Re: [PATCH 2/4] rust: samples: remove redundant `.as_ref()` for `dev_*` print

["Gary Guo" <gary@garyguo.net>]

On Wed Jan 21, 2026 at 6:52 AM GMT, Dirk Behme wrote:
> Hi Gary
>
> On 20/01/2026 19:11, Gary Guo wrote:
>> From: Gary Guo <gary@garyguo.net>
>> 
>> This is now handled by the macro itself.
>> 
>> Signed-off-by: Gary Guo <gary@garyguo.net>
>> ---
>>   samples/rust/rust_dma.rs              |  2 +-
>>   samples/rust/rust_driver_auxiliary.rs |  2 +-
>>   samples/rust/rust_driver_faux.rs      |  2 +-
>>   samples/rust/rust_driver_i2c.rs       |  4 ++--
>>   samples/rust/rust_driver_pci.rs       |  6 +++---
>>   samples/rust/rust_driver_platform.rs  |  2 +-
>>   samples/rust/rust_i2c_client.rs       | 10 ++--------
>>   7 files changed, 11 insertions(+), 17 deletions(-)
>> 
>> diff --git a/samples/rust/rust_dma.rs b/samples/rust/rust_dma.rs
>> index f53bce2a73e3..a9ac7937ebaf 100644
>> --- a/samples/rust/rust_dma.rs
>> +++ b/samples/rust/rust_dma.rs
>> @@ -57,7 +57,7 @@ impl pci::Driver for DmaSampleDriver {
>>   
>>       fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> {
>>           pin_init::pin_init_scope(move || {
>> -            dev_info!(pdev.as_ref(), "Probe DMA test driver.\n");
>> +            dev_info!(pdev, "Probe DMA test driver.\n");
>>   
>>               let mask = DmaMask::new::<64>();
>>   
>> diff --git a/samples/rust/rust_driver_auxiliary.rs b/samples/rust/rust_driver_auxiliary.rs
>> index f148124fe81f..c20961f16835 100644
>> --- a/samples/rust/rust_driver_auxiliary.rs
>> +++ b/samples/rust/rust_driver_auxiliary.rs
>> @@ -39,7 +39,7 @@ impl auxiliary::Driver for AuxiliaryDriver {
>>   
>>       fn probe(adev: &auxiliary::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> {
>>           dev_info!(
>> -            adev.as_ref(),
>> +            adev,
>>               "Probing auxiliary driver for auxiliary device with id={}\n",
>>               adev.id()
>>           );
>> diff --git a/samples/rust/rust_driver_faux.rs b/samples/rust/rust_driver_faux.rs
>> index 5330b77ea986..99876c8e3743 100644
>> --- a/samples/rust/rust_driver_faux.rs
>> +++ b/samples/rust/rust_driver_faux.rs
>> @@ -26,7 +26,7 @@ fn init(_module: &'static ThisModule) -> Result<Self> {
>>   
>>           let reg = faux::Registration::new(c"rust-faux-sample-device", None)?;
>>   
>> -        dev_info!(reg.as_ref(), "Hello from faux device!\n");
>> +        dev_info!(reg, "Hello from faux device!\n");
>>   
>>           Ok(Self { _reg: reg })
>>       }
>> diff --git a/samples/rust/rust_driver_i2c.rs b/samples/rust/rust_driver_i2c.rs
>> index 6be79f9e9fb5..e71b77196163 100644
>> --- a/samples/rust/rust_driver_i2c.rs
>> +++ b/samples/rust/rust_driver_i2c.rs
>> @@ -56,11 +56,11 @@ fn probe(
>>       }
>>   
>>       fn shutdown(idev: &i2c::I2cClient<Core>, _this: Pin<&Self>) {
>> -        dev_info!(idev.as_ref(), "Shutdown Rust I2C driver sample.\n");
>> +        dev_info!(idev, "Shutdown Rust I2C driver sample.\n");
>>       }
>>   
>>       fn unbind(idev: &i2c::I2cClient<Core>, _this: Pin<&Self>) {
>> -        dev_info!(idev.as_ref(), "Unbind Rust I2C driver sample.\n");
>> +        dev_info!(idev, "Unbind Rust I2C driver sample.\n");
>>       }
>>   }
>>   
>> diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs
>> index ef04c6401e6a..d50828b642e5 100644
>> --- a/samples/rust/rust_driver_pci.rs
>> +++ b/samples/rust/rust_driver_pci.rs
>> @@ -75,7 +75,7 @@ fn probe(pdev: &pci::Device<Core>, info: &Self::IdInfo) -> impl PinInit<Self, Er
>>           pin_init::pin_init_scope(move || {
>>               let vendor = pdev.vendor_id();
>>               dev_dbg!(
>> -                pdev.as_ref(),
>> +                pdev,
>>                   "Probe Rust PCI driver sample (PCI ID: {}, 0x{:x}).\n",
>>                   vendor,
>>                   pdev.device_id()
>> @@ -91,7 +91,7 @@ fn probe(pdev: &pci::Device<Core>, info: &Self::IdInfo) -> impl PinInit<Self, Er
>>                       let bar = bar.access(pdev.as_ref())?;
>>   
>>                       dev_info!(
>> -                        pdev.as_ref(),
>> +                        pdev,
>>                           "pci-testdev data-match count: {}\n",
>>                           Self::testdev(info, bar)?
>>                       );
>> @@ -112,7 +112,7 @@ fn unbind(pdev: &pci::Device<Core>, this: Pin<&Self>) {
>>   #[pinned_drop]
>>   impl PinnedDrop for SampleDriver {
>>       fn drop(self: Pin<&mut Self>) {
>> -        dev_dbg!(self.pdev.as_ref(), "Remove Rust PCI driver sample.\n");
>> +        dev_dbg!(self.pdev, "Remove Rust PCI driver sample.\n");
>>       }
>>   }
>>   
>> diff --git a/samples/rust/rust_driver_platform.rs b/samples/rust/rust_driver_platform.rs
>> index 9537dc38c563..f2229d176fb9 100644
>> --- a/samples/rust/rust_driver_platform.rs
>> +++ b/samples/rust/rust_driver_platform.rs
>> @@ -180,7 +180,7 @@ fn properties_parse(dev: &device::Device) -> Result {
>>   
>>   impl Drop for SampleDriver {
>>       fn drop(&mut self) {
>> -        dev_dbg!(self.pdev.as_ref(), "Remove Rust Platform driver sample.\n");
>> +        dev_dbg!(self.pdev, "Remove Rust Platform driver sample.\n");
>>       }
>>   }
>>   
>> diff --git a/samples/rust/rust_i2c_client.rs b/samples/rust/rust_i2c_client.rs
>> index 8d2c12e535b0..72da5499f150 100644
>> --- a/samples/rust/rust_i2c_client.rs
>> +++ b/samples/rust/rust_i2c_client.rs
>> @@ -113,10 +113,7 @@ fn probe(
>>           pdev: &platform::Device<device::Core>,
>>           _info: Option<&Self::IdInfo>,
>>       ) -> impl PinInit<Self, Error> {
>> -        dev_info!(
>> -            pdev.as_ref(),
>> -            "Probe Rust I2C Client registration sample.\n"
>> -        );
>> +        dev_info!(pdev, "Probe Rust I2C Client registration sample.\n");
>>   
>>           kernel::try_pin_init!( Self {
>>               parent_dev: pdev.into(),
>> @@ -130,10 +127,7 @@ fn probe(
>>       }
>>   
>>       fn unbind(pdev: &platform::Device<device::Core>, _this: Pin<&Self>) {
>> -        dev_info!(
>> -            pdev.as_ref(),
>> -            "Unbind Rust I2C Client registration sample.\n"
>> -        );
>> +        dev_info!(pdev, "Unbind Rust I2C Client registration sample.\n");
>>       }
>>   }
>
>
> At least in samples/rust we have several places where we added helper 
> variables for `dev`. For example in rust_driver_platform.rs [1] we have
>
> let dev = pdev.as_ref();
> dev_dbg!(dev, "Probe Rust Platform driver sample.\n");
>
> Do we want to keep this?
>
> I think there are places where this `dev` helper variable is used for 
> printing, only. And there are places, like in the `probe()` of 
> rust_driver_platform.rs, where the `dev` helper is additionally used 
> elsewhere:
>
> ... Self::properties_parse(dev)?;
>
> Hmm, I'm somehow under the impression what to use when in the end 
> becomes slightly confusing in sum?

Hi Dirk,

If you already need to be obtain `&Device`, then I would say either is fine.
The `AsRef` impl of devices are zero-cost operations anyway.

The motivation behind the patch is that in a lot of cases we only need `&Device`
specifically to print, which is something that I want to avoid.

Best,
Gary