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Date: Sat, 21 Feb 2026 16:09:41 +0100
Message-Id: <DGKQH7Q9QONY.4GLSDMQ8DOY1@kernel.org>
Subject: Re: [PATCH v4 3/6] rust: gpuvm: add GpuVm::obtain()
Cc: "Daniel Almeida" <daniel.almeida@collabora.com>, "Boris Brezillon"
 <boris.brezillon@collabora.com>, "Janne Grunau" <j@jannau.net>, "Matthew
 Brost" <matthew.brost@intel.com>, =?utf-8?q?Thomas_Hellstr=C3=B6m?=
 <thomas.hellstrom@linux.intel.com>, "Lyude Paul" <lyude@redhat.com>, "Asahi
 Lina" <lina+kernel@asahilina.net>, <dri-devel@lists.freedesktop.org>,
 <linux-kernel@vger.kernel.org>, <rust-for-linux@vger.kernel.org>
To: "Alice Ryhl" <aliceryhl@google.com>
From: "Danilo Krummrich" <dakr@kernel.org>
References: <20260130-gpuvm-rust-v4-0-8364d104ff40@google.com>
 <20260130-gpuvm-rust-v4-3-8364d104ff40@google.com>
 <DGJ6LHIVMV03.MM7RWYBJHBIQ@kernel.org> <aZgYY_fetgz_GDR8@google.com>
 <DGJX3FI97W1G.371MAMC60FX24@kernel.org> <aZlw3SGmLetHwaTM@google.com>
In-Reply-To: <aZlw3SGmLetHwaTM@google.com>

On Sat Feb 21, 2026 at 9:46 AM CET, Alice Ryhl wrote:
> So, should we get rid of GpuVmBoRegistered in favor of ARef<GpuVm<T>>?

I wanted to avoid exposing the reference count, as I suspect drivers might =
not
need it in Rust, but I don't know for sure.

We could also define it as GpuVmBo<T>(ARef<GpuVmBoInner<T>>), where
GpuVmBoInner<T> is private, but I also don't want you to go back and forth =
with
this in case it turns out we do need drivers to be able to take a reference
count and I also don't think it hurts too much exposing the reference count=
,
even if not needed.

So, either is fine with me, ARef<GpuVmBo<T>> or
GpuVmBo<T>(ARef<GpuVmBoInner<T>>).