Work Queues in Drivers

[trishabhc]

Hi
I am making a Linux driver module. I am making my own work queue to submit tasks to.

What I want to ask is that when I declare a workqueue_struct as regular a variable it gives the following error:

Declaration:
struct kt_dev {
int id;
struct cdev chardevice;
spinlock_t spinl;
struct workqueue_struct workq;
};

error: field ‘workq’ has incomplete type

Apparently workqueue_struct is only allowing pointer declaraitons. So the following has no problem:

struct kt_dev {
int id;
struct cdev chardevice;
spinlock_t spinl;
struct workqueue_struct *workq;
};

Why is this so?
Thanks
Trishabh

[Rubberman]

That's because you are not including the header file with the actual struct workqueue_struct definition. The pointer is an opaque value, so it can be set by some other bit of code that does know about the structure and its size, members, etc.