5 files changed, 10 insertions, 54 deletions

diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 6298cf58ff9e..4b9bc81ae1a3 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -31,8 +31,6 @@ struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
         .lhash_lock     = RW_LOCK_UNLOCKED,
         .lhash_users    = ATOMIC_INIT(0),
         .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
-        .portalloc_lock = SPIN_LOCK_UNLOCKED,
-        .port_rover     = 1024 - 1,
 };
 
 EXPORT_SYMBOL_GPL(dccp_hashinfo);
@@ -125,36 +123,15 @@ static int dccp_v4_hash_connect(struct sock *sk)
         int ret;
 
         if (snum == 0) {
-                int rover;
                 int low = sysctl_local_port_range[0];
                 int high = sysctl_local_port_range[1];
                 int remaining = (high - low) + 1;
+                int rover = net_random() % (high - low) + low;
                 struct hlist_node *node;
                 struct inet_timewait_sock *tw = NULL;
 
                 local_bh_disable();
-
-                /* TODO. Actually it is not so bad idea to remove
-                 * dccp_hashinfo.portalloc_lock before next submission to
-                 * Linus.
-                 * As soon as we touch this place at all it is time to think.
-                 *
-                 * Now it protects single _advisory_ variable
-                 * dccp_hashinfo.port_rover, hence it is mostly useless.
-                 * Code will work nicely if we just delete it, but
-                 * I am afraid in contented case it will work not better or
-                 * even worse: another cpu just will hit the same bucket
-                 * and spin there.
-                 * So some cpu salt could remove both contention and
-                 * memory pingpong. Any ideas how to do this in a nice way?
-                 */
-                spin_lock(&dccp_hashinfo.portalloc_lock);
-                rover = dccp_hashinfo.port_rover;
-
                 do {
-                        rover++;
-                        if ((rover < low) || (rover > high))
-                                rover = low;
                         head = &dccp_hashinfo.bhash[inet_bhashfn(rover,
                                                     dccp_hashinfo.bhash_size)];
                         spin_lock(&head->lock);
@@ -187,9 +164,9 @@ static int dccp_v4_hash_connect(struct sock *sk)
 
                 next_port:
                         spin_unlock(&head->lock);
+                        if (++rover > high)
+                                rover = low;
                 } while (--remaining > 0);
-                dccp_hashinfo.port_rover = rover;
-                spin_unlock(&dccp_hashinfo.portalloc_lock);
 
                 local_bh_enable();
 
@@ -197,9 +174,6 @@ static int dccp_v4_hash_connect(struct sock *sk)
 
 ok:
                 /* All locks still held and bhs disabled */
-                dccp_hashinfo.port_rover = rover;
-                spin_unlock(&dccp_hashinfo.portalloc_lock);
-
                 inet_bind_hash(sk, tb, rover);
                 if (sk_unhashed(sk)) {
                         inet_sk(sk)->sport = htons(rover);
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 94468a76c5b4..3fe021f1a566 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -78,17 +78,9 @@ int inet_csk_get_port(struct inet_hashinfo *hashinfo,
                 int low = sysctl_local_port_range[0];
                 int high = sysctl_local_port_range[1];
                 int remaining = (high - low) + 1;
-                int rover;
+                int rover = net_random() % (high - low) + low;
 
-                spin_lock(&hashinfo->portalloc_lock);
-                if (hashinfo->port_rover < low)
-                        rover = low;
-                else
-                        rover = hashinfo->port_rover;
                 do {
-                        rover++;
-                        if (rover > high)
-                                rover = low;
                         head = &hashinfo->bhash[inet_bhashfn(rover, hashinfo->bhash_size)];
                         spin_lock(&head->lock);
                         inet_bind_bucket_for_each(tb, node, &head->chain)
@@ -97,9 +89,9 @@ int inet_csk_get_port(struct inet_hashinfo *hashinfo,
                         break;
                 next:
                         spin_unlock(&head->lock);
+                        if (++rover > high)
+                                rover = low;
                 } while (--remaining > 0);
-                hashinfo->port_rover = rover;
-                spin_unlock(&hashinfo->portalloc_lock);
 
                 /* Exhausted local port range during search?  It is not
                  * possible for us to be holding one of the bind hash
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f3f0013a9580..72b7c22e1ea5 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2112,7 +2112,6 @@ void __init tcp_init(void)
                 sysctl_tcp_max_orphans >>= (3 - order);
                 sysctl_max_syn_backlog = 128;
         }
-        tcp_hashinfo.port_rover = sysctl_local_port_range[0] - 1;
 
         sysctl_tcp_mem[0] =  768 << order;
         sysctl_tcp_mem[1] = 1024 << order;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index c85819d8474b..49d67cd75edd 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -93,8 +93,6 @@ struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
         .lhash_lock     = RW_LOCK_UNLOCKED,
         .lhash_users    = ATOMIC_INIT(0),
         .lhash_wait     = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
-        .portalloc_lock = SPIN_LOCK_UNLOCKED,
-        .port_rover     = 1024 - 1,
 };
 
 static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index d693cb988b78..d746d3b27efb 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -114,16 +114,9 @@ static int tcp_v6_get_port(struct sock *sk, unsigned short snum)
                 int low = sysctl_local_port_range[0];
                 int high = sysctl_local_port_range[1];
                 int remaining = (high - low) + 1;
-                int rover;
+                int rover = net_random() % (high - low) + low;
 
-                spin_lock(&tcp_hashinfo.portalloc_lock);
-                if (tcp_hashinfo.port_rover < low)
-                        rover = low;
-                else
-                        rover = tcp_hashinfo.port_rover;
-                do {    rover++;
-                        if (rover > high)
-                                rover = low;
+                do {
                         head = &tcp_hashinfo.bhash[inet_bhashfn(rover, tcp_hashinfo.bhash_size)];
                         spin_lock(&head->lock);
                         inet_bind_bucket_for_each(tb, node, &head->chain)
@@ -132,9 +125,9 @@ static int tcp_v6_get_port(struct sock *sk, unsigned short snum)
                         break;
                 next:
                         spin_unlock(&head->lock);
+                        if (++rover > high)
+                                rover = low;
                 } while (--remaining > 0);
-                tcp_hashinfo.port_rover = rover;
-                spin_unlock(&tcp_hashinfo.portalloc_lock);
 
                 /* Exhausted local port range during search?  It is not
                  * possible for us to be holding one of the bind hash