PCI/portdrv: Remove pcie_port_bus_type link order dependency

The pcie_port_bus_type must be registered before drivers that depend on it
can be registered.  Those drivers include:

  pcied_init()                # PCIe native hotplug driver
  aer_service_init()          # AER driver
  dpc_service_init()          # DPC driver
  pcie_pme_service_init()     # PME driver

Previously we registered pcie_port_bus_type from pcie_portdrv_init(), a
device_initcall.  The callers of pcie_port_service_register() (above) are
also device_initcalls.  This is fragile because the device_initcall
ordering depends on link order, which is not explicit.

Register pcie_port_bus_type from pci_driver_init() along with pci_bus_type.
This removes the link order dependency between portdrv and the pciehp, AER,
DPC, and PCIe PME drivers.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 43 insertions, 1 deletions

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 646da0d2d7a8..21eb2f7ad95d 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -19,6 +19,7 @@
 #include <linux/suspend.h>
 #include <linux/kexec.h>
 #include "pci.h"
+#include "pcie/portdrv.h"
 
 struct pci_dynid {
 	struct list_head node;
@@ -1552,8 +1553,49 @@ struct bus_type pci_bus_type = {
 };
 EXPORT_SYMBOL(pci_bus_type);
 
+#ifdef CONFIG_PCIEPORTBUS
+static int pcie_port_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct pcie_device *pciedev;
+	struct pcie_port_service_driver *driver;
+
+	if (drv->bus != &pcie_port_bus_type || dev->bus != &pcie_port_bus_type)
+		return 0;
+
+	pciedev = to_pcie_device(dev);
+	driver = to_service_driver(drv);
+
+	if (driver->service != pciedev->service)
+		return 0;
+
+	if (driver->port_type != PCIE_ANY_PORT &&
+	    driver->port_type != pci_pcie_type(pciedev->port))
+		return 0;
+
+	return 1;
+}
+
+struct bus_type pcie_port_bus_type = {
+	.name		= "pci_express",
+	.match		= pcie_port_bus_match,
+};
+EXPORT_SYMBOL_GPL(pcie_port_bus_type);
+#endif
+
 static int __init pci_driver_init(void)
 {
-	return bus_register(&pci_bus_type);
+	int ret;
+
+	ret = bus_register(&pci_bus_type);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_PCIEPORTBUS
+	ret = bus_register(&pcie_port_bus_type);
+	if (ret)
+		return ret;
+#endif
+
+	return 0;
 }
 postcore_initcall(pci_driver_init);