rust: drm: Wrap ioctl dispatch in RegistrationGuard

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Make Ioctl handlers receive a &Device<T, Registered> reference, proving
at the type level that the device is registered and its parent bus
device is bound.

This is achieved by calling registration_guard() on the Device<T, Ioctl>
obtained in ioctl dispatch context. If the device has been unplugged,
the ioctl returns -ENODEV without calling the handler.

To resolve the driver type parameter T for type inference, which the
compiler cannot propagate through method resolution and associated-type
projections alone, a dead-code closure and a helper function are used as
a type-inference anchor.

Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Tested-by: Deborah Brouwer <deborah.brouwer@collabora.com>
Link: https://patch.msgid.link/20260628145406.2107056-14-dakr@kernel.org
[ Use imperative mood in commit message; clarify __dev_ctx_cast() doc
  comment to reflect Ioctl-to-Registered cast. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

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Danilo Krummrich 2026-06-28 16:53:33 +02:00

parent 2455d5f2d5

commit 478da53e5b

3 changed files with 55 additions and 9 deletions

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12

drivers/gpu/drm/nova/file.rs

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7

drivers/gpu/drm/tyr/file.rs

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45

rust/kernel/drm/ioctl.rs

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