From nobody Thu Jun 11 18:58:26 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 94B8834E741 for ; Thu, 7 May 2026 22:01:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778191287; cv=none; b=Zp6nhRx5/oL5IU3oJq+5fQxN7A2XAvkS/+N6dQjD5Pa1gDOzzIMW/H81NauXoF7/X91H6rinPpbNL8vAwjuuSj+m9g9xFPzi1XYlKTJoLvCLOLLBCQ4t/pSNKHk4v+Iefg6G39EHvlT9zpdQN7+gjmD3+1ajE8B6hS9SLcMe7Wo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778191287; c=relaxed/simple; bh=Sz49UixhBltNQZMWKtaKBcFQmTkaRjWEVbhkaPF3X4w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=DGChqkMmfrkz8A78uDxineiwBlytOttMk+Rh/5LD+3tNOMegKxuslfMR5GarXJ3gH2cWT791o8M1jT0mFRi0LWsULaH+p949kPX320seS3x59td4xOzWN3GcyzXTdwOpoSMkGUjimGz0PxwR8ow1xtaMNJIOZoLfAlhnvLTQW0k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=aua+AmYT; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aua+AmYT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1778191282; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=d1EZhmpzBVXcmphP1HLxd8IWryTlhPr7BVI8B51IqrY=; b=aua+AmYTSy9nfwIH/vzo3mbz5mvJCObT/6uAgVckWr8PnJj8fwhcpKlb8T1+ErpncU/Ji1 CI9pjmznPnf7y2EoYyw4XLb9SYcHP6GBV5d03S79pNI0nsvwHlQk+t9HfVxQT/97+0iRJY t0R+2MBkt7bDIsX0FN8be/yppqW+PWU= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-389-fTZGBgrIMzig8WhYMOy45g-1; Thu, 07 May 2026 18:01:17 -0400 X-MC-Unique: fTZGBgrIMzig8WhYMOy45g-1 X-Mimecast-MFC-AGG-ID: fTZGBgrIMzig8WhYMOy45g_1778191272 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0FAC4195608E; Thu, 7 May 2026 22:01:12 +0000 (UTC) Received: from GoldenWind.lan (unknown [10.22.89.165]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B5E6F3002D30; Thu, 7 May 2026 22:01:09 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org Cc: "Gary Guo" , "Miguel Ojeda" , "Simona Vetter" , "Alice Ryhl" , Nova-gpu@lists.linux.dev, "Shankari Anand" , "David Airlie" , "Benno Lossin" , "Danilo Krummrich" , "Asahi Lina" , "Mukesh Kumar Chaurasiya (IBM)" , "Daniel Almeida" , "Lyude Paul" Subject: [PATCH v6 1/3] rust/drm: Introduce DeviceContext Date: Thu, 7 May 2026 17:59:19 -0400 Message-ID: <20260507220044.3204919-2-lyude@redhat.com> In-Reply-To: <20260507220044.3204919-1-lyude@redhat.com> References: <20260507220044.3204919-1-lyude@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 One of the tricky things about DRM bindings in Rust is the fact that initialization of a DRM device is a multi-step process. It's quite normal for a device driver to start making use of its DRM device for tasks like creating GEM objects before userspace registration happens. This is an issue in rust though, since prior to userspace registration the device is only partly initialized. This means there's a plethora of DRM device operations we can't yet expose without opening up the door to UB if the DRM device in question isn't yet registered. Additionally, this isn't something we can reliably check at runtime. And even if we could, performing an operation which requires the device be registered when the device isn't actually registered is a programmer bug, meaning there's no real way to gracefully handle such a mistake at runtime. And even if that wasn't the case, it would be horrendously annoying and noisy to have to check if a device is registered constantly throughout a driver. In order to solve this, we first take inspiration from `kernel::device::DeviceContext` and introduce `kernel::drm::DeviceContext`. This provides us with a ZST type that we can generalize over to represent contexts where a device is known to have been registered with userspace at some point in time (`Registered`), along with contexts where we can't make such a guarantee (`Uninit`). It's important to note we intentionally do not provide a `DeviceContext` which represents an unregistered device. This is because there's no reasonable way to guarantee that a device with long-living references to itself will not be registered eventually with userspace. Instead, we provide a new-type for this: `UnregisteredDevice` which can provide a guarantee that the `Device` has never been registered with userspace. To ensure this, we modify `Registration` so that creating a new `Registration` requires passing ownership of an `UnregisteredDevice`. Signed-off-by: Lyude Paul Reviewed-by: Daniel Almeida --- V2: * Make sure that `UnregisteredDevice` is not thread-safe (since DRM device initialization is also not thread-safe) * Rename from AnyCtx to Uninit, I think this name actually makes a bit more sense. * Change assume_registered() to assume_ctx() Since it looks like in some situations, we'll want to update the DeviceContext of a object to the latest DeviceContext we know the Device to be in. * Rename Init to Uninit When we eventually add KMS support, we're going to have 3 different DeviceContexts - Uninit, Init, Registered. Additionally, aside from not being registered there are a number of portions of the rest of the Device which also aren't usable before at least the Init context - so the naming of Uninit makes this a little clearer. * s/DeviceContext/DeviceContext/ For consistency with the rest of the kernel * Drop as_ref::>() for now since I don't actually think we need this quite yet V3: * Get rid of drm_dev_ctx!, as we don't actually need to implement Send or Sync ourselves * Remove mention of C function in drm::device::Registration rustdoc * Add more documentation to the DeviceContext trait, go into detail about the various setup phases and such. * Add missing period to comment in `UnregisteredDevice::new()`. V4: * Address some comments from Danilo I missed last round: * Remove leftover rebase detritus from new_foreign_owned() (the seemingly useless cast) * Remove no-op mention in Registered device context V5: * Fix incorrect size on Kmalloc (Deborah) V6: * Rebase drivers/gpu/drm/nova/driver.rs | 8 +- drivers/gpu/drm/tyr/driver.rs | 10 +- rust/kernel/drm/device.rs | 222 +++++++++++++++++++++++++-------- rust/kernel/drm/driver.rs | 35 ++++-- rust/kernel/drm/mod.rs | 4 + 5 files changed, 214 insertions(+), 65 deletions(-) diff --git a/drivers/gpu/drm/nova/driver.rs b/drivers/gpu/drm/nova/driver.rs index b1af0a099551d..99d6841b69cbc 100644 --- a/drivers/gpu/drm/nova/driver.rs +++ b/drivers/gpu/drm/nova/driver.rs @@ -21,7 +21,7 @@ pub(crate) struct NovaDriver { } =20 /// Convienence type alias for the DRM device type for this driver -pub(crate) type NovaDevice =3D drm::Device; +pub(crate) type NovaDevice =3D drm::Device; =20 #[pin_data] pub(crate) struct NovaData { @@ -56,10 +56,10 @@ impl auxiliary::Driver for NovaDriver { fn probe(adev: &auxiliary::Device, _info: &Self::IdInfo) -> impl= PinInit { let data =3D try_pin_init!(NovaData { adev: adev.into() }); =20 - let drm =3D drm::Device::::new(adev.as_ref(), data)?; - drm::Registration::new_foreign_owned(&drm, adev.as_ref(), 0)?; + let drm =3D drm::UnregisteredDevice::::new(adev.as_ref(), da= ta)?; + let drm =3D drm::Registration::new_foreign_owned(drm, adev.as_ref(= ), 0)?; =20 - Ok(Self { drm }) + Ok(Self { drm: drm.into() }) } } =20 diff --git a/drivers/gpu/drm/tyr/driver.rs b/drivers/gpu/drm/tyr/driver.rs index e20a5978eed6d..4f96c8f761895 100644 --- a/drivers/gpu/drm/tyr/driver.rs +++ b/drivers/gpu/drm/tyr/driver.rs @@ -49,7 +49,7 @@ pub(crate) struct TyrDrmDriver; =20 /// Convenience type alias for the DRM device type for this driver. -pub(crate) type TyrDrmDevice =3D drm::Device; +pub(crate) type TyrDrmDevice =3D drm::Device; =20 #[pin_data(PinnedDrop)] pub(crate) struct TyrPlatformDriverData { @@ -152,10 +152,12 @@ fn probe( gpu_info, }); =20 - let ddev: ARef =3D drm::Device::new(pdev.as_ref(), d= ata)?; - drm::driver::Registration::new_foreign_owned(&ddev, pdev.as_ref(),= 0)?; + let tdev =3D drm::UnregisteredDevice::::new(pdev.as_= ref(), data)?; + let tdev =3D drm::driver::Registration::new_foreign_owned(tdev, pd= ev.as_ref(), 0)?; =20 - let driver =3D TyrPlatformDriverData { _device: ddev }; + let driver =3D TyrPlatformDriverData { + _device: tdev.into(), + }; =20 // We need this to be dev_info!() because dev_dbg!() does not work= at // all in Rust for now, and we need to see whether probe succeeded. diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs index adbafe8db54d1..27a52a270be66 100644 --- a/rust/kernel/drm/device.rs +++ b/rust/kernel/drm/device.rs @@ -6,10 +6,12 @@ =20 use crate::{ alloc::allocator::Kmalloc, - bindings, device, + bindings, + device, drm::{ self, - driver::AllocImpl, // + driver::AllocImpl, + private::Sealed, // }, error::from_err_ptr, prelude::*, @@ -17,16 +19,20 @@ ARef, AlwaysRefCounted, // }, - types::Opaque, + types::{ + NotThreadSafe, + Opaque, // + }, workqueue::{ HasDelayedWork, HasWork, Work, WorkItem, // - }, + }, // }; use core::{ alloc::Layout, + marker::PhantomData, mem, ops::Deref, ptr::{ @@ -66,26 +72,98 @@ macro_rules! drm_legacy_fields { } } =20 -/// A typed DRM device with a specific `drm::Driver` implementation. +/// A trait implemented by all possible contexts a [`Device`] can be used = in. +/// +/// Setting up a new [`Device`] is a multi-stage process. Each step of the= process that a user +/// interacts with in Rust has a respective [`DeviceContext`] typestate. F= or example, +/// `Device` would be a [`Device`] that reached the [`Regis= tered`] [`DeviceContext`]. +/// +/// Each stage of this process is described below: +/// +/// ```text +/// 1 2 3 +/// +--------------+ +------------------+ +-----------------------+ +/// |Device created| =E2=86=92 |Device initialized| =E2=86=92 |Registered = w/ userspace| +/// +--------------+ +------------------+ +-----------------------+ +/// (Uninit) (Registered) +/// ``` +/// +/// 1. The [`Device`] is in the [`Uninit`] context and is not guaranteed t= o be initialized or +/// registered with userspace. Only a limited subset of DRM core functi= onality is available. +/// 2. The [`Device`] is guaranteed to be fully initialized, but is not gu= aranteed to be registered +/// with userspace. All DRM core functionality which doesn't interact w= ith userspace is +/// available. We currently don't have a context for representing this. +/// 3. The [`Device`] is guaranteed to be fully initialized, and is guaran= teed to have been +/// registered with userspace at some point - thus putting it in the [`= Registered`] context. /// -/// The device is always reference-counted. +/// An important caveat of [`DeviceContext`] which must be kept in mind: w= hen used as a typestate +/// for a reference type, it can only guarantee that a [`Device`] reached = a particular stage in the +/// initialization process _at the time the reference was taken_. No guara= ntee is made in regards to +/// what stage of the process the [`Device`] is currently in. This means f= or instance that a +/// `&Device` may actually be registered with userspace, it jus= t wasn't known to be +/// registered at the time the reference was taken. +pub trait DeviceContext: Sealed + Send + Sync {} + +/// The [`DeviceContext`] of a [`Device`] that was registered with userspa= ce at some point. +/// +/// This represents a [`Device`] which is guaranteed to have been register= ed with userspace at +/// some point in time. Such a DRM device is guaranteed to have been fully= -initialized. +/// +/// Note: A device in this context is not guaranteed to remain registered = with userspace for its +/// entire lifetime, as this is impossible to guarantee at compile-time. /// /// # Invariants /// -/// `self.dev` is a valid instance of a `struct device`. -#[repr(C)] -pub struct Device { - dev: Opaque, - data: T::Data, +/// A [`Device`] in this [`DeviceContext`] is guaranteed to have been regi= stered with userspace +/// at some point in time. +pub struct Registered; + +impl Sealed for Registered {} +impl DeviceContext for Registered {} + +/// The [`DeviceContext`] of a [`Device`] that may be unregistered and par= tly uninitialized. +/// +/// A [`Device`] in this context is only guaranteed to be partly initializ= ed, and may or may not +/// be registered with userspace. Thus operations which depend on the [`De= vice`] being fully +/// initialized, or which depend on the [`Device`] being registered with u= serspace are not +/// available through this [`DeviceContext`]. +/// +/// A [`Device`] in this context can be used to create a +/// [`Registration`](drm::driver::Registration). +pub struct Uninit; + +impl Sealed for Uninit {} +impl DeviceContext for Uninit {} + +/// A [`Device`] which is known at compile-time to be unregistered with us= erspace. +/// +/// This type allows performing operations which are only safe to do befor= e userspace registration, +/// and can be used to create a [`Registration`](drm::driver::Registration= ) once the driver is ready +/// to register the device with userspace. +/// +/// Since DRM device initialization must be single-threaded, this object i= s not thread-safe. +/// +/// # Invariants +/// +/// The device in `self.0` is guaranteed to be a newly created [`Device`] = that has not yet been +/// registered with userspace until this type is dropped. +pub struct UnregisteredDevice(ARef>, Not= ThreadSafe); + +impl Deref for UnregisteredDevice { + type Target =3D Device; + + fn deref(&self) -> &Self::Target { + &self.0 + } } =20 -impl Device { +impl UnregisteredDevice { const VTABLE: bindings::drm_driver =3D drm_legacy_fields! { load: None, open: Some(drm::File::::open_callback), postclose: Some(drm::File::::postclose_callback), unload: None, - release: Some(Self::release), + release: Some(Device::::release), master_set: None, master_drop: None, debugfs_init: None, @@ -113,21 +191,23 @@ impl Device { =20 const GEM_FOPS: bindings::file_operations =3D drm::gem::create_fops(); =20 - /// Create a new `drm::Device` for a `drm::Driver`. - pub fn new(dev: &device::Device, data: impl PinInit) -= > Result> { + /// Create a new `UnregisteredDevice` for a `drm::Driver`. + /// + /// This can be used to create a [`Registration`](kernel::drm::Registr= ation). + pub fn new(dev: &device::Device, data: impl PinInit) -= > Result { // `__drm_dev_alloc` uses `kmalloc()` to allocate memory, hence en= sure a `kmalloc()` // compatible `Layout`. - let layout =3D Kmalloc::aligned_layout(Layout::new::()); + let layout =3D Kmalloc::aligned_layout(Layout::new::>()); =20 // SAFETY: // - `VTABLE`, as a `const` is pinned to the read-only section of = the compilation, // - `dev` is valid by its type invarants, - let raw_drm: *mut Self =3D unsafe { + let raw_drm: *mut Device =3D unsafe { bindings::__drm_dev_alloc( dev.as_raw(), &Self::VTABLE, layout.size(), - mem::offset_of!(Self, dev), + mem::offset_of!(Device, dev), ) } .cast(); @@ -142,7 +222,7 @@ pub fn new(dev: &device::Device, data: impl PinInit) -> Result) -> Result { + dev: Opaque, + data: T::Data, + _ctx: PhantomData, +} =20 +impl Device { pub(crate) fn as_raw(&self) -> *mut bindings::drm_device { self.dev.get() } @@ -179,13 +289,13 @@ unsafe fn into_drm_device(ptr: NonNull) -> *mut= bindings::drm_device { /// /// # Safety /// - /// Callers must ensure that `ptr` is valid, non-null, and has a non-z= ero reference count, - /// i.e. it must be ensured that the reference count of the C `struct = drm_device` `ptr` points - /// to can't drop to zero, for the duration of this function call and = the entire duration when - /// the returned reference exists. - /// - /// Additionally, callers must ensure that the `struct device`, `ptr` = is pointing to, is - /// embedded in `Self`. + /// * Callers must ensure that `ptr` is valid, non-null, and has a non= -zero reference count, + /// i.e. it must be ensured that the reference count of the C `struc= t drm_device` `ptr` points + /// to can't drop to zero, for the duration of this function call an= d the entire duration when + /// the returned reference exists. + /// * Additionally, callers must ensure that the `struct device`, `ptr= ` is pointing to, is + /// embedded in `Self`. + /// * Callers promise that any type invariants of `C` will be upheld. #[doc(hidden)] pub unsafe fn from_raw<'a>(ptr: *const bindings::drm_device) -> &'a Se= lf { // SAFETY: By the safety requirements of this function `ptr` is a = valid pointer to a @@ -205,9 +315,20 @@ extern "C" fn release(ptr: *mut bindings::drm_device) { // - `this` is valid for dropping. unsafe { core::ptr::drop_in_place(this) }; } + + /// Change the [`DeviceContext`] for a [`Device`]. + /// + /// # Safety + /// + /// The caller promises that `self` fulfills all of the guarantees pro= vided by the given + /// [`DeviceContext`]. + pub(crate) unsafe fn assume_ctx(&self) -> &Devi= ce { + // SAFETY: The data layout is identical via our type invariants. + unsafe { mem::transmute(self) } + } } =20 -impl Deref for Device { +impl Deref for Device { type Target =3D T::Data; =20 fn deref(&self) -> &Self::Target { @@ -217,7 +338,7 @@ fn deref(&self) -> &Self::Target { =20 // SAFETY: DRM device objects are always reference counted and the get/put= functions // satisfy the requirements. -unsafe impl AlwaysRefCounted for Device { +unsafe impl AlwaysRefCounted for Device<= T, C> { fn inc_ref(&self) { // SAFETY: The existence of a shared reference guarantees that the= refcount is non-zero. unsafe { bindings::drm_dev_get(self.as_raw()) }; @@ -232,7 +353,7 @@ unsafe fn dec_ref(obj: NonNull) { } } =20 -impl AsRef for Device { +impl AsRef for Device { fn as_ref(&self) -> &device::Device { // SAFETY: `bindings::drm_device::dev` is valid as long as the DRM= device itself is valid, // which is guaranteed by the type invariant. @@ -241,21 +362,22 @@ fn as_ref(&self) -> &device::Device { } =20 // SAFETY: A `drm::Device` can be released from any thread. -unsafe impl Send for Device {} +unsafe impl Send for Device {} =20 // SAFETY: A `drm::Device` can be shared among threads because all immutab= le methods are protected // by the synchronization in `struct drm_device`. -unsafe impl Sync for Device {} +unsafe impl Sync for Device {} =20 -impl WorkItem for Device +impl WorkItem for Device where T: drm::Driver, - T::Data: WorkItem>>, - T::Data: HasWork, ID>, + T::Data: WorkItem>, + T::Data: HasWork, + C: DeviceContext, { - type Pointer =3D ARef>; + type Pointer =3D ARef; =20 - fn run(ptr: ARef>) { + fn run(ptr: ARef) { T::Data::run(ptr); } } @@ -267,40 +389,42 @@ fn run(ptr: ARef>) { // stored inline in `drm::Device`, so the `container_of` call is valid. // // - The two methods are true inverses of each other: given `ptr: *mut -// Device`, `raw_get_work` will return a `*mut Work, ID>` thr= ough -// `T::Data::raw_get_work` and given a `ptr: *mut Work, ID>`, -// `work_container_of` will return a `*mut Device` through `container_o= f`. -unsafe impl HasWork, ID> for Device +// Device`, `raw_get_work` will return a `*mut Work, ID= >` through +// `T::Data::raw_get_work` and given a `ptr: *mut Work, ID>`, +// `work_container_of` will return a `*mut Device` through `containe= r_of`. +unsafe impl HasWork for Device where T: drm::Driver, - T::Data: HasWork, ID>, + T::Data: HasWork, + C: DeviceContext, { - unsafe fn raw_get_work(ptr: *mut Self) -> *mut Work, ID> { - // SAFETY: The caller promises that `ptr` points to a valid `Devic= e`. + unsafe fn raw_get_work(ptr: *mut Self) -> *mut Work { + // SAFETY: The caller promises that `ptr` points to a valid `Devic= e`. let data_ptr =3D unsafe { &raw mut (*ptr).data }; =20 // SAFETY: `data_ptr` is a valid pointer to `T::Data`. unsafe { T::Data::raw_get_work(data_ptr) } } =20 - unsafe fn work_container_of(ptr: *mut Work, ID>) -> *mut Sel= f { + unsafe fn work_container_of(ptr: *mut Work) -> *mut Self { // SAFETY: The caller promises that `ptr` points at a `Work` field= in // `T::Data`. let data_ptr =3D unsafe { T::Data::work_container_of(ptr) }; =20 - // SAFETY: `T::Data` is stored as the `data` field in `Device`. + // SAFETY: `T::Data` is stored as the `data` field in `Device`. unsafe { crate::container_of!(data_ptr, Self, data) } } } =20 // SAFETY: Our `HasWork` implementation returns a `work_struct` tha= t is // stored in the `work` field of a `delayed_work` with the same access rul= es as -// the `work_struct` owing to the bound on `T::Data: HasDelayedWork, +// the `work_struct` owing to the bound on `T::Data: HasDelayedWork, // ID>`, which requires that `T::Data::raw_get_work` return a `work_struct= ` that // is inside a `delayed_work`. -unsafe impl HasDelayedWork, ID> for Device +unsafe impl HasDelayedWork for Device where T: drm::Driver, - T::Data: HasDelayedWork, ID>, + T::Data: HasDelayedWork, + C: DeviceContext, { } diff --git a/rust/kernel/drm/driver.rs b/rust/kernel/drm/driver.rs index 5233bdebc9fcd..55b01ee088548 100644 --- a/rust/kernel/drm/driver.rs +++ b/rust/kernel/drm/driver.rs @@ -13,6 +13,10 @@ prelude::*, sync::aref::ARef, // }; +use core::{ + mem, + ptr::NonNull, // +}; =20 /// Driver use the GEM memory manager. This should be set for all modern d= rivers. pub(crate) const FEAT_GEM: u32 =3D bindings::drm_driver_feature_DRIVER_GEM; @@ -123,21 +127,31 @@ pub trait Driver { pub struct Registration(ARef>); =20 impl Registration { - fn new(drm: &drm::Device, flags: usize) -> Result { + fn new(drm: drm::UnregisteredDevice, flags: usize) -> Result { // SAFETY: `drm.as_raw()` is valid by the invariants of `drm::Devi= ce`. to_result(unsafe { bindings::drm_dev_register(drm.as_raw(), flags)= })?; =20 - Ok(Self(drm.into())) + // SAFETY: We just called `drm_dev_register` above + let new =3D NonNull::from(unsafe { drm.assume_ctx() }); + + // Leak the ARef from UnregisteredDevice in preparation for transf= erring its ownership. + mem::forget(drm); + + // SAFETY: `drm`'s `Drop` constructor was never called, ensuring t= hat there remains at least + // one reference to the device - which we take ownership over here. + let new =3D unsafe { ARef::from_raw(new) }; + + Ok(Self(new)) } =20 - /// Registers a new [`Device`](drm::Device) with userspace. + /// Registers a new [`UnregisteredDevice`](drm::UnregisteredDevice) wi= th userspace. /// /// Ownership of the [`Registration`] object is passed to [`devres::re= gister`]. - pub fn new_foreign_owned( - drm: &drm::Device, - dev: &device::Device, + pub fn new_foreign_owned<'a>( + drm: drm::UnregisteredDevice, + dev: &'a device::Device, flags: usize, - ) -> Result + ) -> Result<&'a drm::Device> where T: 'static, { @@ -146,8 +160,13 @@ pub fn new_foreign_owned( } =20 let reg =3D Registration::::new(drm, flags)?; 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charset="utf-8" This is just a type alias that resolves into the AllocImpl for a given T: drm::gem::DriverObject Signed-off-by: Lyude Paul Reviewed-by: Daniel Almeida --- rust/kernel/drm/gem/mod.rs | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs index 75acda7ba5001..568b5c08019e7 100644 --- a/rust/kernel/drm/gem/mod.rs +++ b/rust/kernel/drm/gem/mod.rs @@ -73,6 +73,11 @@ unsafe fn dec_ref(obj: core::ptr::NonNull) { /// [`DriverFile`]: drm::file::DriverFile pub type DriverFile =3D drm::File<<::Driver as drm::= Driver>::File>; =20 +/// A type alias for retrieving the current [`AllocImpl`] for a given [`Dr= iverObject`]. +/// +/// [`Driver`]: drm::Driver +pub type DriverAllocImpl =3D <::Driver as drm::Drive= r>::Object; + /// GEM object functions, which must be implemented by drivers. pub trait DriverObject: Sync + Send + Sized { /// Parent `Driver` for this object. @@ -89,12 +94,12 @@ fn new( ) -> impl PinInit; 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Thu, 7 May 2026 22:01:17 +0000 (UTC) Received: from GoldenWind.lan (unknown [10.22.89.165]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 112D83002D2F; Thu, 7 May 2026 22:01:14 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org Cc: "Gary Guo" , "Miguel Ojeda" , "Simona Vetter" , "Alice Ryhl" , Nova-gpu@lists.linux.dev, "Shankari Anand" , "David Airlie" , "Benno Lossin" , "Danilo Krummrich" , "Asahi Lina" , "Mukesh Kumar Chaurasiya (IBM)" , "Daniel Almeida" , "Lyude Paul" Subject: [PATCH v6 3/3] rust/drm/gem: Use DeviceContext with GEM objects Date: Thu, 7 May 2026 17:59:21 -0400 Message-ID: <20260507220044.3204919-4-lyude@redhat.com> In-Reply-To: <20260507220044.3204919-1-lyude@redhat.com> References: <20260507220044.3204919-1-lyude@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" Now that we have the ability to represent the context in which a DRM device is in at compile-time, we can start carrying around this context with GEM object types in order to allow a driver to safely create GEM objects before a DRM device has registered with userspace. Signed-off-by: Lyude Paul Reviewed-by: Daniel Almeida --- V4: * Add a comment to explain the Uninit DeviceContext usage in the GEM object vtable (tl;dr: the DeviceContext is meaningless here) V5: * Improve invariant comment above drm_gem_object_init() V6: * Rebase drivers/gpu/drm/nova/driver.rs | 2 +- drivers/gpu/drm/nova/gem.rs | 15 +++++--- drivers/gpu/drm/tyr/driver.rs | 2 +- drivers/gpu/drm/tyr/gem.rs | 11 ++++-- rust/kernel/drm/device.rs | 18 ++++++---- rust/kernel/drm/driver.rs | 2 +- rust/kernel/drm/gem/mod.rs | 65 +++++++++++++++++++++++----------- rust/kernel/drm/gem/shmem.rs | 57 +++++++++++++++++------------ 8 files changed, 113 insertions(+), 59 deletions(-) diff --git a/drivers/gpu/drm/nova/driver.rs b/drivers/gpu/drm/nova/driver.rs index 99d6841b69cbc..3e0647dcfe981 100644 --- a/drivers/gpu/drm/nova/driver.rs +++ b/drivers/gpu/drm/nova/driver.rs @@ -67,7 +67,7 @@ fn probe(adev: &auxiliary::Device, _info: &Self::Id= Info) -> impl PinInit; + type Object =3D gem::Object; =20 const INFO: drm::DriverInfo =3D INFO; =20 diff --git a/drivers/gpu/drm/nova/gem.rs b/drivers/gpu/drm/nova/gem.rs index e073e174e2578..9d8ff7de2c0f7 100644 --- a/drivers/gpu/drm/nova/gem.rs +++ b/drivers/gpu/drm/nova/gem.rs @@ -2,7 +2,7 @@ =20 use kernel::{ drm, - drm::{gem, gem::BaseObject}, + drm::{gem, gem::BaseObject, DeviceContext}, page, prelude::*, sync::aref::ARef, @@ -21,20 +21,27 @@ impl gem::DriverObject for NovaObject { type Driver =3D NovaDriver; type Args =3D (); =20 - fn new(_dev: &NovaDevice, _size: usize, _args: Self::Args) -> impl Pin= Init { + fn new( + _dev: &NovaDevice, + _size: usize, + _args: Self::Args, + ) -> impl PinInit { try_pin_init!(NovaObject {}) } } =20 impl NovaObject { /// Create a new DRM GEM object. - pub(crate) fn new(dev: &NovaDevice, size: usize) -> Result>> { + pub(crate) fn new( + dev: &NovaDevice, + size: usize, + ) -> Result>> { if size =3D=3D 0 { return Err(EINVAL); } let aligned_size =3D page::page_align(size).ok_or(EINVAL)?; =20 - gem::Object::new(dev, aligned_size, ()) + gem::Object::::new(dev, aligned_size, ()) } =20 /// Look up a GEM object handle for a `File` and return an `ObjectRef`= for it. diff --git a/drivers/gpu/drm/tyr/driver.rs b/drivers/gpu/drm/tyr/driver.rs index 4f96c8f761895..756a93210fc95 100644 --- a/drivers/gpu/drm/tyr/driver.rs +++ b/drivers/gpu/drm/tyr/driver.rs @@ -185,7 +185,7 @@ fn drop(self: Pin<&mut Self>) {} impl drm::Driver for TyrDrmDriver { type Data =3D TyrDrmDeviceData; type File =3D TyrDrmFileData; - type Object =3D drm::gem::shmem::Object; + type Object =3D drm::gem::shmem::Object; =20 const INFO: drm::DriverInfo =3D INFO; =20 diff --git a/drivers/gpu/drm/tyr/gem.rs b/drivers/gpu/drm/tyr/gem.rs index 1640a161754b2..c6d4d6f9bae39 100644 --- a/drivers/gpu/drm/tyr/gem.rs +++ b/drivers/gpu/drm/tyr/gem.rs @@ -5,7 +5,10 @@ //! DRM's GEM subsystem with shmem backing. =20 use kernel::{ - drm::gem, + drm::{ + gem, + DeviceContext, // + }, prelude::*, // }; =20 @@ -30,7 +33,11 @@ impl gem::DriverObject for BoData { type Driver =3D TyrDrmDriver; type Args =3D BoCreateArgs; =20 - fn new(_dev: &TyrDrmDevice, _size: usize, args: BoCreateArgs) -> impl = PinInit { + fn new( + _dev: &TyrDrmDevice, + _size: usize, + args: BoCreateArgs, + ) -> impl PinInit { try_pin_init!(Self { flags: args.flags }) } } diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs index 27a52a270be66..e0864ed843075 100644 --- a/rust/kernel/drm/device.rs +++ b/rust/kernel/drm/device.rs @@ -167,13 +167,17 @@ impl UnregisteredDevice { master_set: None, master_drop: None, debugfs_init: None, - gem_create_object: T::Object::ALLOC_OPS.gem_create_object, - prime_handle_to_fd: T::Object::ALLOC_OPS.prime_handle_to_fd, - prime_fd_to_handle: T::Object::ALLOC_OPS.prime_fd_to_handle, - gem_prime_import: T::Object::ALLOC_OPS.gem_prime_import, - gem_prime_import_sg_table: T::Object::ALLOC_OPS.gem_prime_import_s= g_table, - dumb_create: T::Object::ALLOC_OPS.dumb_create, - dumb_map_offset: T::Object::ALLOC_OPS.dumb_map_offset, + + // Ignore the Uninit DeviceContext below. It is only provided beca= use it is required by the + // compiler, and it is not actually used by these functions. + gem_create_object: T::Object::::ALLOC_OPS.gem_create_objec= t, + prime_handle_to_fd: T::Object::::ALLOC_OPS.prime_handle_to= _fd, + prime_fd_to_handle: T::Object::::ALLOC_OPS.prime_fd_to_han= dle, + gem_prime_import: T::Object::::ALLOC_OPS.gem_prime_import, + gem_prime_import_sg_table: T::Object::::ALLOC_OPS.gem_prim= e_import_sg_table, + dumb_create: T::Object::::ALLOC_OPS.dumb_create, + dumb_map_offset: T::Object::::ALLOC_OPS.dumb_map_offset, + show_fdinfo: None, fbdev_probe: None, =20 diff --git a/rust/kernel/drm/driver.rs b/rust/kernel/drm/driver.rs index 55b01ee088548..294e17af86a32 100644 --- a/rust/kernel/drm/driver.rs +++ b/rust/kernel/drm/driver.rs @@ -109,7 +109,7 @@ pub trait Driver { type Data: Sync + Send; =20 /// The type used to manage memory for this driver. - type Object: AllocImpl; + type Object: AllocImpl; =20 /// The type used to represent a DRM File (client) type File: drm::file::DriverFile; diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs index 568b5c08019e7..d91e01e897c4d 100644 --- a/rust/kernel/drm/gem/mod.rs +++ b/rust/kernel/drm/gem/mod.rs @@ -8,6 +8,10 @@ bindings, drm::{ self, + device::{ + DeviceContext, + Registered, // + }, driver::{ AllocImpl, AllocOps, // @@ -22,6 +26,7 @@ types::Opaque, }; use core::{ + marker::PhantomData, ops::Deref, ptr::NonNull, // }; @@ -76,7 +81,8 @@ unsafe fn dec_ref(obj: core::ptr::NonNull) { /// A type alias for retrieving the current [`AllocImpl`] for a given [`Dr= iverObject`]. /// /// [`Driver`]: drm::Driver -pub type DriverAllocImpl =3D <::Driver as drm::Drive= r>::Object; +pub type DriverAllocImpl =3D + <::Driver as drm::Driver>::Object; =20 /// GEM object functions, which must be implemented by drivers. pub trait DriverObject: Sync + Send + Sized { @@ -87,8 +93,8 @@ pub trait DriverObject: Sync + Send + Sized { type Args; =20 /// Create a new driver data object for a GEM object of a given size. - fn new( - dev: &drm::Device, + fn new( + dev: &drm::Device, size: usize, args: Self::Args, ) -> impl PinInit; @@ -125,9 +131,12 @@ extern "C" fn open_callback( // SAFETY: `open_callback` is only ever called with a valid pointer to= a `struct drm_file`. let file =3D unsafe { DriverFile::::from_raw(raw_file) }; =20 - // SAFETY: `open_callback` is specified in the AllocOps structure for = `DriverObject`, - // ensuring that `raw_obj` is contained within a `DriverObject` - let obj =3D unsafe { <::Object as IntoGEMObj= ect>::from_raw(raw_obj) }; + // SAFETY: + // * `open_callback` is specified in the AllocOps structure for `Drive= rObject`, ensuring that + // `raw_obj` is contained within a `DriverAllocImpl` + // * It is only possible for `open_callback` to be called after device= registration, ensuring + // that the object's device is in the `Registered` state. + let obj: &DriverAllocImpl =3D unsafe { IntoGEMObject::from_raw(raw_= obj) }; =20 match T::open(obj, file) { Err(e) =3D> e.to_errno(), @@ -144,12 +153,12 @@ extern "C" fn close_callback( =20 // SAFETY: `close_callback` is specified in the AllocOps structure for= `Object`, ensuring // that `raw_obj` is indeed contained within a `Object`. - let obj =3D unsafe { <::Object as IntoGEMObj= ect>::from_raw(raw_obj) }; + let obj: &DriverAllocImpl =3D unsafe { IntoGEMObject::from_raw(raw_= obj) }; =20 T::close(obj, file); } =20 -impl IntoGEMObject for Object { +impl IntoGEMObject for Object= { fn as_raw(&self) -> *mut bindings::drm_gem_object { self.obj.get() } @@ -157,7 +166,7 @@ fn as_raw(&self) -> *mut bindings::drm_gem_object { unsafe fn from_raw<'a>(self_ptr: *mut bindings::drm_gem_object) -> &'a= Self { // SAFETY: `obj` is guaranteed to be in an `Object` via the saf= ety contract of this // function - unsafe { &*crate::container_of!(Opaque::cast_from(self_ptr), Objec= t, obj) } + unsafe { &*crate::container_of!(Opaque::cast_from(self_ptr), Objec= t, obj) } } } =20 @@ -174,7 +183,7 @@ fn size(&self) -> usize { fn create_handle(&self, file: &drm::File) -> Result where Self: AllocImpl, - D: drm::Driver, + D: drm::Driver =3D Self, File =3D F>, F: drm::file::DriverFile, { let mut handle: u32 =3D 0; @@ -189,7 +198,7 @@ fn create_handle(&self, file: &drm::File) -> R= esult fn lookup_handle(file: &drm::File, handle: u32) -> Result> where Self: AllocImpl, - D: drm::Driver, + D: drm::Driver =3D Self, File =3D F>, F: drm::file::DriverFile, { // SAFETY: The arguments are all valid per the type invariants. @@ -241,16 +250,18 @@ impl BaseObjectPrivate for T {} /// /// # Invariants /// -/// - `self.obj` is a valid instance of a `struct drm_gem_object`. +/// * `self.obj` is a valid instance of a `struct drm_gem_object`. +/// * Any type invariants of `Ctx` apply to the parent DRM device for this= GEM object. #[repr(C)] #[pin_data] -pub struct Object { +pub struct Object { obj: Opaque, #[pin] data: T, + _ctx: PhantomData, } =20 -impl Object { +impl Object { const OBJECT_FUNCS: bindings::drm_gem_object_funcs =3D bindings::drm_g= em_object_funcs { free: Some(Self::free_callback), open: Some(open_callback::), @@ -270,11 +281,16 @@ impl Object { }; =20 /// Create a new GEM object. - pub fn new(dev: &drm::Device, size: usize, args: T::Args) -= > Result> { + pub fn new( + dev: &drm::Device, + size: usize, + args: T::Args, + ) -> Result> { let obj: Pin> =3D KBox::pin_init( try_pin_init!(Self { obj: Opaque::new(bindings::drm_gem_object::default()), data <- T::new(dev, size, args), + _ctx: PhantomData, }), GFP_KERNEL, )?; @@ -283,6 +299,8 @@ pub fn new(dev: &drm::Device, size: usize, a= rgs: T::Args) -> Result` is alw= ays treated as pinned. @@ -296,13 +314,15 @@ pub fn new(dev: &drm::Device, size: usize,= args: T::Args) -> Result &drm::Device { + pub fn dev(&self) -> &drm::Device { // SAFETY: // - `struct drm_gem_object.dev` is initialized and valid for as l= ong as the GEM // object lives. // - The device we used for creating the gem object is passed as &= drm::Device to // Object::::new(), so we know that `T::Driver` is the right = generic parameter to use // here. + // - Any type invariants of `Ctx` are upheld by using the same `Ct= x` for the `Device` we + // return. unsafe { drm::Device::from_raw((*self.as_raw()).dev) } } =20 @@ -327,11 +347,16 @@ extern "C" fn free_callback(obj: *mut bindings::drm_g= em_object) { } } =20 -impl_aref_for_gem_obj!(impl for Object where T: DriverObject); +impl_aref_for_gem_obj! { + impl for Object + where + T: DriverObject, + C: DeviceContext +} =20 -impl super::private::Sealed for Object {} +impl super::private::Sealed for Objec= t {} =20 -impl Deref for Object { +impl Deref for Object { type Target =3D T; =20 fn deref(&self) -> &Self::Target { @@ -339,7 +364,7 @@ fn deref(&self) -> &Self::Target { } } =20 -impl AllocImpl for Object { +impl AllocImpl for Object { type Driver =3D T::Driver; =20 const ALLOC_OPS: AllocOps =3D AllocOps { diff --git a/rust/kernel/drm/gem/shmem.rs b/rust/kernel/drm/gem/shmem.rs index e1b648920d2f6..e6ba17459fb73 100644 --- a/rust/kernel/drm/gem/shmem.rs +++ b/rust/kernel/drm/gem/shmem.rs @@ -15,7 +15,9 @@ device, driver, gem, - private::Sealed, // + private::Sealed, + DeviceContext, + Registered, // }, error::to_result, prelude::*, @@ -23,11 +25,12 @@ types::Opaque, // }; use core::{ + marker::PhantomData, ops::{ Deref, DerefMut, // }, - ptr::NonNull, + ptr::NonNull, // }; use gem::{ BaseObjectPrivate, @@ -40,42 +43,49 @@ /// This is used with [`Object::new()`] to control various properties that= can only be set when /// initially creating a shmem-backed GEM object. #[derive(Default)] -pub struct ObjectConfig<'a, T: DriverObject> { +pub struct ObjectConfig<'a, T: DriverObject, C: DeviceContext =3D Register= ed> { /// Whether to set the write-combine map flag. pub map_wc: bool, =20 /// Reuse the DMA reservation from another GEM object. /// /// The newly created [`Object`] will hold an owned refcount to `paren= t_resv_obj` if specified. - pub parent_resv_obj: Option<&'a Object>, + pub parent_resv_obj: Option<&'a Object>, } =20 /// A shmem-backed GEM object. /// /// # Invariants /// -/// `obj` contains a valid initialized `struct drm_gem_shmem_object` for t= he lifetime of this -/// object. +/// - `obj` contains a valid initialized `struct drm_gem_shmem_object` for= the lifetime of this +/// object. +/// - Any type invariants of `C` apply to the parent DRM device for this G= EM object. #[repr(C)] #[pin_data] -pub struct Object { +pub struct Object { #[pin] obj: Opaque, /// Parent object that owns this object's DMA reservation object. - parent_resv_obj: Option>>, + parent_resv_obj: Option>>, #[pin] inner: T, + _ctx: PhantomData, } =20 -super::impl_aref_for_gem_obj!(impl for Object where T: DriverObject); +super::impl_aref_for_gem_obj! { + impl for Object + where + T: DriverObject, + C: DeviceContext +} =20 // SAFETY: All GEM objects are thread-safe. -unsafe impl Send for Object {} +unsafe impl Send for Object {} =20 // SAFETY: All GEM objects are thread-safe. -unsafe impl Sync for Object {} +unsafe impl Sync for Object {} =20 -impl Object { +impl Object { /// `drm_gem_object_funcs` vtable suitable for GEM shmem objects. const VTABLE: bindings::drm_gem_object_funcs =3D bindings::drm_gem_obj= ect_funcs { free: Some(Self::free_callback), @@ -106,9 +116,9 @@ fn as_raw_shmem(&self) -> *mut bindings::drm_gem_shmem_= object { /// /// Additional config options can be specified using `config`. pub fn new( - dev: &device::Device, + dev: &device::Device, size: usize, - config: ObjectConfig<'_, T>, + config: ObjectConfig<'_, T, C>, args: T::Args, ) -> Result> { let new: Pin> =3D KBox::try_pin_init( @@ -116,6 +126,7 @@ pub fn new( obj <- Opaque::init_zeroed(), parent_resv_obj: config.parent_resv_obj.map(|p| p.into()), inner <- T::new(dev, size, args), + _ctx: PhantomData::, }), GFP_KERNEL, )?; @@ -148,7 +159,7 @@ pub fn new( } =20 /// Returns the `Device` that owns this GEM object. - pub fn dev(&self) -> &device::Device { + pub fn dev(&self) -> &device::Device { // SAFETY: `dev` will have been initialized in `Self::new()` by `d= rm_gem_shmem_init()`. unsafe { device::Device::from_raw((*self.as_raw()).dev) } } @@ -168,7 +179,7 @@ extern "C" fn free_callback(obj: *mut bindings::drm_gem= _object) { // SAFETY: // - We verified above that `obj` is valid, which makes `this` val= id // - This function is set in AllocOps, so we know that `this` is c= ontained within a - // `Object` + // `Object` let this =3D unsafe { container_of!(Opaque::cast_from(this), Self,= obj) }.cast_mut(); =20 // SAFETY: We're recovering the Kbox<> we created in gem_create_ob= ject() @@ -176,7 +187,7 @@ extern "C" fn free_callback(obj: *mut bindings::drm_gem= _object) { } } =20 -impl Deref for Object { +impl Deref for Object { type Target =3D T; =20 fn deref(&self) -> &Self::Target { @@ -184,15 +195,15 @@ fn deref(&self) -> &Self::Target { } } =20 -impl DerefMut for Object { +impl DerefMut for Object { fn deref_mut(&mut self) -> &mut Self::Target { &mut self.inner } } =20 -impl Sealed for Object {} +impl Sealed for Object {} =20 -impl gem::IntoGEMObject for Object { +impl gem::IntoGEMObject for Object { fn as_raw(&self) -> *mut bindings::drm_gem_object { // SAFETY: // - Our immutable reference is proof that this is safe to derefer= ence. @@ -200,18 +211,18 @@ fn as_raw(&self) -> *mut bindings::drm_gem_object { unsafe { &raw mut (*self.obj.get()).base } } =20 - unsafe fn from_raw<'a>(obj: *mut bindings::drm_gem_object) -> &'a Obje= ct { + unsafe fn from_raw<'a>(obj: *mut bindings::drm_gem_object) -> &'a Self= { // SAFETY: The safety contract of from_gem_obj() guarantees that `= obj` is contained within // `Self` unsafe { let obj =3D Opaque::cast_from(container_of!(obj, bindings::drm= _gem_shmem_object, base)); =20 - &*container_of!(obj, Object, obj) + &*container_of!(obj, Self, obj) } } } =20 -impl driver::AllocImpl for Object { +impl driver::AllocImpl for Object= { type Driver =3D T::Driver; =20 const ALLOC_OPS: driver::AllocOps =3D driver::AllocOps { --=20 2.54.0