void flush_dcache_page()

in mm/cache.c [124:171]

• 25 lines of code
• 8 McCabe index (conditional complexity)

void flush_dcache_page(struct page *page)
{
	struct address_space *mapping = page_mapping_file(page);

	/*
	 * If we have a mapping but the page is not mapped to user-space
	 * yet, we simply mark this page dirty and defer flushing the 
	 * caches until update_mmu().
	 */

	if (mapping && !mapping_mapped(mapping)) {
		if (!test_bit(PG_arch_1, &page->flags))
			set_bit(PG_arch_1, &page->flags);
		return;

	} else {

		unsigned long phys = page_to_phys(page);
		unsigned long temp = page->index << PAGE_SHIFT;
		unsigned long alias = !(DCACHE_ALIAS_EQ(temp, phys));
		unsigned long virt;

		/* 
		 * Flush the page in kernel space and user space.
		 * Note that we can omit that step if aliasing is not
		 * an issue, but we do have to synchronize I$ and D$
		 * if we have a mapping.
		 */

		if (!alias && !mapping)
			return;

		preempt_disable();
		virt = TLBTEMP_BASE_1 + (phys & DCACHE_ALIAS_MASK);
		__flush_invalidate_dcache_page_alias(virt, phys);

		virt = TLBTEMP_BASE_1 + (temp & DCACHE_ALIAS_MASK);

		if (alias)
			__flush_invalidate_dcache_page_alias(virt, phys);

		if (mapping)
			__invalidate_icache_page_alias(virt, phys);
		preempt_enable();
	}

	/* There shouldn't be an entry in the cache for this page anymore. */
}