p4d_index
#define p4d_index(addr) (((addr) >> P4D_SHIFT) & (PTRS_PER_P4D - 1))
#define p4d_index(addr) (((addr) >> P4D_SHIFT) & (PTRS_PER_P4D - 1))
#define p4d_index(address) (((address) >> P4D_SHIFT) & (PTRS_PER_P4D - 1))
#define p4d_index(addr) (((addr) >> P4D_SHIFT) & (PTRS_PER_P4D - 1))
#define p4d_index(address) (((address) >> P4D_SHIFT) & (PTRS_PER_P4D-1))
static inline unsigned long p4d_index(unsigned long address)