From: Jesse Gross <jesse@nicira.com>
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [PATCH 2/2] sky2: convert to new VLAN model
Date: Sun, 9 Jan 2011 10:50:36 -0500 [thread overview]
Message-ID: <AANLkTimMHxOVTDm7+8qnoRjHb1BOvDOjDqyHCgHKocTD@mail.gmail.com> (raw)
In-Reply-To: <20110107092758.7dc1152f@nehalam>
On Fri, Jan 7, 2011 at 12:27 PM, Stephen Hemminger
<shemminger@vyatta.com> wrote:
> On Fri, 7 Jan 2011 12:14:51 -0500
> Jesse Gross <jesse@nicira.com> wrote:
>
>> On Thu, Jan 6, 2011 at 11:41 PM, Stephen Hemminger
>> <shemminger@vyatta.com> wrote:
>> > +/* Features available on VLAN with transmit tag stripped */
>> > +#define VLAN_FEAT (NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO)
>> > +
>> > +static void sky2_vlan_mode(struct net_device *dev)
>> > {
>> > - if (onoff) {
>> > + struct sky2_port *sky2 = netdev_priv(dev);
>> > + struct sky2_hw *hw = sky2->hw;
>> > + u16 port = sky2->port;
>> > +
>> > + if (dev->features & NETIF_F_HW_VLAN_RX)
>> > sky2_write32(hw, SK_REG(port, RX_GMF_CTRL_T),
>> > RX_VLAN_STRIP_ON);
>> > + else
>> > + sky2_write32(hw, SK_REG(port, RX_GMF_CTRL_T),
>> > + RX_VLAN_STRIP_OFF);
>> > +
>> > + if (dev->features & NETIF_F_HW_VLAN_TX) {
>> > sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T),
>> > TX_VLAN_TAG_ON);
>> > + dev->vlan_features = dev->features & VLAN_FEAT;
>> > } else {
>> > - sky2_write32(hw, SK_REG(port, RX_GMF_CTRL_T),
>> > - RX_VLAN_STRIP_OFF);
>> > sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T),
>> > TX_VLAN_TAG_OFF);
>> > + dev->vlan_features = dev->features & NETIF_F_HIGHDMA;
>>
>> Hmm, the chip supports SG only when TX vlan is on and HIGHDMA only
>> when it is off? Currently skb_needs_linearize() assumes that when not
>> using vlan acceleration, the DMA engine doesn't care about the
>> presence of a vlan tag and directly uses dev->features.
>
> The chip supports checksum offload only if TX_VLAN is enabled.
> Scatter/gather without checksum offload is not allowed by kernel
> because checksum offload is needed for sendfile.
OK, it sounds like skb_needs_linearize() needs to be more intelligent.
I will send a patch for that shortly.
next prev parent reply other threads:[~2011-01-09 15:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-07 4:41 [PATCH 2/2] sky2: convert to new VLAN model Stephen Hemminger
2011-01-07 17:14 ` Jesse Gross
2011-01-07 17:27 ` Stephen Hemminger
2011-01-09 15:50 ` Jesse Gross [this message]
2011-01-08 4:13 ` [PATCH 2/2] sky2: convert to new VLAN model (v0.2) Stephen Hemminger
2011-01-09 16:13 ` Jesse Gross
2011-01-09 23:54 ` David Miller
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