#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
/* to find an entry in a page-table-directory */
-static inline pgd_t * pgd_offset(struct mm_struct * mm, unsigned long address)
+static inline pgd_t * pgd_offset(const struct mm_struct *mm, unsigned long address)
{
return mm->pgd + pgd_index(address);
}