FIX_PMD
#define pmd_set_fixmap(addr) ((pmd_t *)set_fixmap_offset(FIX_PMD, addr))
#define pmd_clear_fixmap() clear_fixmap(FIX_PMD)
clear_fixmap(FIX_PMD);
clear_fixmap(FIX_PMD);
return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);