From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout02.posteo.de (mout02.posteo.de [185.67.36.66]) (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 90E675AA66D for ; Fri, 16 Oct 2026 18:00:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.67.36.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792173648; cv=none; b=tB1v2HvbHPvZwPlkPiZwt6RX83EHLhmUK8FppcTaoOx6C+Ye2L25SLLEJ9gqcGs53PXsIV/Y0XWDsLS8RwhXOadLAaoZbI79Yqp01VWvY2/zctUNPbOYO2gIkap+Nxn+IspURoSFLvDudpN+tqBbn5LTv6nwkcRUTkg3o6C4j6Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792173648; c=relaxed/simple; bh=WQslHMs2svOlSFQafK7q53v+0G7DlzBK6lZSGEX3Nu4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=rDZEGZ5EdCBUZRBwJQ+EMaPPfQwuE2PwYbXCSbv1hGd7i8ONbijE8X7O3GGNJOlGamAmhc6oUmdZUVO2kFwxDbG6YzRWGrm0hYEM7UmQG6vYxgffZRQiT2y1yOro4eYUAhUpcPBcC7XCjLc3GeEcGBsTPZRMp5fVIwqJbu5zWxM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de; spf=pass smtp.mailfrom=posteo.de; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b=E8mEeGbc; arc=none smtp.client-ip=185.67.36.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=posteo.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b="E8mEeGbc" Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 58D83240101 for ; Fri, 16 Oct 2026 20:00:42 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=1984.8680eb; t=1792173642; bh=v2EF/fsRX2gtP/07bUp+y+QrpNj7xZBjUZMkm63RIN4=; h=From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:To:Cc:Autocrypt:OpenPGP:From; b=E8mEeGbcsM4FZ5vU3t1xfVbT/lxJla1IYt6q102bSZeH9Oa/f9dyXaLIIeROwgziu dXFZELKXjpINwuWRgsW+rUC2IK6WfdcwUf5zs/gGbEN0Yt+epre3OLfnNu28i9naAE 7pB/3H3too7dgBM9iriaTaog6pjj1+1vq/p/kTpsx8740cZeG7s04VkwfJ5sdPmawS BkrgYpV+h63/CnRsxArJdvSNFThi2kgab7YmLenOG4RC1mNls8QM8apPHeYFY+3rt8 Wy+LhhGCGNEZA7LsR4RUcgpaPgFRSgifTBOwBzNh4n8NU8UXGKF5ABJqslSbGmhyZo e941oZXmfuZtA== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4j5t5f2Dphz9rxF; Fri, 16 Oct 2026 20:00:38 +0200 (CEST) From: Markus Probst Date: Fri, 16 Oct 2026 18:00:41 +0000 Subject: [PATCH v4 4/4] rust: serdev: Simplify callbacks 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="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261016-rust_serdev_probe_refactor-v4-4-46832e034757@posteo.de> References: <20261016-rust_serdev_probe_refactor-v4-0-46832e034757@posteo.de> In-Reply-To: <20261016-rust_serdev_probe_refactor-v4-0-46832e034757@posteo.de> To: Ayush Singh , Johan Hovold , Alex Elder , Greg Kroah-Hartman , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , =?utf-8?q?Onur_=C3=96zkan?= , Eric Biggers , Ard Biesheuvel , Lorenzo Stoakes , Vlastimil Babka , "Liam R. Howlett" , Uladzislau Rezki , Jiri Slaby , "Rafael J. Wysocki" Cc: greybus-dev@lists.linaro.org, linux-serial@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, Markus Probst X-Developer-Signature: v=1; a=openpgp-sha256; l=8348; i=markus.probst@posteo.de; h=from:subject:message-id; bh=WQslHMs2svOlSFQafK7q53v+0G7DlzBK6lZSGEX3Nu4=; b=owEBiQJ2/ZANAwAIATR2H/jnrUPSAcsmYgBq0mY5HjDmlBQrrLlK+gbfKefRRlMg2Q572EcLJ 18iEa5nDwmJAk8EAAEIADkWIQSCdBjE9KxY53IwxHM0dh/4561D0gUCatJmORsUgAAAAAAEAA5t YW51MiwyLjUrMS4xMiwyLDIACgkQNHYf+OetQ9K8yRAAhqrPRMO6LvhLA1iqtztQ8QbCIxWs7Pn fcvnAFhQOab4F9wAi9CcT+SlmsGPZei3jJqBorgujsuiqZVjgLN0m7kLmI7pdBb7b+2vL1AeBwV p5OZBeZ6ex9Y7fQTsn04iJ6q+qBooGzG/7EhwjJZ9QkbfioSt2kGJUpykqlap7/3+QsdU2I+0Gb u7o1OozX0icofcSLNUazYyAFujABQhk1GR7N/5lMcyBtWOZ/FFes243ltDpt+PFR+c2/TEU+JtQ 6aQWTOttwp4q8bWRbglSKIGmPqmKQStBQSIHAMlwigu+2vuQsJD0/gavT8E5vgAv9K5WktE10R0 jCXtqChxDilFcqoqH74FS4c/vq0KBc12nyAnsxzMND1yhPkxxZuL/Fv3A9FDqkwBZI+nqsUUONO s+NRUdwI+xCvWu2shWnAqDAZNoJ9ZqpiZazQ6QZ/khhtEyLZAhfmCExGlmnyL2dTZnw5+hfeIFX OrVxqEwOJTFkV1Zs6BeM80prVvFB8Y+l0QZ+FX0pW1+GhLFQfnHBGMcputAaXhCKApV7wWRmL+8 A34SuwXOUignQDv+wGx7qxozvwIyy1jUCoZLEkMJL5fxBAL7eGbz61K9V5ul97+POQeaSE/eGmB x3VvQh6lT12Cm9Vh0+y6zVOK80UhcdlbeYS9p57xd7vKpHC7imNw= X-Developer-Key: i=markus.probst@posteo.de; a=openpgp; fpr=827418C4F4AC58E77230C47334761FF8E7AD43D2 Autocrypt: addr=markus.probst@posteo.de; prefer-encrypt=mutual; keydata=xsFNBGiDvXgBEADAXUceKafpl46S35UmDh2wRvvx+UfZbcTjeQOlSwKP7YVJ4JOZrVs93qReNLkO WguIqPBxR9blQ4nyYrqSCV+MMw/3ifyXIm6Pw2YRUDg+WTEOjTixRCoWDgUj1nOsvJ9tVAm76Ww+ /pAnepVRafMID0rqEfD9oGv1YrfpeFJhyE2zUw3SyyNLIKWD6QeLRhKQRbSnsXhGLFBXCqt9k5JA RhgQof9zvztcCVlT5KVvuyfC4H+HzeGmu9201BVyihJwKdcKPq+n/aY5FUVxNTgtI9f8wIbmfAja oT1pjXSp+dszakA98fhONM98pOq723o/1ZGMZukyXFfsDGtA3BB79HoopHKujLGWAGskzClwTjRQ xBqxh/U/lL1pc+0xPWikTNCmtziCOvv0KA0arDOMQlyFvImzX6oGVgE4ksKQYbMZ3Ikw6L1Rv1J+ FvN0aNwOKgL2ztBRYscUGcQvA0Zo1fGCAn/BLEJvQYShWKeKqjyncVGoXFsz2AcuFKe1pwETSsN6 OZncjy32e4ktgs07cWBfx0v62b8md36jau+B6RVnnodaA8++oXl3FRwiEW8XfXWIjy4umIv93tb8 8ekYsfOfWkTSewZYXGoqe4RtK80ulMHb/dh2FZQIFyRdN4HOmB4FYO5sEYFr9YjHLmDkrUgNodJC XCeMe4BO4iaxUQARAQABzRdtYXJrdXMucHJvYnN0QHBvc3Rlby5kZcLBkQQTAQgAOxYhBIJ0GMT0 rFjncjDEczR2H/jnrUPSBQJog714AhsDBQsJCAcCAiICBhUKCQgLAgQWAgMBAh4HAheAAAoJEDR2 H/jnrUPSgdkQAISaTk2D345ehXEkn5z2yUEjaVjHIE7ziqRaOgn/QanCgeTUinIv6L6QXUFvvIfH 1OLPwQ1hfvEg9NnNLyFezWSy6jvoVBTIPqicD/r3FkithnQ1IDkdSjrarPMxJkvuh3l7XZHo49GV HQ8i5zh5w4YISrcEtE99lJisvni2Jqx7we5tey9voQFDyM8jxlSWv3pmoUTCtBkX/eKHJXosgsuS B4TGDCVPOjla/emI5c9MhMG7O4WEEmoSdPbmraPw66YZD6uLyhV4DPHbiDWRzXWnClHSyjB9rky9 lausFxogvu4l9H+KDsXIadNDWdLdu1/enS/wDd9zh5S78rY2jeXaG4mnf4seEKamZ7KQ6FIHrcyP ezdDzssPQcTQcGRMQzCn6wP3tlGk7rsfmyHMlFqdRoNNv+ZER/OkmZFPW655zRfbMi0vtrqK2Awm 9ggobb1oktfd9PPNXMUY+DNVlgR2G7jLnenSoQausLUm0pHoNE8TWFv851Y6SOYnvn488sP1Tki5 F3rKwclawQFHUXTCQw+QSh9ay8xgnNZfH+u9NY7w3gPoeKBOAFcBc2BtzcgekeWS8qgEmm2/oNFV G0ivPQbRx8FjRKbuF7g3YhgNZZ0ac8FneuUtJ2PkSIFTZhaAiC0utvxk0ndmWFiW4acEkMZGrLaM L2zWNjrqwsD2zsFNBGiDvXgBEADCXQy1n7wjRxG12DOVADawjghKcG+5LtEf31WftHKLFbp/HArj BhkT6mj+CCI1ClqY+FYU5CK/s0ScMfLxRGLZ0Ktzawb78vOgBVFT3yB1yWBTewsAXdqNqRooaUNo 8cG/NNJLjhccH/7PO/FWX5qftOVUJ/AIsAhKQJ18Tc8Ik73v427EDxuKb9mTAnYQFA3Ev3hAiVbO 6Rv39amVOfJ8sqwiSUGidj2Fctg2aB5JbeMln0KCUbTD1LhEFepeKypfofAXQbGwaCjAhmkWy/q3 IT1mUrPxOngbxdRoOx1tGUC0HCMUW1sFaJgQPMmDcR0JGPOpgsKnitsSnN7ShcCr1buel7vLnUMD +TAZ5opdoF6HjAvAnBQaijtK6minkrM0seNXnCg0KkV8xhMNa6zCs1rq4GgjNLJue2EmuyHooHA4 7JMoLVHcxVeuNTp6K2+XRx0Pk4e2Lj8IVy9yEYyrywEOC5XRW37KJjsiOAsumi1rkvM7QREWgUDe Xs0+RpxI3QrrANh71fLMRo7LKRF3Gvw13NVCCC9ea20P4PwhgWKStkwO2NO+YJsAoS1QycMi/vKu 0EHhknYXamaSV50oZzHKmX56vEeJHTcngrM8R1SwJCYopCx9gkz90bTVYlitJa5hloWTYeMD7FNj Y6jfVSzgM/K4gMgUNDW/PPGeMwARAQABwsF2BBgBCAAgFiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IF AmiDvXgCGwwACgkQNHYf+OetQ9LHDBAAhk+ab8+WrbS/b1/gYW3q1KDiXU719nCtfkUVXKidW5Ec Idlr5HGt8ilLoxSWT2Zi368iHCXS0WenGgPwlv8ifvB7TOZiiTDZROZkXjEBmU4nYjJ7GymawpWv oQwjMsPuq6ysbzWtOZ7eILx7cI0FjQeJ/Q2baRJub0uAZNwBOxCkAS6lpk5Fntd2u8CWmDQo4SYp xeuQ+pwkp0yEP30RhN2BO2DXiBEGSZSYh+ioGbCHQPIV3iVj0h6lcCPOqopZqyeCfigeacBI0nvN jHWz/spzF3+4OS+3RJvoHtAQmProxyGib8iVsTxgZO3UUi4TSODeEt0i0kHSPY4sCciOyXfAyYoD DFqhRjOEwBBxhr+scU4C1T2AflozvDwq3VSONjrKJUkhd8+WsdXxMdPFgBQuiKKwUy11mz6KQfcR wmDehF3UaUoxa+YIhWPbKmycxuX/D8SvnqavzAeAL1OcRbEI/HsoroVlEFbBRNBZLJUlnTPs8ZcU 4+8rq5YX1GUrJL3jf6SAfSgO7UdkEET3PdcKFYtS+ruV1Cp5V0q4kCfI5jk25iiz8grM2wOzVSsc l1mEkhiEPH87HP0whhb544iioSnumd3HJKL7dzhRegsMizatupp8D65A2JziW0WKopa1iw9fti3A aBeNN4ijKZchBXHPgVx+YtWRHfcm4l8= OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt Initialize the driver's private data directly on `PrivateData`. Introduce `OpenGuard` for resource cleanup. Signed-off-by: Markus Probst --- rust/kernel/serdev.rs | 131 ++++++++++++++++++++------------------------------ 1 file changed, 52 insertions(+), 79 deletions(-) diff --git a/rust/kernel/serdev.rs b/rust/kernel/serdev.rs index c16d6593a8d2..3f9165e16776 100644 --- a/rust/kernel/serdev.rs +++ b/rust/kernel/serdev.rs @@ -17,16 +17,12 @@ prelude::*, sync::aref::AlwaysRefCounted, time::Jiffies, - types::{ - Opaque, - ScopeGuard, // - }, // + types::Opaque, // }; use core::{ - cell::UnsafeCell, marker::PhantomData, - mem::{offset_of, MaybeUninit}, + mem::offset_of, ptr::NonNull, // }; @@ -92,24 +88,36 @@ unsafe fn unregister(sdrv: &Opaque) { } } +struct OpenGuard<'bound> { + sdev: &'bound Device, +} + +impl Drop for OpenGuard<'_> { + fn drop(&mut self) { + // SAFETY: + // - `self.sdev.as_raw()` is guaranteed to be a pointer to a valid + // `struct serdev_device`. + // - The existence of self proves that the device is open. + unsafe { bindings::serdev_device_close(self.sdev.as_raw()) }; + } +} + #[doc(hidden)] -#[pin_data(PinnedDrop)] +#[pin_data] pub struct PrivateData<'bound, T: Driver> { - sdev: &'bound Device, #[pin] - driver: UnsafeCell>>, - open: UnsafeCell, + driver: T::Data<'bound>, + open: OpenGuard<'bound>, } -#[pinned_drop] -impl PinnedDrop for PrivateData<'_, T> { - fn drop(self: Pin<&mut Self>) { - // SAFETY: We have exclusive access to `self.open`. - if unsafe { *self.open.get() } { - // SAFETY: `self.sdev.as_raw()` is guaranteed to be a pointer to a valid - // `struct serdev_device`. - unsafe { bindings::serdev_device_close(self.sdev.as_raw()) }; - } +impl<'bound, T: Driver> PrivateData<'bound, T> { + #[inline] + fn driver_data(self: Pin<&Self>) -> Pin<&T::Data<'bound>> { + // SAFETY: We treat the result as pinned. + let inner = unsafe { Pin::into_inner_unchecked(self) }; + + // SAFETY: `self.driver` is pinned. + unsafe { Pin::new_unchecked(&inner.driver) } } } @@ -134,46 +142,30 @@ extern "C" fn probe_callback(sdev: *mut bindings::serdev_device) -> kernel::ffi: from_result(|| { sdev.as_ref().set_drvdata(try_pin_init!(PrivateData:: { - sdev: &**sdev, - driver: MaybeUninit::>::zeroed().into(), - open: false.into(), + open: { + // SAFETY: + // - `sdev.as_raw()` is guaranteed to be a valid pointer to + // `serdev_device`. + // - It is safe to call before open. + unsafe { bindings::serdev_device_set_client_ops(sdev.as_raw(), Self::OPS) }; + + // SAFETY: `sdev.as_raw()` is guaranteed to be a valid pointer to + // `serdev_device`. + unsafe { bindings::serdev_device_pause_rx(sdev.as_raw()) }; + + // SAFETY: `sdev.as_raw()` is guaranteed to be a valid pointer to + // `serdev_device`. + to_result(unsafe { bindings::serdev_device_open(sdev.as_raw()) })?; + + OpenGuard { sdev } + }, + driver <- T::probe(sdev, info), }))?; - // SAFETY: We just set drvdata to `PrivateData<'_, T>`. - let private_data = unsafe { sdev.as_ref().drvdata_borrow::>() }; - let private_data = ScopeGuard::new_with_data(private_data, |_| { - // SAFETY: We just set drvdata to `PrivateData<'_, T>`. - drop(unsafe { sdev.as_ref().drvdata_obtain::>() }); - }); - // SAFETY: `sdev.as_raw()` is guaranteed to be a valid pointer to `serdev_device`. - unsafe { bindings::serdev_device_set_client_ops(sdev.as_raw(), Self::OPS) }; // SAFETY: `sdev.as_raw()` is guaranteed to be a valid pointer to `serdev_device`. - unsafe { bindings::serdev_device_pause_rx(sdev.as_raw()) }; - - // SAFETY: The serial device bus only ever calls the probe callback with a valid pointer - // to a `serdev_device`. - to_result(unsafe { bindings::serdev_device_open(sdev.as_raw()) })?; - - // SAFETY: We have exclusive access to `private_data.open`. - unsafe { *private_data.open.get() = true }; - - let data = T::probe(sdev, info); + unsafe { bindings::serdev_device_resume_rx(sdev.as_raw()) }; - // SAFETY: We have exclusive access to `private_data.driver`. - let driver = unsafe { &mut *private_data.driver.get() }; - // SAFETY: - // - `driver.as_mut_ptr()` is a valid pointer to uninitialized data. - // - `private_data.driver` is pinned. - let result = unsafe { pin_init::raw_try_init(driver.as_mut_ptr(), data) }; - - result.map(|()| { - private_data.dismiss(); - - // SAFETY: `sdev.as_raw()` is guaranteed to be a valid pointer to `serdev_device`. - unsafe { bindings::serdev_device_resume_rx(sdev.as_raw()) }; - - 0 - }) + Ok(0) }) } @@ -189,21 +181,10 @@ extern "C" fn remove_callback(sdev: *mut bindings::serdev_device) { // and stored a `Pin>>`. let private_data = unsafe { sdev.as_ref().drvdata_borrow::>() }; - // SAFETY: No one has exclusive access to `private_data.driver`. - let data = unsafe { &*private_data.driver.get() }; - // SAFETY: - // - `private_data.driver` is pinned. - // - `remove_callback` is only ever called after a successful call to `probe_callback`, - // hence it's guaranteed that `private_data.driver` was initialized. - let data_pinned = unsafe { Pin::new_unchecked(data.assume_init_ref()) }; - - T::unbind(sdev, data_pinned); + T::unbind(sdev, private_data.driver_data()); // SAFETY: `sdev.as_raw()` is guaranteed to be a valid pointer to `serdev_device`. unsafe { bindings::serdev_device_pause_rx(sdev.as_raw()) }; - - // SAFETY: We already established that `data` is guaranteed to be initialized. - unsafe { data.assume_init_drop() }; } extern "C" fn receive_buf_callback( @@ -211,6 +192,9 @@ extern "C" fn receive_buf_callback( buf: *const u8, length: usize, ) -> usize { + // SAFETY: `buf` is guaranteed to be non-null and has the size of `length`. + let buf = unsafe { core::slice::from_raw_parts(buf, length) }; + // SAFETY: The serial device bus only ever calls the receive buf callback with a valid // pointer to a `struct serdev_device`. // @@ -222,18 +206,7 @@ extern "C" fn receive_buf_callback( // and stored a `Pin>>`. let private_data = unsafe { sdev.as_ref().drvdata_borrow::>() }; - // SAFETY: No one has exclusive access to `private_data.driver`. - let data = unsafe { &*private_data.driver.get() }; - // SAFETY: - // - `private_data.driver` is pinned. - // - `receive_buf_callback` is only ever called after a successful call to `probe_callback`, - // hence it's guaranteed that `private_data.driver` was initialized. - let data_pinned = unsafe { Pin::new_unchecked(data.assume_init_ref()) }; - - // SAFETY: `buf` is guaranteed to be non-null and has the size of `length`. - let buf = unsafe { core::slice::from_raw_parts(buf, length) }; - - T::receive(sdev, data_pinned, buf) + T::receive(sdev, private_data.driver_data(), buf) } } -- 2.55.0