Re: [PATCH linux-next] genirq: use sysfs_emit() instead of scnprintf().

[Jiri Slaby]

On 17. 03. 25, 7:12, Jiri Slaby wrote:
> > > --- a/kernel/irq/irqdesc.c
> > >
> > > +++ b/kernel/irq/irqdesc.c
> > >
> > > @@ -257,11 +257,11 @@ static ssize_t per_cpu_count_show(struct 
> > > kobject *kobj,
> > >
> > > for_each_possible_cpu(cpu) {
> > >
> > > unsigned int c = irq_desc_kstat_cpu(desc, cpu);
> > >
> > > -ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%u", p, c);
> > >
> > > +ret += sysfs_emit(buf + ret, "%s%u", p, c);
> >
> > Well, so the PAGE_SIZE boundary is never checked for this stacking 
> > write now, right?
>
> ^^^ not really clear what I mean, so:
>
> If you advance buf by ret every time, sysfs_emit() still would only 
> check if buf is not written more than "PAGE_SIZE" bytes. But the 
> original code performs this proper "PAGE_SIZE - ret" check.

Apparently, sysfs_emit_at() is your friend here.

> > thanks,
--
js
suse labs