From: Timur Tabi <ttabi@nvidia.com>
To: "dakr@kernel.org" <dakr@kernel.org>, John Hubbard <jhubbard@nvidia.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>,
"lossin@kernel.org" <lossin@kernel.org>,
"a.hindborg@kernel.org" <a.hindborg@kernel.org>,
"boqun.feng@gmail.com" <boqun.feng@gmail.com>,
"aliceryhl@google.com" <aliceryhl@google.com>,
Zhi Wang <zhiw@nvidia.com>, "simona@ffwll.ch" <simona@ffwll.ch>,
"alex.gaynor@gmail.com" <alex.gaynor@gmail.com>,
"ojeda@kernel.org" <ojeda@kernel.org>,
"tmgross@umich.edu" <tmgross@umich.edu>,
"nouveau@lists.freedesktop.org" <nouveau@lists.freedesktop.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"rust-for-linux@vger.kernel.org" <rust-for-linux@vger.kernel.org>,
"bjorn3_gh@protonmail.com" <bjorn3_gh@protonmail.com>,
Edwin Peer <epeer@nvidia.com>,
"airlied@gmail.com" <airlied@gmail.com>,
Joel Fernandes <joelagnelf@nvidia.com>,
"bhelgaas@google.com" <bhelgaas@google.com>,
"gary@garyguo.net" <gary@garyguo.net>,
Alistair Popple <apopple@nvidia.com>
Subject: Re: [PATCH] gpu: nova-core: bitfield: use &mut self setters instead of builder pattern
Date: Wed, 31 Dec 2025 22:33:41 +0000 [thread overview]
Message-ID: <9db27bd6015ccebaa20e51450d8c42eb2864cb2e.camel@nvidia.com> (raw)
In-Reply-To: <20251231214727.448776-1-jhubbard@nvidia.com>
On Wed, 2025-12-31 at 13:47 -0800, John Hubbard wrote:
> The builder-pattern setters (self -> Self) enabled method chaining like:
>
> reg.set_foo(x).set_sec(y).write(bar);
>
> This made separate operations appear as a single expression, obscuring
> that each setter is a distinct mutation.
So you're concerned about the fact that the compiler is not merging the set_foo(x) and the
set_sec(y) into a single read-modify-write?
> These setters are infallible,
> so the chaining provides no error-propagation benefit—it just obscures
> what are simple, independent assignments.
>
> Change the bitfield!() macro to generate `&mut self` setters, so each
> operation is a distinct statement:
>
> reg.set_foo(x);
> reg.set_sec(y);
> reg.write(bar);
Are you sure about this? It just seems like you're throwing out a neat little feature of Rust and
replacing it with something that's very C-like. This breaks compatible with all users of the regs
macros. Seems really disruptive for what seems to me like a cosmetic change.
next prev parent reply other threads:[~2025-12-31 22:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-31 21:47 John Hubbard
2025-12-31 22:33 ` Timur Tabi [this message]
2025-12-31 22:47 ` John Hubbard
2026-01-01 0:15 ` Joel Fernandes
2026-01-01 0:46 ` John Hubbard
2026-01-01 2:42 ` Joel Fernandes
2026-01-01 2:52 ` John Hubbard
2026-01-01 4:05 ` Joel Fernandes
2026-01-01 4:28 ` Gary Guo
2026-01-01 10:01 ` Joel Fernandes
2026-01-01 8:42 ` kernel test robot
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