On Wed, Apr 26, 2006 at 11:23:39AM +0530, Vishal Sharda wrote:
>
> In the function "class_device_add" in inux26/drivers/base/class.c
> There is one statement:
>
> parent = class_get(class_dev->class);
>
> My question is that can return value of class_get i.e. value of parent
> be NULL?
>
> I tried to track it down and couldn't find the instance where it can be
> NULL.
Hi,
>From linux-2.6.16, the class_get function is :
struct class * class_get(struct class * cls)
{
if (cls)
return container_of(subsys_get(&cls->subsys), struct class, subsys);
return NULL;
}
So class_get(class_dev->class) returns NULL if class_dev->class is NULL.
If a class_dev struct has been allocated but not been init, the pointer
will be NULL.
It's just a sanity check.
--
tyler
tyler@xxxxxxxx
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