ice: Validate config for SW DCB map

Validate the inputs for SW DCB config received either via lldptool or pcap
file. And don't apply DCB for bad bandwidth inputs. Without this patch, any
config having bad inputs will cause the loss of link making PF unusable
even after driver reload. Recoverable only via system reboot.

Signed-off-by: Avinash Dayanand <[e-mail]>
Signed-off-by: Tony Nguyen <[e-mail]>
Tested-by: Andrew Bowers <[e-mail]>
Signed-off-by: Jeff Kirsher <[e-mail]>

drivers/net/ethernet/intel/ice/ice_dcb_lib.c

···
 }
 
 /**
+ * ice_dcb_bwchk - check if ETS bandwidth input parameters are correct
+ * @pf: pointer to the PF struct
+ * @dcbcfg: pointer to DCB config structure
+ */
+int ice_dcb_bwchk(struct ice_pf *pf, struct ice_dcbx_cfg *dcbcfg)
+{
+	struct ice_dcb_ets_cfg *etscfg = &dcbcfg->etscfg;
+	u8 num_tc, total_bw = 0;
+	int i;
+
+	/* returns number of contigous TCs and 1 TC for non-contigous TCs,
+	 * since at least 1 TC has to be configured
+	 */
+	num_tc = ice_dcb_get_num_tc(dcbcfg);
+
+	/* no bandwidth checks required if there's only one TC, so assign
+	 * all bandwidth to TC0 and return
+	 */
+	if (num_tc == 1) {
+		etscfg->tcbwtable[0] = ICE_TC_MAX_BW;
+		return 0;
+	}
+
+	for (i = 0; i < num_tc; i++)
+		total_bw += etscfg->tcbwtable[i];
+
+	if (!total_bw) {
+		etscfg->tcbwtable[0] = ICE_TC_MAX_BW;
+	} else if (total_bw != ICE_TC_MAX_BW) {
+		dev_err(ice_pf_to_dev(pf), "Invalid config, total bandwidth must equal 100\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
  * ice_pf_dcb_cfg - Apply new DCB configuration
  * @pf: pointer to the PF struct
  * @new_cfg: DCBX config to apply
···
 		dev_dbg(dev, "No change in DCB config required\n");
 		return ret;
 	}
+
+	if (ice_dcb_bwchk(pf, new_cfg))
+		return -EINVAL;
 
 	/* Store old config in case FW config fails */
 	old_cfg = kmemdup(curr_cfg, sizeof(*old_cfg), GFP_KERNEL);

drivers/net/ethernet/intel/ice/ice_dcb_lib.h

···
 u8 ice_dcb_get_tc(struct ice_vsi *vsi, int queue_index);
 int
 ice_pf_dcb_cfg(struct ice_pf *pf, struct ice_dcbx_cfg *new_cfg, bool locked);
+int ice_dcb_bwchk(struct ice_pf *pf, struct ice_dcbx_cfg *dcbcfg);
 void ice_pf_dcb_recfg(struct ice_pf *pf);
 void ice_vsi_cfg_dcb_rings(struct ice_vsi *vsi);
 int ice_init_pf_dcb(struct ice_pf *pf, bool locked);

drivers/net/ethernet/intel/ice/ice_dcb_nl.c

···
 		new_cfg->etsrec.prio_table[i] = ets->reco_prio_tc[i];
 	}
 
+	if (ice_dcb_bwchk(pf, new_cfg)) {
+		err = -EINVAL;
+		goto ets_out;
+	}
+
 	/* max_tc is a 1-8 value count of number of TC's, not a 0-7 value
 	 * for the TC's index number.  Add one to value if not zero, and
 	 * for zero set it to the FW's default value
···
 	if (err == ICE_DCB_NO_HW_CHG)
 		err = ICE_DCB_HW_CHG_RST;
 
+ets_out:
 	mutex_unlock(&pf->tc_mutex);
 	return err;
 }