5 files changed, 22 insertions, 6 deletions

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 4616f468d599..1540f9c2fcf4 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -50,6 +50,13 @@ struct Qdisc {
 #define TCQ_F_INGRESS           2
 #define TCQ_F_CAN_BYPASS        4
 #define TCQ_F_MQROOT            8
+#define TCQ_F_ONETXQUEUE        0x10 /* dequeue_skb() can assume all skbs are for
+                                      * q->dev_queue : It can test
+                                      * netif_xmit_frozen_or_stopped() before
+                                      * dequeueing next packet.
+                                      * Its true for MQ/MQPRIO slaves, or non
+                                      * multiqueue device.
+                                      */
 #define TCQ_F_WARN_NONWC        (1 << 16)
         int                     padded;
         const struct Qdisc_ops  *ops;
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 4799c4840c1a..d84f7e734cd7 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -833,6 +833,8 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
                                 goto err_out3;
                 }
                 lockdep_set_class(qdisc_lock(sch), &qdisc_tx_lock);
+                if (!netif_is_multiqueue(dev))
+                        sch->flags |= TCQ_F_ONETXQUEUE;
         }
 
         sch->handle = handle;
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index aefc1504dc88..5d81a4478514 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -53,20 +53,19 @@ static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
 static inline struct sk_buff *dequeue_skb(struct Qdisc *q)
 {
         struct sk_buff *skb = q->gso_skb;
+        const struct netdev_queue *txq = q->dev_queue;
 
         if (unlikely(skb)) {
-                struct net_device *dev = qdisc_dev(q);
-                struct netdev_queue *txq;
-
                 /* check the reason of requeuing without tx lock first */
-                txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
+                txq = netdev_get_tx_queue(txq->dev, skb_get_queue_mapping(skb));
                 if (!netif_xmit_frozen_or_stopped(txq)) {
                         q->gso_skb = NULL;
                         q->q.qlen--;
                 } else
                         skb = NULL;
         } else {
-                skb = q->dequeue(q);
+                if (!(q->flags & TCQ_F_ONETXQUEUE) || !netif_xmit_frozen_or_stopped(txq))
+                        skb = q->dequeue(q);
         }
 
         return skb;
@@ -686,6 +685,8 @@ static void attach_one_default_qdisc(struct net_device *dev,
                         netdev_info(dev, "activation failed\n");
                         return;
                 }
+                if (!netif_is_multiqueue(dev))
+                        qdisc->flags |= TCQ_F_ONETXQUEUE;
         }
         dev_queue->qdisc_sleeping = qdisc;
 }
diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c
index 0a4b2f9a0094..5da78a19ac9a 100644
--- a/net/sched/sch_mq.c
+++ b/net/sched/sch_mq.c
@@ -63,6 +63,7 @@ static int mq_init(struct Qdisc *sch, struct nlattr *opt)
                 if (qdisc == NULL)
                         goto err;
                 priv->qdiscs[ntx] = qdisc;
+                qdisc->flags |= TCQ_F_ONETXQUEUE;
         }
 
         sch->flags |= TCQ_F_MQROOT;
@@ -150,7 +151,8 @@ static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
                 dev_deactivate(dev);
 
         *old = dev_graft_qdisc(dev_queue, new);
-
+        if (new)
+                new->flags |= TCQ_F_ONETXQUEUE;
         if (dev->flags & IFF_UP)
                 dev_activate(dev);
         return 0;
diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c
index d1831ca966d4..accec33c454c 100644
--- a/net/sched/sch_mqprio.c
+++ b/net/sched/sch_mqprio.c
@@ -132,6 +132,7 @@ static int mqprio_init(struct Qdisc *sch, struct nlattr *opt)
                         goto err;
                 }
                 priv->qdiscs[i] = qdisc;
+                qdisc->flags |= TCQ_F_ONETXQUEUE;
         }
 
         /* If the mqprio options indicate that hardware should own
@@ -205,6 +206,9 @@ static int mqprio_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
 
         *old = dev_graft_qdisc(dev_queue, new);
 
+        if (new)
+                new->flags |= TCQ_F_ONETXQUEUE;
+
         if (dev->flags & IFF_UP)
                 dev_activate(dev);