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-rw-r--r--Documentation/networking/multiqueue.txt14
-rw-r--r--net/sched/sch_multiq.c13
2 files changed, 16 insertions, 11 deletions
diff --git a/Documentation/networking/multiqueue.txt b/Documentation/networking/multiqueue.txt
index 8c2b06b77f61..4caa0e314cc2 100644
--- a/Documentation/networking/multiqueue.txt
+++ b/Documentation/networking/multiqueue.txt
@@ -29,15 +29,15 @@ Section 2: Qdisc support for multiqueue devices
-----------------------------------------------
-Currently two qdiscs support multiqueue devices. The first is the default
-pfifo_fast qdisc. This qdisc supports one qdisc per hardware queue. A new
-round-robin qdisc, sch_multiq also supports multiple hardware queues. The
+Currently two qdiscs are optimized for multiqueue devices. The first is the
+default pfifo_fast qdisc. This qdisc supports one qdisc per hardware queue.
+A new round-robin qdisc, sch_multiq also supports multiple hardware queues. The
qdisc is responsible for classifying the skb's and then directing the skb's to
bands and queues based on the value in skb->queue_mapping. Use this field in
the base driver to determine which queue to send the skb to.
-sch_multiq has been added for hardware that wishes to avoid unnecessary
-requeuing. It will cycle though the bands and verify that the hardware queue
+sch_multiq has been added for hardware that wishes to avoid head-of-line
+blocking. It will cycle though the bands and verify that the hardware queue
associated with the band is not stopped prior to dequeuing a packet.
On qdisc load, the number of bands is based on the number of queues on the
@@ -63,8 +63,8 @@ band 1 => queue 1
band 2 => queue 2
band 3 => queue 3
-Traffic will begin flowing through each queue if your base device has either
-the default simple_tx_hash or a custom netdev->select_queue() defined.
+Traffic will begin flowing through each queue based on either the simple_tx_hash
+function or based on netdev->select_queue() if you have it defined.
The behavior of tc filters remains the same. However a new tc action,
skbedit, has been added. Assuming you wanted to route all traffic to a
diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c
index 49a8b67ed3b8..5d9cd68e91d1 100644
--- a/net/sched/sch_multiq.c
+++ b/net/sched/sch_multiq.c
@@ -214,8 +214,8 @@ static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
sch_tree_lock(sch);
q->bands = qopt->bands;
for (i = q->bands; i < q->max_bands; i++) {
- struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
- if (child != &noop_qdisc) {
+ if (q->queues[i] != &noop_qdisc) {
+ struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
qdisc_tree_decrease_qlen(child, child->q.qlen);
qdisc_destroy(child);
}
@@ -250,7 +250,7 @@ static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
{
struct multiq_sched_data *q = qdisc_priv(sch);
- int i;
+ int i, err;
q->queues = NULL;
@@ -265,7 +265,12 @@ static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
for (i = 0; i < q->max_bands; i++)
q->queues[i] = &noop_qdisc;
- return multiq_tune(sch, opt);
+ err = multiq_tune(sch,opt);
+
+ if (err)
+ kfree(q->queues);
+
+ return err;
}
static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)