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2025-05-12rust: devres: fix doctest build under `!CONFIG_PCI`Miguel Ojeda1-0/+1
The doctest requires `CONFIG_PCI`: error[E0432]: unresolved import `kernel::pci` --> rust/doctests_kernel_generated.rs:2689:44 | 2689 | use kernel::{device::Core, devres::Devres, pci}; | ^^^ no `pci` in the root | note: found an item that was configured out --> rust/kernel/lib.rs:96:9 note: the item is gated here --> rust/kernel/lib.rs:95:1 Thus conditionally compile it (which still checks the syntax). Fixes: f301cb978c06 ("rust: devres: implement Devres::access()") Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Link: https://lore.kernel.org/r/20250511182533.1016163-1-ojeda@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-05-04rust: devres: implement Devres::access()Danilo Krummrich1-0/+38
Implement a direct accessor for the data stored within the Devres for cases where we can prove that we own a reference to a Device<Bound> (i.e. a bound device) of the same device that was used to create the corresponding Devres container. Usually, when accessing the data stored within a Devres container, it is not clear whether the data has been revoked already due to the device being unbound and, hence, we have to try whether the access is possible and subsequently keep holding the RCU read lock for the duration of the access. However, when we can prove that we hold a reference to Device<Bound> matching the device the Devres container has been created with, we can guarantee that the device is not unbound for the duration of the lifetime of the Device<Bound> reference and, hence, it is not possible for the data within the Devres container to be revoked. Therefore, in this case, we can bypass the atomic check and the RCU read lock, which is a great optimization and simplification for drivers. Reviewed-by: Christian Schrefl <chrisi.schrefl@gmail.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com> Link: https://lore.kernel.org/r/20250428140137.468709-3-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-04-17rust: devres: require a bound deviceDanilo Krummrich1-10/+7
Require the Bound device context to be able to a new Devres container. This ensures that we can't register devres callbacks for unbound devices. Link: https://lore.kernel.org/r/20250413173758.12068-9-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-02-25rust: io: fix devres test with new io accessor functionsFiona Behrens1-1/+1
Fix doctest of `Devres` which still used `writeb` instead of `write8`. Fixes: 354fd6e86fac ("rust: io: rename `io::Io` accessors") Signed-off-by: Fiona Behrens <me@kloenk.dev> Link: https://lore.kernel.org/r/20250224-rust-iowrite-read8-fix-v1-1-c6abee346897@kloenk.dev Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-10rust: devres: remove action in `Devres::drop`Danilo Krummrich1-12/+35
So far `DevresInner` is kept alive, even if `Devres` is dropped until the devres callback is executed to avoid a WARN() when the action has been released already. With the introduction of devm_remove_action_nowarn() we can remove the action in `Devres::drop`, handle the case where the action has been released already and hence also free `DevresInner`. Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250107122609.8135-2-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: add devres abstractionDanilo Krummrich1-0/+178
Add a Rust abstraction for the kernel's devres (device resource management) implementation. The Devres type acts as a container to manage the lifetime and accessibility of device bound resources. Therefore it registers a devres callback and revokes access to the resource on invocation. Users of the Devres abstraction can simply free the corresponding resources in their Drop implementation, which is invoked when either the Devres instance goes out of scope or the devres callback leads to the resource being revoked, which implies a call to drop_in_place(). Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Link: https://lore.kernel.org/r/20241219170425.12036-9-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>