inet: cleanup of local_port_range

I noticed sysctl_local_port_range[] and its associated seqlock
sysctl_local_port_range_lock were on separate cache lines.
Moreover, sysctl_local_port_range[] was close to unrelated
variables, highly modified, leading to cache misses.

Moving these two variables in a structure can help data
locality and moving this structure to read_mostly section
helps sharing of this data among cpus.

Cleanup of extern declarations (moved in include file where
they belong), and use of inet_get_local_port_range()
accessor instead of direct access to ports values.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 7 deletions

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 21fcc5a9045f..bd1278a2d828 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -30,20 +30,22 @@ EXPORT_SYMBOL(inet_csk_timer_bug_msg);
 #endif
 
 /*
- * This array holds the first and last local port number.
+ * This struct holds the first and last local port number.
  */
-int sysctl_local_port_range[2] = { 32768, 61000 };
-DEFINE_SEQLOCK(sysctl_port_range_lock);
+struct local_ports sysctl_local_ports __read_mostly = {
+        .lock = SEQLOCK_UNLOCKED,
+        .range = { 32768, 61000 },
+};
 
 void inet_get_local_port_range(int *low, int *high)
 {
         unsigned seq;
         do {
-                seq = read_seqbegin(&sysctl_port_range_lock);
+                seq = read_seqbegin(&sysctl_local_ports.lock);
 
-                *low = sysctl_local_port_range[0];
-                *high = sysctl_local_port_range[1];
-        } while (read_seqretry(&sysctl_port_range_lock, seq));
+                *low = sysctl_local_ports.range[0];
+                *high = sysctl_local_ports.range[1];
+        } while (read_seqretry(&sysctl_local_ports.lock, seq));
 }
 EXPORT_SYMBOL(inet_get_local_port_range);