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 D24CA1E52C; Wed, 2 Oct 2024 13:58:36 +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=1727877516; cv=none; b=XxXuS6lmZocpgoM/9uQl/Yoluc5uX4h6JOWfdIBtlj7bM3dehYKySxV1PhrJAgFuhdbdnsY+DgXsmZH430Lo/7l++wdAIxtL8hG3z3Hr4z1La6BRV6gnezRlEjaDzJ7913o0bSo/cBb2XMAF0FXyAgXqpa13ygmdZlOjLmpJfWM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727877516; c=relaxed/simple; bh=/UXfQLbEpKjaSF6OXS1imF5v7Ha5rnonCoD0u2Kgl6Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eQ9HrDTl8DP4uJVcPoCGfjSdVaFZvgA3TGpsM6b+P9jGIuRSl7LNzrZXNuI/3cJs3mTvaqfBZyqKPxu2U6SzCb1qG84mjh4E3/FRV/04ebQ5SzJFeY2Sbjg0+4TJl9Nd4bNaDRHrvkGwlk9234yKKUQXc4bX+wLi5YHJE2OBXOw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=psncEfsd; 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="psncEfsd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58D4EC4CEC2; Wed, 2 Oct 2024 13:58:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727877516; bh=/UXfQLbEpKjaSF6OXS1imF5v7Ha5rnonCoD0u2Kgl6Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=psncEfsdP2bKWXOPokOvAFp48D4oK+45oNqooMAw3+cdUNscGoNuR+Dpka1ZIECPK mdcUUAMkKEyHCBdDrMfh+Gy3Bluk8qIk7Jf8SQV6wVBORRg/FOq4FOk4nSieOH81Th ZtrNnvOYgyzGN02TD/zR4tnH76QXTxbR+YslKQBzfyT+Zf8PZWJUtDFyyUFKJ+3RPV XXGYkZ1sMOgP6boBj4Iq21QkK92qU2CXcgT896UOWCnKbL1LlsCmITjQH3Duv67vBT mWYh+59vmhahjFVSNCs2U2boOuYlSA4nVyvQOaAdGLYatWYDt1fSjv7zjvAVGGT3Zu JpGWkzpbNs6pw== Date: Wed, 2 Oct 2024 15:58:29 +0200 From: Danilo Krummrich To: Guilherme Giacomo Simoes Cc: gregkh@linuxfoundation.org, rafael@kernel.org, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, aliceryhl@google.com, mcgrof@kernel.org, russ.weight@linux.dev, dakr@redhat.com, a.hindborg@kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] rust: device: change the from_raw() function Message-ID: References: <20241001205603.106278-1-trintaeoitogc@gmail.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241001205603.106278-1-trintaeoitogc@gmail.com> On Tue, Oct 01, 2024 at 05:56:03PM -0300, Guilherme Giacomo Simoes wrote: > The function Device::from_raw() increments a refcount by a call to > bindings::get_device(ptr). This can be confused because usually > from_raw() functions don't increment a refcount. > Hence, rename Device::from_raw() to avoid confuion with other "from_raw" > semantics. > > The new name of function should be "get_device" to be consistent with > the function get_device() already exist in .c files. > > This function body also changed, because the `into()` will convert the > `&'a Device` into `ARef` and also call `inc_ref` from the > `AlwaysRefCounted` trait implemented for Device. > > Signed-off-by: Guilherme Giacomo Simoes Acked-by: Danilo Krummrich > --- > differences from v1 to v2: > - remove the 0/1 patch > - refactor get_device() function > > differences from v2: > - fix the place of changelog. > > The motivation from this change was will discussion in: > https://rust-for-linux.zulipchat.com/#narrow/stream/291566-Library/topic/Inconsistency.20of.20.60from_raw.60.2E > > I would like to thanks for Greg , Danilo > and Alice for help me with this > patch. > --- > rust/kernel/device.rs | 15 +++------------ > rust/kernel/firmware.rs | 2 +- > 2 files changed, 4 insertions(+), 13 deletions(-) > > diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs > index 851018eef885..c8199ee079ef 100644 > --- a/rust/kernel/device.rs > +++ b/rust/kernel/device.rs > @@ -51,18 +51,9 @@ impl Device { > /// > /// It must also be ensured that `bindings::device::release` can be called from any thread. > /// While not officially documented, this should be the case for any `struct device`. > - pub unsafe fn from_raw(ptr: *mut bindings::device) -> ARef { > - // SAFETY: By the safety requirements, ptr is valid. > - // Initially increase the reference count by one to compensate for the final decrement once > - // this newly created `ARef` instance is dropped. > - unsafe { bindings::get_device(ptr) }; > - > - // CAST: `Self` is a `repr(transparent)` wrapper around `bindings::device`. > - let ptr = ptr.cast::(); > - > - // SAFETY: `ptr` is valid by the safety requirements of this function. By the above call to > - // `bindings::get_device` we also own a reference to the underlying `struct device`. > - unsafe { ARef::from_raw(ptr::NonNull::new_unchecked(ptr)) } > + pub unsafe fn get_device(ptr: *mut bindings::device) -> ARef { > + // SAFETY: By the safety requirements ptr is valid > + unsafe { Self::as_ref(ptr) }.into() > } > > /// Obtain the raw `struct device *`. > diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs > index dee5b4b18aec..13a374a5cdb7 100644 > --- a/rust/kernel/firmware.rs > +++ b/rust/kernel/firmware.rs > @@ -44,7 +44,7 @@ fn request_nowarn() -> Self { > /// > /// # fn no_run() -> Result<(), Error> { > /// # // SAFETY: *NOT* safe, just for the example to get an `ARef` instance > -/// # let dev = unsafe { Device::from_raw(core::ptr::null_mut()) }; > +/// # let dev = unsafe { Device::get_device(core::ptr::null_mut()) }; > /// > /// let fw = Firmware::request(c_str!("path/to/firmware.bin"), &dev)?; > /// let blob = fw.data(); > -- > 2.46.2 >