[PATCH ethtool v2 2/2] netlink: cable_test: require a value for the TDR parameters

[Dave Seddon <dave.seddon.ca@gmail.com>]

first, last, step and pair (--cable-test-tdr) take a value, but their
parser entries leave min_argc at 0. Given as the last word on the
line, the value handler reads the NULL that ends argv and the error
message prints it:

  # ethtool --cable-test-tdr eth0 first 1 last
  ethtool (--cable-test-tdr): invalid value '(null)' for parameter 'last'

Set min_argc to 1, as every other value-taking parameter does, so the
parser reports the missing value itself:

  # ethtool --cable-test-tdr eth0 first 1 last
  ethtool (--cable-test-tdr): no value for parameter 'last'

Only the message changes: the exit status was already 1 and no request
was sent.

Fixes: 9561db9b76f4 ("Add cable test TDR support")
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Dave Seddon <dave.seddon.ca@gmail.com>
---
 netlink/cable_test.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/netlink/cable_test.c b/netlink/cable_test.c
index fdb046e..648bf74 100644
--- a/netlink/cable_test.c
+++ b/netlink/cable_test.c
@@ -544,24 +544,28 @@ static const struct param_parser tdr_params[] = {
 		.type		= ETHTOOL_A_CABLE_TEST_TDR_CFG_FIRST,
 		.group		= ETHTOOL_A_CABLE_TEST_TDR_CFG,
 		.handler	= nl_parse_direct_m2cm,
+		.min_argc	= 1,
 	},
 	{
 		.arg		= "last",
 		.type		= ETHTOOL_A_CABLE_TEST_TDR_CFG_LAST,
 		.group		= ETHTOOL_A_CABLE_TEST_TDR_CFG,
 		.handler	= nl_parse_direct_m2cm,
+		.min_argc	= 1,
 	},
 	{
 		.arg		= "step",
 		.type		= ETHTOOL_A_CABLE_TEST_TDR_CFG_STEP,
 		.group		= ETHTOOL_A_CABLE_TEST_TDR_CFG,
 		.handler	= nl_parse_direct_m2cm,
+		.min_argc	= 1,
 	},
 	{
 		.arg		= "pair",
 		.type		= ETHTOOL_A_CABLE_TEST_TDR_CFG_PAIR,
 		.group		= ETHTOOL_A_CABLE_TEST_TDR_CFG,
 		.handler	= nl_parse_direct_u8,
+		.min_argc	= 1,
 	},
 	{}
 };
-- 
2.56.0