static bool pmb_mapping_exists()

in mm/pmb.c [137:189]

• 30 lines of code
• 10 McCabe index (conditional complexity)

static bool pmb_mapping_exists(unsigned long vaddr, phys_addr_t phys,
			       unsigned long size)
{
	int i;

	read_lock(&pmb_rwlock);

	for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
		struct pmb_entry *pmbe, *iter;
		unsigned long span;

		if (!test_bit(i, pmb_map))
			continue;

		pmbe = &pmb_entry_list[i];

		/*
		 * See if VPN and PPN are bounded by an existing mapping.
		 */
		if ((vaddr < pmbe->vpn) || (vaddr >= (pmbe->vpn + pmbe->size)))
			continue;
		if ((phys < pmbe->ppn) || (phys >= (pmbe->ppn + pmbe->size)))
			continue;

		/*
		 * Now see if we're in range of a simple mapping.
		 */
		if (size <= pmbe->size) {
			read_unlock(&pmb_rwlock);
			return true;
		}

		span = pmbe->size;

		/*
		 * Finally for sizes that involve compound mappings, walk
		 * the chain.
		 */
		for (iter = pmbe->link; iter; iter = iter->link)
			span += iter->size;

		/*
		 * Nothing else to do if the range requirements are met.
		 */
		if (size <= span) {
			read_unlock(&pmb_rwlock);
			return true;
		}
	}

	read_unlock(&pmb_rwlock);
	return false;
}