[NET]: move struct proto_ops to const

I noticed that some of 'struct proto_ops' used in the kernel may share
a cache line used by locks or other heavily modified data. (default
linker alignement is 32 bytes, and L1_CACHE_LINE is 64 or 128 at
least)

This patch makes sure a 'struct proto_ops' can be declared as const,
so that all cpus can share all parts of it without false sharing.

This is not mandatory : a driver can still use a read/write structure
if it needs to (and eventually a __read_mostly)

I made a global stubstitute to change all existing occurences to make
them const.

This should reduce the possibility of false sharing on SMP, and
speedup some socket system calls.

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

7 files changed, 10 insertions, 10 deletions

diff --git a/net/bluetooth/bnep/sock.c b/net/bluetooth/bnep/sock.c
index 9778c6acd53b..ccbaf69afc5b 100644
--- a/net/bluetooth/bnep/sock.c
+++ b/net/bluetooth/bnep/sock.c
@@ -146,7 +146,7 @@ static int bnep_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long
         return 0;
 }
 
-static struct proto_ops bnep_sock_ops = {
+static const struct proto_ops bnep_sock_ops = {
         .family     = PF_BLUETOOTH,
         .owner      = THIS_MODULE,
         .release    = bnep_sock_release,
diff --git a/net/bluetooth/cmtp/sock.c b/net/bluetooth/cmtp/sock.c
index beb045bf5714..5e22343b6090 100644
--- a/net/bluetooth/cmtp/sock.c
+++ b/net/bluetooth/cmtp/sock.c
@@ -137,7 +137,7 @@ static int cmtp_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long
         return -EINVAL;
 }
 
-static struct proto_ops cmtp_sock_ops = {
+static const struct proto_ops cmtp_sock_ops = {
         .family         = PF_BLUETOOTH,
         .owner          = THIS_MODULE,
         .release        = cmtp_sock_release,
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index 1d6d0a15c099..84e6c93a044a 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -575,7 +575,7 @@ static int hci_sock_getsockopt(struct socket *sock, int level, int optname, char
         return 0;
 }
 
-static struct proto_ops hci_sock_ops = {
+static const struct proto_ops hci_sock_ops = {
         .family         = PF_BLUETOOTH,
         .owner          = THIS_MODULE,
         .release        = hci_sock_release,
diff --git a/net/bluetooth/hidp/sock.c b/net/bluetooth/hidp/sock.c
index f8986f881431..8f8dd931b294 100644
--- a/net/bluetooth/hidp/sock.c
+++ b/net/bluetooth/hidp/sock.c
@@ -143,7 +143,7 @@ static int hidp_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long
         return -EINVAL;
 }
 
-static struct proto_ops hidp_sock_ops = {
+static const struct proto_ops hidp_sock_ops = {
         .family         = PF_BLUETOOTH,
         .owner          = THIS_MODULE,
         .release        = hidp_sock_release,
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 95f33cc7a24e..7f0781e4326f 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -57,7 +57,7 @@
 
 #define VERSION "2.8"
 
-static struct proto_ops l2cap_sock_ops;
+static const struct proto_ops l2cap_sock_ops;
 
 static struct bt_sock_list l2cap_sk_list = {
         .lock = RW_LOCK_UNLOCKED
@@ -2161,7 +2161,7 @@ static ssize_t l2cap_sysfs_show(struct class *dev, char *buf)
 
 static CLASS_ATTR(l2cap, S_IRUGO, l2cap_sysfs_show, NULL);
 
-static struct proto_ops l2cap_sock_ops = {
+static const struct proto_ops l2cap_sock_ops = {
         .family         = PF_BLUETOOTH,
         .owner          = THIS_MODULE,
         .release        = l2cap_sock_release,
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 6c34261b232e..757d2dd3b02f 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -58,7 +58,7 @@
 #define BT_DBG(D...)
 #endif
 
-static struct proto_ops rfcomm_sock_ops;
+static const struct proto_ops rfcomm_sock_ops;
 
 static struct bt_sock_list rfcomm_sk_list = {
         .lock = RW_LOCK_UNLOCKED
@@ -907,7 +907,7 @@ static ssize_t rfcomm_sock_sysfs_show(struct class *dev, char *buf)
 
 static CLASS_ATTR(rfcomm, S_IRUGO, rfcomm_sock_sysfs_show, NULL);
 
-static struct proto_ops rfcomm_sock_ops = {
+static const struct proto_ops rfcomm_sock_ops = {
         .family         = PF_BLUETOOTH,
         .owner          = THIS_MODULE,
         .release        = rfcomm_sock_release,
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 648181430699..6b61323ce23c 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -56,7 +56,7 @@
 
 #define VERSION "0.5"
 
-static struct proto_ops sco_sock_ops;
+static const struct proto_ops sco_sock_ops;
 
 static struct bt_sock_list sco_sk_list = {
         .lock = RW_LOCK_UNLOCKED
@@ -914,7 +914,7 @@ static ssize_t sco_sysfs_show(struct class *dev, char *buf)
 
 static CLASS_ATTR(sco, S_IRUGO, sco_sysfs_show, NULL);
 
-static struct proto_ops sco_sock_ops = {
+static const struct proto_ops sco_sock_ops = {
         .family         = PF_BLUETOOTH,
         .owner          = THIS_MODULE,
         .release        = sco_sock_release,