mpls: Cleanup the rcu usage in the code.
Sparse was generating a lot of warnings mostly from missing annotations in the code. Add missing annotations and in a few cases tweak the code for performance by moving work before loops. This also fixes a problematic ommision of rcu_assign_pointer and rcu_dereference. Hopefully with complete rcu annotations any new rcu errors will stick out like a sore thumb. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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d865616e18
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19d0c341d9
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@ -24,7 +24,7 @@
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#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long)))
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struct mpls_route { /* next hop label forwarding entry */
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struct net_device *rt_dev;
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struct net_device __rcu *rt_dev;
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struct rcu_head rt_rcu;
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u32 rt_label[MAX_NEW_LABELS];
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u8 rt_protocol; /* routing protocol that set this entry */
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@ -152,7 +152,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
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goto drop;
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/* Find the output device */
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out_dev = rt->rt_dev;
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out_dev = rcu_dereference(rt->rt_dev);
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if (!mpls_output_possible(out_dev))
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goto drop;
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@ -269,13 +269,15 @@ static void mpls_route_update(struct net *net, unsigned index,
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struct net_device *dev, struct mpls_route *new,
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const struct nl_info *info)
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{
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struct mpls_route __rcu **platform_label;
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struct mpls_route *rt, *old = NULL;
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ASSERT_RTNL();
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rt = net->mpls.platform_label[index];
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if (!dev || (rt && (rt->rt_dev == dev))) {
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rcu_assign_pointer(net->mpls.platform_label[index], new);
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platform_label = rtnl_dereference(net->mpls.platform_label);
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rt = rtnl_dereference(platform_label[index]);
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if (!dev || (rt && (rtnl_dereference(rt->rt_dev) == dev))) {
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rcu_assign_pointer(platform_label[index], new);
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old = rt;
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}
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@ -287,9 +289,14 @@ static void mpls_route_update(struct net *net, unsigned index,
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static unsigned find_free_label(struct net *net)
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{
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struct mpls_route __rcu **platform_label;
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size_t platform_labels;
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unsigned index;
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for (index = 16; index < net->mpls.platform_labels; index++) {
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if (!net->mpls.platform_label[index])
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platform_label = rtnl_dereference(net->mpls.platform_label);
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platform_labels = net->mpls.platform_labels;
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for (index = 16; index < platform_labels; index++) {
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if (!rtnl_dereference(platform_label[index]))
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return index;
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}
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return LABEL_NOT_SPECIFIED;
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@ -297,6 +304,7 @@ static unsigned find_free_label(struct net *net)
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static int mpls_route_add(struct mpls_route_config *cfg)
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{
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struct mpls_route __rcu **platform_label;
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struct net *net = cfg->rc_nlinfo.nl_net;
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struct net_device *dev = NULL;
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struct mpls_route *rt, *old;
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@ -345,7 +353,8 @@ static int mpls_route_add(struct mpls_route_config *cfg)
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goto errout;
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err = -EEXIST;
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old = net->mpls.platform_label[index];
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platform_label = rtnl_dereference(net->mpls.platform_label);
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old = rtnl_dereference(platform_label[index]);
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if ((cfg->rc_nlflags & NLM_F_EXCL) && old)
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goto errout;
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@ -366,7 +375,7 @@ static int mpls_route_add(struct mpls_route_config *cfg)
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for (i = 0; i < rt->rt_labels; i++)
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rt->rt_label[i] = cfg->rc_output_label[i];
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rt->rt_protocol = cfg->rc_protocol;
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rt->rt_dev = dev;
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RCU_INIT_POINTER(rt->rt_dev, dev);
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rt->rt_via_family = cfg->rc_via_family;
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memcpy(rt->rt_via, cfg->rc_via, cfg->rc_via_alen);
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@ -406,14 +415,16 @@ errout:
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static void mpls_ifdown(struct net_device *dev)
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{
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struct mpls_route __rcu **platform_label;
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struct net *net = dev_net(dev);
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unsigned index;
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platform_label = rtnl_dereference(net->mpls.platform_label);
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for (index = 0; index < net->mpls.platform_labels; index++) {
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struct mpls_route *rt = net->mpls.platform_label[index];
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struct mpls_route *rt = rtnl_dereference(platform_label[index]);
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if (!rt)
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continue;
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if (rt->rt_dev != dev)
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if (rtnl_dereference(rt->rt_dev) != dev)
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continue;
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rt->rt_dev = NULL;
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}
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@ -653,6 +664,7 @@ static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh)
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static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
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u32 label, struct mpls_route *rt, int flags)
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{
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struct net_device *dev;
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struct nlmsghdr *nlh;
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struct rtmsg *rtm;
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@ -676,7 +688,8 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
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goto nla_put_failure;
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if (nla_put_via(skb, rt->rt_via_family, rt->rt_via, rt->rt_via_alen))
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goto nla_put_failure;
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if (rt->rt_dev && nla_put_u32(skb, RTA_OIF, rt->rt_dev->ifindex))
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dev = rtnl_dereference(rt->rt_dev);
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if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
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goto nla_put_failure;
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if (nla_put_labels(skb, RTA_DST, 1, &label))
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goto nla_put_failure;
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@ -692,6 +705,8 @@ nla_put_failure:
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static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
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{
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struct net *net = sock_net(skb->sk);
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struct mpls_route __rcu **platform_label;
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size_t platform_labels;
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unsigned int index;
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ASSERT_RTNL();
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@ -700,9 +715,11 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
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if (index < 16)
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index = 16;
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for (; index < net->mpls.platform_labels; index++) {
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platform_label = rtnl_dereference(net->mpls.platform_label);
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platform_labels = net->mpls.platform_labels;
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for (; index < platform_labels; index++) {
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struct mpls_route *rt;
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rt = net->mpls.platform_label[index];
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rt = rtnl_dereference(platform_label[index]);
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if (!rt)
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continue;
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@ -780,7 +797,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
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rt0 = mpls_rt_alloc(lo->addr_len);
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if (!rt0)
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goto nort0;
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rt0->rt_dev = lo;
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RCU_INIT_POINTER(rt0->rt_dev, lo);
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rt0->rt_protocol = RTPROT_KERNEL;
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rt0->rt_via_family = AF_PACKET;
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memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
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@ -790,7 +807,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
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rt2 = mpls_rt_alloc(lo->addr_len);
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if (!rt2)
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goto nort2;
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rt2->rt_dev = lo;
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RCU_INIT_POINTER(rt2->rt_dev, lo);
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rt2->rt_protocol = RTPROT_KERNEL;
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rt2->rt_via_family = AF_PACKET;
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memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len);
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@ -798,7 +815,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
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rtnl_lock();
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/* Remember the original table */
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old = net->mpls.platform_label;
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old = rtnl_dereference(net->mpls.platform_label);
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old_limit = net->mpls.platform_labels;
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/* Free any labels beyond the new table */
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@ -815,19 +832,19 @@ static int resize_platform_label_table(struct net *net, size_t limit)
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/* If needed set the predefined labels */
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if ((old_limit <= LABEL_IPV6_EXPLICIT_NULL) &&
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(limit > LABEL_IPV6_EXPLICIT_NULL)) {
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labels[LABEL_IPV6_EXPLICIT_NULL] = rt2;
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RCU_INIT_POINTER(labels[LABEL_IPV6_EXPLICIT_NULL], rt2);
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rt2 = NULL;
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}
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if ((old_limit <= LABEL_IPV4_EXPLICIT_NULL) &&
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(limit > LABEL_IPV4_EXPLICIT_NULL)) {
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labels[LABEL_IPV4_EXPLICIT_NULL] = rt0;
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RCU_INIT_POINTER(labels[LABEL_IPV4_EXPLICIT_NULL], rt0);
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rt0 = NULL;
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}
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/* Update the global pointers */
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net->mpls.platform_labels = limit;
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net->mpls.platform_label = labels;
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rcu_assign_pointer(net->mpls.platform_label, labels);
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rtnl_unlock();
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@ -903,6 +920,8 @@ static int mpls_net_init(struct net *net)
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static void mpls_net_exit(struct net *net)
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{
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struct mpls_route __rcu **platform_label;
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size_t platform_labels;
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struct ctl_table *table;
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unsigned int index;
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@ -910,8 +929,8 @@ static void mpls_net_exit(struct net *net)
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unregister_net_sysctl_table(net->mpls.ctl);
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kfree(table);
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/* An rcu grace period haselapsed since there was a device in
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* the network namespace (and thus the last in fqlight packet)
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/* An rcu grace period has passed since there was a device in
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* the network namespace (and thus the last in flight packet)
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* left this network namespace. This is because
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* unregister_netdevice_many and netdev_run_todo has completed
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* for each network device that was in this network namespace.
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@ -920,14 +939,16 @@ static void mpls_net_exit(struct net *net)
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* freeing the platform_label table.
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*/
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rtnl_lock();
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for (index = 0; index < net->mpls.platform_labels; index++) {
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struct mpls_route *rt = net->mpls.platform_label[index];
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rcu_assign_pointer(net->mpls.platform_label[index], NULL);
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platform_label = rtnl_dereference(net->mpls.platform_label);
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platform_labels = net->mpls.platform_labels;
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for (index = 0; index < platform_labels; index++) {
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struct mpls_route *rt = rtnl_dereference(platform_label[index]);
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RCU_INIT_POINTER(platform_label[index], NULL);
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mpls_rt_free(rt);
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}
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rtnl_unlock();
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kvfree(net->mpls.platform_label);
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kvfree(platform_label);
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}
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static struct pernet_operations mpls_net_ops = {
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