[RFC PATCH 1/3] genirq: add support for per-cpu dev_id interrupts
Marc Zyngier
marc.zyngier at arm.com
Fri Sep 16 04:20:24 EDT 2011
Hi Michał,
On 15/09/11 22:36, Michał Mirosław wrote:
> 2011/9/15 Marc Zyngier <marc.zyngier at arm.com>:
> [...]
>> diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
>> index a103732..f9b7fa3 100644
>> --- a/include/linux/interrupt.h
>> +++ b/include/linux/interrupt.h
>> @@ -95,6 +95,7 @@ typedef irqreturn_t (*irq_handler_t)(int, void *);
>> * @flags: flags (see IRQF_* above)
>> * @name: name of the device
>> * @dev_id: cookie to identify the device
>> + * @percpu_dev_id: cookie to identify the device
>> * @next: pointer to the next irqaction for shared interrupts
>> * @irq: interrupt number
>> * @dir: pointer to the proc/irq/NN/name entry
>> @@ -104,17 +105,20 @@ typedef irqreturn_t (*irq_handler_t)(int, void *);
>> * @thread_mask: bitmask for keeping track of @thread activity
>> */
>> struct irqaction {
> [...]
>> + void *dev_id;
>> +#ifdef CONFIG_IRQ_PERCPU_DEVID
>> + void __percpu *percpu_dev_id;
>> +#endif
>
> Those two can share the memory (in a anonymous union), if I read the
> idea correctly.
That was the initial implementation, and everything was fine until I
tried gcc 4.4.1. Having an anonymous union breaks static initialization
of the structure.
Try the following:
$ cat x.c
struct foo {
int a;
union {
int b1;
void * b2;
};
int c;
};
struct foo bar = {
.a = 1,
.b1 = 0,
.c = 2,
};
$ gcc -c -Wall x.c
x.c:13: error: unknown field ‘b1’ specified in initializer
x.c:13: warning: missing braces around initializer
x.c:13: warning: (near initialization for ‘bar.<anonymous>’)
GCC 4.6 seem fine though. Haven't tried anything in between.
A possible solution would be to name the union and fix all the accesses
to .dev_id. Ugly at best...
Cheers,
M.
--
Jazz is not dead. It just smells funny...
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