drivers/xen/unpopulated-alloc.c

Source file repositories/reference/linux-study-clean/drivers/xen/unpopulated-alloc.c

File Facts

System
Linux kernel
Corpus path
drivers/xen/unpopulated-alloc.c
Extension
.c
Size
5603 bytes
Lines
252
Domain
Driver Families
Bucket
drivers/xen
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!tmp_res) {
			ret = -ENOMEM;
			goto err_insert;
		}

		tmp_res->name = res->name;
		tmp_res->start = res->start;
		tmp_res->end = res->end;
		tmp_res->flags = res->flags;

		ret = request_resource(&iomem_resource, tmp_res);
		if (ret < 0) {
			pr_err("Cannot request resource %pR (%d)\n", tmp_res, ret);
			kfree(tmp_res);
			goto err_insert;
		}
	}

	pgmap = kzalloc_obj(*pgmap);
	if (!pgmap) {
		ret = -ENOMEM;
		goto err_pgmap;
	}

	pgmap->type = MEMORY_DEVICE_GENERIC;
	pgmap->range = (struct range) {
		.start = res->start,
		.end = res->end,
	};
	pgmap->nr_range = 1;
	pgmap->owner = res;

#ifdef CONFIG_XEN_HAVE_PVMMU
        /*
         * memremap will build page tables for the new memory so
         * the p2m must contain invalid entries so the correct
         * non-present PTEs will be written.
         *
         * If a failure occurs, the original (identity) p2m entries
         * are not restored since this region is now known not to
         * conflict with any devices.
         */
	if (xen_pv_domain()) {
		xen_pfn_t pfn = PFN_DOWN(res->start);

		for (i = 0; i < alloc_pages; i++) {
			if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
				pr_warn("set_phys_to_machine() failed, no memory added\n");
				ret = -ENOMEM;
				goto err_memremap;
			}
                }
	}
#endif

	vaddr = memremap_pages(pgmap, NUMA_NO_NODE);
	if (IS_ERR(vaddr)) {
		pr_err("Cannot remap memory range\n");
		ret = PTR_ERR(vaddr);
		goto err_memremap;
	}

	for (i = 0; i < alloc_pages; i++) {
		struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i);

		pg->zone_device_data = page_list;
		page_list = pg;
		list_count++;
	}

	return 0;

err_memremap:
	kfree(pgmap);
err_pgmap:
	if (tmp_res) {
		release_resource(tmp_res);
		kfree(tmp_res);
	}
err_insert:
	release_resource(res);
err_resource:
	kfree(res);
	return ret;
}

/**
 * xen_alloc_unpopulated_pages - alloc unpopulated pages
 * @nr_pages: Number of pages
 * @pages: pages returned

Annotation

Implementation Notes