Run every ioctl handler inside a drm_dev_enter/exit critical section via RegistrationGuard. If the device has been unplugged, the ioctl returns ENODEV without calling the handler.
A never-called closure anchors the driver type for the compiler by tying dev's type to the handler's first parameter, which the compiler cannot infer through method resolution and associated-type projections alone. Signed-off-by: Danilo Krummrich <[email protected]> --- rust/kernel/drm/ioctl.rs | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/rust/kernel/drm/ioctl.rs b/rust/kernel/drm/ioctl.rs index cf328101dde4..c6a03be018e6 100644 --- a/rust/kernel/drm/ioctl.rs +++ b/rust/kernel/drm/ioctl.rs @@ -87,7 +87,10 @@ pub mod internal { /// file: &kernel::drm::File<Self::File>, /// ) -> Result<u32> /// ``` -/// where `Self` is the drm::drv::Driver implementation these ioctls are being declared within. +/// where `Self` is the `drm::Driver` implementation these ioctls are being declared within. +/// +/// The ioctl runs inside a `drm_dev_enter/exit` critical section. If the device has been +/// unplugged, the ioctl returns `ENODEV` without calling the handler. /// /// # Examples /// @@ -135,6 +138,16 @@ macro_rules! declare_drm_ioctls { // 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 = $crate::drm::device::Device::from_raw(raw_dev); + + // Type-inference anchor: the closure is never called but ties `dev`'s + // type to `$func`'s first parameter, which the compiler cannot infer + // through method resolution and associated-type projections alone. + #[allow(unreachable_code)] + let _ = || $func(dev, unreachable!(), unreachable!()); + + let Some(_guard) = dev.registration_guard() else { + return $crate::error::code::ENODEV.to_errno(); + }; // 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. -- 2.54.0
