error: dereferencing pointer to incomplete type

I got following error:

debug.c: In function '_get_pid':
debug.c:6: error: dereferencing pointer to incomplete type

while compiling module on 2.6.35 contain following code:

static inline pid_t *_get_pid(void)
{
return current->pid;
}

The same module has no issue on 2.6.31.

Strange error(dereferencing pointer to incomplete type)
http://stackoverflow.com/questions/2693393/strange-errordereferencing-pointer-to-incomplete-type

The solution is to include both of these headers:

#include <linux/sched.h>
#include <linux/fs_struct.h>