From: "Alexandre Courbot" <acourbot@nvidia.com>
To: "Danilo Krummrich" <dakr@kernel.org>
Cc: <abdiel.janulgue@gmail.com>, <daniel.almeida@collabora.com>,
<robin.murphy@arm.com>, <a.hindborg@kernel.org>,
<ojeda@kernel.org>, <boqun@kernel.org>, <gary@garyguo.net>,
<bjorn3_gh@protonmail.com>, <lossin@kernel.org>,
<aliceryhl@google.com>, <tmgross@umich.edu>,
<driver-core@lists.linux.dev>, <rust-for-linux@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>
Subject: Re: [PATCH 1/2] rust: dma: remove DMA_ATTR_NO_KERNEL_MAPPING from public attrs
Date: Sun, 22 Mar 2026 23:52:29 +0900 [thread overview]
Message-ID: <DH9E9U6RVA1J.NILSW02GNOBN@nvidia.com> (raw)
In-Reply-To: <20260321172749.592387-1-dakr@kernel.org>
On Sun Mar 22, 2026 at 2:27 AM JST, Danilo Krummrich wrote:
> When DMA_ATTR_NO_KERNEL_MAPPING is passed to dma_alloc_attrs(), the
> returned CPU address is not a pointer to the allocated memory but an
> opaque handle (e.g. struct page *).
>
> Coherent<T> (or CoherentAllocation<T> respectively) stores this value as
> NonNull<T> and exposes methods that dereference it and even modify its
> contents.
>
> Remove the flag from the public attrs module such that drivers cannot
> pass it to Coherent<T> (or CoherentAllocation<T> respectively) in the
> first place.
>
> Instead DMA_ATTR_NO_KERNEL_MAPPING can be supported with an additional
> opaque type (e.g. CoherentHandle) which does not provide access to the
> allocated memory.
>
> Cc: stable@vger.kernel.org
> Fixes: ad2907b4e308 ("rust: add dma coherent allocator abstraction")
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
next prev parent reply other threads:[~2026-03-22 14:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-21 17:27 [PATCH 1/2] rust: dma: remove DMA_ATTR_NO_KERNEL_MAPPING from public attrs Danilo Krummrich
2026-03-21 17:27 ` [PATCH 2/2] rust: dma: add CoherentHandle for DMA allocations without kernel mapping Danilo Krummrich
2026-03-22 14:52 ` Alexandre Courbot
2026-03-22 15:21 ` Danilo Krummrich
2026-03-24 20:10 ` Gary Guo
2026-03-24 22:20 ` Danilo Krummrich
2026-03-25 13:09 ` Gary Guo
2026-03-25 17:18 ` Danilo Krummrich
2026-03-26 13:37 ` Gary Guo
2026-03-21 18:42 ` [PATCH 1/2] rust: dma: remove DMA_ATTR_NO_KERNEL_MAPPING from public attrs Gary Guo
2026-03-22 11:07 ` Alice Ryhl
2026-03-22 14:52 ` Alexandre Courbot [this message]
2026-03-28 14:51 ` Alexandre Courbot
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