Trait AlwaysRefCounted 

pub unsafe trait AlwaysRefCounted {
    // Required methods
    fn inc_ref(&self);
    unsafe fn dec_ref(obj: NonNull<Self>);
}

Types that are always reference counted.

It allows such types to define their own custom ref increment and decrement functions. Additionally, it allows users to convert from a shared reference &T to an owned reference ARef<T>.

This is usually implemented by wrappers to existing structures on the C side of the code. For Rust code, the recommendation is to use Arc to create reference-counted instances of a type.

Safety

Implementers must ensure that increments to the reference count keep the object alive in memory at least until matching decrements are performed.

Implementers must also ensure that all instances are reference-counted. (Otherwise they won’t be able to honour the requirement that AlwaysRefCounted::inc_ref keep the object alive.)

Required Methods

fn inc_ref(&self)

Increments the reference count on the object.

unsafe fn dec_ref(obj: NonNull<Self>)

Decrements the reference count on the object.

Frees the object when the count reaches zero.

Safety

Callers must ensure that there was a previous matching increment to the reference count, and that the object is no longer used after its reference count is decremented (as it may result in the object being freed), unless the caller owns another increment on the refcount (e.g., it calls AlwaysRefCounted::inc_ref twice, then calls AlwaysRefCounted::dec_ref once).

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl AlwaysRefCounted for Credential

impl AlwaysRefCounted for kernel::auxiliary::Device

impl AlwaysRefCounted for kernel::device::Device

impl AlwaysRefCounted for kernel::pci::Device

impl AlwaysRefCounted for kernel::platform::Device

impl AlwaysRefCounted for kernel::serdev::Device

impl AlwaysRefCounted for Fence

impl AlwaysRefCounted for File

impl AlwaysRefCounted for FwNode

impl AlwaysRefCounted for I2cAdapter

impl AlwaysRefCounted for I2cClient

impl AlwaysRefCounted for Interface

impl AlwaysRefCounted for LocalFile

impl AlwaysRefCounted for Mm

impl AlwaysRefCounted for MmWithUser

impl AlwaysRefCounted for MmWithUserAsync

impl AlwaysRefCounted for OPP

SAFETY: The type invariants guarantee that OPP is always refcounted.

impl AlwaysRefCounted for PidNamespace

impl AlwaysRefCounted for Task

impl<T: Driver> AlwaysRefCounted for kernel::drm::device::Device<T>

impl<T: DriverGpuVm> AlwaysRefCounted for GpuVm<T>

impl<T: DriverGpuVm> AlwaysRefCounted for GpuVmBo<T>

impl<T: Operations> AlwaysRefCounted for kernel::fwctl::Device<T>

impl<T: Operations> AlwaysRefCounted for Request<T>

impl<T: PwmOps> AlwaysRefCounted for Chip<T>

impl<T> AlwaysRefCounted for kernel::drm::gem::shmem::Object<T>

where Self: IntoGEMObject, T: DriverObject,

impl<T> AlwaysRefCounted for kernel::drm::gem::Object<T>

where Self: IntoGEMObject, T: DriverObject,