[PATCH] ipvlan: constify l3mdev_ops structure

From: Julia Lawall
Date: Sat Oct 15 2016 - 11:59:39 EST


This l3mdev_ops structure is only stored in the l3mdev_ops field of a
net_device structure. This field is declared const, so the l3mdev_ops
structure can be declared as const also. Additionally drop the
__read_mostly annotation.

The semantic patch that adds const is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct l3mdev_ops i@p = { ... };

@ok@
identifier r.i;
struct net_device *e;
position p;
@@
e->l3mdev_ops = &i@p;

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct l3mdev_ops e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
struct l3mdev_ops i = { ... };
// </smpl>

The effect on the layout of the .o file is shown by the following output
of the size command, first before then after the transformation:

text data bss dec hex filename
7364 466 52 7882 1eca drivers/net/ipvlan/ipvlan_main.o
7412 434 52 7898 1eda drivers/net/ipvlan/ipvlan_main.o

Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx>

---
drivers/net/ipvlan/ipvlan_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff -u -p a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -26,7 +26,7 @@ static struct nf_hook_ops ipvl_nfops[] _
},
};

-static struct l3mdev_ops ipvl_l3mdev_ops __read_mostly = {
+static const struct l3mdev_ops ipvl_l3mdev_ops = {
.l3mdev_l3_rcv = ipvlan_l3_rcv,
};