ipmr: add rcu protection over (struct vif_device)->dev

[linux-2.6-microblaze.git] / net / ipv4 / ipmr.c

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 8324e54..10371a9 100644 (file)
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -79,6 +79,12 @@ struct ipmr_result {
 
 static DEFINE_RWLOCK(mrt_lock);
 
+static struct net_device *vif_dev_read(const struct vif_device *vif)
+{
+       return rcu_dereference_check(vif->dev,
+                                    lockdep_is_held(&mrt_lock));
+}
+
 /* Multicast router control variables */
 
 /* Special spinlock for queue of unresolved entries */
@@ -586,7 +592,7 @@ static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb,
 
        read_lock(&mrt_lock);
        if (mrt->mroute_reg_vif_num >= 0)
-               reg_dev = mrt->vif_table[mrt->mroute_reg_vif_num].dev;
+               reg_dev = vif_dev_read(&mrt->vif_table[mrt->mroute_reg_vif_num]);
        read_unlock(&mrt_lock);
 
        if (!reg_dev)
@@ -614,10 +620,11 @@ static struct net_device *ipmr_reg_vif(struct net *net, struct mr_table *mrt)
 static int call_ipmr_vif_entry_notifiers(struct net *net,
                                         enum fib_event_type event_type,
                                         struct vif_device *vif,
+                                        struct net_device *vif_dev,
                                         vifi_t vif_index, u32 tb_id)
 {
        return mr_call_vif_notifiers(net, RTNL_FAMILY_IPMR, event_type,
-                                    vif, vif_index, tb_id,
+                                    vif, vif_dev, vif_index, tb_id,
                                     &net->ipv4.ipmr_seq);
 }
 
@@ -649,18 +656,14 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify,
 
        v = &mrt->vif_table[vifi];
 
-       if (VIF_EXISTS(mrt, vifi))
-               call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_DEL, v, vifi,
-                                             mrt->id);
+       dev = rtnl_dereference(v->dev);
+       if (!dev)
+               return -EADDRNOTAVAIL;
 
        write_lock_bh(&mrt_lock);
-       dev = v->dev;
-       v->dev = NULL;
-
-       if (!dev) {
-               write_unlock_bh(&mrt_lock);
-               return -EADDRNOTAVAIL;
-       }
+       call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_DEL, v, dev,
+                                     vifi, mrt->id);
+       RCU_INIT_POINTER(v->dev, NULL);
 
        if (vifi == mrt->mroute_reg_vif_num)
                mrt->mroute_reg_vif_num = -1;
@@ -890,14 +893,15 @@ static int vif_add(struct net *net, struct mr_table *mrt,
 
        /* And finish update writing critical data */
        write_lock_bh(&mrt_lock);
-       v->dev = dev;
+       rcu_assign_pointer(v->dev, dev);
        netdev_tracker_alloc(dev, &v->dev_tracker, GFP_ATOMIC);
        if (v->flags & VIFF_REGISTER)
                mrt->mroute_reg_vif_num = vifi;
        if (vifi+1 > mrt->maxvif)
                mrt->maxvif = vifi+1;
        write_unlock_bh(&mrt_lock);
-       call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, vifi, mrt->id);
+       call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev,
+                                     vifi, mrt->id);
        return 0;
 }
 
@@ -1726,7 +1730,7 @@ static int ipmr_device_event(struct notifier_block *this, unsigned long event, v
        ipmr_for_each_table(mrt, net) {
                v = &mrt->vif_table[0];
                for (ct = 0; ct < mrt->maxvif; ct++, v++) {
-                       if (v->dev == dev)
+                       if (rcu_access_pointer(v->dev) == dev)
                                vif_delete(mrt, ct, 1, NULL);
                }
        }
@@ -1811,19 +1815,21 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 {
        const struct iphdr *iph = ip_hdr(skb);
        struct vif_device *vif = &mrt->vif_table[vifi];
+       struct net_device *vif_dev;
        struct net_device *dev;
        struct rtable *rt;
        struct flowi4 fl4;
        int    encap = 0;
 
-       if (!vif->dev)
+       vif_dev = vif_dev_read(vif);
+       if (!vif_dev)
                goto out_free;
 
        if (vif->flags & VIFF_REGISTER) {
                vif->pkt_out++;
                vif->bytes_out += skb->len;
-               vif->dev->stats.tx_bytes += skb->len;
-               vif->dev->stats.tx_packets++;
+               vif_dev->stats.tx_bytes += skb->len;
+               vif_dev->stats.tx_packets++;
                ipmr_cache_report(mrt, skb, vifi, IGMPMSG_WHOLEPKT);
                goto out_free;
        }
@@ -1881,8 +1887,8 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
        if (vif->flags & VIFF_TUNNEL) {
                ip_encap(net, skb, vif->local, vif->remote);
                /* FIXME: extra output firewall step used to be here. --RR */
-               vif->dev->stats.tx_packets++;
-               vif->dev->stats.tx_bytes += skb->len;
+               vif_dev->stats.tx_packets++;
+               vif_dev->stats.tx_bytes += skb->len;
        }
 
        IPCB(skb)->flags |= IPSKB_FORWARDED;
@@ -1911,7 +1917,7 @@ static int ipmr_find_vif(struct mr_table *mrt, struct net_device *dev)
        int ct;
 
        for (ct = mrt->maxvif-1; ct >= 0; ct--) {
-               if (mrt->vif_table[ct].dev == dev)
+               if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev)
                        break;
        }
        return ct;
@@ -1944,7 +1950,7 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt,
        }
 
        /* Wrong interface: drop packet and (maybe) send PIM assert. */
-       if (mrt->vif_table[vif].dev != dev) {
+       if (rcu_access_pointer(mrt->vif_table[vif].dev) != dev) {
                if (rt_is_output_route(skb_rtable(skb))) {
                        /* It is our own packet, looped back.
                         * Very complicated situation...
@@ -2744,18 +2750,21 @@ static bool ipmr_fill_table(struct mr_table *mrt, struct sk_buff *skb)
 
 static bool ipmr_fill_vif(struct mr_table *mrt, u32 vifid, struct sk_buff *skb)
 {
+       struct net_device *vif_dev;
        struct nlattr *vif_nest;
        struct vif_device *vif;
 
+       vif = &mrt->vif_table[vifid];
+       vif_dev = vif_dev_read(vif);
        /* if the VIF doesn't exist just continue */
-       if (!VIF_EXISTS(mrt, vifid))
+       if (!vif_dev)
                return true;
 
-       vif = &mrt->vif_table[vifid];
        vif_nest = nla_nest_start_noflag(skb, IPMRA_VIF);
        if (!vif_nest)
                return false;
-       if (nla_put_u32(skb, IPMRA_VIFA_IFINDEX, vif->dev->ifindex) ||
+
+       if (nla_put_u32(skb, IPMRA_VIFA_IFINDEX, vif_dev->ifindex) ||
            nla_put_u32(skb, IPMRA_VIFA_VIF_ID, vifid) ||
            nla_put_u16(skb, IPMRA_VIFA_FLAGS, vif->flags) ||
            nla_put_u64_64bit(skb, IPMRA_VIFA_BYTES_IN, vif->bytes_in,
@@ -2919,9 +2928,11 @@ static int ipmr_vif_seq_show(struct seq_file *seq, void *v)
                         "Interface      BytesIn  PktsIn  BytesOut PktsOut Flags Local    Remote\n");
        } else {
                const struct vif_device *vif = v;
-               const char *name =  vif->dev ?
-                                   vif->dev->name : "none";
+               const struct net_device *vif_dev;
+               const char *name;
 
+               vif_dev = vif_dev_read(vif);
+               name = vif_dev ? vif_dev->name : "none";
                seq_printf(seq,
                           "%2td %-10s %8ld %7ld  %8ld %7ld %05X %08X %08X\n",
                           vif - mrt->vif_table,