diff options
| author | Mika Westerberg <mika.westerberg@linux.intel.com> | 2017-10-13 21:35:42 +0300 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2017-11-06 18:48:58 -0600 |
| commit | 4147c2fd9b12ae1e0bdbb2dbb9a9163c94a10a22 (patch) | |
| tree | 89c4bef0de26de5ba5074623b819e2d596f2dd8f /drivers/pci/probe.c | |
| parent | 95e3ba9772331502cc33f1e1d4a96f3310e2f31e (diff) | |
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: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/probe.c')
| -rw-r--r-- | drivers/pci/probe.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 62d45a76f663..61813938d186 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -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++) - for_each_pci_bridge(dev, bus) - max = pci_scan_bridge(bus, dev, max, 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, 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; |