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Fri, 03 Apr 2026 14:29:08 -0700 (PDT) Received: from ar-pc.lan ([2603:8000:bb00:9b3f:5094:4d4:5bc0:f9f9]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-12bede7f542sm5462263c88.14.2026.04.03.14.29.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Apr 2026 14:29:08 -0700 (PDT) From: Aditya Rajan To: dakr@kernel.org, ojeda@kernel.org Cc: abdiel.janulgue@gmail.com, daniel.almeida@collabora.com, robin.murphy@arm.com, a.hindborg@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, Aditya Rajan Subject: [PATCH] rust: dma: return EOVERFLOW instead of ENOMEM on size overflow Date: Fri, 3 Apr 2026 14:28:22 -0700 Message-ID: <20260403212822.294288-1-adi.dev.github@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: driver-core@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In alloc_slice_with_attrs(), the checked_mul() guards against arithmetic overflow when computing the total byte size (size_of::() * len). If this overflows, the current code returns ENOMEM, which is misleading -- the system is not out of memory, the requested size simply cannot be represented in a usize. Return EOVERFLOW instead, which accurately describes the failure. This also distinguishes it from the actual allocation failure two lines below, which correctly returns ENOMEM when dma_alloc_attrs() yields a null pointer. Fixes: d9aee73c56ee ("rust: dma: add generalized container for types other than slices") Link: https://lore.kernel.org/all/20260320194626.36263-3-dakr@kernel.org/ Signed-off-by: Aditya Rajan --- rust/kernel/dma.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs index 4995ee5dc689..179bc8832947 100644 --- a/rust/kernel/dma.rs +++ b/rust/kernel/dma.rs @@ -832,7 +832,7 @@ fn alloc_slice_with_attrs( Err(EINVAL)?; } - let size = core::mem::size_of::().checked_mul(len).ok_or(ENOMEM)?; + let size = core::mem::size_of::().checked_mul(len).ok_or(EOVERFLOW)?; let mut dma_handle = 0; // SAFETY: Device pointer is guaranteed as valid by the type invariant on `Device`. let addr = unsafe { -- 2.53.0