p4d_free_pud_page 1059 include/asm-generic/pgtable.h int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);
p4d_free_pud_page  183 lib/ioremap.c  	if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))