Re: [PATCH net v4 1/2] octeon_ep: Implement helper for iterating packets in Rx queue

[Paolo Abeni <pabeni@redhat.com>]

On 10/12/24 11:49, Aleksandr Mishin wrote:
> diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c b/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c
> index 4746a6b258f0..62db101b2147 100644
> --- a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c
> +++ b/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c
> @@ -336,6 +336,30 @@ static int octep_oq_check_hw_for_pkts(struct octep_device *oct,
>   	return new_pkts;
>   }
>   
> +/**
> + * octep_oq_next_pkt() - Move to the next packet in Rx queue.
> + *
> + * @oq: Octeon Rx queue data structure.
> + * @buff_info: Current packet buffer info.
> + * @read_idx: Current packet index in the ring.
> + * @desc_used: Current packet descriptor number.
> + *
> + * Free the resources associated with a packet.
> + * Increment packet index in the ring and packet descriptor number.
> + */
> +static void octep_oq_next_pkt(struct octep_oq *oq,
> +			      struct octep_rx_buffer *buff_info,
> +			      u32 *read_idx, u32 *desc_used)
> +{
> +	dma_unmap_page(oq->dev, oq->desc_ring[*read_idx].buffer_ptr,
> +		       PAGE_SIZE, DMA_FROM_DEVICE);
> +	buff_info->page = NULL;
> +	(*read_idx)++;
> +	(*desc_used)++;
> +	if (*read_idx == oq->max_count)
> +		*read_idx = 0;
> +}
> +
>   /**
>    * __octep_oq_process_rx() - Process hardware Rx queue and push to stack.
>    *
> @@ -367,10 +391,7 @@ static int __octep_oq_process_rx(struct octep_device *oct,
>   	desc_used = 0;
>   	for (pkt = 0; pkt < pkts_to_process; pkt++) {
>   		buff_info = (struct octep_rx_buffer *)&oq->buff_info[read_idx];
> -		dma_unmap_page(oq->dev, oq->desc_ring[read_idx].buffer_ptr,
> -			       PAGE_SIZE, DMA_FROM_DEVICE);
>   		resp_hw = page_address(buff_info->page);
> -		buff_info->page = NULL;
>   
>   		/* Swap the length field that is in Big-Endian to CPU */
>   		buff_info->len = be64_to_cpu(resp_hw->length);
> @@ -394,36 +415,27 @@ static int __octep_oq_process_rx(struct octep_device *oct,
>   			data_offset = OCTEP_OQ_RESP_HW_SIZE;
>   			rx_ol_flags = 0;
>   		}
> +
> +		skb = build_skb((void *)resp_hw, PAGE_SIZE);
> +		skb_reserve(skb, data_offset);
> +
> +		octep_oq_next_pkt(oq, buff_info, &read_idx, &desc_used);

I'm sorry for not catching the following in the previous iteration (the 
split indeed helped with the review):

build_skb() will write into the paged buffer, I think you should unmap 
it with octep_oq_next_pkt() before the skb creation.

That in turn will have side effect on the following patch (the 'do {} 
while' loop should become a plain 'while' one).

Thanks,

Paolo