selftests: forwarding: ethtool_mm: Skip when MAC Merge is not supported

MAC Merge cannot be tested with veth pairs, resulting in failures:

 # ./ethtool_mm.sh
 [...]
 TEST: Manual configuration with verification: swp1 to swp2          [FAIL]
         Verification did not succeed

Fix by skipping the test when the interfaces do not support MAC Merge.

Fixes: e6991384ace5 ("selftests: forwarding: add a test for MAC Merge layer")
Reported-by: Mirsad Todorovac <[email protected]>
Closes: https://lore.kernel.org/netdev/[email protected]/
Signed-off-by: Ido Schimmel <[email protected]>
Reviewed-by: Hangbin Liu <[email protected]>
Acked-by: Nikolay Aleksandrov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

1 files changed, 13 insertions, 5 deletions

diff --git a/tools/testing/selftests/net/forwarding/ethtool_mm.sh b/tools/testing/selftests/net/forwarding/ethtool_mm.sh
index c580ad623848..39e736f30322 100755
--- a/tools/testing/selftests/net/forwarding/ethtool_mm.sh
+++ b/tools/testing/selftests/net/forwarding/ethtool_mm.sh
@@ -258,11 +258,6 @@ h2_destroy()
 
 setup_prepare()
 {
-	check_ethtool_mm_support
-	check_tc_fp_support
-	require_command lldptool
-	bail_on_lldpad "autoconfigure the MAC Merge layer" "configure it manually"
-
 	h1=${NETIFS[p1]}
 	h2=${NETIFS[p2]}
 
@@ -278,6 +273,19 @@ cleanup()
 	h1_destroy
 }
 
+check_ethtool_mm_support
+check_tc_fp_support
+require_command lldptool
+bail_on_lldpad "autoconfigure the MAC Merge layer" "configure it manually"
+
+for netif in ${NETIFS[@]}; do
+	ethtool --show-mm $netif 2>&1 &> /dev/null
+	if [[ $? -ne 0 ]]; then
+		echo "SKIP: $netif does not support MAC Merge"
+		exit $ksft_skip
+	fi
+done
+
 trap cleanup EXIT
 
 setup_prepare