Re: [PATCH net-next 3/3] page_pool: Track DMA-mapped pages and unmap them when destroying the pool

[Yunsheng Lin <linyunsheng@huawei.com>]

On 2025/3/19 20:18, Toke Høiland-Jørgensen wrote:
>>
>> All I asked is about moving PP_MAGIC_MASK macro into poison.h if you
>> still want to proceed with reusing the page->pp_magic as the masking and
>> the signature to be masked seems reasonable to be in the same file.
> 
> Hmm, my thinking was that this would be a lot of irrelevant stuff to put
> into poison.h, but I suppose we could do so if the mm folks don't object :)

The masking and the signature to be masked is correlated, I am not sure
what you meant by 'irrelevant stuff' here.

As you seemed to have understood most of my concern about reusing
page->pp_magic, I am not going to argue with you about the uncertainty
of security and complexity of different address layout for different
arches again.

But I am still think it is not the way forward with the reusing of
page->pp_magic through doing some homework about the 'POISON_POINTER'.
If you still think my idea is complex and still want to proceed with
reusing the space of page->pp_magic, go ahead and let the maintainers
decide if it is worth the security risk and performance degradation.

> 
> -Toke
> 
>