On Mar 22, 2013, at 10:23 AM, Eric Dumazet <eric.duma...@gmail.com> wrote:
> On Wed, 2011-07-13 at 08:52 -0500, Andy Fleming wrote:
>> The QDisc code does a bunch of locking which is unnecessary if
>> you have hardware which handles all of the queueing. Add
>> support for this, and skip over all of the queueing code if
>> the feature is enabled on a given device, which breaks QDisc
>> support on dpaa_eth, and also coopts the FCOE feature bit.
>>
>> Signed-off-by: Andy Fleming <aflem...@freescale.com>
>> Signed-off-by: Ben Collins <be...@servergy.com>
>> Cc: net...@vger.kernel.org
>> ---
>> include/linux/netdev_features.h | 2 ++
>> net/core/dev.c | 6 ++++++
>> 2 files changed, 8 insertions(+)
>>
>> diff --git a/include/linux/netdev_features.h
>> b/include/linux/netdev_features.h
>> index 3dd3934..ffb4587 100644
>> --- a/include/linux/netdev_features.h
>> +++ b/include/linux/netdev_features.h
>> @@ -56,6 +56,7 @@ enum {
>> NETIF_F_LOOPBACK_BIT, /* Enable loopback */
>> NETIF_F_RXFCS_BIT, /* Append FCS to skb pkt data */
>> NETIF_F_RXALL_BIT, /* Receive errored frames too */
>> + NETIF_F_HW_QDISC_BIT, /* Supports hardware Qdisc */
>>
>> /*
>> * Add your fresh new feature above and remember to update
>> @@ -80,6 +81,7 @@ enum {
>> #define NETIF_F_GSO_ROBUST __NETIF_F(GSO_ROBUST)
>> #define NETIF_F_HIGHDMA __NETIF_F(HIGHDMA)
>> #define NETIF_F_HW_CSUM __NETIF_F(HW_CSUM)
>> +#define NETIF_F_HW_QDISC __NETIF_F(HW_QDISC)
>> #define NETIF_F_HW_VLAN_FILTER __NETIF_F(HW_VLAN_FILTER)
>> #define NETIF_F_HW_VLAN_RX __NETIF_F(HW_VLAN_RX)
>> #define NETIF_F_HW_VLAN_TX __NETIF_F(HW_VLAN_TX)
>> diff --git a/net/core/dev.c b/net/core/dev.c
>> index dffbef7..6818b18 100644
>> --- a/net/core/dev.c
>> +++ b/net/core/dev.c
>> @@ -2743,6 +2743,12 @@ int dev_queue_xmit(struct sk_buff *skb)
>>
>> skb_update_prio(skb);
>>
>> + if (dev->features & NETIF_F_HW_QDISC) {
>> + txq = netdev_pick_tx(dev, skb);
>> + rc = dev_hard_start_xmit(skb, dev, txq);
>> + goto out;
>> + }
>> +
>> txq = netdev_pick_tx(dev, skb);
>> q = rcu_dereference_bh(txq->qdisc);
>>
>
> Nobody forces you to use a qdisc.
>
> And if your device really is lockless, it can use NETIF_F_LLTX feature.
NETIF_F_LLTX_BIT, /* LockLess TX - deprecated. Please */
/* do not use LLTX in new drivers */
--
Servergy : http://www.servergy.com/
SwissDisk : http://www.swissdisk.com/
Ubuntu : http://www.ubuntu.com/
My Blog : http://ben-collins.blogspot.com/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
