can: make struct proto const

can_ioctl is the only reason for struct proto to be non-const.
script/check-patch.pl suggests struct proto be const.

Setting the reference to the common can_ioctl() in all CAN protocols directly
removes the need to make the struct proto writable in af_can.c

Signed-off-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 12 insertions, 14 deletions

diff --git a/include/linux/can/core.h b/include/linux/can/core.h
index 6c507bea275f..6f70a6d3a16e 100644
--- a/include/linux/can/core.h
+++ b/include/linux/can/core.h
@@ -36,10 +36,10 @@
  * @prot:       pointer to struct proto structure.
  */
 struct can_proto {
-        int              type;
-        int              protocol;
-        struct proto_ops *ops;
-        struct proto     *prot;
+        int type;
+        int protocol;
+        const struct proto_ops *ops;
+        struct proto *prot;
 };
 
 /* function prototypes for the CAN networklayer core (af_can.c) */
@@ -58,5 +58,6 @@ extern void can_rx_unregister(struct net_device *dev, canid_t can_id,
                               void *data);
 
 extern int can_send(struct sk_buff *skb, int loop);
+extern int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
 
 #endif /* CAN_CORE_H */
diff --git a/net/can/af_can.c b/net/can/af_can.c
index 702be5a2c956..733d66f1b05a 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -95,7 +95,7 @@ struct s_pstats   can_pstats;      /* receive list statistics */
  * af_can socket functions
  */
 
-static int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 {
         struct sock *sk = sock->sk;
 
@@ -108,6 +108,7 @@ static int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
                 return -ENOIOCTLCMD;
         }
 }
+EXPORT_SYMBOL(can_ioctl);
 
 static void can_sock_destruct(struct sock *sk)
 {
@@ -698,13 +699,9 @@ int can_proto_register(struct can_proto *cp)
                 printk(KERN_ERR "can: protocol %d already registered\n",
                        proto);
                 err = -EBUSY;
-        } else {
+        } else
                 proto_tab[proto] = cp;
 
-                /* use generic ioctl function if not defined by module */
-                if (!cp->ops->ioctl)
-                        cp->ops->ioctl = can_ioctl;
-        }
         spin_unlock(&proto_tab_lock);
 
         if (err < 0)
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 092dc88a7c64..871a0ad51025 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -1569,7 +1569,7 @@ static int bcm_recvmsg(struct kiocb *iocb, struct socket *sock,
         return size;
 }
 
-static struct proto_ops bcm_ops __read_mostly = {
+static const struct proto_ops bcm_ops = {
         .family        = PF_CAN,
         .release       = bcm_release,
         .bind          = sock_no_bind,
@@ -1578,7 +1578,7 @@ static struct proto_ops bcm_ops __read_mostly = {
         .accept        = sock_no_accept,
         .getname       = sock_no_getname,
         .poll          = datagram_poll,
-        .ioctl         = NULL,          /* use can_ioctl() from af_can.c */
+        .ioctl         = can_ioctl,     /* use can_ioctl() from af_can.c */
         .listen        = sock_no_listen,
         .shutdown      = sock_no_shutdown,
         .setsockopt    = sock_no_setsockopt,
diff --git a/net/can/raw.c b/net/can/raw.c
index 883e9d74fddf..649acfa7c70a 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -742,7 +742,7 @@ static int raw_recvmsg(struct kiocb *iocb, struct socket *sock,
         return size;
 }
 
-static struct proto_ops raw_ops __read_mostly = {
+static const struct proto_ops raw_ops = {
         .family        = PF_CAN,
         .release       = raw_release,
         .bind          = raw_bind,
@@ -751,7 +751,7 @@ static struct proto_ops raw_ops __read_mostly = {
         .accept        = sock_no_accept,
         .getname       = raw_getname,
         .poll          = datagram_poll,
-        .ioctl         = NULL,          /* use can_ioctl() from af_can.c */
+        .ioctl         = can_ioctl,     /* use can_ioctl() from af_can.c */
         .listen        = sock_no_listen,
         .shutdown      = sock_no_shutdown,
         .setsockopt    = raw_setsockopt,