Re: [PATCH v2 2/2] genirq: Allow irq_desc to carry the union of stacked irq_chip flags

[Jiang Liu <jiang.liu@linux.intel.com>]

On 2015/1/23 23:55, Thomas Gleixner wrote:
> On Wed, 14 Jan 2015, Marc Zyngier wrote:
> 
>> The current infrastructure for stacked domains doesn't propagate
>> irq_chip flags, and as we only look at the top-level irq_chip,
>> we may miss a number of critical flags.
>>
>> This patch accumulates the flags into a new set, stored at the
>> irq_desc level, with an additional flag to indicate that this is
>> a stack of irqchip. The accessor is updated to return the right one.
> 
>>  static inline unsigned long irq_desc_get_chip_flags(struct irq_desc *desc)
>>  {
>> +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
>> +	if (desc->chip_flags & IRQCHIP_STACKED_CHIPS)
>> +		return desc->chip_flags;
>> +#endif
>>  	return desc->irq_data.chip->flags;
> 
> We can avoid the extra conditional if we just make the accumulated
> flags unconditional and collect them even for the !hierarchy case.
> 
> Also this patch is missing that chips can be swapped at runtime either
> via the normal interfaces or via __irq_set_chip_handler_name_locked().
> 
> This needs to be addressed otherwise we might end up looking at the
> wrong flags.
I'm splitting irq_data into irq_common_data and irq_data, seems
we could host flags by using irq_common_data instead of irq_desc.

> 
> Thanks,
> 
> 	tglx
>