Re: [PATCH 1/1] net: mvpp2: fix XDP rx queues registering

Emmanuel Deloget
2021-12-06T15:45:58Z

Hello,

On 10/11/2021 15:41, Louis Amas wrote:
> The registration of XDP queue information is incorrect because the
> RX queue id we use is invalid. When port->id == 0 it appears to works
> as expected yet it's no longer the case when port->id != 0.
>
> When we register the XDP rx queue information (using
> xdp_rxq_info_reg() in function mvpp2_rxq_init()) we tell them to use
> rxq->id as the queue id. This value iscomputed as:
> rxq->id = port->id * max_rxq_count + queue_id
>
> where max_rxq_count depends on the device version. In the MB case,
> this value is 32, meaning that rx queues on eth2 are numbered from
> 32 to 35 - there are four of them.
>
> Clearly, this is not the per-port queue id that XDP is expecting:
> it wants a value in the range [0..3]. It shall directly use queue_id
> which is stored in rxq->logic_rxq -- so let's use that value instead.
>
> This is consistent with the remaining part of the code in
> mvpp2_rxq_init().
>
> Fixes: b27db2274ba8 ("mvpp2: use page_pool allocator")
> Signed-off-by: Louis Amas <louis.amas@eho.link>
> Signed-off-by: Emmanuel Deloget <emmanuel.deloget@eho.link>
> Reviewed-by: Marcin Wojtas <mw@semihalf.com>
> ---
> This is a repost of [1]. The patch itself is not changed, but the
> commit message has been enhanced using part of the explaination in
> order to make it clearer (hopefully) and to incorporate the
> reviewed-by tag from Marcin.
>
> v1: original patch
> v2: revamped commit description (no change in the patch itself)
>
> [1] https://lore.kernel.org/bpf/20211109103101.92382-1-louis.amas@eho.link/
>
> drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> index 587def69a6f7..f0ea377341c6 100644
> --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> @@ -2959,11 +2959,11 @@ static int mvpp2_rxq_init(struct mvpp2_port *port,
> mvpp2_rxq_status_update(port, rxq->id, 0, rxq->size);
>
> if (priv->percpu_pools) {
> - err = xdp_rxq_info_reg(&rxq->xdp_rxq_short, port->dev, rxq->id, 0);
> + err = xdp_rxq_info_reg(&rxq->xdp_rxq_short, port->dev, rxq->logic_rxq, 0);
> if (err < 0)
> goto err_free_dma;
>
> - err = xdp_rxq_info_reg(&rxq->xdp_rxq_long, port->dev, rxq->id, 0);
> + err = xdp_rxq_info_reg(&rxq->xdp_rxq_long, port->dev, rxq->logic_rxq, 0);
> if (err < 0)
> goto err_unregister_rxq_short;
>
>

Is there any update on this patch ? Without it, XDP only partially work
on a MACCHIATOBin (read: it works on some ports, not on others, as
described in our analysis sent together with the original patch).

Best regards,

-- Emmanuel Deloget