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

On Mon, Dec 06, 2021 at 04:37:20PM +0100, Emmanuel Deloget wrote:

Hello,

On 10/11/2021 15:41, Louis Amas wrote:

quoted

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 <redacted>
Signed-off-by: Emmanuel Deloget <redacted>
Reviewed-by: Marcin Wojtas <redacted>
---
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/ (local)

  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).

Hi,

I suspect if you *didn't* thread your updated patch to your previous
submission, then it would end up with a separate entry in
patchwork.kernel.org, and the netdev maintainers will notice that the
patch is ready for inclusion, having been reviewed by Marcin.

Thanks.

-- 
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