PCI: Put pci_dev in device tree as early as possible

We want to put pci_dev structs in the device tree as soon as possible so
for_each_pci_dev() iteration will not miss them, but driver attachment
needs to be delayed until after pci_assign_unassigned_resources() to make
sure all devices have resources assigned first.

This patch moves device registering from pci_bus_add_devices() to
pci_device_add(), which happens earlier, leaving driver attachment in
pci_bus_add_devices().

It also removes unattached child bus handling in pci_bus_add_devices().
That's not needed because child bus via pci_add_new_bus() is already
in parent bus children list.

[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 12 insertions, 66 deletions

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index c8709c6fdb7c9..8647dc6f52d0c 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -161,73 +161,35 @@ pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
 void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
 
 /**
- * pci_bus_add_device - add a single device
+ * pci_bus_add_device - start driver for a single device
  * @dev: device to add
  *
- * This adds a single pci device to the global
- * device list and adds sysfs and procfs entries
+ * This adds add sysfs entries and start device drivers
  */
 int pci_bus_add_device(struct pci_dev *dev)
 {
 	int retval;
 
-	pci_fixup_device(pci_fixup_final, dev);
-
-	retval = pcibios_add_device(dev);
-	if (retval)
-		return retval;
-
-	dev->match_driver = false;
-	retval = device_add(&dev->dev);
-	if (retval)
-		return retval;
+	/*
+	 * Can not put in pci_device_add yet because resources
+	 * are not assigned yet for some devices.
+	 */
+	pci_create_sysfs_dev_files(dev);
 
 	dev->match_driver = true;
 	retval = device_attach(&dev->dev);
 	WARN_ON(retval < 0);
 
 	dev->is_added = 1;
-	pci_proc_attach_device(dev);
-	pci_create_sysfs_dev_files(dev);
-	return 0;
-}
-
-/**
- * pci_bus_add_child - add a child bus
- * @bus: bus to add
- *
- * This adds sysfs entries for a single bus
- */
-int pci_bus_add_child(struct pci_bus *bus)
-{
-	int retval;
-
-	if (bus->bridge)
-		bus->dev.parent = bus->bridge;
-
-	retval = device_register(&bus->dev);
-	if (retval)
-		return retval;
 
-	bus->is_added = 1;
-
-	/* Create legacy_io and legacy_mem files for this bus */
-	pci_create_legacy_files(bus);
-
-	return retval;
+	return 0;
 }
 
 /**
- * pci_bus_add_devices - insert newly discovered PCI devices
+ * pci_bus_add_devices - start driver for PCI devices
  * @bus: bus to check for new devices
  *
- * Add newly discovered PCI devices (which are on the bus->devices
- * list) to the global PCI device list, add the sysfs and procfs
- * entries.  Where a bridge is found, add the discovered bus to
- * the parents list of child buses, and recurse (breadth-first
- * to be compatible with 2.4)
- *
- * Call hotplug for each new devices.
+ * Start driver for PCI devices and add some sysfs entries.
  */
 void pci_bus_add_devices(const struct pci_bus *bus)
 {
@@ -240,36 +202,20 @@ void pci_bus_add_devices(const struct pci_bus *bus)
 		if (dev->is_added)
 			continue;
 		retval = pci_bus_add_device(dev);
-		if (retval)
-			dev_err(&dev->dev, "Error adding device, continuing\n");
 	}
 
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		BUG_ON(!dev->is_added);
 
 		child = dev->subordinate;
-		/*
-		 * If there is an unattached subordinate bus, attach
-		 * it and then scan for unattached PCI devices.
-		 */
+
 		if (!child)
 			continue;
-		if (list_empty(&child->node)) {
-			down_write(&pci_bus_sem);
-			list_add_tail(&child->node, &dev->bus->children);
-			up_write(&pci_bus_sem);
-		}
 		pci_bus_add_devices(child);
 
-		/*
-		 * register the bus with sysfs as the parent is now
-		 * properly registered.
-		 */
 		if (child->is_added)
 			continue;
-		retval = pci_bus_add_child(child);
-		if (retval)
-			dev_err(&dev->dev, "Error adding bus, continuing\n");
+		child->is_added = 1;
 	}
 }