--- linux-2.5/drivers/block/deadline-iosched.c.orig	2002-11-15 23:22:19.000000000 +1100
+++ linux-2.5/drivers/block/deadline-iosched.c	2002-11-16 13:01:01.000000000 +1100
@@ -407,20 +407,46 @@
 	if (rbnext)
 		dd->last_drq[data_dir] = rb_entry_drq(rbnext);
 	
 	/*
 	 * take it off the sort and fifo list, move
 	 * to dispatch queue
 	 */
 	deadline_move_to_dispatch(dd, drq);
 }
 
+static int expire_batch = 8;
+/*
+ * move a batch of entries to dispatch queue
+ */
+static inline void deadline_move_batch(struct deadline_data *dd, struct deadline_rq *drq)
+{
+	const int data_dir = rq_data_dir(drq->request);
+	struct rb_node *rbnext;
+	int i;
+	
+	for (i = 0; i < expire_batch; i++) {
+		struct rb_node *rbnext;
+		rbnext = rb_next(&drq->rb_node);
+		
+		deadline_move_to_dispatch(dd, drq);
+
+		if (!rbnext)
+			break;
+		drq = rb_entry_drq(rbnext);
+	}
+
+	dd->last_drq[data_dir] = NULL;
+	if (rbnext)
+		dd->last_drq[data_dir] = drq;
+}
+
 /*
  * returns 0 if there are no expired reads on the fifo, 1 otherwise
  */
 #define list_entry_fifo(ptr)	list_entry((ptr), struct deadline_rq, fifo)
 static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
 {
 	if (!list_empty(&dd->rw_fifo[ddir])) {
 		struct deadline_rq *drq = list_entry_fifo(dd->rw_fifo[ddir].next);
 
 		/*
@@ -439,56 +465,74 @@
 	struct deadline_rq *drq;
 
 	/*
 	 * if we have expired entries on the fifo list, move some to dispatch
 	 */
 	if (deadline_check_fifo(dd, READ)) {
 		if (writes && (dd->starved++ >= dd->writes_starved))
 			goto dispatch_writes;
 
 		drq = list_entry_fifo(dd->rw_fifo[READ].next);
-dispatch_requests:
-		deadline_move_request(dd, drq);
-		return 1;
+
+		goto dispatch_batch;
 	}
 
 	if (!list_empty(&dd->rw_fifo[READ])) {
 		if (writes && (dd->starved++ >= dd->writes_starved))
 			goto dispatch_writes;
 
 		BUG_ON(RB_EMPTY(&dd->rb_list[READ]));
 
 		drq = dd->last_drq[READ];
 		if (!drq)
 			drq = list_entry_fifo(dd->rw_fifo[READ].next);
 
-		goto dispatch_requests;
+		goto dispatch_request;
 	}
 
 	/*
 	 * either there are no reads expired or on sort list, or the reads
 	 * have starved writes for too long. dispatch some writes
 	 */
+	
 	if (writes) {
 dispatch_writes:
 		BUG_ON(RB_EMPTY(&dd->rb_list[WRITE]));
 
 		dd->starved = 0;
+		
+		if (deadline_check_fifo(dd, WRITE)) {
+			drq = list_entry_fifo(dd->rw_fifo[WRITE].next);
+
+			goto dispatch_batch;
+		}
 
 		drq = dd->last_drq[WRITE];
-		if (!drq || deadline_check_fifo(dd, WRITE))
+		if (!drq) 
 			drq = list_entry_fifo(dd->rw_fifo[WRITE].next);
 
-		goto dispatch_requests;
+		goto dispatch_request;
 	}
 
 	return 0;
+	
+dispatch_request:
+	deadline_move_request(dd, drq);
+	return 1;
+	
+dispatch_batch:
+	/* dispatch in batches to prevent a seek storm if the disk
+	 * can't keep up with the queue size and all entries end up
+	 * being expired and submitted fifo.
+	 */
+	deadline_move_batch(dd, drq);
+	return 1;
 }
 
 static struct request *deadline_next_request(request_queue_t *q)
 {
 	struct deadline_data *dd = q->elevator.elevator_data;
 	struct request *rq;
 
 	/*
 	 * if there are still requests on the dispatch queue, grab the first one
 	 */