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, 4 insertions, 0 deletions

diff --git a/include/net/ip.h b/include/net/ip.h
index d678ea3d474..1cbccaf0de3 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -178,6 +178,10 @@ extern unsigned long snmp_fold_field(void *mib[], int offt);
 extern int snmp_mib_init(void *ptr[2], size_t mibsize);
 extern void snmp_mib_free(void *ptr[2]);
 
+extern struct local_ports {
+	seqlock_t	lock;
+	int		range[2];
+} sysctl_local_ports;
 extern void inet_get_local_port_range(int *low, int *high);
 
 extern int sysctl_ip_default_ttl;