can_tdc_fill_info() depends on some variables which are specific to CAN
FD. Move these to the function parameters list so that, later on, this
function can be reused for the CAN XL TDC.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
Changelog:

  RFC -> v1:

   - Just pass the IFLA index instead of passing each argument
     individually. Instead, derive these as local variables depending
     on whethe the IFLA index is IFLA_CAN_TDC or IFLA_CAN_XL_TDC.
---
 drivers/net/can/dev/netlink.c | 35 ++++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 092031693ce9f55f2c396fc7de8336932f6f5516..2784cacd7adf5e69f24c110e749a651b188f69f4 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -578,21 +578,34 @@ static int can_bitrate_const_fill_info(struct sk_buff *skb,
 			sizeof(*bitrate_const) * cnt, bitrate_const);
 }
 
-static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev)
+static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev,
+			     int ifla_can_tdc)
 {
-	struct nlattr *nest;
 	struct can_priv *priv = netdev_priv(dev);
-	struct can_tdc *tdc = &priv->fd.tdc;
-	const struct can_tdc_const *tdc_const = priv->fd.tdc_const;
+	struct data_bittiming_params *dbt_params;
+	const struct can_tdc_const *tdc_const;
+	struct can_tdc *tdc;
+	struct nlattr *nest;
+	bool tdc_is_enabled, tdc_manual;
+
+	if (ifla_can_tdc == IFLA_CAN_TDC) {
+		dbt_params = &priv->fd;
+		tdc_is_enabled = can_fd_tdc_is_enabled(priv);
+		tdc_manual = priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL;
+	} else {
+		WARN_ON(1); /* Place holder for CAN XL */
+	}
+	tdc_const = dbt_params->tdc_const;
+	tdc = &dbt_params->tdc;
 
 	if (!tdc_const)
 		return 0;
 
-	nest = nla_nest_start(skb, IFLA_CAN_TDC);
+	nest = nla_nest_start(skb, ifla_can_tdc);
 	if (!nest)
 		return -EMSGSIZE;
 
-	if (priv->ctrlmode_supported & CAN_CTRLMODE_TDC_MANUAL &&
+	if (tdc_manual &&
 	    (nla_put_u32(skb, IFLA_CAN_TDC_TDCV_MIN, tdc_const->tdcv_min) ||
 	     nla_put_u32(skb, IFLA_CAN_TDC_TDCV_MAX, tdc_const->tdcv_max)))
 		goto err_cancel;
@@ -604,15 +617,15 @@ 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_fd_tdc_is_enabled(priv)) {
+	if (tdc_is_enabled) {
 		u32 tdcv;
 		int err = -EINVAL;
 
-		if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL) {
+		if (tdc_manual) {
 			tdcv = tdc->tdcv;
 			err = 0;
-		} else if (priv->fd.do_get_auto_tdcv) {
-			err = priv->fd.do_get_auto_tdcv(dev, &tdcv);
+		} else if (dbt_params->do_get_auto_tdcv) {
+			err = dbt_params->do_get_auto_tdcv(dev, &tdcv);
 		}
 		if (!err && nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdcv))
 			goto err_cancel;
@@ -700,7 +713,7 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 		     sizeof(priv->bitrate_max),
 		     &priv->bitrate_max)) ||
 
-	    can_tdc_fill_info(skb, dev) ||
+	    can_tdc_fill_info(skb, dev, IFLA_CAN_TDC) ||
 
 	    can_ctrlmode_ext_fill_info(skb, priv)
 	    )

-- 
2.49.1

Hi Vincent,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 2fd4161d0d2547650d9559d57fc67b4e0a26a9e3]

url:    https://github.com/intel-lab-lkp/linux/commits/Vincent-Mailhol/can-dev-move-struct-data_bittiming_params-to-linux-can-bittiming-h/20250903-170807
base:   2fd4161d0d2547650d9559d57fc67b4e0a26a9e3
patch link:    https://lore.kernel.org/r/20250903-canxl-netlink-prep-v1-18-904bd6037cd9%40kernel.org
patch subject: [PATCH 18/21] can: netlink: make can_tdc_fill_info() FD agnostic
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20250905/202509050541.1FKRbqOi-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250905/202509050541.1FKRbqOi-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509050541.1FKRbqOi-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/net/can/dev/netlink.c:111:6: warning: variable 'is_on' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
     111 |         if (ifla_can_data_bittiming == IFLA_CAN_DATA_BITTIMING) {
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/net/can/dev/netlink.c:119:6: note: uninitialized use occurs here
     119 |         if (is_on) {
         |             ^~~~~
   drivers/net/can/dev/netlink.c:111:2: note: remove the 'if' if its condition is always true
     111 |         if (ifla_can_data_bittiming == IFLA_CAN_DATA_BITTIMING) {
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     112 |                 data_tdc = data[IFLA_CAN_TDC];
     113 |                 tdc_flags = flags & CAN_CTRLMODE_FD_TDC_MASK;
     114 |                 is_on = flags & CAN_CTRLMODE_FD;
     115 |         } else {
         |           ~~~~~~
     116 |                 WARN_ON(1); /* Place holder for CAN XL */
         |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     117 |         }
         |         ~
   drivers/net/can/dev/netlink.c:108:12: note: initialize the variable 'is_on' to silence this warning
     108 |         bool is_on;
         |                   ^
         |                    = 0
   drivers/net/can/dev/netlink.c:281:6: warning: variable 'data_bittiming' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
     281 |         if (fd) {
         |             ^~
   drivers/net/can/dev/netlink.c:290:7: note: uninitialized use occurs here
     290 |         if (!data_bittiming)
         |              ^~~~~~~~~~~~~~
   drivers/net/can/dev/netlink.c:281:2: note: remove the 'if' if its condition is always true
     281 |         if (fd) {
         |         ^~~~~~~
     282 |                 data_bittiming = data[IFLA_CAN_DATA_BITTIMING];
     283 |                 data_tdc = data[IFLA_CAN_TDC];
     284 |                 dbt_params = &priv->fd;
     285 |                 tdc_mask = CAN_CTRLMODE_FD_TDC_MASK;
     286 |         } else {
         |           ~~~~~~
     287 |                 WARN_ON(1); /* Place holder for CAN XL */
         |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     288 |         }
         |         ~
   drivers/net/can/dev/netlink.c:273:31: note: initialize the variable 'data_bittiming' to silence this warning
     273 |         struct nlattr *data_bittiming, *data_tdc;
         |                                      ^
         |                                       = NULL
>> drivers/net/can/dev/netlink.c:591:6: warning: variable 'dbt_params' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
     591 |         if (ifla_can_tdc == IFLA_CAN_TDC) {
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/net/can/dev/netlink.c:598:14: note: uninitialized use occurs here
     598 |         tdc_const = dbt_params->tdc_const;
         |                     ^~~~~~~~~~
   drivers/net/can/dev/netlink.c:591:2: note: remove the 'if' if its condition is always true
     591 |         if (ifla_can_tdc == IFLA_CAN_TDC) {
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     592 |                 dbt_params = &priv->fd;
     593 |                 tdc_is_enabled = can_fd_tdc_is_enabled(priv);
     594 |                 tdc_manual = priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL;
     595 |         } else {
         |           ~~~~~~
     596 |                 WARN_ON(1); /* Place holder for CAN XL */
         |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     597 |         }
         |         ~
   drivers/net/can/dev/netlink.c:585:42: note: initialize the variable 'dbt_params' to silence this warning
     585 |         struct data_bittiming_params *dbt_params;
         |                                                 ^
         |                                                  = NULL
   3 warnings generated.


vim +591 drivers/net/can/dev/netlink.c

   580	
   581	static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev,
   582				     int ifla_can_tdc)
   583	{
   584		struct can_priv *priv = netdev_priv(dev);
   585		struct data_bittiming_params *dbt_params;
   586		const struct can_tdc_const *tdc_const;
   587		struct can_tdc *tdc;
   588		struct nlattr *nest;
   589		bool tdc_is_enabled, tdc_manual;
   590	
 > 591		if (ifla_can_tdc == IFLA_CAN_TDC) {
   592			dbt_params = &priv->fd;
   593			tdc_is_enabled = can_fd_tdc_is_enabled(priv);
   594			tdc_manual = priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL;
   595		} else {
   596			WARN_ON(1); /* Place holder for CAN XL */
   597		}
   598		tdc_const = dbt_params->tdc_const;
   599		tdc = &dbt_params->tdc;
   600	
   601		if (!tdc_const)
   602			return 0;
   603	
   604		nest = nla_nest_start(skb, ifla_can_tdc);
   605		if (!nest)
   606			return -EMSGSIZE;
   607	
   608		if (tdc_manual &&
   609		    (nla_put_u32(skb, IFLA_CAN_TDC_TDCV_MIN, tdc_const->tdcv_min) ||
   610		     nla_put_u32(skb, IFLA_CAN_TDC_TDCV_MAX, tdc_const->tdcv_max)))
   611			goto err_cancel;
   612		if (nla_put_u32(skb, IFLA_CAN_TDC_TDCO_MIN, tdc_const->tdco_min) ||
   613		    nla_put_u32(skb, IFLA_CAN_TDC_TDCO_MAX, tdc_const->tdco_max))
   614			goto err_cancel;
   615		if (tdc_const->tdcf_max &&
   616		    (nla_put_u32(skb, IFLA_CAN_TDC_TDCF_MIN, tdc_const->tdcf_min) ||
   617		     nla_put_u32(skb, IFLA_CAN_TDC_TDCF_MAX, tdc_const->tdcf_max)))
   618			goto err_cancel;
   619	
   620		if (tdc_is_enabled) {
   621			u32 tdcv;
   622			int err = -EINVAL;
   623	
   624			if (tdc_manual) {
   625				tdcv = tdc->tdcv;
   626				err = 0;
   627			} else if (dbt_params->do_get_auto_tdcv) {
   628				err = dbt_params->do_get_auto_tdcv(dev, &tdcv);
   629			}
   630			if (!err && nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdcv))
   631				goto err_cancel;
   632			if (nla_put_u32(skb, IFLA_CAN_TDC_TDCO, tdc->tdco))
   633				goto err_cancel;
   634			if (tdc_const->tdcf_max &&
   635			    nla_put_u32(skb, IFLA_CAN_TDC_TDCF, tdc->tdcf))
   636				goto err_cancel;
   637		}
   638	
   639		nla_nest_end(skb, nest);
   640		return 0;
   641	
   642	err_cancel:
   643		nla_nest_cancel(skb, nest);
   644		return -EMSGSIZE;
   645	}
   646	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki