[PATCH] genirq: error reporting for non-percpu interrupt in request_percpu_irq()

[Vinayak Kale]

Hi Will,


On Fri, Oct 18, 2013 at 4:01 PM, Will Deacon <will.deacon at arm.com> wrote:
> On Fri, Oct 18, 2013 at 11:06:29AM +0100, Vinayak Kale wrote:
>> Return a separate error code when a non-percpu interrupt is passed to
>> request_percpu_irq().
>>
>> Suggested-by: Will Deacon <will.deacon at arm.com>
>> Signed-off-by: Vinayak Kale <vkale at apm.com>
>> ---
>>  kernel/irq/manage.c |    6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
>> index 514bcfd..c2713ae 100644
>> --- a/kernel/irq/manage.c
>> +++ b/kernel/irq/manage.c
>> @@ -1671,10 +1671,12 @@ int request_percpu_irq(unsigned int irq, irq_handler_t handler,
>>               return -EINVAL;
>>
>>       desc = irq_to_desc(irq);
>> -     if (!desc || !irq_settings_can_request(desc) ||
>> -         !irq_settings_is_per_cpu_devid(desc))
>> +     if (!desc || !irq_settings_can_request(desc))
>>               return -EINVAL;
>>
>> +     if (!irq_settings_is_per_cpu_devid(desc))
>> +             return -EPERM;
>
> <bikeshedding> I reckon -ENODEV is clearer here. </bikeshedding>

I looked at the issue as "operation not allowed since interrupt is
non-percpu" and I found below comment for EPERM in
'include/uapi/asm-generic/errno-base.h' . So thought this error code
could be more fitting.

#define EPERM            1      /* Operation not permitted */

>
> Also, there's a counterpart to this code in request_threaded_irq, where I
> think we should do something similar.

So in request_threaded_irq, we would still keep the WARN_ON for percpu
interrupt and return a different error code. Is my understanding
correct?