These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / net / sched / act_mirred.c

diff --git a/kernel/net/sched/act_mirred.c b/kernel/net/sched/act_mirred.c
index 3f63cea..32fcdec 100644 (file)
--- a/kernel/net/sched/act_mirred.c
+++ b/kernel/net/sched/act_mirred.c
@@ -31,13 +31,19 @@
 
 #define MIRRED_TAB_MASK     7
 static LIST_HEAD(mirred_list);
+static DEFINE_SPINLOCK(mirred_list_lock);
 
 static void tcf_mirred_release(struct tc_action *a, int bind)
 {
        struct tcf_mirred *m = to_mirred(a);
+       struct net_device *dev = rcu_dereference_protected(m->tcfm_dev, 1);
+
+       /* We could be called either in a RCU callback or with RTNL lock held. */
+       spin_lock_bh(&mirred_list_lock);
        list_del(&m->tcfm_list);
-       if (m->tcfm_dev)
-               dev_put(m->tcfm_dev);
+       spin_unlock_bh(&mirred_list_lock);
+       if (dev)
+               dev_put(dev);
 }
 
 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
@@ -93,32 +99,37 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
        if (!tcf_hash_check(parm->index, a, bind)) {
                if (dev == NULL)
                        return -EINVAL;
-               ret = tcf_hash_create(parm->index, est, a, sizeof(*m), bind);
+               ret = tcf_hash_create(parm->index, est, a, sizeof(*m),
+                                     bind, true);
                if (ret)
                        return ret;
                ret = ACT_P_CREATED;
        } else {
-               if (!ovr) {
-                       tcf_hash_release(a, bind);
+               if (bind)
+                       return 0;
+
+               tcf_hash_release(a, bind);
+               if (!ovr)
                        return -EEXIST;
-               }
        }
        m = to_mirred(a);
 
-       spin_lock_bh(&m->tcf_lock);
+       ASSERT_RTNL();
        m->tcf_action = parm->action;
        m->tcfm_eaction = parm->eaction;
        if (dev != NULL) {
                m->tcfm_ifindex = parm->ifindex;
                if (ret != ACT_P_CREATED)
-                       dev_put(m->tcfm_dev);
+                       dev_put(rcu_dereference_protected(m->tcfm_dev, 1));
                dev_hold(dev);
-               m->tcfm_dev = dev;
+               rcu_assign_pointer(m->tcfm_dev, dev);
                m->tcfm_ok_push = ok_push;
        }
-       spin_unlock_bh(&m->tcf_lock);
+
        if (ret == ACT_P_CREATED) {
+               spin_lock_bh(&mirred_list_lock);
                list_add(&m->tcfm_list, &mirred_list);
+               spin_unlock_bh(&mirred_list_lock);
                tcf_hash_insert(a);
        }
 
@@ -131,28 +142,30 @@ static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
        struct tcf_mirred *m = a->priv;
        struct net_device *dev;
        struct sk_buff *skb2;
+       int retval, err;
        u32 at;
-       int retval, err = 1;
 
-       spin_lock(&m->tcf_lock);
-       m->tcf_tm.lastuse = jiffies;
-       bstats_update(&m->tcf_bstats, skb);
+       tcf_lastuse_update(&m->tcf_tm);
+
+       bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
 
-       dev = m->tcfm_dev;
-       if (!dev) {
-               printk_once(KERN_NOTICE "tc mirred: target device is gone\n");
+       rcu_read_lock();
+       retval = READ_ONCE(m->tcf_action);
+       dev = rcu_dereference(m->tcfm_dev);
+       if (unlikely(!dev)) {
+               pr_notice_once("tc mirred: target device is gone\n");
                goto out;
        }
 
-       if (!(dev->flags & IFF_UP)) {
+       if (unlikely(!(dev->flags & IFF_UP))) {
                net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
                                       dev->name);
                goto out;
        }
 
        at = G_TC_AT(skb->tc_verd);
-       skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action);
-       if (skb2 == NULL)
+       skb2 = skb_clone(skb, GFP_ATOMIC);
+       if (!skb2)
                goto out;
 
        if (!(at & AT_EGRESS)) {
@@ -166,18 +179,16 @@ static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
 
        skb2->skb_iif = skb->dev->ifindex;
        skb2->dev = dev;
+       skb_sender_cpu_clear(skb2);
        err = dev_queue_xmit(skb2);
 
-out:
        if (err) {
-               m->tcf_qstats.overlimits++;
+out:
+               qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
                if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
                        retval = TC_ACT_SHOT;
-               else
-                       retval = m->tcf_action;
-       } else
-               retval = m->tcf_action;
-       spin_unlock(&m->tcf_lock);
+       }
+       rcu_read_unlock();
 
        return retval;
 }
@@ -216,15 +227,20 @@ static int mirred_device_event(struct notifier_block *unused,
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
        struct tcf_mirred *m;
 
-       if (event == NETDEV_UNREGISTER)
+       ASSERT_RTNL();
+       if (event == NETDEV_UNREGISTER) {
+               spin_lock_bh(&mirred_list_lock);
                list_for_each_entry(m, &mirred_list, tcfm_list) {
-                       spin_lock_bh(&m->tcf_lock);
-                       if (m->tcfm_dev == dev) {
+                       if (rcu_access_pointer(m->tcfm_dev) == dev) {
                                dev_put(dev);
-                               m->tcfm_dev = NULL;
+                               /* Note : no rcu grace period necessary, as
+                                * net_device are already rcu protected.
+                                */
+                               RCU_INIT_POINTER(m->tcfm_dev, NULL);
                        }
-                       spin_unlock_bh(&m->tcf_lock);
                }
+               spin_unlock_bh(&mirred_list_lock);
+       }
 
        return NOTIFY_DONE;
 }