Merge tag 'linux-can-next-for-6.17-20250610' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next

Marc Kleine-Budde says:

====================
pull-request: can-next 2025-06-10

The first 4 patches are by Vincent Mailhol and prepare the CAN netlink
interface for the introduction of CAN XL configuration.

Geert Uytterhoeven's patch updates the CAN networking documentation.

The last 2 patched are by Davide Caratti and introduce skb drop
reasons in the receive path of several CAN protocols.

* tag 'linux-can-next-for-6.17-20250610' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next:
  can: add drop reasons in CAN protocols receive path
  can: add drop reasons in the receive path of AF_CAN
  documentation: networking: can: Document alloc_candev_mqs()
  can: netlink: can_changelink(): rename tdc_mask into fd_tdc_flag_provided
  can: bittiming: rename can_tdc_is_enabled() into can_fd_tdc_is_enabled()
  can: bittiming: rename CAN_CTRLMODE_TDC_MASK into CAN_CTRLMODE_FD_TDC_MASK
  can: netlink: replace tabulation by space in assignment
====================

Link: https://patch.msgid.link/20250610094933.1593081-1-mkl@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

13 files changed, 56 insertions, 37 deletions

diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst
index b018ce346392..bc1b585355f7 100644
--- a/Documentation/networking/can.rst
+++ b/Documentation/networking/can.rst
@@ -1104,15 +1104,12 @@ for writing CAN network device driver are described below:
 General Settings
 ----------------
 
-.. code-block:: C
-
-    dev->type  = ARPHRD_CAN; /* the netdevice hardware type */
-    dev->flags = IFF_NOARP;  /* CAN has no arp */
+CAN network device drivers can use alloc_candev_mqs() and friends instead of
+alloc_netdev_mqs(), to automatically take care of CAN-specific setup:
 
-    dev->mtu = CAN_MTU; /* sizeof(struct can_frame) -> Classical CAN interface */
+.. code-block:: C
 
-    or alternative, when the controller supports CAN with flexible data rate:
-    dev->mtu = CANFD_MTU; /* sizeof(struct canfd_frame) -> CAN FD interface */
+    dev = alloc_candev_mqs(...);
 
 The struct can_frame or struct canfd_frame is the payload of each socket
 buffer (skbuff) in the protocol family PF_CAN.
diff --git a/drivers/net/can/dev/calc_bittiming.c b/drivers/net/can/dev/calc_bittiming.c
index 3809c148fb88..a94bd67c670c 100644
--- a/drivers/net/can/dev/calc_bittiming.c
+++ b/drivers/net/can/dev/calc_bittiming.c
@@ -179,7 +179,7 @@ void can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const,
 	if (!tdc_const || !(ctrlmode_supported & CAN_CTRLMODE_TDC_AUTO))
 		return;
 
-	*ctrlmode &= ~CAN_CTRLMODE_TDC_MASK;
+	*ctrlmode &= ~CAN_CTRLMODE_FD_TDC_MASK;
 
 	/* As specified in ISO 11898-1 section 11.3.3 "Transmitter
 	 * delay compensation" (TDC) is only applicable if data BRP is
diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index a36842ace084..13826e8a707b 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -18,7 +18,7 @@ static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 	[IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
 	[IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 	[IFLA_CAN_DATA_BITTIMING] = { .len = sizeof(struct can_bittiming) },
-	[IFLA_CAN_DATA_BITTIMING_CONST]	= { .len = sizeof(struct can_bittiming_const) },
+	[IFLA_CAN_DATA_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
 	[IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
 	[IFLA_CAN_TDC] = { .type = NLA_NESTED },
 	[IFLA_CAN_CTRLMODE_EXT] = { .type = NLA_NESTED },
@@ -67,12 +67,12 @@ static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 
 	if (data[IFLA_CAN_CTRLMODE]) {
 		struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
-		u32 tdc_flags = cm->flags & CAN_CTRLMODE_TDC_MASK;
+		u32 tdc_flags = cm->flags & CAN_CTRLMODE_FD_TDC_MASK;
 
 		is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 
 		/* CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive */
-		if (tdc_flags == CAN_CTRLMODE_TDC_MASK)
+		if (tdc_flags == CAN_CTRLMODE_FD_TDC_MASK)
 			return -EOPNOTSUPP;
 		/* If one of the CAN_CTRLMODE_TDC_* flag is set then
 		 * TDC must be set and vice-versa
@@ -144,7 +144,7 @@ static int can_tdc_changelink(struct can_priv *priv, const struct nlattr *nla,
 	const struct can_tdc_const *tdc_const = priv->fd.tdc_const;
 	int err;
 
-	if (!tdc_const || !can_tdc_is_enabled(priv))
+	if (!tdc_const || !can_fd_tdc_is_enabled(priv))
 		return -EOPNOTSUPP;
 
 	err = nla_parse_nested(tb_tdc, IFLA_CAN_TDC_MAX, nla,
@@ -189,7 +189,7 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 			  struct netlink_ext_ack *extack)
 {
 	struct can_priv *priv = netdev_priv(dev);
-	u32 tdc_mask = 0;
+	bool fd_tdc_flag_provided = false;
 	int err;
 
 	/* We need synchronization with dev->stop() */
@@ -230,16 +230,16 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 			dev->mtu = CAN_MTU;
 			memset(&priv->fd.data_bittiming, 0,
 			       sizeof(priv->fd.data_bittiming));
-			priv->ctrlmode &= ~CAN_CTRLMODE_TDC_MASK;
+			priv->ctrlmode &= ~CAN_CTRLMODE_FD_TDC_MASK;
 			memset(&priv->fd.tdc, 0, sizeof(priv->fd.tdc));
 		}
 
-		tdc_mask = cm->mask & CAN_CTRLMODE_TDC_MASK;
+		fd_tdc_flag_provided = cm->mask & CAN_CTRLMODE_FD_TDC_MASK;
 		/* CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually
 		 * exclusive: make sure to turn the other one off
 		 */
-		if (tdc_mask)
-			priv->ctrlmode &= cm->flags | ~CAN_CTRLMODE_TDC_MASK;
+		if (fd_tdc_flag_provided)
+			priv->ctrlmode &= cm->flags | ~CAN_CTRLMODE_FD_TDC_MASK;
 	}
 
 	if (data[IFLA_CAN_BITTIMING]) {
@@ -339,10 +339,10 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 			err = can_tdc_changelink(priv, data[IFLA_CAN_TDC],
 						 extack);
 			if (err) {
-				priv->ctrlmode &= ~CAN_CTRLMODE_TDC_MASK;
+				priv->ctrlmode &= ~CAN_CTRLMODE_FD_TDC_MASK;
 				return err;
 			}
-		} else if (!tdc_mask) {
+		} else if (!fd_tdc_flag_provided) {
 			/* Neither of TDC parameters nor TDC flags are
 			 * provided: do calculation
 			 */
@@ -409,7 +409,7 @@ static size_t can_tdc_get_size(const struct net_device *dev)
 		size += nla_total_size(sizeof(u32));	/* IFLA_CAN_TDCF_MAX */
 	}
 
-	if (can_tdc_is_enabled(priv)) {
+	if (can_fd_tdc_is_enabled(priv)) {
 		if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL ||
 		    priv->fd.do_get_auto_tdcv)
 			size += nla_total_size(sizeof(u32));	/* IFLA_CAN_TDCV */
@@ -490,7 +490,7 @@ static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	     nla_put_u32(skb, IFLA_CAN_TDC_TDCF_MAX, tdc_const->tdcf_max)))
 		goto err_cancel;
 
-	if (can_tdc_is_enabled(priv)) {
+	if (can_fd_tdc_is_enabled(priv)) {
 		u32 tdcv;
 		int err = -EINVAL;
 
diff --git a/drivers/net/can/usb/etas_es58x/es58x_fd.c b/drivers/net/can/usb/etas_es58x/es58x_fd.c
index d924b053677b..6476add1c105 100644
--- a/drivers/net/can/usb/etas_es58x/es58x_fd.c
+++ b/drivers/net/can/usb/etas_es58x/es58x_fd.c
@@ -429,7 +429,7 @@ static int es58x_fd_enable_channel(struct es58x_priv *priv)
 		es58x_fd_convert_bittiming(&tx_conf_msg.data_bittiming,
 					   &priv->can.fd.data_bittiming);
 
-		if (can_tdc_is_enabled(&priv->can)) {
+		if (can_fd_tdc_is_enabled(&priv->can)) {
 			tx_conf_msg.tdc_enabled = 1;
 			tx_conf_msg.tdco = cpu_to_le16(priv->can.fd.tdc.tdco);
 			tx_conf_msg.tdcf = cpu_to_le16(priv->can.fd.tdc.tdcf);
diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
index 3f2e378199ab..81baec8eb1e5 100644
--- a/drivers/net/can/xilinx_can.c
+++ b/drivers/net/can/xilinx_can.c
@@ -515,7 +515,7 @@ static int xcan_set_bittiming(struct net_device *ndev)
 	    priv->devtype.cantype == XAXI_CANFD_2_0) {
 		/* Setting Baud Rate prescaler value in F_BRPR Register */
 		btr0 = dbt->brp - 1;
-		if (can_tdc_is_enabled(&priv->can)) {
+		if (can_fd_tdc_is_enabled(&priv->can)) {
 			if (priv->devtype.cantype == XAXI_CANFD)
 				btr0 |= FIELD_PREP(XCAN_BRPR_TDCO_MASK, priv->can.fd.tdc.tdco) |
 					XCAN_BRPR_TDC_ENABLE;
diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h
index 9b8a9c39614b..5dfdbb63b1d5 100644
--- a/include/linux/can/bittiming.h
+++ b/include/linux/can/bittiming.h
@@ -14,7 +14,7 @@
 #define CAN_BITRATE_UNSET 0
 #define CAN_BITRATE_UNKNOWN (-1U)
 
-#define CAN_CTRLMODE_TDC_MASK					\
+#define CAN_CTRLMODE_FD_TDC_MASK				\
 	(CAN_CTRLMODE_TDC_AUTO | CAN_CTRLMODE_TDC_MANUAL)
 
 /*
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 492d23bec7be..9a92cbe5b2cb 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -91,9 +91,9 @@ struct can_priv {
 				   struct can_berr_counter *bec);
 };
 
-static inline bool can_tdc_is_enabled(const struct can_priv *priv)
+static inline bool can_fd_tdc_is_enabled(const struct can_priv *priv)
 {
-	return !!(priv->ctrlmode & CAN_CTRLMODE_TDC_MASK);
+	return !!(priv->ctrlmode & CAN_CTRLMODE_FD_TDC_MASK);
 }
 
 /*
diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h
index bcf9d7467e1a..b9e78290269e 100644
--- a/include/net/dropreason-core.h
+++ b/include/net/dropreason-core.h
@@ -121,6 +121,9 @@
 	FN(ARP_PVLAN_DISABLE)		\
 	FN(MAC_IEEE_MAC_CONTROL)	\
 	FN(BRIDGE_INGRESS_STP_STATE)	\
+	FN(CAN_RX_INVALID_FRAME)	\
+	FN(CANFD_RX_INVALID_FRAME)	\
+	FN(CANXL_RX_INVALID_FRAME)	\
 	FNe(MAX)
 
 /**
@@ -574,6 +577,21 @@ enum skb_drop_reason {
 	 */
 	SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE,
 	/**
+	 * @SKB_DROP_REASON_CAN_RX_INVALID_FRAME: received
+	 * non conform CAN frame (or device is unable to receive CAN frames)
+	 */
+	SKB_DROP_REASON_CAN_RX_INVALID_FRAME,
+	/**
+	 * @SKB_DROP_REASON_CANFD_RX_INVALID_FRAME: received
+	 * non conform CAN-FD frame (or device is unable to receive CAN frames)
+	 */
+	SKB_DROP_REASON_CANFD_RX_INVALID_FRAME,
+	/**
+	 * @SKB_DROP_REASON_CANXL_RX_INVALID_FRAME: received
+	 * non conform CAN-XL frame (or device is unable to receive CAN frames)
+	 */
+	SKB_DROP_REASON_CANXL_RX_INVALID_FRAME,
+	/**
 	 * @SKB_DROP_REASON_MAX: the maximum of core drop reasons, which
 	 * shouldn't be used as a real 'reason' - only for tracing code gen
 	 */
diff --git a/net/can/af_can.c b/net/can/af_can.c
index 4aab7033c933..b2387a46794a 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -683,7 +683,7 @@ static int can_rcv(struct sk_buff *skb, struct net_device *dev,
 		pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
 			     dev->type, skb->len);
 
-		kfree_skb(skb);
+		kfree_skb_reason(skb, SKB_DROP_REASON_CAN_RX_INVALID_FRAME);
 		return NET_RX_DROP;
 	}
 
@@ -698,7 +698,7 @@ static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
 		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
 			     dev->type, skb->len);
 
-		kfree_skb(skb);
+		kfree_skb_reason(skb, SKB_DROP_REASON_CANFD_RX_INVALID_FRAME);
 		return NET_RX_DROP;
 	}
 
@@ -713,7 +713,7 @@ static int canxl_rcv(struct sk_buff *skb, struct net_device *dev,
 		pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n",
 			     dev->type, skb->len);
 
-		kfree_skb(skb);
+		kfree_skb_reason(skb, SKB_DROP_REASON_CANXL_RX_INVALID_FRAME);
 		return NET_RX_DROP;
 	}
 
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 6bc1cc4c94c5..5e690a2377e4 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -359,6 +359,7 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
 	unsigned int datalen = head->nframes * op->cfsiz;
 	int err;
 	unsigned int *pflags;
+	enum skb_drop_reason reason;
 
 	skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
 	if (!skb)
@@ -413,11 +414,11 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
 	addr->can_family  = AF_CAN;
 	addr->can_ifindex = op->rx_ifindex;
 
-	err = sock_queue_rcv_skb(sk, skb);
+	err = sock_queue_rcv_skb_reason(sk, skb, &reason);
 	if (err < 0) {
 		struct bcm_sock *bo = bcm_sk(sk);
 
-		kfree_skb(skb);
+		sk_skb_reason_drop(sk, skb, reason);
 		/* don't care about overflows in this statistic */
 		bo->dropped_usr_msgs++;
 	}
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 1efa377f002e..dee1412b3c9c 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -278,6 +278,7 @@ static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
 static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
 {
 	struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
+	enum skb_drop_reason reason;
 
 	BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
 
@@ -285,8 +286,8 @@ static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
 	addr->can_family = AF_CAN;
 	addr->can_ifindex = skb->dev->ifindex;
 
-	if (sock_queue_rcv_skb(sk, skb) < 0)
-		kfree_skb(skb);
+	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0)
+		sk_skb_reason_drop(sk, skb, reason);
 }
 
 static u8 padlen(u8 datalen)
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index 6fefe7a68761..3d8b588822f9 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c
@@ -311,6 +311,7 @@ static void j1939_sk_recv_one(struct j1939_sock *jsk, struct sk_buff *oskb)
 {
 	const struct j1939_sk_buff_cb *oskcb = j1939_skb_to_cb(oskb);
 	struct j1939_sk_buff_cb *skcb;
+	enum skb_drop_reason reason;
 	struct sk_buff *skb;
 
 	if (oskb->sk == &jsk->sk)
@@ -331,8 +332,8 @@ static void j1939_sk_recv_one(struct j1939_sock *jsk, struct sk_buff *oskb)
 	if (skb->sk)
 		skcb->msg_flags |= MSG_DONTROUTE;
 
-	if (sock_queue_rcv_skb(&jsk->sk, skb) < 0)
-		kfree_skb(skb);
+	if (sock_queue_rcv_skb_reason(&jsk->sk, skb, &reason) < 0)
+		sk_skb_reason_drop(&jsk->sk, skb, reason);
 }
 
 bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
diff --git a/net/can/raw.c b/net/can/raw.c
index 020f21430b1d..76b867d21def 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -129,6 +129,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
 {
 	struct sock *sk = (struct sock *)data;
 	struct raw_sock *ro = raw_sk(sk);
+	enum skb_drop_reason reason;
 	struct sockaddr_can *addr;
 	struct sk_buff *skb;
 	unsigned int *pflags;
@@ -205,8 +206,8 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
 	if (oskb->sk == sk)
 		*pflags |= MSG_CONFIRM;
 
-	if (sock_queue_rcv_skb(sk, skb) < 0)
-		kfree_skb(skb);
+	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0)
+		sk_skb_reason_drop(sk, skb, reason);
 }
 
 static int raw_enable_filters(struct net *net, struct net_device *dev,