net: dynamic ingress_queue allocation

ingress being not used very much, and net_device->ingress_queue being
quite a big object (128 or 256 bytes), use a dynamic allocation if
needed (tc qdisc add dev eth0 ingress ...)

dev_ingress_queue(dev) helper should be used only with RTNL taken.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 62 insertions, 26 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index a313bab1b754..ce6ad88c980b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2702,11 +2702,10 @@ EXPORT_SYMBOL_GPL(br_fdb_test_addr_hook);
  * the ingress scheduler, you just cant add policies on ingress.
  *
  */
-static int ing_filter(struct sk_buff *skb)
+static int ing_filter(struct sk_buff *skb, struct netdev_queue *rxq)
 {
         struct net_device *dev = skb->dev;
         u32 ttl = G_TC_RTTL(skb->tc_verd);
-        struct netdev_queue *rxq;
         int result = TC_ACT_OK;
         struct Qdisc *q;
 
@@ -2720,8 +2719,6 @@ static int ing_filter(struct sk_buff *skb)
         skb->tc_verd = SET_TC_RTTL(skb->tc_verd, ttl);
         skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_INGRESS);
 
-        rxq = &dev->ingress_queue;
-
         q = rxq->qdisc;
         if (q != &noop_qdisc) {
                 spin_lock(qdisc_lock(q));
@@ -2737,7 +2734,9 @@ static inline struct sk_buff *handle_ing(struct sk_buff *skb,
                                          struct packet_type **pt_prev,
                                          int *ret, struct net_device *orig_dev)
 {
-        if (skb->dev->ingress_queue.qdisc == &noop_qdisc)
+        struct netdev_queue *rxq = rcu_dereference(skb->dev->ingress_queue);
+
+        if (!rxq || rxq->qdisc == &noop_qdisc)
                 goto out;
 
         if (*pt_prev) {
@@ -2745,7 +2744,7 @@ static inline struct sk_buff *handle_ing(struct sk_buff *skb,
                 *pt_prev = NULL;
         }
 
-        switch (ing_filter(skb)) {
+        switch (ing_filter(skb, rxq)) {
         case TC_ACT_SHOT:
         case TC_ACT_STOLEN:
                 kfree_skb(skb);
@@ -4940,7 +4939,6 @@ static void __netdev_init_queue_locks_one(struct net_device *dev,
 static void netdev_init_queue_locks(struct net_device *dev)
 {
         netdev_for_each_tx_queue(dev, __netdev_init_queue_locks_one, NULL);
-        __netdev_init_queue_locks_one(dev, &dev->ingress_queue, NULL);
 }
 
 unsigned long netdev_fix_features(unsigned long features, const char *name)
@@ -5452,11 +5450,29 @@ static void netdev_init_one_queue(struct net_device *dev,
 
 static void netdev_init_queues(struct net_device *dev)
 {
-        netdev_init_one_queue(dev, &dev->ingress_queue, NULL);
         netdev_for_each_tx_queue(dev, netdev_init_one_queue, NULL);
         spin_lock_init(&dev->tx_global_lock);
 }
 
+struct netdev_queue *dev_ingress_queue_create(struct net_device *dev)
+{
+        struct netdev_queue *queue = dev_ingress_queue(dev);
+
+#ifdef CONFIG_NET_CLS_ACT
+        if (queue)
+                return queue;
+        queue = kzalloc(sizeof(*queue), GFP_KERNEL);
+        if (!queue)
+                return NULL;
+        netdev_init_one_queue(dev, queue, NULL);
+        __netdev_init_queue_locks_one(dev, queue, NULL);
+        queue->qdisc = &noop_qdisc;
+        queue->qdisc_sleeping = &noop_qdisc;
+        rcu_assign_pointer(dev->ingress_queue, queue);
+#endif
+        return queue;
+}
+
 /**
  *      alloc_netdev_mq - allocate network device
  *      @sizeof_priv:   size of private data to allocate space for
@@ -5559,6 +5575,8 @@ void free_netdev(struct net_device *dev)
 
         kfree(dev->_tx);
 
+        kfree(rcu_dereference_raw(dev->ingress_queue));
+
         /* Flush device addresses */
         dev_addr_flush(dev);
 
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index b8020784d0e9..b22ca2d1cebc 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -240,7 +240,10 @@ struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
         if (q)
                 goto out;
 
-        q = qdisc_match_from_root(dev->ingress_queue.qdisc_sleeping, handle);
+        if (dev_ingress_queue(dev))
+                q = qdisc_match_from_root(
+                        dev_ingress_queue(dev)->qdisc_sleeping,
+                        handle);
 out:
         return q;
 }
@@ -690,6 +693,8 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
                     (new && new->flags & TCQ_F_INGRESS)) {
                         num_q = 1;
                         ingress = 1;
+                        if (!dev_ingress_queue(dev))
+                                return -ENOENT;
                 }
 
                 if (dev->flags & IFF_UP)
@@ -701,7 +706,7 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
                 }
 
                 for (i = 0; i < num_q; i++) {
-                        struct netdev_queue *dev_queue = &dev->ingress_queue;
+                        struct netdev_queue *dev_queue = dev_ingress_queue(dev);
 
                         if (!ingress)
                                 dev_queue = netdev_get_tx_queue(dev, i);
@@ -979,7 +984,8 @@ static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
                                         return -ENOENT;
                                 q = qdisc_leaf(p, clid);
                         } else { /* ingress */
-                                q = dev->ingress_queue.qdisc_sleeping;
+                                if (dev_ingress_queue(dev))
+                                        q = dev_ingress_queue(dev)->qdisc_sleeping;
                         }
                 } else {
                         q = dev->qdisc;
@@ -1043,8 +1049,9 @@ replay:
                                 if ((p = qdisc_lookup(dev, TC_H_MAJ(clid))) == NULL)
                                         return -ENOENT;
                                 q = qdisc_leaf(p, clid);
-                        } else { /*ingress */
-                                q = dev->ingress_queue.qdisc_sleeping;
+                        } else { /* ingress */
+                                if (dev_ingress_queue_create(dev))
+                                        q = dev_ingress_queue(dev)->qdisc_sleeping;
                         }
                 } else {
                         q = dev->qdisc;
@@ -1123,11 +1130,14 @@ replay:
 create_n_graft:
         if (!(n->nlmsg_flags&NLM_F_CREATE))
                 return -ENOENT;
-        if (clid == TC_H_INGRESS)
-                q = qdisc_create(dev, &dev->ingress_queue, p,
-                                 tcm->tcm_parent, tcm->tcm_parent,
-                                 tca, &err);
-        else {
+        if (clid == TC_H_INGRESS) {
+                if (dev_ingress_queue(dev))
+                        q = qdisc_create(dev, dev_ingress_queue(dev), p,
+                                         tcm->tcm_parent, tcm->tcm_parent,
+                                         tca, &err);
+                else
+                        err = -ENOENT;
+        } else {
                 struct netdev_queue *dev_queue;
 
                 if (p && p->ops->cl_ops && p->ops->cl_ops->select_queue)
@@ -1304,8 +1314,10 @@ static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
                 if (tc_dump_qdisc_root(dev->qdisc, skb, cb, &q_idx, s_q_idx) < 0)
                         goto done;
 
-                dev_queue = &dev->ingress_queue;
-                if (tc_dump_qdisc_root(dev_queue->qdisc_sleeping, skb, cb, &q_idx, s_q_idx) < 0)
+                dev_queue = dev_ingress_queue(dev);
+                if (dev_queue &&
+                    tc_dump_qdisc_root(dev_queue->qdisc_sleeping, skb, cb,
+                                       &q_idx, s_q_idx) < 0)
                         goto done;
 
 cont:
@@ -1595,8 +1607,10 @@ static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
         if (tc_dump_tclass_root(dev->qdisc, skb, tcm, cb, &t, s_t) < 0)
                 goto done;
 
-        dev_queue = &dev->ingress_queue;
-        if (tc_dump_tclass_root(dev_queue->qdisc_sleeping, skb, tcm, cb, &t, s_t) < 0)
+        dev_queue = dev_ingress_queue(dev);
+        if (dev_queue &&
+            tc_dump_tclass_root(dev_queue->qdisc_sleeping, skb, tcm, cb,
+                                &t, s_t) < 0)
                 goto done;
 
 done:
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 545278a1c478..3d57681bdb76 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -753,7 +753,8 @@ void dev_activate(struct net_device *dev)
 
         need_watchdog = 0;
         netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
-        transition_one_qdisc(dev, &dev->ingress_queue, NULL);
+        if (dev_ingress_queue(dev))
+                transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
 
         if (need_watchdog) {
                 dev->trans_start = jiffies;
@@ -812,7 +813,8 @@ static bool some_qdisc_is_busy(struct net_device *dev)
 void dev_deactivate(struct net_device *dev)
 {
         netdev_for_each_tx_queue(dev, dev_deactivate_queue, &noop_qdisc);
-        dev_deactivate_queue(dev, &dev->ingress_queue, &noop_qdisc);
+        if (dev_ingress_queue(dev))
+                dev_deactivate_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
 
         dev_watchdog_down(dev);
 
@@ -838,7 +840,8 @@ void dev_init_scheduler(struct net_device *dev)
 {
         dev->qdisc = &noop_qdisc;
         netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
-        dev_init_scheduler_queue(dev, &dev->ingress_queue, &noop_qdisc);
+        if (dev_ingress_queue(dev))
+                dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
 
         setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev);
 }
@@ -861,7 +864,8 @@ static void shutdown_scheduler_queue(struct net_device *dev,
 void dev_shutdown(struct net_device *dev)
 {
         netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
-        shutdown_scheduler_queue(dev, &dev->ingress_queue, &noop_qdisc);
+        if (dev_ingress_queue(dev))
+                shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
         qdisc_destroy(dev->qdisc);
         dev->qdisc = &noop_qdisc;