From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jiri Pirko <jiri@resnulli.us>
Subject: Re: [PATCH net-next 6/8] net/mlx5e: Introduce tc offload support
Date: Tue, 1 Mar 2016 15:52:08 +0100
Message-ID: <20160301145208.GB2098@nanopsycho.orion>
References: <1456842290-7844-1-git-send-email-amir@vadai.me>
 <1456842290-7844-7-git-send-email-amir@vadai.me>
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Cc: "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
	Or Gerlitz <ogerlitz@mellanox.com>,
	John Fastabend <john.r.fastabend@intel.com>,
	Saeed Mahameed <saeedm@mellanox.com>,
	Hadar Har-Zion <hadarh@mellanox.com>,
	Jiri Pirko <jiri@mellanox.com>
To: Amir Vadai <amir@vadai.me>
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Tue, Mar 01, 2016 at 03:24:48PM CET, amir@vadai.me wrote:
>Extend ndo_setup_tc() to support ingress tc offloading. Will be used by
>later patches to offload tc flower filter.
>
>Feature is off by default and could be enabled by issuing:
> # ethtool  -K eth0 hw-tc-offload on
>
>Offloads flow table is dynamically created when first filter is
>added.
>Rules are saved in a hash table that is maintained by the consumer (for
>example - the flower offload in the next patch).
>When last filter is removed and no filters exist in the hash table, the
>offload flow table is destroyed.

<snip>	
	
>@@ -1880,6 +1883,17 @@ static int mlx5e_setup_tc(struct net_device *netdev, u8 tc)
> static int mlx5e_ndo_setup_tc(struct net_device *dev, u32 handle,
> 			      __be16 proto, struct tc_to_netdev *tc)
> {
>+	struct mlx5e_priv *priv = netdev_priv(dev);
>+
>+	if (TC_H_MAJ(handle) != TC_H_MAJ(TC_H_INGRESS))
>+		goto mqprio;
>+
>+	switch (tc->type) {
>+	default:
>+		return -EINVAL;

-EOPNOTSUPP would be better here perhaps?


>+	}
>+
>+mqprio:
> 	if (handle != TC_H_ROOT || tc->type != TC_SETUP_MQPRIO)
> 		return -EINVAL;
> 
>@@ -1963,6 +1977,13 @@ static int mlx5e_set_features(struct net_device *netdev,
> 			mlx5e_disable_vlan_filter(priv);
> 	}
> 
>+	if ((changes & NETIF_F_HW_TC) && !(features & NETIF_F_HW_TC) &&
>+	    mlx5e_tc_num_filters(priv)) {
>+		netdev_err(netdev,
>+			   "Active offloaded tc filters, can't turn hw_tc_offload off\n");
>+		return -EINVAL;

This should not fail I believe. Just disable it in hw. I would even toss
away the rules if necessary.