net: Kill hold_net release_net

hold_net and release_net were an idea that turned out to be useless.
The code has been disabled since 2008.  Kill the code it is long past due.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

11 files changed, 11 insertions, 50 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 962ee9d71964..39fe369b46ad 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6841,8 +6841,6 @@ void free_netdev(struct net_device *dev)
 {
         struct napi_struct *p, *n;
 
-        release_net(dev_net(dev));
-
         netif_free_tx_queues(dev);
 #ifdef CONFIG_SYSFS
         kvfree(dev->_rx);
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index b55677fed1c8..68ea6950cad1 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -31,7 +31,7 @@ int fib_default_rule_add(struct fib_rules_ops *ops,
         r->pref = pref;
         r->table = table;
         r->flags = flags;
-        r->fr_net = hold_net(ops->fro_net);
+        r->fr_net = ops->fro_net;
 
         r->suppress_prefixlen = -1;
         r->suppress_ifgroup = -1;
@@ -116,7 +116,6 @@ static int __fib_rules_register(struct fib_rules_ops *ops)
                 if (ops->family == o->family)
                         goto errout;
 
-        hold_net(net);
         list_add_tail_rcu(&ops->list, &net->rules_ops);
         err = 0;
 errout:
@@ -160,15 +159,6 @@ static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
         }
 }
 
-static void fib_rules_put_rcu(struct rcu_head *head)
-{
-        struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
-        struct net *net = ops->fro_net;
-
-        release_net(net);
-        kfree(ops);
-}
-
 void fib_rules_unregister(struct fib_rules_ops *ops)
 {
         struct net *net = ops->fro_net;
@@ -178,7 +168,7 @@ void fib_rules_unregister(struct fib_rules_ops *ops)
         fib_rules_cleanup_ops(ops);
         spin_unlock(&net->rules_mod_lock);
 
-        call_rcu(&ops->rcu, fib_rules_put_rcu);
+        kfree_rcu(ops, rcu);
 }
 EXPORT_SYMBOL_GPL(fib_rules_unregister);
 
@@ -303,7 +293,7 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
                 err = -ENOMEM;
                 goto errout;
         }
-        rule->fr_net = hold_net(net);
+        rule->fr_net = net;
 
         if (tb[FRA_PRIORITY])
                 rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
@@ -423,7 +413,6 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
         return 0;
 
 errout_free:
-        release_net(rule->fr_net);
         kfree(rule);
 errout:
         rules_ops_put(ops);
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index ad07990e943d..0e8b32efc031 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -591,7 +591,7 @@ struct pneigh_entry * pneigh_lookup(struct neigh_table *tbl,
         if (!n)
                 goto out;
 
-        write_pnet(&n->net, hold_net(net));
+        write_pnet(&n->net, net);
         memcpy(n->key, pkey, key_len);
         n->dev = dev;
         if (dev)
@@ -600,7 +600,6 @@ struct pneigh_entry * pneigh_lookup(struct neigh_table *tbl,
         if (tbl->pconstructor && tbl->pconstructor(n)) {
                 if (dev)
                         dev_put(dev);
-                release_net(net);
                 kfree(n);
                 n = NULL;
                 goto out;
@@ -634,7 +633,6 @@ int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *pkey,
                                 tbl->pdestructor(n);
                         if (n->dev)
                                 dev_put(n->dev);
-                        release_net(pneigh_net(n));
                         kfree(n);
                         return 0;
                 }
@@ -657,7 +655,6 @@ static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev)
                                         tbl->pdestructor(n);
                                 if (n->dev)
                                         dev_put(n->dev);
-                                release_net(pneigh_net(n));
                                 kfree(n);
                                 continue;
                         }
@@ -1428,11 +1425,10 @@ struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
                                 neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
                 dev_hold(dev);
                 p->dev = dev;
-                write_pnet(&p->net, hold_net(net));
+                write_pnet(&p->net, net);
                 p->sysctl_table = NULL;
 
                 if (ops->ndo_neigh_setup && ops->ndo_neigh_setup(dev, p)) {
-                        release_net(net);
                         dev_put(dev);
                         kfree(p);
                         return NULL;
@@ -1472,7 +1468,6 @@ EXPORT_SYMBOL(neigh_parms_release);
 
 static void neigh_parms_destroy(struct neigh_parms *parms)
 {
-        release_net(neigh_parms_net(parms));
         kfree(parms);
 }
 
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index cb5290b8c428..e5e96b0f6717 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -236,10 +236,6 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
         net->user_ns = user_ns;
         idr_init(&net->netns_ids);
 
-#ifdef NETNS_REFCNT_DEBUG
-        atomic_set(&net->use_count, 0);
-#endif
-
         list_for_each_entry(ops, &pernet_list, list) {
                 error = ops_init(ops, net);
                 if (error < 0)
@@ -294,13 +290,6 @@ out_free:
 
 static void net_free(struct net *net)
 {
-#ifdef NETNS_REFCNT_DEBUG
-        if (unlikely(atomic_read(&net->use_count) != 0)) {
-                pr_emerg("network namespace not free! Usage: %d\n",
-                         atomic_read(&net->use_count));
-                return;
-        }
-#endif
         kfree(rcu_access_pointer(net->gen));
         kmem_cache_free(net_cachep, net);
 }
diff --git a/net/core/sock.c b/net/core/sock.c
index a9a9c2ff9260..c8842f279f7a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1455,7 +1455,6 @@ void sk_release_kernel(struct sock *sk)
 
         sock_hold(sk);
         sock_release(sk->sk_socket);
-        release_net(sock_net(sk));
         sock_net_set(sk, get_net(&init_net));
         sock_put(sk);
 }
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index c6d267442dac..66c1e4fbf884 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -213,7 +213,6 @@ static void free_fib_info_rcu(struct rcu_head *head)
                 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
         } endfor_nexthops(fi);
 
-        release_net(fi->fib_net);
         if (fi->fib_metrics != (u32 *) dst_default_metrics)
                 kfree(fi->fib_metrics);
         kfree(fi);
@@ -814,7 +813,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
         } else
                 fi->fib_metrics = (u32 *) dst_default_metrics;
 
-        fi->fib_net = hold_net(net);
+        fi->fib_net = net;
         fi->fib_protocol = cfg->fc_protocol;
         fi->fib_scope = cfg->fc_scope;
         fi->fib_flags = cfg->fc_flags;
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 9111a4e22155..f6a12b97d12b 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -61,7 +61,7 @@ struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
         struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
 
         if (tb != NULL) {
-                write_pnet(&tb->ib_net, hold_net(net));
+                write_pnet(&tb->ib_net, net);
                 tb->port      = snum;
                 tb->fastreuse = 0;
                 tb->fastreuseport = 0;
@@ -79,7 +79,6 @@ void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket
 {
         if (hlist_empty(&tb->owners)) {
                 __hlist_del(&tb->node);
-                release_net(ib_net(tb));
                 kmem_cache_free(cachep, tb);
         }
 }
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 2bd980526631..86ebf020925b 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -98,7 +98,6 @@ void inet_twsk_free(struct inet_timewait_sock *tw)
 #ifdef SOCK_REFCNT_DEBUG
         pr_debug("%s timewait_sock %p released\n", tw->tw_prot->name, tw);
 #endif
-        release_net(twsk_net(tw));
         kmem_cache_free(tw->tw_prot->twsk_prot->twsk_slab, tw);
         module_put(owner);
 }
@@ -196,7 +195,7 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int stat
                 tw->tw_transparent  = inet->transparent;
                 tw->tw_prot         = sk->sk_prot_creator;
                 atomic64_set(&tw->tw_cookie, atomic64_read(&sk->sk_cookie));
-                twsk_net_set(tw, hold_net(sock_net(sk)));
+                twsk_net_set(tw, sock_net(sk));
                 /*
                  * Because we use RCU lookups, we should not set tw_refcnt
                  * to a non null value before everything is setup for this
diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index e43e79d0a612..59c793040498 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -129,9 +129,6 @@ static const __net_initconst struct ip6addrlbl_init_table
 /* Object management */
 static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
 {
-#ifdef CONFIG_NET_NS
-        release_net(p->lbl_net);
-#endif
         kfree(p);
 }
 
@@ -241,7 +238,7 @@ static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net,
         newp->label = label;
         INIT_HLIST_NODE(&newp->list);
 #ifdef CONFIG_NET_NS
-        newp->lbl_net = hold_net(net);
+        newp->lbl_net = net;
 #endif
         atomic_set(&newp->refcnt, 1);
         return newp;
diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index f45d6db50a45..457303886fd4 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -100,7 +100,6 @@ static void fl_free(struct ip6_flowlabel *fl)
         if (fl) {
                 if (fl->share == IPV6_FL_S_PROCESS)
                         put_pid(fl->owner.pid);
-                release_net(fl->fl_net);
                 kfree(fl->opt);
                 kfree_rcu(fl, rcu);
         }
@@ -403,7 +402,7 @@ fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
                 }
         }
 
-        fl->fl_net = hold_net(net);
+        fl->fl_net = net;
         fl->expires = jiffies;
         err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
         if (err)
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 5bae7243c577..096c6276e6b9 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -203,7 +203,6 @@ static void destroy_dp_rcu(struct rcu_head *rcu)
 
         ovs_flow_tbl_destroy(&dp->table);
         free_percpu(dp->stats_percpu);
-        release_net(ovs_dp_get_net(dp));
         kfree(dp->ports);
         kfree(dp);
 }
@@ -1501,7 +1500,7 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
         if (dp == NULL)
                 goto err_free_reply;
 
-        ovs_dp_set_net(dp, hold_net(sock_net(skb->sk)));
+        ovs_dp_set_net(dp, sock_net(skb->sk));
 
         /* Allocate table. */
         err = ovs_flow_tbl_init(&dp->table);
@@ -1575,7 +1574,6 @@ err_destroy_percpu:
 err_destroy_table:
         ovs_flow_tbl_destroy(&dp->table);
 err_free_dp:
-        release_net(ovs_dp_get_net(dp));
         kfree(dp);
 err_free_reply:
         kfree_skb(reply);