Re: [PATCH v4 14/14] of: Improve __of_add_property_sysfs() readability

[Krzysztof Kozlowski]

On Sat, Jan 11, 2025 at 07:48:48AM +0800, Zijun Hu wrote:
> On 2025/1/11 04:41, Rob Herring wrote:
> > On Thu, Jan 09, 2025 at 09:27:05PM +0800, Zijun Hu wrote:
> >> From: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
> >>
> >> __of_add_property_sysfs() hard codes string "security-" length as 9, but
> >> that is not obvious for readers.
> >>
> >> Improve its readability by using strlen().
> > 
> > Does the compiler optimize the strlen call away? Maybe, maybe not. If 
> > not, that's N calls to strlen() where N is the number of properties in 
> > your DT. That's in the 1000s easily.
> > 
> > Do you really want to go test enough compiler versions we support to 
> > feel confident this is optimized away. I don't.
> > 
> 
> i understand your concern about performance.
> perhaps, such impact about performance may be ignored for linux OS.
> 
> what about below solution ?
> 
> const char security_prefix[] = "security-";
> use 'sizeof(security_prefix) - 1' for the length of string.

Code is still not equivalent - just de-assemble it and you will see
some overhead.

Maybe just introduce builtin_strlen() to string.h and use such? It would
be the pretty obvious code.


Best regards,
Krzysztof