From: Ioana Radulescu <ruxandra.radule...@nxp.com>
Date: Thu, 6 Jun 2019 11:50:28 +0300
> DPNI objects can have multiple traffic classes, as reflected by
> the num_tc attribute. Until now we ignored its value and only
> used traffic class 0.
>
> This patch adds support for multiple Tx traffic classes; the skb
> priority information received from the stack is used to select the
> hardware Tx queue on which to enqueue the frame.
>
> Signed-off-by: Ioana Radulescu <ruxandra.radule...@nxp.com>
> ---
> v2: Extra processing on the fast path happens only when TC is used
>
> drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 47
> ++++++++++++++++--------
> drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h | 9 ++++-
> 2 files changed, 40 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> index a12fc45..98de092 100644
> --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> @@ -757,6 +757,7 @@ static netdev_tx_t dpaa2_eth_tx(struct sk_buff *skb,
> struct net_device *net_dev)
> u16 queue_mapping;
> unsigned int needed_headroom;
> u32 fd_len;
> + u8 prio = 0;
> int err, i;
>
> percpu_stats = this_cpu_ptr(priv->percpu_stats);
> @@ -814,6 +815,18 @@ static netdev_tx_t dpaa2_eth_tx(struct sk_buff *skb,
> struct net_device *net_dev)
> * a queue affined to the same core that processed the Rx frame
> */
> queue_mapping = skb_get_queue_mapping(skb);
> +
> + if (net_dev->num_tc) {
> + prio = netdev_txq_to_tc(net_dev, queue_mapping);
> + /* Hardware interprets priority level 0 as being the highest,
> + * so we need to do a reverse mapping to the netdev tc index
> + */
> + prio = net_dev->num_tc - prio - 1;
> + /* We have only one FQ array entry for all Tx hardware queues
> + * with the same flow id (but different priority levels)
> + */
> + queue_mapping %= dpaa2_eth_queue_count(priv);
This doesn't make any sense.
queue_mapping came from skb_get_queue_mapping().
The core limits the queue mapping value to whatever you told the
generic networking layer was the maximum number of queues.
And you set that to dpaa2_eth_queue_count():
/* Set actual number of queues in the net device */
num_queues = dpaa2_eth_queue_count(priv);
err = netif_set_real_num_tx_queues(net_dev, num_queues);
Therfore the modulus cannot be needed.
