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From: Andreas Hindborg <a.hindborg@kernel.org>
To: "Gary Guo" <gary@garyguo.net>,
	"Anna-Maria Behnsen" <anna-maria@linutronix.de>,
	"Frederic Weisbecker" <frederic@kernel.org>,
	"Thomas Gleixner" <tglx@kernel.org>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <lossin@kernel.org>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Trevor Gross" <tmgross@umich.edu>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"Daniel Almeida" <daniel.almeida@collabora.com>,
	"Tamir Duberstein" <tamird@kernel.org>,
	"Alexandre Courbot" <acourbot@nvidia.com>,
	"Onur Özkan" <work@onurozkan.dev>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
	"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
	"Tvrtko Ursulin" <tursulin@ursulin.net>,
	"David Airlie" <airlied@gmail.com>,
	"Simona Vetter" <simona@ffwll.ch>,
	"Lyude Paul" <lyude@redhat.com>,
	"John Stultz" <jstultz@google.com>,
	"Stephen Boyd" <sboyd@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>, Boqun Feng <boqun@kernel.org>,
	Gary Guo <gary@garyguo.net>,
	FUJITA Tomonori <fujita.tomonori@gmail.com>,
	linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org,
	intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 6/6] rust: hrtimer: Make HrTimer repr(transparent)
Date: Wed, 26 Aug 2026 11:30:16 +0200	[thread overview]
Message-ID: <87v78x1b6f.fsf@t14s.mail-host-address-is-not-set> (raw)
In-Reply-To: <DKY2AIA7ELLI.1REFFZGXL78Q5@garyguo.net>

"Gary Guo" <gary@garyguo.net> writes:

> On Tue Aug 25, 2026 at 1:16 PM BST, Andreas Hindborg wrote:
>> From: FUJITA Tomonori <fujita.tomonori@gmail.com>
>>
>> HrTimerCallbackContext acquires a &HrTimer<T> from a
>> NonNull<HrTimer<T>> while a &mut HrTimer<T> can exist at the same
>> time. This is sound only because HrTimer's sole field is
>> Opaque<bindings::hrtimer>, which puts every byte behind an UnsafeCell.
>> Adding a field to HrTimer that is not Opaque would make acquiring that
>> shared reference unsound.
>
> HrTimerCallbackContext is removed in patch 4, though?
>
> Still worh preferring `#[repr(transparent)]` over `#[repr(C)]`, but the
> motivation should be reworded and the comment on `HrTimer` should be removed.

Yes, I was a little too fast when I added this patch. I'd like to keep
it as well, but it needs some edits.

Best regards,
Andreas Hindborg


      parent reply	other threads:[~2026-08-26  9:30 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-25 12:16 [PATCH 0/6] hrtimer: add an expiry injecting callback variant Andreas Hindborg
2026-08-25 12:16 ` [PATCH 1/6] hrtimer: add " Andreas Hindborg
2026-08-25 12:16 ` [PATCH 2/6] drm/i915/pmu: use the expiry injecting hrtimer callback Andreas Hindborg
2026-08-25 12:16 ` [PATCH 3/6] rust: hrtimer: use the expiry injecting callback variant Andreas Hindborg
2026-08-25 12:16 ` [PATCH 4/6] rust: hrtimer: restrict expires() to exclusive access Andreas Hindborg
2026-08-25 12:16 ` [PATCH 5/6] rust: hrtimer: document deadlock when starting a timer in its handler Andreas Hindborg
     [not found]   ` <DKY292V0LWJN.1L3HG02NBW6K5@garyguo.net>
2026-08-26  9:31     ` Andreas Hindborg
2026-08-25 12:16 ` [PATCH 6/6] rust: hrtimer: Make HrTimer repr(transparent) Andreas Hindborg
     [not found]   ` <DKY2AIA7ELLI.1REFFZGXL78Q5@garyguo.net>
2026-08-26  9:30     ` Andreas Hindborg [this message]

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