On Tue, Apr 8, 2014 at 4:20 AM, Liviu Dudau Liviu.Dudau@arm.com wrote:
On Mon, Apr 07, 2014 at 11:44:51PM +0100, Bjorn Helgaas wrote:
Let me try to explain my concern about the pci_create_root_bus_in_domain() interface. We currently have these interfaces:
pci_scan_root_bus() pci_scan_bus() pci_scan_bus_parented() pci_create_root_bus() ...
One alternative is to add an _in_domain() variant of each of these interfaces, but that doesn't seem very convenient either. My idea of passing in a structure would also require adding variants, so there's not really an advantage there, but I am thinking of the next unification effort, e.g., for NUMA node info. I don't really want to have to change all the _in_domain() interfaces to also take yet another parameter for the node number.
OK, what about this: all the functions that you have mentioned take a void *sysdata parameter. Should we convert this opaque pointer into a specific structure that holds the domain_nr and (in future) the NUMA node info?
I doubt if we can make sysdata itself generic because I suspect we need a way to have *some* arch-specific data. But maybe the arch could supply a structure containing a struct device *, domain, struct pci_ops *, list of resources, aperture info, etc. I wonder if struct pci_host_bridge would be a reasonable place to put this stuff, e.g., something like this:
struct pci_host_bridge { int domain; int node; struct device *dev; struct pci_ops *ops; struct list_head resources; void *sysdata; struct pci_bus *bus; /* filled in by core, not by arch */ ... /* other existing contents managed by core */ };
struct pci_bus *pci_scan_host_bridge(struct pci_host_bridge *bridge);