Currently, we do not ensure that APIs that require a bound device instance can
only be called with a bound device.
Examples of such APIs are Devres, dma::CoherentAllocation and
pci::Device::iomap_region().
This patch series introduces the "Bound" device context such that we can ensure
to only ever pass a bound device to APIs that require this precondition.
In order to get there, we need some prerequisites:
(1) Implement macros to consistently derive Deref implementations for the
different device contexts. For instance, Device<Core> can be dereferenced to
Device<Bound>, since all device references we get from "core" bus callbacks
are guaranteed to be from a bound device. Device<Bound> can always be
dereferenced to Device (i.e. Device<Normal>), since the "Normal" device
context has no specific requirements.
(2) Implement device context support for the generic Device type. Some APIs such
as Devres and dma::CoherentAllocation work with generic devices.
(3) Preserve device context generics in bus specific device' AsRef
implementation, such that we can derive the device context when converting
from a bus specific device reference to a generic device reference.
With this, Devres::new(), for instance, can take a &Device<Bound> argument and
hence ensure that it can't be called with a Device reference that is not
guaranteed to be bound to a driver.
A branch containing the patches can be found in [1].
[1] https://web.git.kernel.org/pub/scm/linux/kernel/git/dakr/linux.git/log/?h=rust/device-bound
Changes in v2:
- add a safety requirement for impl_device_context_deref! (thanks to Benno for
working this out)
Danilo Krummrich (9):
rust: device: implement impl_device_context_deref!
rust: device: implement impl_device_context_into_aref!
rust: device: implement device context for Device
rust: platform: preserve device context in AsRef
rust: pci: preserve device context in AsRef
rust: device: implement Bound device context
rust: pci: move iomap_region() to impl Device<Bound>
rust: devres: require a bound device
rust: dma: require a bound device
rust/kernel/device.rs | 90 ++++++++++++++++++++++++++++++++++++++++-
rust/kernel/devres.rs | 17 ++++----
rust/kernel/dma.rs | 14 +++----
rust/kernel/pci.rs | 33 +++++----------
rust/kernel/platform.rs | 32 ++++-----------
5 files changed, 121 insertions(+), 65 deletions(-)
base-commit: 0af2f6be1b4281385b618cb86ad946eded089ac8
--
2.49.0
