Re: [RFC][PATCH] irq_work

Frederic Weisbecker
2010-06-25T09:23:36Z

2010/6/25 Huang Ying <ying.huang@intel.com>:
> On Fri, 2010-06-25 at 15:48 +0800, Peter Zijlstra wrote:
>> On Fri, 2010-06-25 at 10:12 +0800, Huang Ying wrote:
>> >
>> > It is better to add "void *data" field in this struct to allow same
>> > function can be used for multiple struct irq_work.
>>
>> No, simply do:
>>
>> struct my_foo {
>>   struct irq_work work;
>>   /* my extra data */
>> }
>>
>> void my_func(struct irq_work *work)
>> {
>>   struct my_foo *foo = container_of(work, struct my_foo, work);
>>
>>   /* tada! */
>> }
>
> Yes. This works too. But Adding "void *data" field is helpful if you do
> not embed struct irq_work into another struct.

That's what makes most sense. If you use work->data to put foo, then
you can also do the opposite. Now the best is to pick the choice that
gives you a real type and a typechecking, and not an error-prone and
obfuscated void *

This is the way things are made in the kernel. struct work_struct, struct list,
struct rcu_head, etc... are all embedded into a container, so that we can
use container_of.