[RFC PATCH 08/14] can: netlink: add can_validate_tdc()

[Vincent Mailhol <mailhol.vincent@wanadoo.fr>]

Factorize the TDC validation out of can_validate() and move it in the
new add can_validate_tdc() function. This is a preparation patch for
the introduction of CAN XL because this TDC validation will be reused
later on.

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
 drivers/net/can/dev/netlink.c | 81 +++++++++++++++++++++--------------
 1 file changed, 48 insertions(+), 33 deletions(-)

diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 354846e3a0d0..511f721f4c80 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -49,6 +49,48 @@ static int can_validate_bittiming(const struct can_bittiming *bt,
 	return 0;
 }
 
+static int can_validate_tdc(struct nlattr *data_tdc,
+			    bool tdc_auto, bool tdc_manual,
+			    struct netlink_ext_ack *extack)
+{
+	int err;
+
+	/* CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive */
+	if (tdc_auto == tdc_manual)
+		return -EOPNOTSUPP;
+
+	/* If one of the CAN_CTRLMODE_TDC_* flag is set then
+	 * TDC must be set and vice-versa
+	 */
+	if ((tdc_auto || tdc_manual) != !!data_tdc)
+		return -EOPNOTSUPP;
+
+	/* If providing TDC parameters, at least TDCO is needed. TDCV
+	 * is needed if and only if CAN_CTRLMODE_TDC_MANUAL is set
+	 */
+	if (!data_tdc) {
+		struct nlattr *tb_tdc[IFLA_CAN_TDC_MAX + 1];
+
+		err = nla_parse_nested(tb_tdc, IFLA_CAN_TDC_MAX,
+				       data_tdc, can_tdc_policy, extack);
+		if (err)
+			return err;
+
+		if (tb_tdc[IFLA_CAN_TDC_TDCV]) {
+			if (tdc_auto)
+				return -EOPNOTSUPP;
+		} else {
+			if (tdc_manual)
+				return -EOPNOTSUPP;
+		}
+
+		if (!tb_tdc[IFLA_CAN_TDC_TDCO])
+			return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
 static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 			struct netlink_ext_ack *extack)
 {
@@ -67,42 +109,15 @@ 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_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_FD_TDC_MASK)
-			return -EOPNOTSUPP;
-		/* If one of the CAN_CTRLMODE_TDC_* flag is set then
-		 * TDC must be set and vice-versa
-		 */
-		if (!!tdc_flags != !!data[IFLA_CAN_TDC])
-			return -EOPNOTSUPP;
-		/* If providing TDC parameters, at least TDCO is
-		 * needed. TDCV is needed if and only if
-		 * CAN_CTRLMODE_TDC_MANUAL is set
-		 */
-		if (data[IFLA_CAN_TDC]) {
-			struct nlattr *tb_tdc[IFLA_CAN_TDC_MAX + 1];
-
-			err = nla_parse_nested(tb_tdc, IFLA_CAN_TDC_MAX,
-					       data[IFLA_CAN_TDC],
-					       can_tdc_policy, extack);
-			if (err)
-				return err;
-
-			if (tb_tdc[IFLA_CAN_TDC_TDCV]) {
-				if (tdc_flags & CAN_CTRLMODE_TDC_AUTO)
-					return -EOPNOTSUPP;
-			} else {
-				if (tdc_flags & CAN_CTRLMODE_TDC_MANUAL)
-					return -EOPNOTSUPP;
-			}
-
-			if (!tb_tdc[IFLA_CAN_TDC_TDCO])
-				return -EOPNOTSUPP;
-		}
+		err = can_validate_tdc(data[IFLA_CAN_TDC],
+				       cm->flags & CAN_CTRLMODE_TDC_AUTO,
+				       cm->flags & CAN_CTRLMODE_TDC_MANUAL,
+				       extack);
+		if (err)
+			return err;
 	}
 
 	if (data[IFLA_CAN_BITTIMING]) {
-- 
2.45.2