DRM ioctls run in process context without any guarantee that the parent bus device is still bound. This series solves the problem by introducing UnbindGuard -- a guard representing a drm_dev_enter/exit SRCU critical section that proves the parent bus device is bound for the lifetime of the guard.
On top of that, add RegistrationData as a ForLt associated type on drm::Driver, allowing drivers to store data whose lifetime is tied to the parent bus device binding scope. The data is allocated in Registration::new(), lifetime-erased to 'static for storage, and made accessible through UnbindGuard::registration_data() with the lifetime shortened back via ForLt::cast_ref. Also update the ioctl dispatch macro to wrap every handler in an UnbindGuard, returning ENODEV if the device has been unplugged, and pass both the bound parent bus device and the registration data as arguments to handlers. This series is based on [1], as well as Lyudes drm::DeviceContext work; a branch with all patches can be found in [2]. [1] https://lore.kernel.org/driver-core/[email protected]/ [2] https://git.kernel.org/pub/scm/linux/kernel/git/dakr/linux.git/log/?h=drm-lifetime Danilo Krummrich (6): rust: drm: Add Driver::ParentDevice associated type rust: drm: Add UnbindGuard for drm_dev_enter/exit critical sections rust: drm: Add RegistrationData to drm::Driver rust: drm: Wrap ioctl dispatch in UnbindGuard rust: drm: Pass registration data to ioctl handlers rust: drm: Pass bound parent device to ioctl handlers drivers/gpu/drm/nova/driver.rs | 14 +++- drivers/gpu/drm/nova/file.rs | 8 ++ drivers/gpu/drm/tyr/driver.rs | 12 ++- drivers/gpu/drm/tyr/file.rs | 4 + rust/kernel/drm/device.rs | 134 ++++++++++++++++++++++++++++++++- rust/kernel/drm/driver.rs | 100 +++++++++++++++++++----- rust/kernel/drm/ioctl.rs | 17 ++++- rust/kernel/drm/mod.rs | 1 + 8 files changed, 258 insertions(+), 32 deletions(-) -- 2.54.0
