Merge patch series "can: raw: better approach to instantly reject unsupported CAN frames"

Oliver Hartkopp <socketcan@hartkopp.net> says:

This series reverts commit 1a620a723853 ("can: raw: instantly reject
unsupported CAN frames").

and its follow-up fixes for the introduced dependency issues.

commit 1a620a723853 ("can: raw: instantly reject unsupported CAN frames")
commit cb2dc6d2869a ("can: Kconfig: select CAN driver infrastructure by default")
commit 6abd4577bccc ("can: fix build dependency")
commit 5a5aff6338c0 ("can: fix build dependency")

The reverted patch was accessing CAN device internal data structures
from the network layer because it needs to know about the CAN protocol
capabilities of the CAN devices.

This data access caused build problems between the CAN network and the
CAN driver layer which introduced unwanted Kconfig dependencies and fixes.

The patches 2 & 3 implement a better approach which makes use of the
CAN specific ml_priv data which is accessible from both sides.

With this change the CAN network layer can check the required features
and the decoupling of the driver layer and network layer is restored.

Link: https://patch.msgid.link/20260109144135.8495-1-socketcan@hartkopp.net
[mkl: give series a more descriptive name]
[mkl: properly format reverted patch commitish]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

2 files changed, 25 insertions, 7 deletions

diff --git a/include/linux/can/can-ml.h b/include/linux/can/can-ml.h
index 8afa92d15a66..1e99fda2b380 100644
--- a/include/linux/can/can-ml.h
+++ b/include/linux/can/can-ml.h
@@ -46,6 +46,12 @@
 #include <linux/list.h>
 #include <linux/netdevice.h>
 
+/* exposed CAN device capabilities for network layer */
+#define CAN_CAP_CC BIT(0) /* CAN CC aka Classical CAN */
+#define CAN_CAP_FD BIT(1) /* CAN FD */
+#define CAN_CAP_XL BIT(2) /* CAN XL */
+#define CAN_CAP_RO BIT(3) /* read-only mode (LISTEN/RESTRICTED) */
+
 #define CAN_SFF_RCV_ARRAY_SZ (1 << CAN_SFF_ID_BITS)
 #define CAN_EFF_RCV_HASH_BITS 10
 #define CAN_EFF_RCV_ARRAY_SZ (1 << CAN_EFF_RCV_HASH_BITS)
@@ -64,6 +70,7 @@ struct can_ml_priv {
 #ifdef CAN_J1939
 	struct j1939_priv *j1939_priv;
 #endif
+	u32 can_cap;
 };
 
 static inline struct can_ml_priv *can_get_ml_priv(struct net_device *dev)
@@ -77,4 +84,21 @@ static inline void can_set_ml_priv(struct net_device *dev,
 	netdev_set_ml_priv(dev, ml_priv, ML_PRIV_CAN);
 }
 
+static inline bool can_cap_enabled(struct net_device *dev, u32 cap)
+{
+	struct can_ml_priv *can_ml = can_get_ml_priv(dev);
+
+	if (!can_ml)
+		return false;
+
+	return (can_ml->can_cap & cap);
+}
+
+static inline void can_set_cap(struct net_device *dev, u32 cap)
+{
+	struct can_ml_priv *can_ml = can_get_ml_priv(dev);
+
+	can_ml->can_cap = cap;
+}
+
 #endif /* CAN_ML_H */
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index f6416a56e95d..6d0710d6f571 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -111,18 +111,12 @@ struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
 void free_candev(struct net_device *dev);
 
 /* a candev safe wrapper around netdev_priv */
-#if IS_ENABLED(CONFIG_CAN_NETLINK)
 struct can_priv *safe_candev_priv(struct net_device *dev);
-#else
-static inline struct can_priv *safe_candev_priv(struct net_device *dev)
-{
-	return NULL;
-}
-#endif
 
 int open_candev(struct net_device *dev);
 void close_candev(struct net_device *dev);
 void can_set_default_mtu(struct net_device *dev);
+void can_set_cap_info(struct net_device *dev);
 int __must_check can_set_static_ctrlmode(struct net_device *dev,
 					 u32 static_mode);
 int can_hwtstamp_get(struct net_device *netdev,