DCB: Add interface to query the state of PFC feature.

Adds a netlink interface for Data Center Bridging (DCB) to get and set
the enable state of the Priority Flow Control (PFC) feature.
Primarily, this is a way to turn off PFC in the driver while DCB
remains enabled.

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>

4 files changed, 62 insertions, 1 deletions

diff --git a/drivers/net/ixgbe/ixgbe_dcb_nl.c b/drivers/net/ixgbe/ixgbe_dcb_nl.c
index 5921795f8403..dd940a8f9357 100644
--- a/drivers/net/ixgbe/ixgbe_dcb_nl.c
+++ b/drivers/net/ixgbe/ixgbe_dcb_nl.c
@@ -405,6 +405,18 @@ static u8 ixgbe_dcbnl_setnumtcs(struct net_device *netdev, int tcid, u8 num)
         return -EINVAL;
 }
 
+static u8 ixgbe_dcbnl_getpfcstate(struct net_device *netdev)
+{
+        struct ixgbe_adapter *adapter = netdev_priv(netdev);
+
+        return !!(adapter->flags & IXGBE_FLAG_DCB_ENABLED);
+}
+
+static void ixgbe_dcbnl_setpfcstate(struct net_device *netdev, u8 state)
+{
+        return;
+}
+
 struct dcbnl_rtnl_ops dcbnl_ops = {
         .getstate       = ixgbe_dcbnl_get_state,
         .setstate       = ixgbe_dcbnl_set_state,
@@ -422,6 +434,8 @@ struct dcbnl_rtnl_ops dcbnl_ops = {
         .setall         = ixgbe_dcbnl_set_all,
         .getcap         = ixgbe_dcbnl_getcap,
         .getnumtcs      = ixgbe_dcbnl_getnumtcs,
-        .setnumtcs      = ixgbe_dcbnl_setnumtcs
+        .setnumtcs      = ixgbe_dcbnl_setnumtcs,
+        .getpfcstate    = ixgbe_dcbnl_getpfcstate,
+        .setpfcstate    = ixgbe_dcbnl_setpfcstate
 };
 
diff --git a/include/linux/dcbnl.h b/include/linux/dcbnl.h
index 1077fba1dadc..6cc4560bc376 100644
--- a/include/linux/dcbnl.h
+++ b/include/linux/dcbnl.h
@@ -66,6 +66,8 @@ enum dcbnl_commands {
         DCB_CMD_GCAP,
         DCB_CMD_GNUMTCS,
         DCB_CMD_SNUMTCS,
+        DCB_CMD_PFC_GSTATE,
+        DCB_CMD_PFC_SSTATE,
 
         __DCB_CMD_ENUM_MAX,
         DCB_CMD_MAX = __DCB_CMD_ENUM_MAX - 1,
diff --git a/include/net/dcbnl.h b/include/net/dcbnl.h
index f0a65281ea73..c7d87caf3f99 100644
--- a/include/net/dcbnl.h
+++ b/include/net/dcbnl.h
@@ -42,6 +42,8 @@ struct dcbnl_rtnl_ops {
         u8   (*getcap)(struct net_device *, int, u8 *);
         u8   (*getnumtcs)(struct net_device *, int, u8 *);
         u8   (*setnumtcs)(struct net_device *, int, u8);
+        u8   (*getpfcstate)(struct net_device *);
+        void (*setpfcstate)(struct net_device *, u8);
 };
 
 #endif /* __NET_DCBNL_H__ */
diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c
index 5ff7e3c0c172..758419c6f59b 100644
--- a/net/dcb/dcbnl.c
+++ b/net/dcb/dcbnl.c
@@ -62,6 +62,7 @@ static struct nla_policy dcbnl_rtnl_policy[DCB_ATTR_MAX + 1] = {
         [DCB_ATTR_SET_ALL]   = {.type = NLA_U8},
         [DCB_ATTR_PERM_HWADDR] = {.type = NLA_FLAG},
         [DCB_ATTR_CAP]       = {.type = NLA_NESTED},
+        [DCB_ATTR_PFC_STATE] = {.type = NLA_U8},
 };
 
 /* DCB priority flow control to User Priority nested attributes */
@@ -471,6 +472,40 @@ err:
         return ret;
 }
 
+static int dcbnl_getpfcstate(struct net_device *netdev, struct nlattr **tb,
+                             u32 pid, u32 seq, u16 flags)
+{
+        int ret = -EINVAL;
+
+        if (!netdev->dcbnl_ops->getpfcstate)
+                return ret;
+
+        ret = dcbnl_reply(netdev->dcbnl_ops->getpfcstate(netdev), RTM_GETDCB,
+                          DCB_CMD_PFC_GSTATE, DCB_ATTR_PFC_STATE,
+                          pid, seq, flags);
+
+        return ret;
+}
+
+static int dcbnl_setpfcstate(struct net_device *netdev, struct nlattr **tb,
+                             u32 pid, u32 seq, u16 flags)
+{
+        int ret = -EINVAL;
+        u8 value;
+
+        if (!tb[DCB_ATTR_PFC_STATE] || !netdev->dcbnl_ops->setpfcstate)
+                return ret;
+
+        value = nla_get_u8(tb[DCB_ATTR_PFC_STATE]);
+
+        netdev->dcbnl_ops->setpfcstate(netdev, value);
+
+        ret = dcbnl_reply(0, RTM_SETDCB, DCB_CMD_PFC_SSTATE, DCB_ATTR_PFC_STATE,
+                          pid, seq, flags);
+
+        return ret;
+}
+
 static int __dcbnl_pg_getcfg(struct net_device *netdev, struct nlattr **tb,
                              u32 pid, u32 seq, u16 flags, int dir)
 {
@@ -889,6 +924,14 @@ static int dcb_doit(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
                 ret = dcbnl_setnumtcs(netdev, tb, pid, nlh->nlmsg_seq,
                                       nlh->nlmsg_flags);
                 goto out;
+        case DCB_CMD_PFC_GSTATE:
+                ret = dcbnl_getpfcstate(netdev, tb, pid, nlh->nlmsg_seq,
+                                        nlh->nlmsg_flags);
+                goto out;
+        case DCB_CMD_PFC_SSTATE:
+                ret = dcbnl_setpfcstate(netdev, tb, pid, nlh->nlmsg_seq,
+                                        nlh->nlmsg_flags);
+                goto out;
         default:
                 goto errout;
         }