Commit 4147c2fd authored by Mika Westerberg's avatar Mika Westerberg Committed by Bjorn Helgaas
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PCI: Open-code the two pass loop when scanning bridges 



The current scanning code is really hard to understand because it calls
the same function in a loop where pass value is changed without any
comments explaining it:

  for (pass = 0; pass < 2; pass++)
    for_each_pci_bridge(dev, bus)
      max = pci_scan_bridge(bus, dev, max, pass);

Unfamiliar reader cannot tell easily what is the purpose of this loop
without looking at internals of pci_scan_bridge().

In order to make this bit easier to understand, open-code the loop in
pci_scan_child_bus() and pci_hp_add_bridge() with added comments.

No functional changes intended.

Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 95e3ba97

drivers/pci/probe.c

+20 −7
Original line number Diff line number Diff line
@@ -2398,7 +2398,7 @@ void __weak pcibios_fixup_bus(struct pci_bus *bus) 


unsigned int pci_scan_child_bus(struct pci_bus *bus)

{

	unsigned int devfn, pass, max = bus->busn_res.start;

	unsigned int devfn, max = bus->busn_res.start;

	struct pci_dev *dev;



	dev_dbg(&bus->dev, "scanning bus\n");
@@ -2420,9 +2420,17 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus) 
		bus->is_added = 1;

	}



	for (pass = 0; pass < 2; pass++)

	/*

	 * Scan bridges that are already configured. We don't touch them

	 * unless they are misconfigured (which will be done in the second

	 * scan below).

	 */

	for_each_pci_bridge(dev, bus)

		max = pci_scan_bridge(bus, dev, max, 0);



	/* Scan bridges that need to be reconfigured */

	for_each_pci_bridge(dev, bus)

			max = pci_scan_bridge(bus, dev, max, pass);

		max = pci_scan_bridge(bus, dev, max, 1);



	/*

	 * Make sure a hotplug bridge has at least the minimum requested
@@ -2739,7 +2747,7 @@ void __init pci_sort_breadthfirst(void) 
int pci_hp_add_bridge(struct pci_dev *dev)

{

	struct pci_bus *parent = dev->bus;

	int pass, busnr, start = parent->busn_res.start;

	int busnr, start = parent->busn_res.start;

	int end = parent->busn_res.end;



	for (busnr = start; busnr <= end; busnr++) {
@@ -2750,8 +2758,13 @@ int pci_hp_add_bridge(struct pci_dev *dev) 
		dev_err(&dev->dev, "No bus number available for hot-added bridge\n");

		return -1;

	}

	for (pass = 0; pass < 2; pass++)

		busnr = pci_scan_bridge(parent, dev, busnr, pass);



	/* Scan bridges that are already configured */

	busnr = pci_scan_bridge(parent, dev, busnr, 0);



	/* Scan bridges that need to be reconfigured */

	pci_scan_bridge(parent, dev, busnr, 1);



	if (!dev->subordinate)

		return -1;

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