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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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d88f27d7f4
Convert all imports to use "kernel vertical" style. With this, subsequent patches neither introduce unrelated changes nor leave an inconsistent import pattern. While at it, drop unnecessary imports covered by prelude::*. Link: https://docs.kernel.org/rust/coding-guidelines.html#imports Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://patch.msgid.link/20260105142123.95030-5-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
87 lines
3.0 KiB
Rust
87 lines
3.0 KiB
Rust
// SPDX-License-Identifier: GPL-2.0-only
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//! Abstractions for the faux bus.
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//!
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//! This module provides bindings for working with faux devices in kernel modules.
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//!
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//! C header: [`include/linux/device/faux.h`](srctree/include/linux/device/faux.h)
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use crate::{
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bindings,
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device,
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prelude::*, //
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};
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use core::ptr::{
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addr_of_mut,
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null,
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null_mut,
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NonNull, //
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};
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/// The registration of a faux device.
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///
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/// This type represents the registration of a [`struct faux_device`]. When an instance of this type
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/// is dropped, its respective faux device will be unregistered from the system.
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///
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/// # Invariants
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///
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/// `self.0` always holds a valid pointer to an initialized and registered [`struct faux_device`].
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///
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/// [`struct faux_device`]: srctree/include/linux/device/faux.h
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pub struct Registration(NonNull<bindings::faux_device>);
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impl Registration {
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/// Create and register a new faux device with the given name.
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#[inline]
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pub fn new(name: &CStr, parent: Option<&device::Device>) -> Result<Self> {
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// SAFETY:
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// - `name` is copied by this function into its own storage
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// - `faux_ops` is safe to leave NULL according to the C API
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// - `parent` can be either NULL or a pointer to a `struct device`, and `faux_device_create`
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// will take a reference to `parent` using `device_add` - ensuring that it remains valid
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// for the lifetime of the faux device.
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let dev = unsafe {
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bindings::faux_device_create(
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name.as_char_ptr(),
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parent.map_or(null_mut(), |p| p.as_raw()),
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null(),
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)
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};
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// The above function will return either a valid device, or NULL on failure
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// INVARIANT: The device will remain registered until faux_device_destroy() is called, which
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// happens in our Drop implementation.
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Ok(Self(NonNull::new(dev).ok_or(ENODEV)?))
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}
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fn as_raw(&self) -> *mut bindings::faux_device {
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self.0.as_ptr()
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}
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}
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impl AsRef<device::Device> for Registration {
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fn as_ref(&self) -> &device::Device {
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// SAFETY: The underlying `device` in `faux_device` is guaranteed by the C API to be
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// a valid initialized `device`.
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unsafe { device::Device::from_raw(addr_of_mut!((*self.as_raw()).dev)) }
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}
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}
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impl Drop for Registration {
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#[inline]
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fn drop(&mut self) {
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// SAFETY: `self.0` is a valid registered faux_device via our type invariants.
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unsafe { bindings::faux_device_destroy(self.as_raw()) }
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}
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}
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// SAFETY: The faux device API is thread-safe as guaranteed by the device core, as long as
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// faux_device_destroy() is guaranteed to only be called once - which is guaranteed by our type not
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// having Copy/Clone.
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unsafe impl Send for Registration {}
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// SAFETY: The faux device API is thread-safe as guaranteed by the device core, as long as
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// faux_device_destroy() is guaranteed to only be called once - which is guaranteed by our type not
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// having Copy/Clone.
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unsafe impl Sync for Registration {}
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