Re: [PATCH net-next] ice: access @pp through netmem_desc instead of page

[Pavel Begunkov <asml.silence@gmail.com>]

On 12/16/25 04:20, Matthew Wilcox wrote:
> On Tue, Dec 16, 2025 at 01:07:23PM +0900, Byungchul Park wrote:
>> +++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
>> @@ -1251,7 +1251,7 @@ static int ice_lbtest_receive_frames(struct ice_rx_ring *rx_ring)
>>   		rx_buf = &rx_ring->rx_fqes[i];
>>   		page = __netmem_to_page(rx_buf->netmem);
>>   		received_buf = page_address(page) + rx_buf->offset +
>> -			       page->pp->p.offset;
>> +			       pp_page_to_nmdesc(page)->pp->p.offset;
> 
> Shouldn't we rather use:
> 
> 		nmdesc = __netmem_to_nmdesc(rx_buf->netmem);
> 		received_buf = nmdesc_address(nmdesc) + rx_buf->offset +
> 				nmdesc->pp->p_offset;
> 
> (also. i think we're missing a nmdesc_address() function in our API).

It wouldn't make sense as net_iov backed nmdescs don't have/expose
host addresses (only dma addresses). nmdesc_address() would still
need to rely on the caller knowing that it's a page. An explicit
cast with *netmem_to_page() should be better.

-- 
Pavel Begunkov