ixgbe: Don't priority tag control frames in DCB mode

Certain types of control packets (LLDP, LACP, etc.) are not supposed to have a
priority tag or vlan tag inserted.  Ixgbe driver is currently priority
tagging everything (if packet is not on a VLAN interface).

This patch modifies DCB mode, so that packets marked with skb priority
TC_PRIO_CONTROL are not priority tagged.  It also transmits these packets on
the highest priority traffic class.
Programs (like dcbd) can set the skb priority using a socket option.  Or, a tc
filter can be configured to set the priority value. Using the value
TC_PRIO_CONTROL (7) has the benefit that it is already defined in the kernel,
and the bonding LACP code already sets the skb->priority field to this value.

Signed-off-by: Lucy Liu <lucy.liu@intel.com>
Acked-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 6 deletions

diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index a2119d79ccdd..47a3c6d70569 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -34,6 +34,7 @@
 #include <linux/in.h>
 #include <linux/ip.h>
 #include <linux/tcp.h>
+#include <linux/pkt_sched.h>
 #include <linux/ipv6.h>
 #include <net/checksum.h>
 #include <net/ip6_checksum.h>
@@ -5126,9 +5127,6 @@ static int ixgbe_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         int count = 0;
         unsigned int f;
 
-        r_idx = skb->queue_mapping;
-        tx_ring = &adapter->tx_ring[r_idx];
-
         if (adapter->vlgrp && vlan_tx_tag_present(skb)) {
                 tx_flags |= vlan_tx_tag_get(skb);
                 if (adapter->flags & IXGBE_FLAG_DCB_ENABLED) {
@@ -5138,11 +5136,19 @@ static int ixgbe_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
                 tx_flags <<= IXGBE_TX_FLAGS_VLAN_SHIFT;
                 tx_flags |= IXGBE_TX_FLAGS_VLAN;
         } else if (adapter->flags & IXGBE_FLAG_DCB_ENABLED) {
-                tx_flags |= (skb->queue_mapping << 13);
-                tx_flags <<= IXGBE_TX_FLAGS_VLAN_SHIFT;
-                tx_flags |= IXGBE_TX_FLAGS_VLAN;
+                if (skb->priority != TC_PRIO_CONTROL) {
+                        tx_flags |= (skb->queue_mapping << 13);
+                        tx_flags <<= IXGBE_TX_FLAGS_VLAN_SHIFT;
+                        tx_flags |= IXGBE_TX_FLAGS_VLAN;
+                } else {
+                        skb->queue_mapping =
+                                adapter->ring_feature[RING_F_DCB].indices-1;
+                }
         }
 
+        r_idx = skb->queue_mapping;
+        tx_ring = &adapter->tx_ring[r_idx];
+
         if ((adapter->flags & IXGBE_FLAG_FCOE_ENABLED) &&
             (skb->protocol == htons(ETH_P_FCOE)))
                 tx_flags |= IXGBE_TX_FLAGS_FCOE;