Re: [RFC PATCH 00/11] Rust null block driver

From: Keith Busch <kbusch@kernel.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: "Andreas Hindborg" <nmi@metaspace.dk>,
	"Jens Axboe" <axboe@kernel.dk>, "Christoph Hellwig" <hch@lst.de>,
	"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,
	"Matthew Wilcox" <willy@infradead.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>,
	"Björn 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 00/11] Rust null block driver
Date: Thu, 4 May 2023 12:52:33 -0600	[thread overview]
Message-ID: <ZFP+8apHunCCMmOZ@kbusch-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <b9a1c1b2-3baa-2cad-31ae-8b14e4ee5709@acm.org>

On Thu, May 04, 2023 at 11:36:01AM -0700, Bart Van Assche wrote:
> On 5/4/23 11:15, Andreas Hindborg wrote:
> > If it is still unclear to you why this effort was started, please do let
> > me know and I shall try to clarify further :)
> 
> It seems like I was too polite in my previous email. What I meant is that
> rewriting code is useful if it provides a clear advantage to the users of
> a driver. For null_blk, the users are kernel developers. The code that has
> been posted is the start of a rewrite of the null_blk driver. The benefits
> of this rewrite (making low-level memory errors less likely) do not outweigh
> the risks that this effort will introduce functional or performance regressions.

Instead of replacing, would co-existing be okay? Of course as long as
there's no requirement to maintain feature parity between the two.
Actually, just call it "rust_blk" and declare it has no relationship to
null_blk, despite their functional similarities: it's a developer
reference implementation for a rust block driver.