net/dcb: Validate bandwidth for non-ETS traffic classes

The IEEE 802.1Qaz standard defines that bandwidth allocation percentages
only apply to ETS traffic classes. Reject ETS configurations that
specify non-zero bandwidth for non-ETS traffic classes.

Placing this check in dcbnl_ieee_set() enforces the constraint uniformly
for all drivers rather than relying on each driver to validate it
independently.

Drop the equivalent check from NFP's dcb_ets_check(). Keep ETS
bandwidth-sum validation unchanged.

Signed-off-by: Alexei Lazar <alazar@nvidia.com>
Reviewed-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20261011083929.739261-1-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/netronome/nfp/nic/dcb.c

@@ -218,9 +218,6 @@ static int dcb_ets_check(struct net_device *dev, struct ieee_ets *ets)
 		if (ets->tc_tsa[i] == IEEE_8021QAZ_TSA_ETS) {
 			ets_exists = true;
 			sum += ets->tc_tx_bw[i];
-		} else if (ets->tc_tx_bw[i]) {
-			nfp_warn(app->cpp, "ETS BW for strict/vendor TC must be 0.");
-			return -EINVAL;
 		}
 	}
 

net/dcb/dcbnl.c

@@ -1578,6 +1578,15 @@ static int dcbnl_ieee_set(struct net_device *netdev, struct nlmsghdr *nlh,
 
 	if (ieee[DCB_ATTR_IEEE_ETS] && ops->ieee_setets) {
 		struct ieee_ets *ets = nla_data(ieee[DCB_ATTR_IEEE_ETS]);
+
+		/* IEEE 802.1Qaz: BW allocation applies only to ETS TCs */
+		for (int i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
+			if (ets->tc_tsa[i] != IEEE_8021QAZ_TSA_ETS &&
+			    ets->tc_tx_bw[i]) {
+				err = -EINVAL;
+				goto err;
+			}
+		}
 		err = ops->ieee_setets(netdev, ets);
 		if (err)
 			goto err;