In support of detecting whether a resource might have been been claimed, report the parent to the walk_iomem_res_desc() callback. For example, the ACPI HMAT parser publishes "hmem" platform devices per target range. However, if the HMAT is disabled / missing a fallback driver can attach devices to the raw memory ranges as a fallback if it sees unclaimed / orphan "Soft Reserved" resources in the resource tree. Otherwise, find_next_iomem_res() returns a resource with garbage data from the stack allocation in __walk_iomem_res_desc() for the res->parent field. Cc: Jason Gunthorpe <jgg@xxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> Cc: Tom Lendacky <thomas.lendacky@xxxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> --- kernel/resource.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/resource.c b/kernel/resource.c index 76036a41143b..6e22e312fd55 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -386,6 +386,7 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end, res->end = min(end, p->end); res->flags = p->flags; res->desc = p->desc; + res->parent = p->parent; } read_unlock(&resource_lock);
