DCB: Add interface to query # of TCs supported by device

Adds interface for Data Center Bridging (DCB) to query (and set if
supported) the number of traffic classes currently supported by the
device for the two (DCB) features: priority groups (PG) and priority
flow control (PFC).
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ixgbe/ixgbe_dcb_nl.c

@@ -376,6 +376,35 @@ static u8 ixgbe_dcbnl_getcap(struct net_device *netdev, int capid, u8 *cap)
 	return rval;
 }
 
+static u8 ixgbe_dcbnl_getnumtcs(struct net_device *netdev, int tcid, u8 *num)
+{
+	struct ixgbe_adapter *adapter = netdev_priv(netdev);
+	u8 rval = 0;
+
+	if (adapter->flags & IXGBE_FLAG_DCB_ENABLED) {
+		switch (tcid) {
+		case DCB_NUMTCS_ATTR_PG:
+			*num = MAX_TRAFFIC_CLASS;
+			break;
+		case DCB_NUMTCS_ATTR_PFC:
+			*num = MAX_TRAFFIC_CLASS;
+			break;
+		default:
+			rval = -EINVAL;
+			break;
+		}
+	} else {
+		rval = -EINVAL;
+	}
+
+	return rval;
+}
+
+static u8 ixgbe_dcbnl_setnumtcs(struct net_device *netdev, int tcid, u8 num)
+{
+	return -EINVAL;
+}
+
 struct dcbnl_rtnl_ops dcbnl_ops = {
 	.getstate	= ixgbe_dcbnl_get_state,
 	.setstate	= ixgbe_dcbnl_set_state,
@@ -391,6 +420,8 @@ struct dcbnl_rtnl_ops dcbnl_ops = {
 	.setpfccfg	= ixgbe_dcbnl_set_pfc_cfg,
 	.getpfccfg	= ixgbe_dcbnl_get_pfc_cfg,
 	.setall		= ixgbe_dcbnl_set_all,
-	.getcap		= ixgbe_dcbnl_getcap
+	.getcap		= ixgbe_dcbnl_getcap,
+	.getnumtcs	= ixgbe_dcbnl_getnumtcs,
+	.setnumtcs	= ixgbe_dcbnl_setnumtcs
 };
 

include/linux/dcbnl.h

@@ -44,6 +44,8 @@ struct dcbmsg {
  * @DCB_CMD_GPERM_HWADDR: get the permanent MAC address of the underlying
  *                        device.  Only useful when using bonding.
  * @DCB_CMD_GCAP: request the DCB capabilities of the device
+ * @DCB_CMD_GNUMTCS: get the number of traffic classes currently supported
+ * @DCB_CMD_SNUMTCS: set the number of traffic classes
  */
 enum dcbnl_commands {
 	DCB_CMD_UNDEFINED,
@@ -62,6 +64,8 @@ enum dcbnl_commands {
 	DCB_CMD_SET_ALL,
 	DCB_CMD_GPERM_HWADDR,
 	DCB_CMD_GCAP,
+	DCB_CMD_GNUMTCS,
+	DCB_CMD_SNUMTCS,
 
 	__DCB_CMD_ENUM_MAX,
 	DCB_CMD_MAX = __DCB_CMD_ENUM_MAX - 1,
@@ -81,6 +85,7 @@ enum dcbnl_commands {
  * @DCB_ATTR_SET_ALL: bool to commit changes to hardware or not (NLA_U8)
  * @DCB_ATTR_PERM_HWADDR: MAC address of the physical device (NLA_NESTED)
  * @DCB_ATTR_CAP: DCB capabilities of the device (NLA_NESTED)
+ * @DCB_ATTR_NUMTCS: number of traffic classes supported (NLA_NESTED)
  */
 enum dcbnl_attrs {
 	DCB_ATTR_UNDEFINED,
@@ -94,6 +99,7 @@ enum dcbnl_attrs {
 	DCB_ATTR_SET_ALL,
 	DCB_ATTR_PERM_HWADDR,
 	DCB_ATTR_CAP,
+	DCB_ATTR_NUMTCS,
 
 	__DCB_ATTR_ENUM_MAX,
 	DCB_ATTR_MAX = __DCB_ATTR_ENUM_MAX - 1,
@@ -253,6 +259,27 @@ enum dcbnl_cap_attrs {
 	__DCB_CAP_ATTR_ENUM_MAX,
 	DCB_CAP_ATTR_MAX = __DCB_CAP_ATTR_ENUM_MAX - 1,
 };
+
+/**
+ * enum dcbnl_numtcs_attrs - number of traffic classes
+ *
+ * @DCB_NUMTCS_ATTR_UNDEFINED: unspecified attribute to catch errors
+ * @DCB_NUMTCS_ATTR_ALL: (NLA_FLAG) all traffic class attributes
+ * @DCB_NUMTCS_ATTR_PG: (NLA_U8) number of traffic classes used for
+ *                               priority groups
+ * @DCB_NUMTCS_ATTR_PFC: (NLA_U8) number of traffic classes which can
+ *                                support priority flow control
+ */
+enum dcbnl_numtcs_attrs {
+	DCB_NUMTCS_ATTR_UNDEFINED,
+	DCB_NUMTCS_ATTR_ALL,
+	DCB_NUMTCS_ATTR_PG,
+	DCB_NUMTCS_ATTR_PFC,
+
+	__DCB_NUMTCS_ATTR_ENUM_MAX,
+	DCB_NUMTCS_ATTR_MAX = __DCB_NUMTCS_ATTR_ENUM_MAX - 1,
+};
+
 /**
  * enum dcb_general_attr_values - general DCB attribute values
  *

include/net/dcbnl.h

@@ -40,6 +40,8 @@ struct dcbnl_rtnl_ops {
 	void (*getpfccfg)(struct net_device *, int, u8 *);
 	u8   (*setall)(struct net_device *);
 	u8   (*getcap)(struct net_device *, int, u8 *);
+	u8   (*getnumtcs)(struct net_device *, int, u8 *);
+	u8   (*setnumtcs)(struct net_device *, int, u8);
 };
 
 #endif /* __NET_DCBNL_H__ */

net/dcb/dcbnl.c

@@ -120,6 +120,13 @@ static struct nla_policy dcbnl_cap_nest[DCB_CAP_ATTR_MAX + 1] = {
 	[DCB_CAP_ATTR_BCN]     = {.type = NLA_U8},
 };
 
+/* DCB capabilities nested attributes. */
+static struct nla_policy dcbnl_numtcs_nest[DCB_NUMTCS_ATTR_MAX + 1] = {
+	[DCB_NUMTCS_ATTR_ALL]     = {.type = NLA_FLAG},
+	[DCB_NUMTCS_ATTR_PG]      = {.type = NLA_U8},
+	[DCB_NUMTCS_ATTR_PFC]     = {.type = NLA_U8},
+};
+
 /* standard netlink reply call */
 static int dcbnl_reply(u8 value, u8 event, u8 cmd, u8 attr, u32 pid,
                        u32 seq, u16 flags)
@@ -347,6 +354,123 @@ err_out:
 	return -EINVAL;
 }
 
+static int dcbnl_getnumtcs(struct net_device *netdev, struct nlattr **tb,
+                           u32 pid, u32 seq, u16 flags)
+{
+	struct sk_buff *dcbnl_skb;
+	struct nlmsghdr *nlh;
+	struct dcbmsg *dcb;
+	struct nlattr *data[DCB_NUMTCS_ATTR_MAX + 1], *nest;
+	u8 value;
+	int ret = -EINVAL;
+	int i;
+	int getall = 0;
+
+	if (!tb[DCB_ATTR_NUMTCS] || !netdev->dcbnl_ops->getnumtcs)
+		return ret;
+
+	ret = nla_parse_nested(data, DCB_NUMTCS_ATTR_MAX, tb[DCB_ATTR_NUMTCS],
+	                       dcbnl_numtcs_nest);
+	if (ret) {
+		ret = -EINVAL;
+		goto err_out;
+	}
+
+	dcbnl_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!dcbnl_skb) {
+		ret = -EINVAL;
+		goto err_out;
+	}
+
+	nlh = NLMSG_NEW(dcbnl_skb, pid, seq, RTM_GETDCB, sizeof(*dcb), flags);
+
+	dcb = NLMSG_DATA(nlh);
+	dcb->dcb_family = AF_UNSPEC;
+	dcb->cmd = DCB_CMD_GNUMTCS;
+
+	nest = nla_nest_start(dcbnl_skb, DCB_ATTR_NUMTCS);
+	if (!nest) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	if (data[DCB_NUMTCS_ATTR_ALL])
+		getall = 1;
+
+	for (i = DCB_NUMTCS_ATTR_ALL+1; i <= DCB_NUMTCS_ATTR_MAX; i++) {
+		if (!getall && !data[i])
+			continue;
+
+		ret = netdev->dcbnl_ops->getnumtcs(netdev, i, &value);
+		if (!ret) {
+			ret = nla_put_u8(dcbnl_skb, i, value);
+
+			if (ret) {
+				nla_nest_cancel(dcbnl_skb, nest);
+				ret = -EINVAL;
+				goto err;
+			}
+		} else {
+			goto err;
+		}
+	}
+	nla_nest_end(dcbnl_skb, nest);
+
+	nlmsg_end(dcbnl_skb, nlh);
+
+	ret = rtnl_unicast(dcbnl_skb, &init_net, pid);
+	if (ret) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	return 0;
+nlmsg_failure:
+err:
+	kfree(dcbnl_skb);
+err_out:
+	return ret;
+}
+
+static int dcbnl_setnumtcs(struct net_device *netdev, struct nlattr **tb,
+                           u32 pid, u32 seq, u16 flags)
+{
+	struct nlattr *data[DCB_NUMTCS_ATTR_MAX + 1];
+	int ret = -EINVAL;
+	u8 value;
+	int i;
+
+	if (!tb[DCB_ATTR_NUMTCS] || !netdev->dcbnl_ops->setstate)
+		return ret;
+
+	ret = nla_parse_nested(data, DCB_NUMTCS_ATTR_MAX, tb[DCB_ATTR_NUMTCS],
+	                       dcbnl_numtcs_nest);
+
+	if (ret) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	for (i = DCB_NUMTCS_ATTR_ALL+1; i <= DCB_NUMTCS_ATTR_MAX; i++) {
+		if (data[i] == NULL)
+			continue;
+
+		value = nla_get_u8(data[i]);
+
+		ret = netdev->dcbnl_ops->setnumtcs(netdev, i, value);
+
+		if (ret)
+			goto operr;
+	}
+
+operr:
+	ret = dcbnl_reply(!!ret, RTM_SETDCB, DCB_CMD_SNUMTCS,
+	                  DCB_ATTR_NUMTCS, pid, seq, flags);
+
+err:
+	return ret;
+}
+
 static int __dcbnl_pg_getcfg(struct net_device *netdev, struct nlattr **tb,
                              u32 pid, u32 seq, u16 flags, int dir)
 {
@@ -757,6 +881,14 @@ static int dcb_doit(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 		ret = dcbnl_getcap(netdev, tb, pid, nlh->nlmsg_seq,
 		                   nlh->nlmsg_flags);
 		goto out;
+	case DCB_CMD_GNUMTCS:
+		ret = dcbnl_getnumtcs(netdev, tb, pid, nlh->nlmsg_seq,
+		                      nlh->nlmsg_flags);
+		goto out;
+	case DCB_CMD_SNUMTCS:
+		ret = dcbnl_setnumtcs(netdev, tb, pid, nlh->nlmsg_seq,
+		                      nlh->nlmsg_flags);
+		goto out;
 	default:
 		goto errout;
 	}