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AJvYcCWo9ct89nl43XpPFfoISr83ZE7rlyTT/LkIg6QcMj8vaAzLidI18kpWXkNI1V/+JdjrRASu7mo9@lists.freedesktop.org X-Gm-Message-State: AOJu0YzJVzgd67TXJPkE4N/5Ao8dcqj+tIZ+JlNuTBmXgFTM/4XrInoZ rPTk8L56L+VPUdvfqI5wsK7lvp1KFx0DFJD9zp2lr440DkGaFwlNs+cK+0kOa6K1D/znQWqc6gI XXSHqA6P3VWT0vYukbA== X-Received: from edrd8.prod.google.com ([2002:aa7:d688:0:b0:660:cd0d:914e]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:27ce:b0:663:8841:17c9 with SMTP id 4fb4d7f45d1cf-663babc44ecmr8734757a12.10.1773730340157; Mon, 16 Mar 2026 23:52:20 -0700 (PDT) Date: Tue, 17 Mar 2026 06:52:19 +0000 In-Reply-To: <20260303162314.94363-5-dakr@kernel.org> Mime-Version: 1.0 References: <20260303162314.94363-1-dakr@kernel.org> <20260303162314.94363-5-dakr@kernel.org> Message-ID: Subject: Re: [PATCH 4/8] rust: dma: introduce dma::CoherentInit for memory initialization From: Alice Ryhl To: Danilo Krummrich Content-Type: text/plain; charset="utf-8" Message-ID-Hash: CPH5Q33WLSVG77WMF2ZSCIFP2E3WE5RG X-Message-ID-Hash: CPH5Q33WLSVG77WMF2ZSCIFP2E3WE5RG X-MailFrom: 3JPq4aQkKB1Et41vxAH04z77z4x.v7567DExtD41BCB.yAxxwxB3C78.7Az@flex--aliceryhl.bounces.google.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: acourbot@nvidia.com, ojeda@kernel.org, boqun@kernel.org, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, tmgross@umich.edu, abdiel.janulgue@gmail.com, daniel.almeida@collabora.com, robin.murphy@arm.com, driver-core@lists.linux.dev, nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org X-Mailman-Version: 3.3.8 Precedence: list List-Id: Nouveau development list Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Tue, Mar 03, 2026 at 05:22:55PM +0100, Danilo Krummrich wrote: > Currently, dma::Coherent cannot safely provide (mutable) access to its > underlying memory because the memory might be concurrently accessed by a > DMA device. This makes it difficult to safely initialize the memory > before handing it over to the hardware. > > Introduce dma::CoherentInit, a type that encapsulates a dma::Coherent > before its DMA address is exposed to the device. dma::CoherentInit can > guarantee exclusive access to the inner dma::Coherent and implement > Deref and DerefMut. > > Once the memory is properly initialized, dma::CoherentInit can be > converted into a regular dma::Coherent. > > Signed-off-by: Danilo Krummrich overall LGTM Reviewed-by: Alice Ryhl > + let ptr = core::ptr::from_mut(&mut self[i]); &raw mut self[i]. Alice