Re: [PATCH v5 7/7] string: Implement strstarts() with strprefix()

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Fri, Nov 13, 2026 at 03:59:46PM +0100, Alejandro Colomar wrote:
> > On Fri, Nov 13, 2026 at 02:11:17PM +0100, Alejandro Colomar wrote:

...

> > >  static inline bool strstarts(const char *str, const char *prefix)
> > >  {
> > > -	return strncmp(str, prefix, strlen(prefix)) == 0;
> > > +	return strprefix(str, prefix);
> > >  }
> > 
> > There is no sense to keep strstarts() at this point.
> 
> I agree.  Actually, it seems my guess that strprefix() would be
> optimized out was wrong, because the kernel builds with
> -fno-delete-null-pointer-checks and other flags that prevent this
> optimization.
> 
> > Can it be simply redefinition?
> 
> I was thinking that we could just do a simple search and replace
> s/strstarts/strends/, prepending !! in some cases if needed.
> 
> By 'redefinition', do you mean making strstarts() return a pointer
> instead of a bool?  A problem with strstarts() is again the function
> name: it doesn't seem to naturally fit with a function that returns a
> pointer to the position.  It also doesn't clarify whether it searches
> for a string, or for a list of characters (like for example strspn(3)).

We have str_has_*() for that?

> I prefer replacing strstarts()/strends() with strprefix()/strsuffix().
> 
> But if you prefer changing strstarts() to return a pointer, I'm also
> okay-ish with it.  It's not a perfect name, but I can live with it.
> 
> > However, after looking at the uses in the kernel, I prefer
> > to see the strprefix() be not implemented at all, just optimization against
> > strstarts()/strends() if required can be performed.
> 
> I don't understand this last sentence.

It's basically repeats the idea of having only one pair out of two.

With this series will be

str_has_previx()
strstarts()
strends()
strprefix()
// potentially strsuffix()

To me seems too many for the similar task. I understand that trace user is
special one, but does it use strstarts()/strends()?

Despite on naming I think we just good to have only str_has*() and one of
strprefix()/strsuffix(), strstarts()/strends().

-- 
With Best Regards,
Andy Shevchenko