linux-kernel - Re: [RFC mm v5 1/2] page_pool: check nmdesc->pp to see its usage as page pool for net

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Message-ID: <20251106173320.2f8e683a@kernel.org>
Date: Thu, 6 Nov 2025 17:33:20 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Byungchul Park <byungchul@...com>
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Subject: Re: [RFC mm v5 1/2] page_pool: check nmdesc->pp to see its usage as
 page pool for net_iov not page-backed

On Mon,  3 Nov 2025 16:51:07 +0900 Byungchul Park wrote:
> However, for net_iov not
> page-backed, the identification cannot be based on the page_type.
> Instead, nmdesc->pp can be used to see if it belongs to a page pool, by
> making sure nmdesc->pp is NULL otherwise.

Please explain why. Isn't the type just a value in a field?
Which net_iov could also set accordingly.. ?