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 6ACA43AB262; Mon, 27 Apr 2026 22:13:49 +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=1777328029; cv=none; b=K7d6IxoE7DrnrwGqc3vVz1T4wCRMxUC33dnm0dVwCwxoZdHqFEpjsdJ0YM96EG2b9b9bcP0/NFA7UpWboycJ5vfJLntUNdiJsqfWOw4ad0jCFJFX+P/iMjtzXH9usXNy5Ll9U6is/2gN5mgLK/Y7KGYRd91Qygzte7qR21FIU9w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777328029; c=relaxed/simple; bh=LqoJmyLMcfvlHKDJq6T+tkDE6stHA+a+dnj6GefZ9os=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JeJvrDbN6o3nxFjS0YwoYqR3LHJKn+NczTQ8ZBnIS9SdK8a7Wuc/sZYhqyKFPN0hpL6RKVwnJ8BPGjUGD0eZPl/gr+6MZmuz1q1MYy4UNTfMNBhYHNYHYTzgHeE4V0qAoJBGQ4Bce9C1wbBa3b/wAkraWhDX/cyEjw+pHx2yRic= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aFiYEfVB; 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="aFiYEfVB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 410D6C2BCB6; Mon, 27 Apr 2026 22:13:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777328029; bh=LqoJmyLMcfvlHKDJq6T+tkDE6stHA+a+dnj6GefZ9os=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aFiYEfVByRv2PjDa9rjYPjgR9q/fQlaBcDWAP+n9ARzSi35I3fnQBQL4jXkKGDFqb Z+VfYo+FSkRbNwQd6HzuNL2R+VKCaOPP2Vt7a5oRB1f1lN8QHUS7mkwa2kqHPVBPHD l03xRWXLrvCwYveEXJEMCVnnLbogwLsr1wkfNlkwlAmoq9F+HdY8YjBxU3qt84QonQ vdiQnv2fsuVsGsUCmq1lVdBEMwCQFAmiGn60q3rtrxY6WPr2VXXMG+6L4Xh1xwYO4V WJEmvDbKfwovia/wetB+zMtncjlIo7goJfWZX5JKqF73OCnqP5s8BCruWMyK6RvsV7 duihnqd6v+KKw== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, acourbot@nvidia.com, aliceryhl@google.com, david.m.ertman@intel.com, ira.weiny@intel.com, leon@kernel.org, viresh.kumar@linaro.org, m.wilczynski@samsung.com, ukleinek@kernel.org, bhelgaas@google.com, kwilczynski@kernel.org, abdiel.janulgue@gmail.com, robin.murphy@arm.com, markus.probst@posteo.de, ojeda@kernel.org, boqun@kernel.org, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, tmgross@umich.edu Cc: driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, nova-gpu@lists.linux.dev, dri-devel@lists.freedesktop.org, linux-pm@vger.kernel.org, linux-pwm@vger.kernel.org, linux-pci@vger.kernel.org, rust-for-linux@vger.kernel.org, Danilo Krummrich Subject: [PATCH 16/24] rust: usb: make Driver trait lifetime-parameterized Date: Tue, 28 Apr 2026 00:11:14 +0200 Message-ID: <20260427221155.2144848-17-dakr@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260427221155.2144848-1-dakr@kernel.org> References: <20260427221155.2144848-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Make usb::Driver take a lifetime parameter 'a that ties device resources to the binding scope. Internally, Adapter becomes Adapter with a bound for<'a> F::Of<'a>: Driver<'a>; module_usb_driver! wraps the driver type in ForLt!() so drivers don't have to. Signed-off-by: Danilo Krummrich --- rust/kernel/usb.rs | 84 ++++++++++++++++++++------------- samples/rust/rust_driver_usb.rs | 14 +++--- 2 files changed, 58 insertions(+), 40 deletions(-) diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs index 442e456fd2d3..f519444cf8d0 100644 --- a/rust/kernel/usb.rs +++ b/rust/kernel/usb.rs @@ -35,22 +35,34 @@ }; /// An adapter for the registration of USB drivers. -pub struct Adapter(T); +/// +/// `F` is a [`ForLt`](trait@ForLt) type that maps lifetimes to the driver's device +/// private data type, i.e. `F::Of<'a>` is the driver struct parameterized by `'a`. The macro +/// `module_usb_driver!` generates this automatically via `ForLt!()`. +pub struct Adapter(PhantomData); // SAFETY: // - `bindings::usb_driver` is a C type declared as `repr(C)`. -// - `T` is the type of the driver's device private data. +// - `F::Of<'static>` is the stored type of the driver's device private data. // - `struct usb_driver` embeds a `struct device_driver`. // - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`. -unsafe impl driver::DriverLayout for Adapter { +unsafe impl driver::DriverLayout for Adapter +where + F: ForLt + 'static, + for<'a> F::Of<'a>: Driver<'a>, +{ type DriverType = bindings::usb_driver; - type DriverData = ForLt!(T); + type DriverData = F; const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver); } // SAFETY: A call to `unregister` for a given instance of `DriverType` is guaranteed to be valid if // a preceding call to `register` has been successful. -unsafe impl driver::RegistrationOps for Adapter { +unsafe impl driver::RegistrationOps for Adapter +where + F: ForLt + 'static, + for<'a> F::Of<'a>: Driver<'a>, +{ unsafe fn register( udrv: &Opaque, name: &'static CStr, @@ -61,7 +73,7 @@ unsafe fn register( (*udrv.get()).name = name.as_char_ptr(); (*udrv.get()).probe = Some(Self::probe_callback); (*udrv.get()).disconnect = Some(Self::disconnect_callback); - (*udrv.get()).id_table = T::ID_TABLE.as_ptr(); + (*udrv.get()).id_table = as Driver<'static>>::ID_TABLE.as_ptr(); } // SAFETY: `udrv` is guaranteed to be a valid `DriverType`. @@ -76,7 +88,11 @@ unsafe fn unregister(udrv: &Opaque) { } } -impl Adapter { +impl Adapter +where + F: ForLt + 'static, + for<'a> F::Of<'a>: Driver<'a>, +{ extern "C" fn probe_callback( intf: *mut bindings::usb_interface, id: *const bindings::usb_device_id, @@ -87,16 +103,16 @@ extern "C" fn probe_callback( // INVARIANT: `intf` is valid for the duration of `probe_callback()`. let intf = unsafe { &*intf.cast::>() }; - from_result(|| { - // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct usb_device_id` and - // does not add additional invariants, so it's safe to transmute. - let id = unsafe { &*id.cast::() }; + // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct usb_device_id` and + // does not add additional invariants, so it's safe to transmute. + let id = unsafe { &*id.cast::() }; - let info = T::ID_TABLE.info(id.index()); - let data = T::probe(intf, id, info); + from_result(|| { + let info = as Driver<'_>>::ID_TABLE.info(id.index()); + let data = as Driver<'_>>::probe(intf, id, info); let dev: &device::Device = intf.as_ref(); - dev.set_drvdata::(data)?; + dev.set_drvdata::(data)?; Ok(0) }) } @@ -111,11 +127,10 @@ extern "C" fn disconnect_callback(intf: *mut bindings::usb_interface) { let dev: &device::Device = intf.as_ref(); // SAFETY: `disconnect_callback` is only ever called after a successful call to - // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called - // and stored a `Pin>`. - let data = unsafe { dev.drvdata_borrow::() }; + // `probe_callback`, hence it's guaranteed that drvdata has been set. + let data = unsafe { dev.drvdata_borrow::() }; - T::disconnect(intf, data); + as Driver<'_>>::disconnect(intf, data); } } @@ -281,29 +296,29 @@ macro_rules! usb_device_table { /// kernel::usb_device_table!( /// USB_TABLE, /// MODULE_USB_TABLE, -/// ::IdInfo, +/// >::IdInfo, /// [ /// (usb::DeviceId::from_id(0x1234, 0x5678), ()), /// (usb::DeviceId::from_id(0xabcd, 0xef01), ()), /// ] /// ); /// -/// impl usb::Driver for MyDriver { +/// impl<'a> usb::Driver<'a> for MyDriver { /// type IdInfo = (); /// const ID_TABLE: usb::IdTable = &USB_TABLE; /// /// fn probe( -/// _interface: &usb::Interface, -/// _id: &usb::DeviceId, -/// _info: &Self::IdInfo, -/// ) -> impl PinInit { +/// _interface: &'a usb::Interface, +/// _id: &'a usb::DeviceId, +/// _info: &'a Self::IdInfo, +/// ) -> impl PinInit + 'a { /// Err(ENODEV) /// } /// -/// fn disconnect(_interface: &usb::Interface, _data: Pin<&Self>) {} +/// fn disconnect(_interface: &'a usb::Interface, _data: Pin<&'a Self>) {} /// } ///``` -pub trait Driver { +pub trait Driver<'a> { /// The type holding information about each one of the device ids supported by the driver. type IdInfo: 'static; @@ -315,15 +330,15 @@ pub trait Driver { /// Called when a new USB interface is bound to this driver. /// Implementers should attempt to initialize the interface here. fn probe( - interface: &Interface, - id: &DeviceId, - id_info: &Self::IdInfo, - ) -> impl PinInit; + interface: &'a Interface, + id: &'a DeviceId, + id_info: &'a Self::IdInfo, + ) -> impl PinInit + 'a; /// USB driver disconnect. /// /// Called when the USB interface is about to be unbound from this driver. - fn disconnect(interface: &Interface, data: Pin<&Self>); + fn disconnect(interface: &'a Interface, data: Pin<&'a Self>); } /// A USB interface. @@ -486,7 +501,10 @@ unsafe impl Sync for Device {} /// ``` #[macro_export] macro_rules! module_usb_driver { - ($($f:tt)*) => { - $crate::module_driver!(, $crate::usb::Adapter, { $($f)* }); + (type: $type:ty, $($rest:tt)*) => { + $crate::module_driver!(, $crate::usb::Adapter, { + type: $crate::types::ForLt!($type), + $($rest)* + }); } } diff --git a/samples/rust/rust_driver_usb.rs b/samples/rust/rust_driver_usb.rs index ab72e99e1274..6f3e5db9f35d 100644 --- a/samples/rust/rust_driver_usb.rs +++ b/samples/rust/rust_driver_usb.rs @@ -20,26 +20,26 @@ struct SampleDriver { kernel::usb_device_table!( USB_TABLE, MODULE_USB_TABLE, - ::IdInfo, + >::IdInfo, [(usb::DeviceId::from_id(0x1234, 0x5678), ()),] ); -impl usb::Driver for SampleDriver { +impl<'a> usb::Driver<'a> for SampleDriver { type IdInfo = (); const ID_TABLE: usb::IdTable = &USB_TABLE; fn probe( - intf: &usb::Interface, - _id: &usb::DeviceId, - _info: &Self::IdInfo, - ) -> impl PinInit { + intf: &'a usb::Interface, + _id: &'a usb::DeviceId, + _info: &'a Self::IdInfo, + ) -> impl PinInit + 'a { let dev: &device::Device = intf.as_ref(); dev_info!(dev, "Rust USB driver sample probed\n"); Ok(Self { _intf: intf.into() }) } - fn disconnect(intf: &usb::Interface, _data: Pin<&Self>) { + fn disconnect(intf: &'a usb::Interface, _data: Pin<&'a Self>) { let dev: &device::Device = intf.as_ref(); dev_info!(dev, "Rust USB driver sample disconnected\n"); } -- 2.54.0