tcp_metrics: Use a single hash table for all network namespaces.

Now that all of the operations are safe on a single hash table
accross network namespaces, allocate a single global hash table
and update the code to use it.

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

1 files changed, 30 insertions, 36 deletions

diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index baccb070427d..366728cbee4a 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -97,6 +97,9 @@ struct tcpm_hash_bucket {
         struct tcp_metrics_block __rcu  *chain;
 };
 
+static struct tcpm_hash_bucket  *tcp_metrics_hash __read_mostly;
+static unsigned int             tcp_metrics_hash_log __read_mostly;
+
 static DEFINE_SPINLOCK(tcp_metrics_lock);
 
 static void tcpm_suck_dst(struct tcp_metrics_block *tm,
@@ -177,7 +180,7 @@ static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
         if (unlikely(reclaim)) {
                 struct tcp_metrics_block *oldest;
 
-                oldest = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain);
+                oldest = rcu_dereference(tcp_metrics_hash[hash].chain);
                 for (tm = rcu_dereference(oldest->tcpm_next); tm;
                      tm = rcu_dereference(tm->tcpm_next)) {
                         if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp))
@@ -196,8 +199,8 @@ static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
         tcpm_suck_dst(tm, dst, true);
 
         if (likely(!reclaim)) {
-                tm->tcpm_next = net->ipv4.tcp_metrics_hash[hash].chain;
-                rcu_assign_pointer(net->ipv4.tcp_metrics_hash[hash].chain, tm);
+                tm->tcpm_next = tcp_metrics_hash[hash].chain;
+                rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm);
         }
 
 out_unlock:
@@ -221,7 +224,7 @@ static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *s
         struct tcp_metrics_block *tm;
         int depth = 0;
 
-        for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
+        for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
              tm = rcu_dereference(tm->tcpm_next)) {
                 if (addr_same(&tm->tcpm_saddr, saddr) &&
                     addr_same(&tm->tcpm_daddr, daddr) &&
@@ -261,9 +264,9 @@ static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
 
         net = dev_net(dst->dev);
         hash ^= net_hash_mix(net);
-        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
+        hash = hash_32(hash, tcp_metrics_hash_log);
 
-        for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
+        for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
              tm = rcu_dereference(tm->tcpm_next)) {
                 if (addr_same(&tm->tcpm_saddr, &saddr) &&
                     addr_same(&tm->tcpm_daddr, &daddr) &&
@@ -310,9 +313,9 @@ static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock
 
         net = twsk_net(tw);
         hash ^= net_hash_mix(net);
-        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
+        hash = hash_32(hash, tcp_metrics_hash_log);
 
-        for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
+        for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
              tm = rcu_dereference(tm->tcpm_next)) {
                 if (addr_same(&tm->tcpm_saddr, &saddr) &&
                     addr_same(&tm->tcpm_daddr, &daddr) &&
@@ -360,7 +363,7 @@ static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
 
         net = dev_net(dst->dev);
         hash ^= net_hash_mix(net);
-        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
+        hash = hash_32(hash, tcp_metrics_hash_log);
 
         tm = __tcp_get_metrics(&saddr, &daddr, net, hash);
         if (tm == TCP_METRICS_RECLAIM_PTR)
@@ -911,13 +914,13 @@ static int tcp_metrics_nl_dump(struct sk_buff *skb,
                                struct netlink_callback *cb)
 {
         struct net *net = sock_net(skb->sk);
-        unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
+        unsigned int max_rows = 1U << tcp_metrics_hash_log;
         unsigned int row, s_row = cb->args[0];
         int s_col = cb->args[1], col = s_col;
 
         for (row = s_row; row < max_rows; row++, s_col = 0) {
                 struct tcp_metrics_block *tm;
-                struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash + row;
+                struct tcpm_hash_bucket *hb = tcp_metrics_hash + row;
 
                 rcu_read_lock();
                 for (col = 0, tm = rcu_dereference(hb->chain); tm;
@@ -1010,10 +1013,10 @@ static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
                 goto nla_put_failure;
 
         hash ^= net_hash_mix(net);
-        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
+        hash = hash_32(hash, tcp_metrics_hash_log);
         ret = -ESRCH;
         rcu_read_lock();
-        for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
+        for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
              tm = rcu_dereference(tm->tcpm_next)) {
                 if (addr_same(&tm->tcpm_daddr, &daddr) &&
                     (!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
@@ -1045,8 +1048,8 @@ out_free:
 
 static void tcp_metrics_flush_all(struct net *net)
 {
-        unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
-        struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash;
+        unsigned int max_rows = 1U << tcp_metrics_hash_log;
+        struct tcpm_hash_bucket *hb = tcp_metrics_hash;
         struct tcp_metrics_block *tm;
         unsigned int row;
 
@@ -1090,8 +1093,8 @@ static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
                 src = false;
 
         hash ^= net_hash_mix(net);
-        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
-        hb = net->ipv4.tcp_metrics_hash + hash;
+        hash = hash_32(hash, tcp_metrics_hash_log);
+        hb = tcp_metrics_hash + hash;
         pp = &hb->chain;
         spin_lock_bh(&tcp_metrics_lock);
         for (tm = deref_locked_genl(*pp); tm; tm = deref_locked_genl(*pp)) {
@@ -1147,6 +1150,9 @@ static int __net_init tcp_net_metrics_init(struct net *net)
         size_t size;
         unsigned int slots;
 
+        if (!net_eq(net, &init_net))
+                return 0;
+
         slots = tcpmhash_entries;
         if (!slots) {
                 if (totalram_pages >= 128 * 1024)
@@ -1155,14 +1161,14 @@ static int __net_init tcp_net_metrics_init(struct net *net)
                         slots = 8 * 1024;
         }
 
-        net->ipv4.tcp_metrics_hash_log = order_base_2(slots);
-        size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log;
+        tcp_metrics_hash_log = order_base_2(slots);
+        size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log;
 
-        net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
-        if (!net->ipv4.tcp_metrics_hash)
-                net->ipv4.tcp_metrics_hash = vzalloc(size);
+        tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
+        if (!tcp_metrics_hash)
+                tcp_metrics_hash = vzalloc(size);
 
-        if (!net->ipv4.tcp_metrics_hash)
+        if (!tcp_metrics_hash)
                 return -ENOMEM;
 
         return 0;
@@ -1170,19 +1176,7 @@ static int __net_init tcp_net_metrics_init(struct net *net)
 
 static void __net_exit tcp_net_metrics_exit(struct net *net)
 {
-        unsigned int i;
-
-        for (i = 0; i < (1U << net->ipv4.tcp_metrics_hash_log) ; i++) {
-                struct tcp_metrics_block *tm, *next;
-
-                tm = rcu_dereference_protected(net->ipv4.tcp_metrics_hash[i].chain, 1);
-                while (tm) {
-                        next = rcu_dereference_protected(tm->tcpm_next, 1);
-                        kfree(tm);
-                        tm = next;
-                }
-        }
-        kvfree(net->ipv4.tcp_metrics_hash);
+        tcp_metrics_flush_all(net);
 }
 
 static __net_initdata struct pernet_operations tcp_net_metrics_ops = {