selftest: netdevsim: Add devlink rate grouping test

Test verifies that netdevsim correctly implements devlink ops callbacks
that set node as a parent of devlink leaf or node rate object.

Co-developed-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Dmytro Linkin <dlinkin@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/netdevsim/devlink.sh

@@ -563,6 +563,26 @@ rate_attr_tx_rate_check()
 	check_err $? "Unexpected $name attr value $api_value != $rate"
 }
 
+rate_attr_parent_check()
+{
+	local handle=$1
+	local parent=$2
+	local debug_file=$3
+
+	rate_attr_set $handle parent $parent
+	check_err $? "Failed to set parent"
+
+	debug_value=$(cat $debug_file)
+	check_err $? "Failed to get parent debugfs value"
+	[ "$debug_value" == "$parent" ]
+	check_err $? "Unexpected parent debug value $debug_value != $parent"
+
+	api_value=$(rate_attr_get $r_obj parent)
+	check_err $? "Failed to get parent attr value"
+	[ "$api_value" == "$parent" ]
+	check_err $? "Unexpected parent attr value $api_value != $parent"
+}
+
 rate_node_add()
 {
 	local handle=$1
@@ -627,6 +647,28 @@ rate_test()
 	[ $num_nodes == 0 ]
 	check_err $? "Expected 0 rate node but got $num_nodes"
 
+	local node1_name='group1'
+	local node1="$DL_HANDLE/$node1_name"
+	rate_node_add "$node1"
+	check_err $? "Failed to add node $node1"
+
+	rate_attr_parent_check $r_obj $node1_name \
+		$DEBUGFS_DIR/ports/${r_obj##*/}/rate_parent
+
+	local node2_name='group2'
+	local node2="$DL_HANDLE/$node2_name"
+	rate_node_add "$node2"
+	check_err $? "Failed to add node $node2"
+
+	rate_attr_parent_check $node2 $node1_name \
+		$DEBUGFS_DIR/rate_nodes/$node2_name/rate_parent
+	rate_node_del "$node2"
+	check_err $? "Failed to delete node $node2"
+	rate_attr_set "$r_obj" noparent
+	check_err $? "Failed to unset $r_obj parent node"
+	rate_node_del "$node1"
+	check_err $? "Failed to delete node $node1"
+
 	log_test "rate test"
 }