linux-kernel - Re: [PATCH v2 16/16] mt76: use netmem descriptor and APIs for page pool

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Message-ID: <87v7plmbo9.fsf@toke.dk>
Date: Wed, 28 May 2025 09:33:58 +0200
From: Toke Høiland-Jørgensen <toke@...hat.com>
To: Byungchul Park <byungchul@...com>, willy@...radead.org,
 netdev@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
 kernel_team@...ynix.com, kuba@...nel.org, almasrymina@...gle.com,
 ilias.apalodimas@...aro.org, harry.yoo@...cle.com, hawk@...nel.org,
 akpm@...ux-foundation.org, davem@...emloft.net, john.fastabend@...il.com,
 andrew+netdev@...n.ch, asml.silence@...il.com, tariqt@...dia.com,
 edumazet@...gle.com, pabeni@...hat.com, saeedm@...dia.com,
 leon@...nel.org, ast@...nel.org, daniel@...earbox.net, david@...hat.com,
 lorenzo.stoakes@...cle.com, Liam.Howlett@...cle.com, vbabka@...e.cz,
 rppt@...nel.org, surenb@...gle.com, mhocko@...e.com, horms@...nel.org,
 linux-rdma@...r.kernel.org, bpf@...r.kernel.org, vishal.moola@...il.com
Subject: Re: [PATCH v2 16/16] mt76: use netmem descriptor and APIs for page
 pool

Byungchul Park <byungchul@...com> writes:

> On Wed, May 28, 2025 at 11:29:11AM +0900, Byungchul Park wrote:
>> To simplify struct page, the effort to separate its own descriptor from
>> struct page is required and the work for page pool is on going.
>> 
>> Use netmem descriptor and APIs for page pool in mt76 code.
>> 
>> Signed-off-by: Byungchul Park <byungchul@...com>
>> ---
>>  drivers/net/wireless/mediatek/mt76/dma.c      |  6 ++---
>>  drivers/net/wireless/mediatek/mt76/mt76.h     | 12 +++++-----
>>  .../net/wireless/mediatek/mt76/sdio_txrx.c    | 24 +++++++++----------
>>  drivers/net/wireless/mediatek/mt76/usb.c      | 10 ++++----
>>  4 files changed, 26 insertions(+), 26 deletions(-)
>> 
>> diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
>> index 35b4ec91979e..cceff435ec4a 100644
>> --- a/drivers/net/wireless/mediatek/mt76/dma.c
>> +++ b/drivers/net/wireless/mediatek/mt76/dma.c
>> @@ -820,10 +820,10 @@ mt76_add_fragment(struct mt76_dev *dev, struct mt76_queue *q, void *data,
>>  	int nr_frags = shinfo->nr_frags;
>>  
>>  	if (nr_frags < ARRAY_SIZE(shinfo->frags)) {
>> -		struct page *page = virt_to_head_page(data);
>> -		int offset = data - page_address(page) + q->buf_offset;
>> +		netmem_ref netmem = netmem_compound_head(virt_to_netmem(data));
>> +		int offset = data - netmem_address(netmem) + q->buf_offset;
>>  
>> -		skb_add_rx_frag(skb, nr_frags, page, offset, len, q->buf_size);
>> +		skb_add_rx_frag_netmem(skb, nr_frags, netmem, offset, len, q->buf_size);
>>  	} else {
>>  		mt76_put_page_pool_buf(data, allow_direct);
>>  	}
>> diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
>> index 5f8d81cda6cd..f075c1816554 100644
>> --- a/drivers/net/wireless/mediatek/mt76/mt76.h
>> +++ b/drivers/net/wireless/mediatek/mt76/mt76.h
>> @@ -1795,21 +1795,21 @@ int mt76_rx_token_consume(struct mt76_dev *dev, void *ptr,
>>  int mt76_create_page_pool(struct mt76_dev *dev, struct mt76_queue *q);
>>  static inline void mt76_put_page_pool_buf(void *buf, bool allow_direct)
>>  {
>> -	struct page *page = virt_to_head_page(buf);
>> +	netmem_ref netmem = netmem_compound_head(virt_to_netmem(buf));
>>  
>> -	page_pool_put_full_page(page->pp, page, allow_direct);
>
> To Mina,
>
> They touch ->pp field.  That's why I thought they use page pool.  Am I
> missing something?

It does, since commit: 2f5c3c77fc9b ("wifi: mt76: switch to page_pool allocator")

-Toke