Re: [PATCH v2 0/1] device: rust: change the name function

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Sep 30, 2024 at 09:39:55AM -0300, Guilherme Giacomo Simoes wrote:
> Why did I make this change?
> This function "Device::from_raw()" increments the refcount by this command "bindings::get_device(prt)". This can be confused because the function Arc::from_raw() from the standard library, doesn't increment the refcount.
> 
> This discussion is in
> https://rust-for-linux.zulipchat.com/#narrow/stream/291566-Library/topic/Inconsistency.20of.20.60from_raw.60.2E
> 
> The options can be:
> 1) Rename the function for don't make confusing with the Arc::from_raw().
> 2) Remove this function and use the unsafe { Device::as_ref(ptr) }.into() when I need the get pointer for the device.
> 
> Proposed solution
> I like the first option. Because, how was will commented by Boqun Feng , when the people write the "unsafe { Device::as_ref(ptr) }.into()" again, again and again... inevitably anybody will create a help function for this.
> 
> Then I think that we should rename this function for Device::get_from_raw() or maybe Device::get_device() and I like more of the second option because, this will be equal the get_device() function that already exists in .c code.
> 
> 
> How do I test this:
> I create this simple file in sample/rust/device.rs
> """"""""
> use kernel::device::Device;
> use kernel::prelude::*;
> use kernel::types::ARef;
> 
> module! {
>     type: DeviceTest,
>     name: "device_test",
>     author: "Test device",
>     description: "A simple module for test device",
>     license: "GPL",
> }
> 
> struct DeviceTest;
> 
> impl kernel::Module for DeviceTest {
>     fn init(_module: &'static ThisModule) -> Result<Self> {
>         pr_info!("initial device test");
>         let device = create_and_get_device();
>         pr_info!("device created");
> 
>         Ok(DeviceTest)
>     }
> }
> 
> impl Drop for DeviceTest {
>     fn drop(&mut self) {
>         pr_info!("bye bye driver test");
>     }
> }
> 
> fn create_and_get_device() -> ARef<Device> {
>     let device = unsafe { Device::get_device(core::ptr::null_mut()) };
>     device
> }
> """"""""
> 
> I set this in Kconfig
> diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
> index b0f74a81c8f9..7779969e7dd6 100644
> --- a/samples/rust/Kconfig
> +++ b/samples/rust/Kconfig
> @@ -37,4 +37,9 @@ config SAMPLE_RUST_HOSTPROGS
> 
>           If unsure, say N.
> 
> +config SAMPLE_DEVICE_TEST
> +       tristate "Device test"
> +       help
> +               This option is for device test
> +
>  endif # SAMPLES_RUST
> 
> 
> and in Makefile
> diff --git a/samples/rust/Makefile b/samples/rust/Makefile
> index 03086dabbea4..85a8b30100e7 100644
> --- a/samples/rust/Makefile
> +++ b/samples/rust/Makefile
> @@ -2,5 +2,6 @@
> 
>  obj-$(CONFIG_SAMPLE_RUST_MINIMAL)              += rust_minimal.o
>  obj-$(CONFIG_SAMPLE_RUST_PRINT)                        += rust_print.o
> +obj-$(CONFIG_SAMPLE_DEVICE_TEST)                       += device.o
> 
>  subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)         += hostprogs
> 
> 
> Then I enable this in menu config... compile the kernel e run this in a qemu:
> qemu-system-x86_64 -kernel bzImage -initrd initramfs.img -m 2G -machine q35 -device ich9-ahci,id=sata -drive id=disk,file=rootfs.img,if=none,format=raw -device ide-hd,drive=disk,bus=sata.0 -append "root=/dev/sda console=ttyS0" -nographic -monitor telnet:127.0.0.1:5555,server,nowai
> 
> the expected print is showing
> [    2.786174] device_test: initial device test
> [    2.786541] device_test: device created
> 
> 
> Guilherme Giacomo Simoes (1):
>   device: rust: change the name function
> 
>  rust/kernel/device.rs   | 2 +-
>  rust/kernel/firmware.rs | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> -- 
> 2.46.2
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
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