can: dev: replace can_priv::ctrlmode_static by can_get_static_ctrlmode()

The statically enabled features of a CAN controller can be retrieved
using below formula:

| u32 ctrlmode_static = priv->ctrlmode & ~priv->ctrlmode_supported;

As such, there is no need to store this information. This patch remove
the field ctrlmode_static of struct can_priv and provides, in
replacement, the inline function can_get_static_ctrlmode() which
returns the same value.

Link: https://lore.kernel.org/all/20211213160226.56219-2-mailhol.vincent@wanadoo.frSigned-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/dev/dev.c

@@ -296,6 +296,7 @@ EXPORT_SYMBOL_GPL(free_candev);
 int can_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct can_priv *priv = netdev_priv(dev);
+	u32 ctrlmode_static = can_get_static_ctrlmode(priv);
 
 	/* Do not allow changing the MTU while running */
 	if (dev->flags & IFF_UP)
@@ -305,7 +306,7 @@ int can_change_mtu(struct net_device *dev, int new_mtu)
 	switch (new_mtu) {
 	case CAN_MTU:
 		/* 'CANFD-only' controllers can not switch to CAN_MTU */
-		if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
+		if (ctrlmode_static & CAN_CTRLMODE_FD)
 			return -EINVAL;
 
 		priv->ctrlmode &= ~CAN_CTRLMODE_FD;
@@ -314,7 +315,7 @@ int can_change_mtu(struct net_device *dev, int new_mtu)
 	case CANFD_MTU:
 		/* check for potential CANFD ability */
 		if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
-		    !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
+		    !(ctrlmode_static & CAN_CTRLMODE_FD))
 			return -EINVAL;
 
 		priv->ctrlmode |= CAN_CTRLMODE_FD;

drivers/net/can/dev/netlink.c

@@ -211,7 +211,7 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 		if (dev->flags & IFF_UP)
 			return -EBUSY;
 		cm = nla_data(data[IFLA_CAN_CTRLMODE]);
-		ctrlstatic = priv->ctrlmode_static;
+		ctrlstatic = can_get_static_ctrlmode(priv);
 		maskedflags = cm->flags & cm->mask;
 
 		/* check whether provided bits are allowed to be passed */

include/linux/can/dev.h

@@ -69,7 +69,6 @@ struct can_priv {
 	/* CAN controller features - see include/uapi/linux/can/netlink.h */
 	u32 ctrlmode;		/* current options setting */
 	u32 ctrlmode_supported;	/* options that can be modified by netlink */
-	u32 ctrlmode_static;	/* static enabled options for driver/hardware */
 
 	int restart_ms;
 	struct delayed_work restart_work;
@@ -139,13 +138,17 @@ static inline void can_set_static_ctrlmode(struct net_device *dev,
 
 	/* alloc_candev() succeeded => netdev_priv() is valid at this point */
 	priv->ctrlmode = static_mode;
-	priv->ctrlmode_static = static_mode;
 
 	/* override MTU which was set by default in can_setup()? */
 	if (static_mode & CAN_CTRLMODE_FD)
 		dev->mtu = CANFD_MTU;
 }
 
+static inline u32 can_get_static_ctrlmode(struct can_priv *priv)
+{
+	return priv->ctrlmode & ~priv->ctrlmode_supported;
+}
+
 void can_setup(struct net_device *dev);
 
 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,