net/dcb: Add an optional max rate attribute

Although not specified in 8021Qaz spec, it could be useful to enable drivers
whose HW supports setting a rate limit for an ETS TC. This patch adds this
optional attribute to DCB netlink. To use it, drivers should implement and
register the callbacks ieee_setmaxrate and ieee_getmaxrate. The units are 64
bits long and specified in Kbps to enable usage over both slow and very fast
networks.

Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 34 insertions, 0 deletions

diff --git a/include/linux/dcbnl.h b/include/linux/dcbnl.h
index 65a2562f66b4..6bb43382f3f3 100644
--- a/include/linux/dcbnl.h
+++ b/include/linux/dcbnl.h
@@ -67,6 +67,17 @@ struct ieee_ets {
         __u8    reco_prio_tc[IEEE_8021QAZ_MAX_TCS];
 };
 
+/* This structure contains rate limit extension to the IEEE 802.1Qaz ETS
+ * managed object.
+ * Values are 64 bits long and specified in Kbps to enable usage over both
+ * slow and very fast networks.
+ *
+ * @tc_maxrate: maximal tc tx bandwidth indexed by traffic class
+ */
+struct ieee_maxrate {
+        __u64   tc_maxrate[IEEE_8021QAZ_MAX_TCS];
+};
+
 /* This structure contains the IEEE 802.1Qaz PFC managed object
  *
  * @pfc_cap: Indicates the number of traffic classes on the local device
@@ -321,6 +332,7 @@ enum ieee_attrs {
         DCB_ATTR_IEEE_PEER_ETS,
         DCB_ATTR_IEEE_PEER_PFC,
         DCB_ATTR_IEEE_PEER_APP,
+        DCB_ATTR_IEEE_MAXRATE,
         __DCB_ATTR_IEEE_MAX
 };
 #define DCB_ATTR_IEEE_MAX (__DCB_ATTR_IEEE_MAX - 1)
diff --git a/include/net/dcbnl.h b/include/net/dcbnl.h
index f55c980d8e23..fc5d5dcebb00 100644
--- a/include/net/dcbnl.h
+++ b/include/net/dcbnl.h
@@ -48,6 +48,8 @@ struct dcbnl_rtnl_ops {
         /* IEEE 802.1Qaz std */
         int (*ieee_getets) (struct net_device *, struct ieee_ets *);
         int (*ieee_setets) (struct net_device *, struct ieee_ets *);
+        int (*ieee_getmaxrate) (struct net_device *, struct ieee_maxrate *);
+        int (*ieee_setmaxrate) (struct net_device *, struct ieee_maxrate *);
         int (*ieee_getpfc) (struct net_device *, struct ieee_pfc *);
         int (*ieee_setpfc) (struct net_device *, struct ieee_pfc *);
         int (*ieee_getapp) (struct net_device *, struct dcb_app *);
diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c
index 36f37af63bf2..8dfa1da7c40d 100644
--- a/net/dcb/dcbnl.c
+++ b/net/dcb/dcbnl.c
@@ -178,6 +178,7 @@ static const struct nla_policy dcbnl_ieee_policy[DCB_ATTR_IEEE_MAX + 1] = {
         [DCB_ATTR_IEEE_ETS]         = {.len = sizeof(struct ieee_ets)},
         [DCB_ATTR_IEEE_PFC]         = {.len = sizeof(struct ieee_pfc)},
         [DCB_ATTR_IEEE_APP_TABLE]   = {.type = NLA_NESTED},
+        [DCB_ATTR_IEEE_MAXRATE]   = {.len = sizeof(struct ieee_maxrate)},
 };
 
 static const struct nla_policy dcbnl_ieee_app[DCB_ATTR_IEEE_APP_MAX + 1] = {
@@ -1246,6 +1247,17 @@ static int dcbnl_ieee_fill(struct sk_buff *skb, struct net_device *netdev)
                         goto nla_put_failure;
         }
 
+        if (ops->ieee_getmaxrate) {
+                struct ieee_maxrate maxrate;
+                err = ops->ieee_getmaxrate(netdev, &maxrate);
+                if (!err) {
+                        err = nla_put(skb, DCB_ATTR_IEEE_MAXRATE,
+                                      sizeof(maxrate), &maxrate);
+                        if (err)
+                                goto nla_put_failure;
+                }
+        }
+
         if (ops->ieee_getpfc) {
                 struct ieee_pfc pfc;
                 err = ops->ieee_getpfc(netdev, &pfc);
@@ -1601,6 +1613,14 @@ static int dcbnl_ieee_set(struct net_device *netdev, struct nlattr **tb,
                         goto err;
         }
 
+        if (ieee[DCB_ATTR_IEEE_MAXRATE] && ops->ieee_setmaxrate) {
+                struct ieee_maxrate *maxrate =
+                        nla_data(ieee[DCB_ATTR_IEEE_MAXRATE]);
+                err = ops->ieee_setmaxrate(netdev, maxrate);
+                if (err)
+                        goto err;
+        }
+
         if (ieee[DCB_ATTR_IEEE_PFC] && ops->ieee_setpfc) {
                 struct ieee_pfc *pfc = nla_data(ieee[DCB_ATTR_IEEE_PFC]);
                 err = ops->ieee_setpfc(netdev, pfc);