On Wed, Jul 17, 2019 at 07:11:47PM +0800, Herbert Xu wrote:
> On Tue, Jul 16, 2019 at 12:32:53PM -0400, Daniel Jordan wrote:
> > Testing padata with the tcrypt module on a 5.2 kernel...
>
> Thanks for the patch!
>
> And here is an incremental patch to get rid of the timer that
> appears to be an attempt at fixing a problem related to this.
Nice, +1 for getting rid of the timer.
> diff --git a/kernel/padata.c b/kernel/padata.c
> index 15a8ad63f4ff..b5dfc21e976f 100644
> --- a/kernel/padata.c
> +++ b/kernel/padata.c
> @@ -165,23 +165,12 @@ EXPORT_SYMBOL(padata_do_parallel);
> */
> static struct padata_priv *padata_get_next(struct parallel_data *pd)
> {
> - int cpu, num_cpus;
> - unsigned int next_nr, next_index;
> struct padata_parallel_queue *next_queue;
> struct padata_priv *padata;
> struct padata_list *reorder;
> + int cpu = pd->cpu;
>
> - num_cpus = cpumask_weight(pd->cpumask.pcpu);
> -
> - /*
> - * Calculate the percpu reorder queue and the sequence
> - * number of the next object.
> - */
> - next_nr = pd->processed;
> - next_index = next_nr % num_cpus;
> - cpu = padata_index_to_cpu(pd, next_index);
> next_queue = per_cpu_ptr(pd->pqueue, cpu);
> -
> reorder = &next_queue->reorder;
>
> spin_lock(&reorder->lock);
> @@ -192,7 +181,8 @@ static struct padata_priv *padata_get_next(struct parallel_data *pd)
> list_del_init(&padata->list);
> atomic_dec(&pd->reorder_objects);
>
> - pd->processed++;
> + pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, 0,
> + false);
We'll crash when cpumask_next_wrap returns nr_cpumask_bits and later try to get
the corresponding per-cpu queue.
This handles that as well as the case where there's only 1 CPU in the parallel
mask:
diff --git a/kernel/padata.c b/kernel/padata.c
index b5dfc21e976f..ab352839df04 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -181,8 +181,10 @@ static struct padata_priv *padata_get_next(struct parallel_data *pd)
list_del_init(&padata->list);
atomic_dec(&pd->reorder_objects);
- pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, 0,
- false);
+ if (cpumask_weight(pd->cpumask.pcpu) > 1) {
+ pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, cpu,
+ false);
+ }
spin_unlock(&reorder->lock);
goto out;
Haven't finished looking at the patch, but have to run somewhere for now, will
pick it up later today.
