[INET]: Generalise the tcp_listen_ lock routines

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 94 insertions, 87 deletions

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index da07411b36d2..f5d65121f7b7 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -19,10 +19,14 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/tcp.h>          /* only for TCP_LISTEN, damn :-( */
 #include <linux/types.h>
+#include <linux/wait.h>
 
 #include <net/sock.h>
 
+#include <asm/atomic.h>
+
 /* This is for all connections with a full identity, no wildcards.
  * New scheme, half the table is for TIME_WAIT, the other half is
  * for the rest.  I'll experiment with dynamic table growth later.
@@ -192,4 +196,48 @@ static inline void inet_inherit_port(struct inet_hashinfo *table,
 
 extern void inet_put_port(struct inet_hashinfo *table, struct sock *sk);
 
+extern void inet_listen_wlock(struct inet_hashinfo *hashinfo);
+
+/*
+ * - We may sleep inside this lock.
+ * - If sleeping is not required (or called from BH),
+ *   use plain read_(un)lock(&inet_hashinfo.lhash_lock).
+ */
+static inline void inet_listen_lock(struct inet_hashinfo *hashinfo)
+{
+        /* read_lock synchronizes to candidates to writers */
+        read_lock(&hashinfo->lhash_lock);
+        atomic_inc(&hashinfo->lhash_users);
+        read_unlock(&hashinfo->lhash_lock);
+}
+
+static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
+{
+        if (atomic_dec_and_test(&hashinfo->lhash_users))
+                wake_up(&hashinfo->lhash_wait);
+}
+
+static inline void __inet_hash(struct inet_hashinfo *hashinfo,
+                               struct sock *sk, const int listen_possible)
+{
+        struct hlist_head *list;
+        rwlock_t *lock;
+
+        BUG_TRAP(sk_unhashed(sk));
+        if (listen_possible && sk->sk_state == TCP_LISTEN) {
+                list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
+                lock = &hashinfo->lhash_lock;
+                inet_listen_wlock(hashinfo);
+        } else {
+                sk->sk_hashent = inet_sk_ehashfn(sk, hashinfo->ehash_size);
+                list = &hashinfo->ehash[sk->sk_hashent].chain;
+                lock = &hashinfo->ehash[sk->sk_hashent].lock;
+                write_lock(lock);
+        }
+        __sk_add_node(sk, list);
+        sock_prot_inc_use(sk->sk_prot);
+        write_unlock(lock);
+        if (listen_possible && sk->sk_state == TCP_LISTEN)
+                wake_up(&hashinfo->lhash_wait);
+}
 #endif /* _INET_HASHTABLES_H */
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 99e47695d4b6..bc110cc7022b 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1447,27 +1447,6 @@ static __inline__ void tcp_openreq_init(struct request_sock *req,
 
 extern void tcp_enter_memory_pressure(void);
 
-extern void tcp_listen_wlock(void);
-
-/* - We may sleep inside this lock.
- * - If sleeping is not required (or called from BH),
- *   use plain read_(un)lock(&inet_hashinfo.lhash_lock).
- */
-
-static inline void tcp_listen_lock(void)
-{
-        /* read_lock synchronizes to candidates to writers */
-        read_lock(&tcp_hashinfo.lhash_lock);
-        atomic_inc(&tcp_hashinfo.lhash_users);
-        read_unlock(&tcp_hashinfo.lhash_lock);
-}
-
-static inline void tcp_listen_unlock(void)
-{
-        if (atomic_dec_and_test(&tcp_hashinfo.lhash_users))
-                wake_up(&tcp_hashinfo.lhash_wait);
-}
-
 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
 {
         return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 33d6cbe32cdc..06cbc6f689c5 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -15,7 +15,9 @@
 
 #include <linux/config.h>
 #include <linux/module.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/wait.h>
 
 #include <net/inet_hashtables.h>
 
@@ -89,3 +91,33 @@ void inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk)
 }
 
 EXPORT_SYMBOL(inet_put_port);
+
+/*
+ * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
+ * Look, when several writers sleep and reader wakes them up, all but one
+ * immediately hit write lock and grab all the cpus. Exclusive sleep solves
+ * this, _but_ remember, it adds useless work on UP machines (wake up each
+ * exclusive lock release). It should be ifdefed really.
+ */
+void inet_listen_wlock(struct inet_hashinfo *hashinfo)
+{
+        write_lock(&hashinfo->lhash_lock);
+
+        if (atomic_read(&hashinfo->lhash_users)) {
+                DEFINE_WAIT(wait);
+
+                for (;;) {
+                        prepare_to_wait_exclusive(&hashinfo->lhash_wait,
+                                                  &wait, TASK_UNINTERRUPTIBLE);
+                        if (!atomic_read(&hashinfo->lhash_users))
+                                break;
+                        write_unlock_bh(&hashinfo->lhash_lock);
+                        schedule();
+                        write_lock_bh(&hashinfo->lhash_lock);
+                }
+
+                finish_wait(&hashinfo->lhash_wait, &wait);
+        }
+}
+
+EXPORT_SYMBOL(inet_listen_wlock);
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index 0ae738b455f0..1a89a03c449b 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -589,7 +589,7 @@ static int tcpdiag_dump(struct sk_buff *skb, struct netlink_callback *cb)
         if (cb->args[0] == 0) {
                 if (!(r->tcpdiag_states&(TCPF_LISTEN|TCPF_SYN_RECV)))
                         goto skip_listen_ht;
-                tcp_listen_lock();
+                inet_listen_lock(&tcp_hashinfo);
                 for (i = s_i; i < INET_LHTABLE_SIZE; i++) {
                         struct sock *sk;
                         struct hlist_node *node;
@@ -613,7 +613,7 @@ static int tcpdiag_dump(struct sk_buff *skb, struct netlink_callback *cb)
                                         goto syn_recv;
 
                                 if (tcpdiag_dump_sock(skb, sk, cb) < 0) {
-                                        tcp_listen_unlock();
+                                        inet_listen_unlock(&tcp_hashinfo);
                                         goto done;
                                 }
 
@@ -622,7 +622,7 @@ syn_recv:
                                         goto next_listen;
 
                                 if (tcpdiag_dump_reqs(skb, sk, cb) < 0) {
-                                        tcp_listen_unlock();
+                                        inet_listen_unlock(&tcp_hashinfo);
                                         goto done;
                                 }
 
@@ -636,7 +636,7 @@ next_listen:
                         cb->args[3] = 0;
                         cb->args[4] = 0;
                 }
-                tcp_listen_unlock();
+                inet_listen_unlock(&tcp_hashinfo);
 skip_listen_ht:
                 cb->args[0] = 1;
                 s_i = num = s_num = 0;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index f5373f9f00ac..5f9ad95304ca 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -228,62 +228,11 @@ fail:
         return ret;
 }
 
-/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
- * Look, when several writers sleep and reader wakes them up, all but one
- * immediately hit write lock and grab all the cpus. Exclusive sleep solves
- * this, _but_ remember, it adds useless work on UP machines (wake up each
- * exclusive lock release). It should be ifdefed really.
- */
-
-void tcp_listen_wlock(void)
-{
-        write_lock(&tcp_hashinfo.lhash_lock);
-
-        if (atomic_read(&tcp_hashinfo.lhash_users)) {
-                DEFINE_WAIT(wait);
-
-                for (;;) {
-                        prepare_to_wait_exclusive(&tcp_hashinfo.lhash_wait,
-                                                &wait, TASK_UNINTERRUPTIBLE);
-                        if (!atomic_read(&tcp_hashinfo.lhash_users))
-                                break;
-                        write_unlock_bh(&tcp_hashinfo.lhash_lock);
-                        schedule();
-                        write_lock_bh(&tcp_hashinfo.lhash_lock);
-                }
-
-                finish_wait(&tcp_hashinfo.lhash_wait, &wait);
-        }
-}
-
-static __inline__ void __tcp_v4_hash(struct sock *sk, const int listen_possible)
-{
-        struct hlist_head *list;
-        rwlock_t *lock;
-
-        BUG_TRAP(sk_unhashed(sk));
-        if (listen_possible && sk->sk_state == TCP_LISTEN) {
-                list = &tcp_hashinfo.listening_hash[inet_sk_listen_hashfn(sk)];
-                lock = &tcp_hashinfo.lhash_lock;
-                tcp_listen_wlock();
-        } else {
-                sk->sk_hashent = inet_sk_ehashfn(sk, tcp_hashinfo.ehash_size);
-                list = &tcp_hashinfo.ehash[sk->sk_hashent].chain;
-                lock = &tcp_hashinfo.ehash[sk->sk_hashent].lock;
-                write_lock(lock);
-        }
-        __sk_add_node(sk, list);
-        sock_prot_inc_use(sk->sk_prot);
-        write_unlock(lock);
-        if (listen_possible && sk->sk_state == TCP_LISTEN)
-                wake_up(&tcp_hashinfo.lhash_wait);
-}
-
 static void tcp_v4_hash(struct sock *sk)
 {
         if (sk->sk_state != TCP_CLOSE) {
                 local_bh_disable();
-                __tcp_v4_hash(sk, 1);
+                __inet_hash(&tcp_hashinfo, sk, 1);
                 local_bh_enable();
         }
 }
@@ -297,7 +246,7 @@ void tcp_unhash(struct sock *sk)
 
         if (sk->sk_state == TCP_LISTEN) {
                 local_bh_disable();
-                tcp_listen_wlock();
+                inet_listen_wlock(&tcp_hashinfo);
                 lock = &tcp_hashinfo.lhash_lock;
         } else {
                 struct inet_ehash_bucket *head = &tcp_hashinfo.ehash[sk->sk_hashent];
@@ -624,7 +573,7 @@ ok:
                 inet_bind_hash(sk, tb, port);
                 if (sk_unhashed(sk)) {
                         inet_sk(sk)->sport = htons(port);
-                        __tcp_v4_hash(sk, 0);
+                        __inet_hash(&tcp_hashinfo, sk, 0);
                 }
                 spin_unlock(&head->lock);
 
@@ -641,7 +590,7 @@ ok:
         tb  = inet_sk(sk)->bind_hash;
         spin_lock_bh(&head->lock);
         if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
-                __tcp_v4_hash(sk, 0);
+                __inet_hash(&tcp_hashinfo, sk, 0);
                 spin_unlock_bh(&head->lock);
                 return 0;
         } else {
@@ -1479,7 +1428,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
         newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
         tcp_initialize_rcv_mss(newsk);
 
-        __tcp_v4_hash(newsk, 0);
+        __inet_hash(&tcp_hashinfo, newsk, 0);
         __inet_inherit_port(&tcp_hashinfo, sk, newsk);
 
         return newsk;
@@ -2102,12 +2051,12 @@ static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
         void *rc;
         struct tcp_iter_state* st = seq->private;
 
-        tcp_listen_lock();
+        inet_listen_lock(&tcp_hashinfo);
         st->state = TCP_SEQ_STATE_LISTENING;
         rc        = listening_get_idx(seq, &pos);
 
         if (!rc) {
-                tcp_listen_unlock();
+                inet_listen_unlock(&tcp_hashinfo);
                 local_bh_disable();
                 st->state = TCP_SEQ_STATE_ESTABLISHED;
                 rc        = established_get_idx(seq, pos);
@@ -2140,7 +2089,7 @@ static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
         case TCP_SEQ_STATE_LISTENING:
                 rc = listening_get_next(seq, v);
                 if (!rc) {
-                        tcp_listen_unlock();
+                        inet_listen_unlock(&tcp_hashinfo);
                         local_bh_disable();
                         st->state = TCP_SEQ_STATE_ESTABLISHED;
                         rc        = established_get_first(seq);
@@ -2168,7 +2117,7 @@ static void tcp_seq_stop(struct seq_file *seq, void *v)
                 }
         case TCP_SEQ_STATE_LISTENING:
                 if (v != SEQ_START_TOKEN)
-                        tcp_listen_unlock();
+                        inet_listen_unlock(&tcp_hashinfo);
                 break;
         case TCP_SEQ_STATE_TIME_WAIT:
         case TCP_SEQ_STATE_ESTABLISHED:
@@ -2431,7 +2380,6 @@ void __init tcp_v4_init(struct net_proto_family *ops)
 EXPORT_SYMBOL(ipv4_specific);
 EXPORT_SYMBOL(inet_bind_bucket_create);
 EXPORT_SYMBOL(tcp_hashinfo);
-EXPORT_SYMBOL(tcp_listen_wlock);
 EXPORT_SYMBOL(tcp_prot);
 EXPORT_SYMBOL(tcp_unhash);
 EXPORT_SYMBOL(tcp_v4_conn_request);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 362ef5a64062..93a66b9a76e1 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -229,7 +229,7 @@ static __inline__ void __tcp_v6_hash(struct sock *sk)
         if (sk->sk_state == TCP_LISTEN) {
                 list = &tcp_hashinfo.listening_hash[inet_sk_listen_hashfn(sk)];
                 lock = &tcp_hashinfo.lhash_lock;
-                tcp_listen_wlock();
+                inet_listen_wlock(&tcp_hashinfo);
         } else {
                 sk->sk_hashent = tcp_v6_sk_hashfn(sk);
                 list = &tcp_hashinfo.ehash[sk->sk_hashent].chain;