selftests: spectrum-2: tc_flower_scale: Dynamically set scale target

Instead of hard coding the scale target in the test, dynamically set it
based on the maximum number of flow counters and their current
occupancy.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/mlxsw/spectrum-2/tc_flower_scale.sh

@@ -4,17 +4,22 @@ source ../tc_flower_scale.sh
 tc_flower_get_target()
 {
 	local should_fail=$1; shift
+	local max_cnts
 
 	# The driver associates a counter with each tc filter, which means the
 	# number of supported filters is bounded by the number of available
 	# counters.
-	# Currently, the driver supports 30K (30,720) flow counters and six of
-	# these are used for multicast routing.
-	local target=30714
+	max_cnts=$(devlink_resource_size_get counters flow)
+
+	# Remove already allocated counters.
+	((max_cnts -= $(devlink_resource_occ_get counters flow)))
+
+	# Each rule uses two counters, for packets and bytes.
+	((max_cnts /= 2))
 
 	if ((! should_fail)); then
-		echo $target
+		echo $max_cnts
 	else
-		echo $((target + 1))
+		echo $((max_cnts + 1))
 	fi
 }