From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 27C951CD204; Tue, 3 Dec 2024 09:21:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733217675; cv=none; b=P4AQUV3W4c+/IGl+tgSZWH8qafCqsrzXNA2llwxs6MlZqMIEJB5g+B5p27X+CAnGTLI2x2g/2yCZt07Y07tmAztrYieMZNKC3yXaFrtMrHjx5Y/2nFvfIrvcfBHrpwCTq+w4grTojfJAWZXgmXFyFTDfT8Y/nM1ULDYNEOzZOMk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733217675; c=relaxed/simple; bh=cPYxrvjdP6SGqJbH8TZQtoM+u/6iqcvQ/yJ8kNSftb0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=T7gb8RJbA5KmKDzeNyRr7m1gKKEZKoambeG77th9g3yNwX3mUFEy+CQUXCRY+bmsGGq6BI2LAi0fdfTiXB6VmXxn7uZ24gjeKaohIJtaH968/ofKGzngMB0Ls8YDZLwYg3wLlYvNjgDWCOqq+he/3/ZOGLkTQYTpOUPGoPhmVH4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=I613wnmC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="I613wnmC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9DB9DC4CECF; Tue, 3 Dec 2024 09:21:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733217673; bh=cPYxrvjdP6SGqJbH8TZQtoM+u/6iqcvQ/yJ8kNSftb0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=I613wnmCIOKB15gqKYn613rxiX9OCD+ZyVVZ0fdR2WDw3y6R35QUap4YmrOQl9G4M mwvfoBCKYaj3bg9pw9wXeBlHZyiOqHDdh4EEYkf1/0fabi+WFZemOAbDBDkxT062uG Zb2Jztog5RsBdsYi7054ut+oKquO1QmbE5qnnjv9vYdiK08WqHzptNQFVToLqikPW+ o/YTkv07I/vOagqwWeIvVbj99ZQ27uOuKUbaiPKIazE/xHYUI+khDZ3WwyvWUZCMf5 zMOlxWKsZSfS2lUslV2y0Q15OmM+m5hgl5FNHW1eigyW3w61e/BEpzP7+rBaJIeDZi RIzt/9q5DKWbw== Message-ID: Date: Tue, 3 Dec 2024 10:21:06 +0100 Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 07/16] rust: add `Revocable` type To: Alice Ryhl Cc: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Wedson Almeida Filho References: <20241022213221.2383-1-dakr@kernel.org> <20241022213221.2383-8-dakr@kernel.org> From: Danilo Krummrich Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/29/24 2:26 PM, Alice Ryhl wrote: > On Tue, Oct 22, 2024 at 11:33 PM Danilo Krummrich wrote: >> +/// A guard that allows access to a revocable object and keeps it alive. >> +/// >> +/// CPUs may not sleep while holding on to [`RevocableGuard`] because it's in atomic context >> +/// holding the RCU read-side lock. >> +/// >> +/// # Invariants >> +/// >> +/// The RCU read-side lock is held while the guard is alive. >> +pub struct RevocableGuard<'a, T> { >> + data_ref: *const T, >> + _rcu_guard: rcu::Guard, >> + _p: PhantomData<&'a ()>, >> +} > > Is this needed? Can't all users just use `try_access_with_guard`? Without this guard, how to we access `T` with just the `rcu::Guard`? > > Alice >