The core library's `CStr` has a `from_bytes_until_nul` method that we
can leverage to simplify this function.

Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpu/nova-core/util.rs | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/nova-core/util.rs b/drivers/gpu/nova-core/util.rs
index 8b2a4b99c55b..2cccbce78c14 100644
--- a/drivers/gpu/nova-core/util.rs
+++ b/drivers/gpu/nova-core/util.rs
@@ -2,15 +2,10 @@
 
 /// Converts a null-terminated byte slice to a string, or `None` if the array does not
 /// contains any null byte or contains invalid characters.
-///
-/// Contrary to [`core::ffi::CStr::from_bytes_with_nul`], the null byte can be anywhere in the
-/// slice, and not only in the last position.
 pub(crate) fn str_from_null_terminated(bytes: &[u8]) -> Option<&str> {
     use core::ffi::CStr;
 
-    bytes
-        .iter()
-        .position(|&b| b == 0)
-        .and_then(|null_pos| CStr::from_bytes_with_nul(&bytes[..=null_pos]).ok())
+    CStr::from_bytes_until_nul(bytes)
+        .ok()
         .and_then(|cstr| cstr.to_str().ok())
 }

-- 
2.52.0

On 12/15/25 8:27 PM, Alexandre Courbot wrote:
> The core library's `CStr` has a `from_bytes_until_nul` method that we
> can leverage to simplify this function.
> 
> Reviewed-by: Lyude Paul <lyude@redhat.com>
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---
>  drivers/gpu/nova-core/util.rs | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/nova-core/util.rs b/drivers/gpu/nova-core/util.rs
> index 8b2a4b99c55b..2cccbce78c14 100644
> --- a/drivers/gpu/nova-core/util.rs
> +++ b/drivers/gpu/nova-core/util.rs
> @@ -2,15 +2,10 @@
>  
>  /// Converts a null-terminated byte slice to a string, or `None` if the array does not
>  /// contains any null byte or contains invalid characters.
> -///
> -/// Contrary to [`core::ffi::CStr::from_bytes_with_nul`], the null byte can be anywhere in the
> -/// slice, and not only in the last position.
>  pub(crate) fn str_from_null_terminated(bytes: &[u8]) -> Option<&str> {
>      use core::ffi::CStr;
>  
> -    bytes
> -        .iter()
> -        .position(|&b| b == 0)
> -        .and_then(|null_pos| CStr::from_bytes_with_nul(&bytes[..=null_pos]).ok())
> +    CStr::from_bytes_until_nul(bytes)
> +        .ok()

I guess I should have reviewed this patch, before creating my version of this.
I went so far as to delete this file entirely, see if you prefer that, it's
otherwise the same core idea, but with more cleanup. [1]

[1] https://lore.kernel.org/20260103013438.247759-1-jhubbard@nvidia.com

>          .and_then(|cstr| cstr.to_str().ok())
>  }
> 

thanks,
-- 
John Hubbard

On Sat Jan 3, 2026 at 4:37 AM CET, John Hubbard wrote:
> On 12/15/25 8:27 PM, Alexandre Courbot wrote:
>> The core library's `CStr` has a `from_bytes_until_nul` method that we
>> can leverage to simplify this function.
>> 
>> Reviewed-by: Lyude Paul <lyude@redhat.com>
>> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
>> ---
>>  drivers/gpu/nova-core/util.rs | 9 ++-------
>>  1 file changed, 2 insertions(+), 7 deletions(-)
>> 
>> diff --git a/drivers/gpu/nova-core/util.rs b/drivers/gpu/nova-core/util.rs
>> index 8b2a4b99c55b..2cccbce78c14 100644
>> --- a/drivers/gpu/nova-core/util.rs
>> +++ b/drivers/gpu/nova-core/util.rs
>> @@ -2,15 +2,10 @@
>>  
>>  /// Converts a null-terminated byte slice to a string, or `None` if the array does not
>>  /// contains any null byte or contains invalid characters.
>> -///
>> -/// Contrary to [`core::ffi::CStr::from_bytes_with_nul`], the null byte can be anywhere in the
>> -/// slice, and not only in the last position.
>>  pub(crate) fn str_from_null_terminated(bytes: &[u8]) -> Option<&str> {
>>      use core::ffi::CStr;
>>  
>> -    bytes
>> -        .iter()
>> -        .position(|&b| b == 0)
>> -        .and_then(|null_pos| CStr::from_bytes_with_nul(&bytes[..=null_pos]).ok())
>> +    CStr::from_bytes_until_nul(bytes)
>> +        .ok()
>
> I guess I should have reviewed this patch, before creating my version of this.
> I went so far as to delete this file entirely, see if you prefer that, it's
> otherwise the same core idea, but with more cleanup. [1]
>
> [1] https://lore.kernel.org/20260103013438.247759-1-jhubbard@nvidia.com

Yes, let's remove str_from_null_terminated() entirely.

>>          .and_then(|cstr| cstr.to_str().ok())

Additionally, why do we return an Option here? While an error can only ever happen if
the given slice does not contain any NULL byte, I don't see why we discard the
error code.

On Sat Jan 3, 2026 at 7:14 PM JST, Danilo Krummrich wrote:
> On Sat Jan 3, 2026 at 4:37 AM CET, John Hubbard wrote:
>> On 12/15/25 8:27 PM, Alexandre Courbot wrote:
>>> The core library's `CStr` has a `from_bytes_until_nul` method that we
>>> can leverage to simplify this function.
>>> 
>>> Reviewed-by: Lyude Paul <lyude@redhat.com>
>>> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
>>> ---
>>>  drivers/gpu/nova-core/util.rs | 9 ++-------
>>>  1 file changed, 2 insertions(+), 7 deletions(-)
>>> 
>>> diff --git a/drivers/gpu/nova-core/util.rs b/drivers/gpu/nova-core/util.rs
>>> index 8b2a4b99c55b..2cccbce78c14 100644
>>> --- a/drivers/gpu/nova-core/util.rs
>>> +++ b/drivers/gpu/nova-core/util.rs
>>> @@ -2,15 +2,10 @@
>>>  
>>>  /// Converts a null-terminated byte slice to a string, or `None` if the array does not
>>>  /// contains any null byte or contains invalid characters.
>>> -///
>>> -/// Contrary to [`core::ffi::CStr::from_bytes_with_nul`], the null byte can be anywhere in the
>>> -/// slice, and not only in the last position.
>>>  pub(crate) fn str_from_null_terminated(bytes: &[u8]) -> Option<&str> {
>>>      use core::ffi::CStr;
>>>  
>>> -    bytes
>>> -        .iter()
>>> -        .position(|&b| b == 0)
>>> -        .and_then(|null_pos| CStr::from_bytes_with_nul(&bytes[..=null_pos]).ok())
>>> +    CStr::from_bytes_until_nul(bytes)
>>> +        .ok()
>>
>> I guess I should have reviewed this patch, before creating my version of this.
>> I went so far as to delete this file entirely, see if you prefer that, it's
>> otherwise the same core idea, but with more cleanup. [1]
>>
>> [1] https://lore.kernel.org/20260103013438.247759-1-jhubbard@nvidia.com
>
> Yes, let's remove str_from_null_terminated() entirely.

Removing that method is perfectly fine IMHO, it was only using in a
couple of places and is easily emulated.

>
>>>          .and_then(|cstr| cstr.to_str().ok())
>
> Additionally, why do we return an Option here? While an error can only ever happen if
> the given slice does not contain any NULL byte, I don't see why we discard the
> error code.

I guess I didn't want to change the function's prototype, but yeah this
is sloppy and another good reason to get rid of it.

I'll respin the series once the patches in -fixes are visible in -next.