Merge tag 'linux-can-fixes-for-6.15-20250506' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2025-05-06

The first patch is by Antonios Salios and adds a missing
spin_lock_init() to the m_can driver.

The next 3 patches are by me and fix the unregistration order in the
mcp251xfd, rockchip_canfd and m_can driver.

The last patch is by Oliver Hartkopp and fixes RCU and BH
locking/handling in the CAN gw protocol.

* tag 'linux-can-fixes-for-6.15-20250506' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can:
can: gw: fix RCU/BH usage in cgw_create_job()
can: mcan: m_can_class_unregister(): fix order of unregistration calls
can: rockchip_canfd: rkcanfd_remove(): fix order of unregistration calls
can: mcp251xfd: mcp251xfd_remove(): fix order of unregistration calls
can: mcp251xfd: fix TDC setting for low data bit rates
can: m_can: m_can_class_allocate_dev(): initialize spin lock on device probe
====================

Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/can/m_can/m_can.c

···
 	SET_NETDEV_DEV(net_dev, dev);
 
 	m_can_of_parse_mram(class_dev, mram_config_vals);
+	spin_lock_init(&class_dev->tx_handling_spinlock);
 out:
 	return class_dev;
 }
···
 
 void m_can_class_unregister(struct m_can_classdev *cdev)
 {
+	unregister_candev(cdev->net);
 	if (cdev->is_peripheral)
 		can_rx_offload_del(&cdev->offload);
-	unregister_candev(cdev->net);
 }
 EXPORT_SYMBOL_GPL(m_can_class_unregister);
 

drivers/net/can/rockchip/rockchip_canfd-core.c

···
 	struct rkcanfd_priv *priv = platform_get_drvdata(pdev);
 	struct net_device *ndev = priv->ndev;
 
-	can_rx_offload_del(&priv->offload);
 	rkcanfd_unregister(priv);
+	can_rx_offload_del(&priv->offload);
 	free_candev(ndev);
 }
 

drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c

···
 	.brp_inc = 1,
 };
 
+/* The datasheet of the mcp2518fd (DS20006027B) specifies a range of
+ * [-64,63] for TDCO, indicating a relative TDCO.
+ *
+ * Manual tests have shown, that using a relative TDCO configuration
+ * results in bus off, while an absolute configuration works.
+ *
+ * For TDCO use the max value (63) from the data sheet, but 0 as the
+ * minimum.
+ */
+static const struct can_tdc_const mcp251xfd_tdc_const = {
+	.tdcv_min = 0,
+	.tdcv_max = 63,
+	.tdco_min = 0,
+	.tdco_max = 63,
+	.tdcf_min = 0,
+	.tdcf_max = 0,
+};
+
 static const char *__mcp251xfd_get_model_str(enum mcp251xfd_model model)
 {
 	switch (model) {
···
 {
 	const struct can_bittiming *bt = &priv->can.bittiming;
 	const struct can_bittiming *dbt = &priv->can.data_bittiming;
-	u32 val = 0;
-	s8 tdco;
+	u32 tdcmod, val = 0;
 	int err;
 
 	/* CAN Control Register
···
 		return err;
 
 	/* Transmitter Delay Compensation */
-	tdco = clamp_t(int, dbt->brp * (dbt->prop_seg + dbt->phase_seg1),
-		       -64, 63);
-	val = FIELD_PREP(MCP251XFD_REG_TDC_TDCMOD_MASK,
-			 MCP251XFD_REG_TDC_TDCMOD_AUTO) |
-		FIELD_PREP(MCP251XFD_REG_TDC_TDCO_MASK, tdco);
+	if (priv->can.ctrlmode & CAN_CTRLMODE_TDC_AUTO)
+		tdcmod = MCP251XFD_REG_TDC_TDCMOD_AUTO;
+	else if (priv->can.ctrlmode & CAN_CTRLMODE_TDC_MANUAL)
+		tdcmod = MCP251XFD_REG_TDC_TDCMOD_MANUAL;
+	else
+		tdcmod = MCP251XFD_REG_TDC_TDCMOD_DISABLED;
+
+	val = FIELD_PREP(MCP251XFD_REG_TDC_TDCMOD_MASK, tdcmod) |
+		FIELD_PREP(MCP251XFD_REG_TDC_TDCV_MASK, priv->can.tdc.tdcv) |
+		FIELD_PREP(MCP251XFD_REG_TDC_TDCO_MASK, priv->can.tdc.tdco);
 
 	return regmap_write(priv->map_reg, MCP251XFD_REG_TDC, val);
 }
···
 	priv->can.do_get_berr_counter = mcp251xfd_get_berr_counter;
 	priv->can.bittiming_const = &mcp251xfd_bittiming_const;
 	priv->can.data_bittiming_const = &mcp251xfd_data_bittiming_const;
+	priv->can.tdc_const = &mcp251xfd_tdc_const;
 	priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
 		CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_BERR_REPORTING |
 		CAN_CTRLMODE_FD | CAN_CTRLMODE_FD_NON_ISO |
-		CAN_CTRLMODE_CC_LEN8_DLC;
+		CAN_CTRLMODE_CC_LEN8_DLC | CAN_CTRLMODE_TDC_AUTO |
+		CAN_CTRLMODE_TDC_MANUAL;
 	set_bit(MCP251XFD_FLAGS_DOWN, priv->flags);
 	priv->ndev = ndev;
 	priv->spi = spi;
···
 	struct mcp251xfd_priv *priv = spi_get_drvdata(spi);
 	struct net_device *ndev = priv->ndev;
 
-	can_rx_offload_del(&priv->offload);
 	mcp251xfd_unregister(priv);
+	can_rx_offload_del(&priv->offload);
 	spi->max_speed_hz = priv->spi_max_speed_hz_orig;
 	free_candev(ndev);
 }

net/can/gw.c

···
 	u32 handled_frames;
 	u32 dropped_frames;
 	u32 deleted_frames;
-	struct cf_mod mod;
+	struct cf_mod __rcu *cf_mod;
 	union {
 		/* CAN frame data source */
 		struct net_device *dev;
···
 	struct cgw_job *gwj = (struct cgw_job *)data;
 	struct canfd_frame *cf;
 	struct sk_buff *nskb;
+	struct cf_mod *mod;
 	int modidx = 0;
 
 	/* process strictly Classic CAN or CAN FD frames */
···
 	 * When there is at least one modification function activated,
 	 * we need to copy the skb as we want to modify skb->data.
 	 */
-	if (gwj->mod.modfunc[0])
+	mod = rcu_dereference(gwj->cf_mod);
+	if (mod->modfunc[0])
 		nskb = skb_copy(skb, GFP_ATOMIC);
 	else
 		nskb = skb_clone(skb, GFP_ATOMIC);
···
 	cf = (struct canfd_frame *)nskb->data;
 
 	/* perform preprocessed modification functions if there are any */
-	while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
-		(*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
+	while (modidx < MAX_MODFUNCTIONS && mod->modfunc[modidx])
+		(*mod->modfunc[modidx++])(cf, mod);
 
 	/* Has the CAN frame been modified? */
 	if (modidx) {
···
 		}
 
 		/* check for checksum updates */
-		if (gwj->mod.csumfunc.crc8)
-			(*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
+		if (mod->csumfunc.crc8)
+			(*mod->csumfunc.crc8)(cf, &mod->csum.crc8);
 
-		if (gwj->mod.csumfunc.xor)
-			(*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
+		if (mod->csumfunc.xor)
+			(*mod->csumfunc.xor)(cf, &mod->csum.xor);
 	}
 
 	/* clear the skb timestamp if not configured the other way */
···
 {
 	struct cgw_job *gwj = container_of(rcu_head, struct cgw_job, rcu);
 
+	/* cgw_job::cf_mod is always accessed from the same cgw_job object within
+	 * the same RCU read section. Once cgw_job is scheduled for removal,
+	 * cf_mod can also be removed without mandating an additional grace period.
+	 */
+	kfree(rcu_access_pointer(gwj->cf_mod));
 	kmem_cache_free(cgw_cache, gwj);
+}
+
+/* Return cgw_job::cf_mod with RTNL protected section */
+static struct cf_mod *cgw_job_cf_mod(struct cgw_job *gwj)
+{
+	return rcu_dereference_protected(gwj->cf_mod, rtnl_is_locked());
 }
 
 static int cgw_notifier(struct notifier_block *nb,
···
 {
 	struct rtcanmsg *rtcan;
 	struct nlmsghdr *nlh;
+	struct cf_mod *mod;
 
 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
 	if (!nlh)
···
 			goto cancel;
 	}
 
+	mod = cgw_job_cf_mod(gwj);
 	if (gwj->flags & CGW_FLAGS_CAN_FD) {
 		struct cgw_fdframe_mod mb;
 
-		if (gwj->mod.modtype.and) {
-			memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.and;
+		if (mod->modtype.and) {
+			memcpy(&mb.cf, &mod->modframe.and, sizeof(mb.cf));
+			mb.modtype = mod->modtype.and;
 			if (nla_put(skb, CGW_FDMOD_AND, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.or) {
-			memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.or;
+		if (mod->modtype.or) {
+			memcpy(&mb.cf, &mod->modframe.or, sizeof(mb.cf));
+			mb.modtype = mod->modtype.or;
 			if (nla_put(skb, CGW_FDMOD_OR, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.xor) {
-			memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.xor;
+		if (mod->modtype.xor) {
+			memcpy(&mb.cf, &mod->modframe.xor, sizeof(mb.cf));
+			mb.modtype = mod->modtype.xor;
 			if (nla_put(skb, CGW_FDMOD_XOR, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.set) {
-			memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.set;
+		if (mod->modtype.set) {
+			memcpy(&mb.cf, &mod->modframe.set, sizeof(mb.cf));
+			mb.modtype = mod->modtype.set;
 			if (nla_put(skb, CGW_FDMOD_SET, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 	} else {
 		struct cgw_frame_mod mb;
 
-		if (gwj->mod.modtype.and) {
-			memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.and;
+		if (mod->modtype.and) {
+			memcpy(&mb.cf, &mod->modframe.and, sizeof(mb.cf));
+			mb.modtype = mod->modtype.and;
 			if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.or) {
-			memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.or;
+		if (mod->modtype.or) {
+			memcpy(&mb.cf, &mod->modframe.or, sizeof(mb.cf));
+			mb.modtype = mod->modtype.or;
 			if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.xor) {
-			memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.xor;
+		if (mod->modtype.xor) {
+			memcpy(&mb.cf, &mod->modframe.xor, sizeof(mb.cf));
+			mb.modtype = mod->modtype.xor;
 			if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 
-		if (gwj->mod.modtype.set) {
-			memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
-			mb.modtype = gwj->mod.modtype.set;
+		if (mod->modtype.set) {
+			memcpy(&mb.cf, &mod->modframe.set, sizeof(mb.cf));
+			mb.modtype = mod->modtype.set;
 			if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
 				goto cancel;
 		}
 	}
 
-	if (gwj->mod.uid) {
-		if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0)
+	if (mod->uid) {
+		if (nla_put_u32(skb, CGW_MOD_UID, mod->uid) < 0)
 			goto cancel;
 	}
 
-	if (gwj->mod.csumfunc.crc8) {
+	if (mod->csumfunc.crc8) {
 		if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
-			    &gwj->mod.csum.crc8) < 0)
+			    &mod->csum.crc8) < 0)
 			goto cancel;
 	}
 
-	if (gwj->mod.csumfunc.xor) {
+	if (mod->csumfunc.xor) {
 		if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
-			    &gwj->mod.csum.xor) < 0)
+			    &mod->csum.xor) < 0)
 			goto cancel;
 	}
 
···
 	struct net *net = sock_net(skb->sk);
 	struct rtcanmsg *r;
 	struct cgw_job *gwj;
-	struct cf_mod mod;
+	struct cf_mod *mod;
 	struct can_can_gw ccgw;
 	u8 limhops = 0;
 	int err = 0;
···
 	if (r->gwtype != CGW_TYPE_CAN_CAN)
 		return -EINVAL;
 
-	err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
-	if (err < 0)
-		return err;
+	mod = kmalloc(sizeof(*mod), GFP_KERNEL);
+	if (!mod)
+		return -ENOMEM;
 
-	if (mod.uid) {
+	err = cgw_parse_attr(nlh, mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
+	if (err < 0)
+		goto out_free_cf;
+
+	if (mod->uid) {
 		ASSERT_RTNL();
 
 		/* check for updating an existing job with identical uid */
 		hlist_for_each_entry(gwj, &net->can.cgw_list, list) {
-			if (gwj->mod.uid != mod.uid)
+			struct cf_mod *old_cf;
+
+			old_cf = cgw_job_cf_mod(gwj);
+			if (old_cf->uid != mod->uid)
 				continue;
 
 			/* interfaces & filters must be identical */
-			if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
-				return -EINVAL;
+			if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) {
+				err = -EINVAL;
+				goto out_free_cf;
+			}
 
-			/* update modifications with disabled softirq & quit */
-			local_bh_disable();
-			memcpy(&gwj->mod, &mod, sizeof(mod));
-			local_bh_enable();
+			rcu_assign_pointer(gwj->cf_mod, mod);
+			kfree_rcu_mightsleep(old_cf);
 			return 0;
 		}
 	}
 
 	/* ifindex == 0 is not allowed for job creation */
-	if (!ccgw.src_idx || !ccgw.dst_idx)
-		return -ENODEV;
+	if (!ccgw.src_idx || !ccgw.dst_idx) {
+		err = -ENODEV;
+		goto out_free_cf;
+	}
 
 	gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
-	if (!gwj)
-		return -ENOMEM;
+	if (!gwj) {
+		err = -ENOMEM;
+		goto out_free_cf;
+	}
 
 	gwj->handled_frames = 0;
 	gwj->dropped_frames = 0;
···
 	gwj->limit_hops = limhops;
 
 	/* insert already parsed information */
-	memcpy(&gwj->mod, &mod, sizeof(mod));
+	RCU_INIT_POINTER(gwj->cf_mod, mod);
 	memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw));
 
 	err = -ENODEV;
···
 	if (!err)
 		hlist_add_head_rcu(&gwj->list, &net->can.cgw_list);
 out:
-	if (err)
+	if (err) {
 		kmem_cache_free(cgw_cache, gwj);
-
+out_free_cf:
+		kfree(mod);
+	}
 	return err;
 }
 
···
 
 	/* remove only the first matching entry */
 	hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
+		struct cf_mod *cf_mod;
+
 		if (gwj->flags != r->flags)
 			continue;
 
 		if (gwj->limit_hops != limhops)
 			continue;
 
+		cf_mod = cgw_job_cf_mod(gwj);
 		/* we have a match when uid is enabled and identical */
-		if (gwj->mod.uid || mod.uid) {
-			if (gwj->mod.uid != mod.uid)
+		if (cf_mod->uid || mod.uid) {
+			if (cf_mod->uid != mod.uid)
 				continue;
 		} else {
 			/* no uid => check for identical modifications */
-			if (memcmp(&gwj->mod, &mod, sizeof(mod)))
+			if (memcmp(cf_mod, &mod, sizeof(mod)))
 				continue;
 		}