On Mon, 2022-03-14 at 21:05 +0000, Bezdeka, Florian via Xenomai wrote:
> Hi Richard,
>
> On Mon, 2022-03-14 at 21:38 +0100, Richard Weinberger via Xenomai
> wrote:
> > BITS_PER_LONG is too broad, the max number of usable bits is limited
> > by nr_cpumask_bits.
>
> I agree, BITS_PER_LONG seems wrong. But couldn't it be too small as
> well? It depends on NR_CPUS which might be > BITS_PER_LONG.
Sorry that was unclear. I assume that the size of the cpumask depends
somehow on NR_CPUS, which might be > BITS_PER_LONG. So BITS_PER_LONG
might be too small AND might be too broad.
>
> Regards,
> Florian
>
> > Found while debugging a system with CONFIG_DEBUG_PER_CPU_MAPS enabled.
> >
> > Signed-off-by: Richard Weinberger <rich...@nod.at>
> > ---
> > kernel/cobalt/sched.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/cobalt/sched.c b/kernel/cobalt/sched.c
> > index 88c4951ed814..aa65fd7f5d63 100644
> > --- a/kernel/cobalt/sched.c
> > +++ b/kernel/cobalt/sched.c
> > @@ -1370,7 +1370,7 @@ static int affinity_vfile_show(struct
> > xnvfile_regular_iterator *it,
> > unsigned long val = 0;
> > int cpu;
> >
> > - for (cpu = 0; cpu < BITS_PER_LONG; cpu++)
> > + for (cpu = 0; cpu < nr_cpumask_bits; cpu++)
> > if (cpumask_test_cpu(cpu, &cobalt_cpu_affinity))
> > val |= (1UL << cpu);
> >
> > @@ -1395,7 +1395,7 @@ static ssize_t affinity_vfile_store(struct
> > xnvfile_input *input)
> > affinity = xnsched_realtime_cpus; /* Reset to default. */
> > else {
> > cpumask_clear(&affinity);
> > - for (cpu = 0; cpu < BITS_PER_LONG; cpu++, val >>= 1) {
> > + for (cpu = 0; cpu < nr_cpumask_bits; cpu++, val >>= 1) {
> > if (val & 1) {
> > /*
> > * The new dynamic affinity must be a strict
>
