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From:   Andreas Hindborg <nmi@metaspace.dk>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
        Keith Busch <kbusch@kernel.org>,
        Damien Le Moal <Damien.LeMoal@wdc.com>,
        Hannes Reinecke <hare@suse.de>,
        lsf-pc@lists.linux-foundation.org, rust-for-linux@vger.kernel.org,
        linux-block@vger.kernel.org, Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?utf-8?Q?Bj=C3=B6rn?= Roy Baron <bjorn3_gh@protonmail.com>,
        Benno Lossin <benno.lossin@proton.me>,
        open list <linux-kernel@vger.kernel.org>, gost.dev@samsung.com
Subject: Re: [RFC PATCH 01/11] rust: add radix tree abstraction
Date:   Fri, 05 May 2023 06:49:49 +0200
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Matthew Wilcox <willy@infradead.org> writes:

> On Wed, May 03, 2023 at 11:06:58AM +0200, Andreas Hindborg wrote:
>> From: Andreas Hindborg <a.hindborg@samsung.com>
>> 
>> Add abstractions for the C radix_tree. This abstraction allows Rust code to use
>> the radix_tree as a map from `u64` keys to `ForeignOwnable` values.
>
> Please, no.  The XArray interface is the preferred one; the radix tree
> is legacy.  Don't make Rust code use the radix tree.  It has the GFP
> arguments in the wrong place, for one thing.

I have a similar argument to not using xarrray as to not using folios,
see my other response. But the Rust xarray API is in the works [1].

Best regards,
Andreas

[1] https://lore.kernel.org/rust-for-linux/1bb98ef1-727a-45d6-3cf6-39765fe99c5c@asahilina.net/