Re: [PATCH] powerpc/dt_cpu_ftrs: Avoid separate strlen() in scan_callback()

[Thorsten Blum]

On Tue, Jun 30, 2026 at 06:38:10PM +0100, David Laight wrote:
> On Tue, 30 Jun 2026 17:46:56 +0200
> Thorsten Blum <thorsten.blum@xxxxxxxxx> wrote:
> 
> > Use the return value of strscpy() when copying the display name instead
> > of checking the source string length with strlen() first.
> > 
> > Keep dt_cpu_name static but move it into dt_cpu_ftrs_scan_callback(),
> > where it is assigned.
> > 
> > Signed-off-by: Thorsten Blum <thorsten.blum@xxxxxxxxx>
> > ---
> >  arch/powerpc/kernel/dt_cpu_ftrs.c | 7 ++-----
> >  1 file changed, 2 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
> > index 3af6c06af02f..8d8e94e4d2bc 100644
> > --- a/arch/powerpc/kernel/dt_cpu_ftrs.c
> > +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
> > @@ -90,8 +90,6 @@ static void __restore_cpu_cpufeatures(void)
> >  		init_pmu_registers();
> >  }
> >  
> > -static char dt_cpu_name[64];
> > -
> >  static struct cpu_spec __initdata base_cpu_spec = {
> >  	.cpu_name		= NULL,
> >  	.cpu_features		= CPU_FTRS_DT_CPU_BASE,
> > @@ -1069,6 +1067,7 @@ static int __init count_cpufeatures_subnodes(unsigned long node,
> >  static int __init dt_cpu_ftrs_scan_callback(unsigned long node, const char
> >  					    *uname, int depth, void *data)
> >  {
> > +	static char dt_cpu_name[64];
> >  	const __be32 *prop;
> >  	int count, i;
> >  	u32 isa;
> > @@ -1106,10 +1105,8 @@ static int __init dt_cpu_ftrs_scan_callback(unsigned long node, const char
> >  	}
> >  
> >  	prop = of_get_flat_dt_prop(node, "display-name", NULL);
> > -	if (prop && strlen((char *)prop) != 0) {
> > -		strscpy(dt_cpu_name, (char *)prop, sizeof(dt_cpu_name));
> > +	if (prop && strscpy(dt_cpu_name, (char *)prop) != 0)
> 
> That is different code.
> The old code only did the copy if the new string was non-empty.

Good catch, thanks!

I just sent a v2:
https://lore.kernel.org/lkml/20260701114428.818748-3-thorsten.blum@xxxxxxxxx/