[PKT_SCHED]: GRED: Improve error handling and messages

Try to enqueue packets if we cannot associate it with a VQ, this
basically means that the default VQ has not been set up yet.

We must check if the VQ still exists while requeueing, the VQ
might have been changed between dequeue and the requeue of the
underlying qdisc.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

net/sched/sch_gred.c

@@ -176,20 +176,24 @@ gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 	dp = tc_index_to_dp(skb);
 
 	if (dp >= t->DPs  || (q = t->tab[dp]) == NULL) {
-		printk("GRED: setting to default (%d)\n ",t->def);
-		if (!(q=t->tab[t->def])) {
-			DPRINTK("GRED: setting to default FAILED! dropping!! "
-			    "(%d)\n ", t->def);
-			goto drop;
+		dp = t->def;
+
+		if ((q = t->tab[dp]) == NULL) {
+			/* Pass through packets not assigned to a DP
+			 * if no default DP has been configured. This
+			 * allows for DP flows to be left untouched.
+			 */
+			if (skb_queue_len(&sch->q) < sch->dev->tx_queue_len)
+				return qdisc_enqueue_tail(skb, sch);
+			else
+				goto drop;
 		}
+
 		/* fix tc_index? --could be controvesial but needed for
 		   requeueing */
-		skb->tc_index=(skb->tc_index & ~GRED_VQ_MASK) | t->def;
+		skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
 	}
 
-	D2PRINTK("gred_enqueue virtualQ 0x%x classid %x backlog %d "
-	    "general backlog %d\n",skb->tc_index&0xf,sch->handle,q->backlog,
-	    sch->qstats.backlog);
 	/* sum up all the qaves of prios <= to ours to get the new qave*/
 	if (!gred_wred_mode(t) && gred_rio_mode(t)) {
 		for (i=0;i<t->DPs;i++) {
@@ -254,13 +258,20 @@ static int
 gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
 {
 	struct gred_sched *t = qdisc_priv(sch);
-	struct gred_sched_data *q = t->tab[tc_index_to_dp(skb)];
-/* error checking here -- probably unnecessary */
+	struct gred_sched_data *q;
+	u16 dp = tc_index_to_dp(skb);
 
-	if (red_is_idling(&q->parms))
-		red_end_of_idle_period(&q->parms);
+	if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+		if (net_ratelimit())
+			printk(KERN_WARNING "GRED: Unable to relocate VQ 0x%x "
+			       "for requeue, screwing up backlog.\n",
+			       tc_index_to_dp(skb));
+	} else {
+		if (red_is_idling(&q->parms))
+			red_end_of_idle_period(&q->parms);
+		q->backlog += skb->len;
+	}
 
-	q->backlog += skb->len;
 	return qdisc_requeue(skb, sch);
 }
 
@@ -274,15 +285,20 @@ gred_dequeue(struct Qdisc* sch)
 	skb = qdisc_dequeue_head(sch);
 
 	if (skb) {
-		q = t->tab[tc_index_to_dp(skb)];
-		if (q) {
+		u16 dp = tc_index_to_dp(skb);
+
+		if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+			if (net_ratelimit())
+				printk(KERN_WARNING "GRED: Unable to relocate "
+				       "VQ 0x%x after dequeue, screwing up "
+				       "backlog.\n", tc_index_to_dp(skb));
+		} else {
 			q->backlog -= skb->len;
+
 			if (!q->backlog && !gred_wred_mode(t))
 				red_start_of_idle_period(&q->parms);
-		} else {
-			D2PRINTK("gred_dequeue: skb has bad tcindex %x\n",
-				 tc_index_to_dp(skb));
 		}
+
 		return skb;
 	}
 
@@ -308,15 +324,19 @@ static unsigned int gred_drop(struct Qdisc* sch)
 	skb = qdisc_dequeue_tail(sch);
 	if (skb) {
 		unsigned int len = skb->len;
-		q = t->tab[tc_index_to_dp(skb)];
-		if (q) {
+		u16 dp = tc_index_to_dp(skb);
+
+		if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+			if (net_ratelimit())
+				printk(KERN_WARNING "GRED: Unable to relocate "
+				       "VQ 0x%x while dropping, screwing up "
+				       "backlog.\n", tc_index_to_dp(skb));
+		} else {
 			q->backlog -= len;
 			q->stats.other++;
+
 			if (!q->backlog && !gred_wred_mode(t))
 				red_start_of_idle_period(&q->parms);
-		} else {
-			D2PRINTK("gred_dequeue: skb has bad tcindex %x\n",
-				 tc_index_to_dp(skb));
 		}
 
 		qdisc_drop(skb, sch);