3 files changed, 12 insertions(+), 2 deletions(-)

M port/portdat.h
M port/proc.c
M port/qio.c

@@ 132,6 132,7 @@ struct Block
 	uchar*	wp;			/* first empty byte */
 	uchar*	lim;			/* 1 past the end of the buffer */
 	uchar*	base;			/* start of the buffer */
+	void	(*free)(Block*);
 	ulong	flag;
 };
 #define BLEN(s)	((s)->wp - (s)->rp)

@@ 216,9 216,10 @@ loop:
 		 *  processor can run given affinity constraints
 		 */
 		for(rq = &runq[Nrq-1]; rq >= runq; rq--){
-			if(rq->head == 0)
+			p = rq->head;
+			if(p == 0)
 				continue;
-			for(p = rq->head; p; p = p->rnext){
+			for(; p; p = p->rnext){
 				if(p->mp == m || m->ticks - p->movetime > HZ/2)
 					goto found;
 			}

@@ 109,6 109,14 @@ iallocb(int size)
 void
 freeb(Block *b)
 {
+	/*
+	 * drivers which perform non cache coherent DMA manage their
+	 * own buffer pools, so they provide their own free routines.
+	 */
+	if(b->free) {
+		b->free(b);
+		return;
+	}
 	if(b->flag & BINTR) {
 		ilock(&ialloc);
 		ialloc.bytes -= b->lim - b->base;