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From: Andreas Hindborg <nmi@metaspace.dk>
To: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Wilcox <willy@infradead.org>,  Andreas Hindborg
 <a.hindborg@samsung.com>,  akpm@linux-foundation.org,
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Subject: Re: [PATCH v3 4/4] rust: add abstraction for `struct page`
In-Reply-To: <20240311105056.122734-1-aliceryhl@google.com> (Alice Ryhl's
	message of "Mon, 11 Mar 2024 10:50:56 +0000")
References: <20240311-alice-mm-v3-4-cdf7b3a2049c@google.com>
	<20240311105056.122734-1-aliceryhl@google.com>
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Date: Fri, 15 Mar 2024 09:16:32 +0100
Message-ID: <87ttl7rjtr.fsf@metaspace.dk>
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Alice Ryhl <aliceryhl@google.com> writes:

> Alice Ryhl <aliceryhl@google.com> writes:
>
> Andreas Hindborg: I recall you mentioning that you also needed an
> abstraction for pages. To what extent do these abstractions fit your
> needs? Which gfp flags do you need?
>

I based the block device driver API and null block driver series on v1
of this patch and v3 should still be good for that. The null block
driver uses `Page` indirectly through `UniqueFolio` with `GFP_KERNEL`
alloc flags. I do not need to customize the flags outside of that.

As an aside, I added methods to safely operate on the page contents [1].
`kernel::block::vec::Segment` indirectly uses this to move data to and
from pages [2].

Best regards,
Andreas


[1] https://github.com/metaspace/linux/commit/e88f4dc928233fcedcb0afec40be9bc2f8f74e3b
[2] https://lore.kernel.org/rust-for-linux/87y1akso83.fsf@metaspace.dk/T/#me6497ec69544efd21908f1acc6b3a1ab8b148ba0