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Date: Thu, 16 Apr 2026 23:45:35 +0200
Message-Id: <DHUWPQX14ZGZ.26BV7GQCJDZQI@kernel.org>
Subject: Re: [PATCH v11 07/20] gpu: nova-core: mm: Add TLB flush support
Cc: <linux-kernel@vger.kernel.org>, "Miguel Ojeda" <ojeda@kernel.org>,
 "Boqun Feng" <boqun@kernel.org>, "Gary Guo" <gary@garyguo.net>, "Bjorn Roy
 Baron" <bjorn3_gh@protonmail.com>, "Benno Lossin" <lossin@kernel.org>,
 "Andreas Hindborg" <a.hindborg@kernel.org>, "Alice Ryhl"
 <aliceryhl@google.com>, "Trevor Gross" <tmgross@umich.edu>, "Dave Airlie"
 <airlied@redhat.com>, "Daniel Almeida" <daniel.almeida@collabora.com>,
 "Koen Koning" <koen.koning@linux.intel.com>,
 <dri-devel@lists.freedesktop.org>, <rust-for-linux@vger.kernel.org>,
 "Nikola Djukic" <ndjukic@nvidia.com>, "Maarten Lankhorst"
 <maarten.lankhorst@linux.intel.com>, "Maxime Ripard" <mripard@kernel.org>,
 "Thomas Zimmermann" <tzimmermann@suse.de>, "David Airlie"
 <airlied@gmail.com>, "Simona Vetter" <simona@ffwll.ch>, "Jonathan Corbet"
 <corbet@lwn.net>, "Alex Deucher" <alexander.deucher@amd.com>, "Christian
 Koenig" <christian.koenig@amd.com>, "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>, "Huang Rui" <ray.huang@amd.com>,
 "Matthew Auld" <matthew.auld@intel.com>, "Lucas De Marchi"
 <lucas.demarchi@intel.com>, "Thomas Hellstrom"
 <thomas.hellstrom@linux.intel.com>, "Helge Deller" <deller@gmx.de>, "Alex
 Gaynor" <alex.gaynor@gmail.com>, "Boqun Feng" <boqun.feng@gmail.com>, "John
 Hubbard" <jhubbard@nvidia.com>, "Alistair Popple" <apopple@nvidia.com>,
 "Timur Tabi" <ttabi@nvidia.com>, "Edwin Peer" <epeer@nvidia.com>,
 "Alexandre Courbot" <acourbot@nvidia.com>, "Andrea Righi"
 <arighi@nvidia.com>, "Andy Ritger" <aritger@nvidia.com>, "Zhi Wang"
 <zhiw@nvidia.com>, "Balbir Singh" <balbirs@nvidia.com>, "Philipp Stanner"
 <phasta@kernel.org>, "Elle Rhumsaa" <elle@weathered-steel.dev>,
 <alexeyi@nvidia.com>, "Eliot Courtney" <ecourtney@nvidia.com>,
 <joel@joelfernandes.org>, <linux-doc@vger.kernel.org>,
 <amd-gfx@lists.freedesktop.org>, <intel-gfx@lists.freedesktop.org>,
 <intel-xe@lists.freedesktop.org>, <linux-fbdev@vger.kernel.org>
To: "Joel Fernandes" <joelagnelf@nvidia.com>
From: "Danilo Krummrich" <dakr@kernel.org>
References: <20260415210548.3776595-1-joelagnelf@nvidia.com>
 <20260415210548.3776595-7-joelagnelf@nvidia.com>
 <20260416212312.GA667928@joelbox2>
In-Reply-To: <20260416212312.GA667928@joelbox2>

On Thu Apr 16, 2026 at 11:23 PM CEST, Joel Fernandes wrote:
> Btw, I changed this to doing it in 2 phases to avoid holding the RCU read=
lock
> across read_poll_timeout, which can sleep. Will squash it in for v12.

Why do we need the try_access() dance in the first place? I assume this end=
s up
being called from the BarAccess destructor?

If so, I think this is solvable. Gary and me are currently working on
higher-ranked types and a chained Devres type.

With that, such use-cases should be cleanly solvable without the need for
try_access().

Besides that, I can't find where BarAccess is ever constructed.

It already has a lifetime 'a for &'a Bar1, so I don't see why you can't do =
the
same for Bar0.

But again, I don't see this being constructed and I'm not sure the whole
construct works in the first place.