static int modify_pud_table()

in mm/vmem.c [312:364]

• 52 lines of code
• 21 McCabe index (conditional complexity)

static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
			    bool add, bool direct)
{
	unsigned long next, prot, pages = 0;
	int ret = -ENOMEM;
	pud_t *pud;
	pmd_t *pmd;

	prot = pgprot_val(REGION3_KERNEL);
	if (!MACHINE_HAS_NX)
		prot &= ~_REGION_ENTRY_NOEXEC;
	pud = pud_offset(p4d, addr);
	for (; addr < end; addr = next, pud++) {
		next = pud_addr_end(addr, end);
		if (!add) {
			if (pud_none(*pud))
				continue;
			if (pud_large(*pud)) {
				if (IS_ALIGNED(addr, PUD_SIZE) &&
				    IS_ALIGNED(next, PUD_SIZE)) {
					pud_clear(pud);
					pages++;
				}
				continue;
			}
		} else if (pud_none(*pud)) {
			if (IS_ALIGNED(addr, PUD_SIZE) &&
			    IS_ALIGNED(next, PUD_SIZE) &&
			    MACHINE_HAS_EDAT2 && addr && direct &&
			    !debug_pagealloc_enabled()) {
				pud_val(*pud) = __pa(addr) | prot;
				pages++;
				continue;
			}
			pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
			if (!pmd)
				goto out;
			pud_populate(&init_mm, pud, pmd);
		} else if (pud_large(*pud)) {
			continue;
		}
		ret = modify_pmd_table(pud, addr, next, add, direct);
		if (ret)
			goto out;
		if (!add)
			try_free_pmd_table(pud, addr & PUD_MASK);
	}
	ret = 0;
out:
	if (direct)
		update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages);
	return ret;
}