Re: [net-next PATCH v6 6/6] octeontx2-pf: AF_XDP zero copy transmit support

From: Maciej Fijalkowski
Date: Tue Feb 18 2025 - 08:02:02 EST


On Thu, Feb 13, 2025 at 11:01:41AM +0530, Suman Ghosh wrote:
> This patch implements below changes,
>
> 1. To avoid concurrency with normal traffic uses
> XDP queues.
> 2. Since there are chances that XDP and AF_XDP can
> fall under same queue uses separate flags to handle
> dma buffers.
>
> Signed-off-by: Hariprasad Kelam <hkelam@xxxxxxxxxxx>
> Signed-off-by: Suman Ghosh <sumang@xxxxxxxxxxx>
> ---

[...]

> +void otx2_zc_napi_handler(struct otx2_nic *pfvf, struct xsk_buff_pool *pool,
> + int queue, int budget)
> +{
> + struct xdp_desc *xdp_desc = pool->tx_descs;
> + int err, i, work_done = 0, batch;
> +
> + budget = min(budget, otx2_read_free_sqe(pfvf, queue));
> + batch = xsk_tx_peek_release_desc_batch(pool, budget);
> + if (!batch)
> + return;
> +
> + for (i = 0; i < batch; i++) {
> + dma_addr_t dma_addr;
> +
> + dma_addr = xsk_buff_raw_get_dma(pool, xdp_desc[i].addr);
> + err = otx2_xdp_sq_append_pkt(pfvf, NULL, dma_addr, xdp_desc[i].len,
> + queue, OTX2_AF_XDP_FRAME);
> + if (!err) {
> + netdev_err(pfvf->netdev, "AF_XDP: Unable to transfer packet err%d\n", err);
> + break;
> + }
> + work_done++;
> + }
> +
> + if (work_done)
> + xsk_tx_release(pool);

this is broken actually. the batch api you're using above is doing tx
release internally for you.

Sorry for not catching this earlier but i was never CCed in this series.

> +}
> diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_xsk.h b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_xsk.h
> index 022b3433edbb..8047fafee8fe 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_xsk.h
> +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_xsk.h
> @@ -17,5 +17,8 @@ int otx2_xsk_pool_disable(struct otx2_nic *pf, u16 qid);
> int otx2_xsk_pool_alloc_buf(struct otx2_nic *pfvf, struct otx2_pool *pool,
> dma_addr_t *dma, int idx);
> int otx2_xsk_wakeup(struct net_device *dev, u32 queue_id, u32 flags);
> +void otx2_zc_napi_handler(struct otx2_nic *pfvf, struct xsk_buff_pool *pool,
> + int queue, int budget);
> +void otx2_attach_xsk_buff(struct otx2_nic *pfvf, struct otx2_snd_queue *sq, int qidx);
>
> #endif /* OTX2_XSK_H */
> --
> 2.25.1
>
>