dowakeup = 1;
+	} else
+		dowakeup = 0;
+
 	iunlock(q);
 
 	/* wakeup flow controlled writers */
diff --git a/port/swap.c b/port/swap.c
index 337bdf0788d471d0d16ad0ccaa19c43028c2d8f3..6ee65b0d1e0db595002d60eee5bcb64e82445e15 100644
--- a/port/swap.c
+++ b/port/swap.c
@@ -369,6 +369,9 @@ needpages(void*)
 void
 setswapchan(Chan *c)
 {
+	char dirbuf[DIRLEN];
+	Dir d;
+
 	if(swapimage.c) {
 		if(swapalloc.free != conf.nswap){
 			cclose(c);
@@ -376,5 +379,20 @@ setswapchan(Chan *c)
 		}
 		cclose(swapimage.c);
 	}
+
+	/*
+	 *  if this isn't a file, set the swap space
+	 *  to be at most the size of the partition
+	 */
+	if(devtab[c->type]->dc != L'M'){
+		devtab[c->type]->stat(c, dirbuf);
+		convM2D(dirbuf, &d);
+		if(d.length < conf.nswap*BY2PG){
+			conf.nswap = d.length/BY2PG;
+			swapalloc.top = &swapalloc.swmap[conf.nswap];
+			swapalloc.free = conf.nswap;
+		}
+	}
+
 	swapimage.c = c;
 }