Re: [PATCH 1/5] cpumask: update irq_desc to use cpumask_var_t

From: Mike Travis
Date: Wed Jan 07 2009 - 17:36:29 EST


Yinghai Lu wrote:
> On Wed, Jan 7, 2009 at 11:58 AM, Mike Travis <travis@xxxxxxx> wrote:
> | --- linux-2.6-for-ingo.orig/kernel/irq/numa_migrate.c
> | +++ linux-2.6-for-ingo/kernel/irq/numa_migrate.c
> | @@ -46,6 +46,7 @@ static void init_copy_one_irq_desc(int i
> | desc->cpu = cpu;
> | lockdep_set_class(&desc->lock, &irq_desc_lock_class);
> | init_copy_kstat_irqs(old_desc, desc, cpu, nr_cpu_ids);
> |+ init_copy_desc_masks(old_desc, desc);
> | arch_init_copy_chip_data(old_desc, desc, cpu);
> | }
> |
> |@@ -76,11 +77,20 @@ static struct irq_desc *__real_move_irq_
> | node = cpu_to_node(cpu);
> | desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
> | if (!desc) {
> |- printk(KERN_ERR "irq %d: can not get new irq_desc for migration.\n", irq);
> |+ printk(KERN_ERR "irq %d: can not get new irq_desc "
> |+ "for migration.\n", irq);
> | /* still use old one */
> | desc = old_desc;
> | goto out_unlock;
> | }
> |+ if (!init_alloc_desc_masks(desc, node, false)) {
> |+ printk(KERN_ERR "irq %d: can not get new irq_desc cpumask "
> |+ "for migration.\n", irq);
> |+ /* still use old one */
> |+ kfree(desc);
> |+ desc = old_desc;
> |+ goto out_unlock;
> |+ }
> | init_copy_one_irq_desc(irq, old_desc, desc, cpu);
>
> desc new mask_var (allocated) aka the pointer is overwritten here...
> you may need to calling move init_alloc_desc_masks() into
> init_copy_one_irq_desc()

Wouldn't this in init_copy_one_irq_desc() take care of that?

@@ -46,6 +46,7 @@ static void init_copy_one_irq_desc(int i
desc->cpu = cpu;
lockdep_set_class(&desc->lock, &irq_desc_lock_class);
init_copy_kstat_irqs(old_desc, desc, cpu, nr_cpu_ids);
+ init_copy_desc_masks(old_desc, desc);
arch_init_copy_chip_data(old_desc, desc, cpu);

where:

static inline void init_copy_desc_masks(struct irq_desc *old_desc,
struct irq_desc *new_desc)
{
#ifdef CONFIG_CPUMASKS_OFFSTACK
cpumask_copy(new_desc->affinity, old_desc->affinity);

#ifdef CONFIG_GENERIC_PENDING_IRQ
cpumask_copy(new_desc->pending_mask, old_desc->pending_mask);
#endif
#endif
}

In other words if the masks are not a cpumask[1] but instead a
*cpumask pointer, then the old masks are copied to the new desc/

Or am I missing your point?

Thanks!
Mike

>
> | irq_desc_ptrs[irq] = desc;
>
> YH
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