tcp: replace ehash_size by ehash_mask

Storing the mask (size - 1) instead of the size allows fast path to be
a bit faster.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 11 insertions, 12 deletions

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index a706a47f4dbb..cb73fdefba91 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -774,7 +774,7 @@ skip_listen_ht:
         if (!(r->idiag_states & ~(TCPF_LISTEN | TCPF_SYN_RECV)))
                 goto unlock;
 
-        for (i = s_i; i < hashinfo->ehash_size; i++) {
+        for (i = s_i; i <= hashinfo->ehash_mask; i++) {
                 struct inet_ehash_bucket *head = &hashinfo->ehash[i];
                 spinlock_t *lock = inet_ehash_lockp(hashinfo, i);
                 struct sock *sk;
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 625cc5f64c94..a45aaf3d48b1 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -209,7 +209,7 @@ struct sock * __inet_lookup_established(struct net *net,
          * have wildcards anyways.
          */
         unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
-        unsigned int slot = hash & (hashinfo->ehash_size - 1);
+        unsigned int slot = hash & hashinfo->ehash_mask;
         struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
 
         rcu_read_lock();
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 13f0781f35cd..2fe571155b22 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -430,7 +430,7 @@ void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo,
         int h;
 
         local_bh_disable();
-        for (h = 0; h < (hashinfo->ehash_size); h++) {
+        for (h = 0; h <= hashinfo->ehash_mask; h++) {
                 struct inet_ehash_bucket *head =
                         inet_ehash_bucket(hashinfo, h);
                 spinlock_t *lock = inet_ehash_lockp(hashinfo, h);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 64d0af675823..cf13726259cd 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2865,11 +2865,10 @@ void __init tcp_init(void)
                                         (totalram_pages >= 128 * 1024) ?
                                         13 : 15,
                                         0,
-                                        &tcp_hashinfo.ehash_size,
                                         NULL,
+                                        &tcp_hashinfo.ehash_mask,
                                         thash_entries ? 0 : 512 * 1024);
-        tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
-        for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
+        for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
                 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
                 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
         }
@@ -2878,7 +2877,7 @@ void __init tcp_init(void)
         tcp_hashinfo.bhash =
                 alloc_large_system_hash("TCP bind",
                                         sizeof(struct inet_bind_hashbucket),
-                                        tcp_hashinfo.ehash_size,
+                                        tcp_hashinfo.ehash_mask + 1,
                                         (totalram_pages >= 128 * 1024) ?
                                         13 : 15,
                                         0,
@@ -2933,8 +2932,8 @@ void __init tcp_init(void)
         sysctl_tcp_rmem[2] = max(87380, max_share);
 
         printk(KERN_INFO "TCP: Hash tables configured "
-               "(established %d bind %d)\n",
-               tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
+               "(established %u bind %u)\n",
+               tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
 
         tcp_register_congestion_control(&tcp_reno);
 }
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 7cda24b53f61..99718703d040 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2000,7 +2000,7 @@ static void *established_get_first(struct seq_file *seq)
         struct net *net = seq_file_net(seq);
         void *rc = NULL;
 
-        for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
+        for (st->bucket = 0; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
                 struct sock *sk;
                 struct hlist_nulls_node *node;
                 struct inet_timewait_sock *tw;
@@ -2061,10 +2061,10 @@ get_tw:
                 st->state = TCP_SEQ_STATE_ESTABLISHED;
 
                 /* Look for next non empty bucket */
-                while (++st->bucket < tcp_hashinfo.ehash_size &&
+                while (++st->bucket <= tcp_hashinfo.ehash_mask &&
                                 empty_bucket(st))
                         ;
-                if (st->bucket >= tcp_hashinfo.ehash_size)
+                if (st->bucket > tcp_hashinfo.ehash_mask)
                         return NULL;
 
                 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));