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Howlett" , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?Q?Bj=C3=B6rn?= Roy Baron , Benno Lossin , Trevor Gross , Danilo Krummrich , Will Deacon , Peter Zijlstra , Mark Rutland , linux-mm@kvack.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] rust: page: add byte-wise atomic memory copy methods In-Reply-To: References: <20260212-page-volatile-io-v2-1-a36cb97d15c2@kernel.org> Date: Thu, 12 Feb 2026 18:10:13 +0100 Message-ID: <87ikc1ubuy.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Rspamd-Queue-Id: 3221BA0007 X-Rspamd-Server: rspam07 X-Stat-Signature: bu58bs7en3nmxbk7yzt4cdobgz4eifqg X-HE-Tag: 1770916233-509036 X-HE-Meta: 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 52thcTh9 d5SSynSnVUHlU58wmSylGl6GO7SQfVAcSg1h/1SEYUjfhwhkaaEJ8HeeVWDScvtCAYcU7R1+hM50k8eHeda4U+pskBaXTPoBikRF9SSojBfeuD2g4Mnx0kjXjtoOmhLwqDwhGepAZoLzylpSwYB9MIV6flm9YgmRf00oj0v/ByiqHvpS7Rd0CZKKOpQJQ0udYk3H8XNwoIfT4l9J4MgEQs3iO+7jMEexad8VZPrH97Q+bwZPSzd7gpzJOf2zDRVmPPdedwkijZvvCPQlnhmdt2RoC0ci+INOVQJBk+Lua7oBN1BA= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: "Boqun Feng" writes: > On Thu, Feb 12, 2026 at 03:51:24PM +0100, Andreas Hindborg wrote: >> When copying data from buffers that are mapped to user space, it is >> impossible to guarantee absence of concurrent memory operations on those >> buffers. Copying data to/from `Page` from/to these buffers would be >> undefined behavior if no special considerations are made. >> >> Add methods on `Page` to read and write the contents using byte-wise atomic >> operations. >> > > Thank you, but in this patch we still have "the given IO memory" and use > memcpy_{from,to}io() as the implementation, is that intended? No that is a mistake. Please pretend it is regular `memcpy`. I'll send v3 soon. Best regards, Andreas Hindborg