int map_page()

in mm/pgtable.c [137:161]

• 20 lines of code
• 3 McCabe index (conditional complexity)

int map_page(unsigned long va, phys_addr_t pa, int flags)
{
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pd;
	pte_t *pg;
	int err = -ENOMEM;

	/* Use upper 10 bits of VA to index the first level map */
	p4d = p4d_offset(pgd_offset_k(va), va);
	pud = pud_offset(p4d, va);
	pd = pmd_offset(pud, va);
	/* Use middle 10 bits of VA to index the second-level map */
	pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
	/* pg = pte_alloc_kernel(&init_mm, pd, va); */

	if (pg != NULL) {
		err = 0;
		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
				__pgprot(flags)));
		if (unlikely(mem_init_done))
			_tlbie(va);
	}
	return err;
}