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drm: rust: rename as_ref() to from_raw() for drm constructors

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The prefix as_* should not be used for a constructor. Constructors
usually use the prefix from_* instead.

Some prior art in the stdlib: Box::from_raw, CString::from_raw,
Rc::from_raw, Arc::from_raw, Waker::from_raw, File::from_raw_fd.

There is also prior art in the kernel crate: cpufreq::Policy::from_raw,
fs::File::from_raw_file, Kuid::from_raw, ARef::from_raw,
SeqFile::from_raw, VmaNew::from_raw, Io::from_raw.

Link: https://lore.kernel.org/r/aCd8D5IA0RXZvtcv@pollux
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250711-device-as-ref-v2-2-1b16ab6402d7@google.com
This commit is contained in:
Alice Ryhl 2025-07-11 08:04:38 +00:00 committed by Danilo Krummrich
parent 667efb3419
commit 917b10d909
4 changed files with 15 additions and 15 deletions
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2
rust/kernel/drm/device.rs
View File

@ -154,7 +154,7 @@ unsafe fn from_drm_device(ptr: *const bindings::drm_device) -> *mut Self {
/// Additionally, callers must ensure that the `struct device`, `ptr` is pointing to, is
/// embedded in `Self`.
#[doc(hidden)]
pub unsafe fn as_ref<'a>(ptr: *const bindings::drm_device) -> &'a Self {
pub unsafe fn from_raw<'a>(ptr: *const bindings::drm_device) -> &'a Self {
// SAFETY: By the safety requirements of this function `ptr` is a valid pointer to a
// `struct drm_device` embedded in `Self`.
let ptr = unsafe { Self::from_drm_device(ptr) };

8
rust/kernel/drm/file.rs
View File

@ -32,7 +32,7 @@ impl<T: DriverFile> File<T> {
/// # Safety
///
/// `raw_file` must be a valid pointer to an open `struct drm_file`, opened through `T::open`.
pub unsafe fn as_ref<'a>(ptr: *mut bindings::drm_file) -> &'a File<T> {
pub unsafe fn from_raw<'a>(ptr: *mut bindings::drm_file) -> &'a File<T> {
// SAFETY: `raw_file` is valid by the safety requirements of this function.
unsafe { &*ptr.cast() }
}
@ -61,10 +61,10 @@ pub(crate) extern "C" fn open_callback(
// SAFETY: A callback from `struct drm_driver::open` guarantees that
// - `raw_dev` is valid pointer to a `struct drm_device`,
// - the corresponding `struct drm_device` has been registered.
let drm = unsafe { drm::Device::as_ref(raw_dev) };
let drm = unsafe { drm::Device::from_raw(raw_dev) };
// SAFETY: `raw_file` is a valid pointer to a `struct drm_file`.
let file = unsafe { File::<T>::as_ref(raw_file) };
let file = unsafe { File::<T>::from_raw(raw_file) };
let inner = match T::open(drm) {
Err(e) => {
@ -89,7 +89,7 @@ pub(crate) extern "C" fn postclose_callback(
raw_file: *mut bindings::drm_file,
) {
// SAFETY: This reference won't escape this function
let file = unsafe { File::<T>::as_ref(raw_file) };
let file = unsafe { File::<T>::from_raw(raw_file) };
// SAFETY: `file.driver_priv` has been created in `open_callback` through `KBox::into_raw`.
let _ = unsafe { KBox::from_raw(file.driver_priv()) };

16
rust/kernel/drm/gem/mod.rs
View File

@ -51,7 +51,7 @@ pub trait IntoGEMObject: Sized + super::private::Sealed + AlwaysRefCounted {
/// - `self_ptr` must be a valid pointer to `Self`.
/// - The caller promises that holding the immutable reference returned by this function does
/// not violate rust's data aliasing rules and remains valid throughout the lifetime of `'a`.
unsafe fn as_ref<'a>(self_ptr: *mut bindings::drm_gem_object) -> &'a Self;
unsafe fn from_raw<'a>(self_ptr: *mut bindings::drm_gem_object) -> &'a Self;
}
// SAFETY: All gem objects are refcounted.
@ -86,12 +86,12 @@ extern "C" fn open_callback<T: BaseDriverObject<U>, U: BaseObject>(
) -> core::ffi::c_int {
// SAFETY: `open_callback` is only ever called with a valid pointer to a `struct drm_file`.
let file = unsafe {
drm::File::<<<U as IntoGEMObject>::Driver as drm::Driver>::File>::as_ref(raw_file)
drm::File::<<<U as IntoGEMObject>::Driver as drm::Driver>::File>::from_raw(raw_file)
};
// SAFETY: `open_callback` is specified in the AllocOps structure for `Object<T>`, ensuring that
// `raw_obj` is indeed contained within a `Object<T>`.
let obj = unsafe {
<<<U as IntoGEMObject>::Driver as drm::Driver>::Object as IntoGEMObject>::as_ref(raw_obj)
<<<U as IntoGEMObject>::Driver as drm::Driver>::Object as IntoGEMObject>::from_raw(raw_obj)
};
match T::open(obj, file) {
@ -106,12 +106,12 @@ extern "C" fn close_callback<T: BaseDriverObject<U>, U: BaseObject>(
) {
// SAFETY: `open_callback` is only ever called with a valid pointer to a `struct drm_file`.
let file = unsafe {
drm::File::<<<U as IntoGEMObject>::Driver as drm::Driver>::File>::as_ref(raw_file)
drm::File::<<<U as IntoGEMObject>::Driver as drm::Driver>::File>::from_raw(raw_file)
};
// SAFETY: `close_callback` is specified in the AllocOps structure for `Object<T>`, ensuring
// that `raw_obj` is indeed contained within a `Object<T>`.
let obj = unsafe {
<<<U as IntoGEMObject>::Driver as drm::Driver>::Object as IntoGEMObject>::as_ref(raw_obj)
<<<U as IntoGEMObject>::Driver as drm::Driver>::Object as IntoGEMObject>::from_raw(raw_obj)
};
T::close(obj, file);
@ -124,7 +124,7 @@ fn as_raw(&self) -> *mut bindings::drm_gem_object {
self.obj.get()
}
unsafe fn as_ref<'a>(self_ptr: *mut bindings::drm_gem_object) -> &'a Self {
unsafe fn from_raw<'a>(self_ptr: *mut bindings::drm_gem_object) -> &'a Self {
let self_ptr: *mut Opaque<bindings::drm_gem_object> = self_ptr.cast();
// SAFETY: `obj` is guaranteed to be in an `Object<T>` via the safety contract of this
@ -170,9 +170,9 @@ fn lookup_handle(
// - A `drm::Driver` can only have a single `File` implementation.
// - `file` uses the same `drm::Driver` as `Self`.
// - Therefore, we're guaranteed that `ptr` must be a gem object embedded within `Self`.
// - And we check if the pointer is null befoe calling as_ref(), ensuring that `ptr` is a
// - And we check if the pointer is null befoe calling from_raw(), ensuring that `ptr` is a
// valid pointer to an initialized `Self`.
let obj = unsafe { Self::as_ref(ptr) };
let obj = unsafe { Self::from_raw(ptr) };
// SAFETY:
// - We take ownership of the reference of `drm_gem_object_lookup()`.

4
rust/kernel/drm/ioctl.rs
View File

@ -134,7 +134,7 @@ macro_rules! declare_drm_ioctls {
// FIXME: Currently there is nothing enforcing that the types of the
// dev/file match the current driver these ioctls are being declared
// for, and it's not clear how to enforce this within the type system.
let dev = $crate::drm::device::Device::as_ref(raw_dev);
let dev = $crate::drm::device::Device::from_raw(raw_dev);
// SAFETY: The ioctl argument has size `_IOC_SIZE(cmd)`, which we
// asserted above matches the size of this type, and all bit patterns of
// UAPI structs must be valid.
@ -142,7 +142,7 @@ macro_rules! declare_drm_ioctls {
&*(raw_data as *const $crate::types::Opaque<$crate::uapi::$struct>)
};
// SAFETY: This is just the DRM file structure
let file = unsafe { $crate::drm::File::as_ref(raw_file) };
let file = unsafe { $crate::drm::File::from_raw(raw_file) };
match $func(dev, data, file) {
Err(e) => e.to_errno(),