From: Matteo Kloiber <kernel@matt3o12.de>
To: Alexandre Courbot <acourbot@nvidia.com>
Cc: dakr@kernel.org, aliceryhl@google.com, ojeda@kernel.org,
airlied@gmail.com, simona@ffwll.ch, abdiel.janulgue@gmail.com,
daniel.almeida@collabora.com, robin.murphy@arm.com,
a.hindborg@kernel.org, nova-gpu@lists.linux.dev,
dri-devel@lists.freedesktop.org, driver-core@lists.linux.dev,
rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] rust: scatterlist: honor the device's maximum segment size
Date: Sun, 13 Sep 2026 23:08:03 +0200 [thread overview]
Message-ID: <20260913210806.125589-1-kernel@matt3o12.de> (raw)
In-Reply-To: <DL8QLYLQJEL1.3F653J67DYZ47@nvidia.com>
On Mon Sep 7, 2026 at 11:43 AM JST, Alexandre Courbot wrote:
> I guess what this last paragraph wants to state is that no user is
> affected by this patch? There is another subtle user though: the Rust
> DMA sample.
Yes, that's what I meant. I missed the sample, but it wouldn't make a
difference anyway. So I just removed the paragraph in v2.
> nit: if we rename this variable, let's name it `max_mapping_size` for
> consistency.
Agreed. Fixed. Let me know if everything is fixed in v2.
> It also means that without patch 1, nova-core would split the firmware
> into hundreds of 64KB SG entries, which is not breaking but still
> something we want to avoid. The correct fix is to make sure that
> `dma_set_max_seg_size` is called by the driver, and while we are at it
> we also want every driver to call `dma_set_mask_and_coherent`. Ideally
> we would use the type system to make sure that both functions are called
> before any DMA operation can take place (using a safe interface), but
> I'm not quite sure yet how we can do this.
This sounds sensible indeed. Should I open a thread regarding that on Zulip?
prev parent reply other threads:[~2026-09-13 21:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-31 23:32 [PATCH 0/2] rust: honor the maximum DMA segment size Matteo Kloiber
2026-08-31 23:32 ` [PATCH 1/2] gpu: nova-core: declare unlimited DMA max " Matteo Kloiber
2026-09-07 2:10 ` Alexandre Courbot
2026-09-13 21:07 ` Matteo Kloiber
2026-08-31 23:32 ` [PATCH 2/2] rust: scatterlist: honor the device's maximum " Matteo Kloiber
2026-09-07 2:43 ` Alexandre Courbot
2026-09-13 21:08 ` Matteo Kloiber [this message]
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