Commit a095d0d1 authored by Danilo Krummrich's avatar Danilo Krummrich
Browse files

rust: pci: impl TryFrom<&Device> for &pci::Device 



Implement TryFrom<&device::Device> for &Device.

This allows us to get a &pci::Device from a generic &Device in a safe
way; the conversion fails if the device' bus type does not match with
the PCI bus type.

Reviewed-by: default avatarAlice Ryhl <aliceryhl@google.com>
Reviewed-by: default avatarBenno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20250321214826.140946-3-dakr@kernel.org


[ Support device context types, use dev_is_pci() helper. - Danilo ]
Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent cfec9a16

rust/helpers/pci.c

+5 −0
Original line number Diff line number Diff line
@@ -16,3 +16,8 @@ resource_size_t rust_helper_pci_resource_len(struct pci_dev *pdev, int bar) 
{

	return pci_resource_len(pdev, bar);

}



bool rust_helper_dev_is_pci(const struct device *dev)

{

	return dev_is_pci(dev);

}

rust/kernel/pci.rs

+21 −1
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ 


use crate::{

    alloc::flags::*,

    bindings, device,

    bindings, container_of, device,

    device_id::RawDeviceId,

    devres::Devres,

    driver,
@@ -455,6 +455,26 @@ fn as_ref(&self) -> &device::Device<Ctx> { 
    }

}



impl<Ctx: device::DeviceContext> TryFrom<&device::Device<Ctx>> for &Device<Ctx> {

    type Error = kernel::error::Error;



    fn try_from(dev: &device::Device<Ctx>) -> Result<Self, Self::Error> {

        // SAFETY: By the type invariant of `Device`, `dev.as_raw()` is a valid pointer to a

        // `struct device`.

        if !unsafe { bindings::dev_is_pci(dev.as_raw()) } {

            return Err(EINVAL);

        }



        // SAFETY: We've just verified that the bus type of `dev` equals `bindings::pci_bus_type`,

        // hence `dev` must be embedded in a valid `struct pci_dev` as guaranteed by the

        // corresponding C code.

        let pdev = unsafe { container_of!(dev.as_raw(), bindings::pci_dev, dev) };



        // SAFETY: `pdev` is a valid pointer to a `struct pci_dev`.

        Ok(unsafe { &*pdev.cast() })

    }

}



// SAFETY: A `Device` is always reference-counted and can be released from any thread.

unsafe impl Send for Device {}