static void __init init_resources()

in kernel/setup.c [154:250]

• 68 lines of code
• 11 McCabe index (conditional complexity)

static void __init init_resources(void)
{
	struct memblock_region *region = NULL;
	struct resource *res = NULL;
	struct resource *mem_res = NULL;
	size_t mem_res_sz = 0;
	int num_resources = 0, res_idx = 0;
	int ret = 0;

	/* + 1 as memblock_alloc() might increase memblock.reserved.cnt */
	num_resources = memblock.memory.cnt + memblock.reserved.cnt + 1;
	res_idx = num_resources - 1;

	mem_res_sz = num_resources * sizeof(*mem_res);
	mem_res = memblock_alloc(mem_res_sz, SMP_CACHE_BYTES);
	if (!mem_res)
		panic("%s: Failed to allocate %zu bytes\n", __func__, mem_res_sz);

	/*
	 * Start by adding the reserved regions, if they overlap
	 * with /memory regions, insert_resource later on will take
	 * care of it.
	 */
	ret = add_kernel_resources();
	if (ret < 0)
		goto error;

#ifdef CONFIG_KEXEC_CORE
	if (crashk_res.start != crashk_res.end) {
		ret = add_resource(&iomem_resource, &crashk_res);
		if (ret < 0)
			goto error;
	}
#endif

#ifdef CONFIG_CRASH_DUMP
	if (elfcorehdr_size > 0) {
		elfcorehdr_res.start = elfcorehdr_addr;
		elfcorehdr_res.end = elfcorehdr_addr + elfcorehdr_size - 1;
		elfcorehdr_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
		add_resource(&iomem_resource, &elfcorehdr_res);
	}
#endif

	for_each_reserved_mem_region(region) {
		res = &mem_res[res_idx--];

		res->name = "Reserved";
		res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
		res->start = __pfn_to_phys(memblock_region_reserved_base_pfn(region));
		res->end = __pfn_to_phys(memblock_region_reserved_end_pfn(region)) - 1;

		/*
		 * Ignore any other reserved regions within
		 * system memory.
		 */
		if (memblock_is_memory(res->start)) {
			/* Re-use this pre-allocated resource */
			res_idx++;
			continue;
		}

		ret = add_resource(&iomem_resource, res);
		if (ret < 0)
			goto error;
	}

	/* Add /memory regions to the resource tree */
	for_each_mem_region(region) {
		res = &mem_res[res_idx--];

		if (unlikely(memblock_is_nomap(region))) {
			res->name = "Reserved";
			res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
		} else {
			res->name = "System RAM";
			res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
		}

		res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
		res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;

		ret = add_resource(&iomem_resource, res);
		if (ret < 0)
			goto error;
	}

	/* Clean-up any unused pre-allocated resources */
	if (res_idx >= 0)
		memblock_free(mem_res, (res_idx + 1) * sizeof(*mem_res));
	return;

 error:
	/* Better an empty resource tree than an inconsistent one */
	release_child_resources(&iomem_resource);
	memblock_free(mem_res, mem_res_sz);
}