PCI: pci_scan_slot() returns newly found devices

pci_scan_slot() has been rewritten to be less complex and will now
return the number of *new* devices found.

Existing callers need not worry because they already assume that
they can't call pci_scan_slot() on an already-scanned slot.

Thus, there is no semantic change for existing callers: returning
newly found devices (this patch) is exactly equal to returning all
found devices (before this patch).

This patch adds some more groundwork to allow us to rescan the
PCI bus during runtime to discover newly added devices.
Signed-off-by: NTrent Piepho <xyzzy@speakeasy.org>
Reviewed-by: NAlex Chiang <achiang@hp.com>
Signed-off-by: NAlex Chiang <achiang@hp.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/probe.c

@@ -1043,36 +1043,28 @@ EXPORT_SYMBOL(pci_scan_single_device);
  * Scan a PCI slot on the specified PCI bus for devices, adding
  * discovered devices to the @bus->devices list.  New devices
  * will not have is_added set.
+ *
+ * Returns the number of new devices found.
  */
 int pci_scan_slot(struct pci_bus *bus, int devfn)
 {
-	int func, nr = 0;
-	int scan_all_fns;
-
-	scan_all_fns = pcibios_scan_all_fns(bus, devfn);
-
-	for (func = 0; func < 8; func++, devfn++) {
+	int fn, nr = 0;
 	struct pci_dev *dev;
 
 	dev = pci_scan_single_device(bus, devfn);
-		if (dev) {
+	if (dev && !dev->is_added)	/* new device? */
 		nr++;
 
-			/*
-		 	 * If this is a single function device,
-		 	 * don't scan past the first function.
-		 	 */
-			if (!dev->multifunction) {
-				if (func > 0) {
+	if ((dev && dev->multifunction) ||
+	    (!dev && pcibios_scan_all_fns(bus, devfn))) {
+		for (fn = 1; fn < 8; fn++) {
+			dev = pci_scan_single_device(bus, devfn + fn);
+			if (dev) {
+				if (!dev->is_added)
+					nr++;
 				dev->multifunction = 1;
-				} else {
- 					break;
 			}
 		}
-		} else {
-			if (func == 0 && !scan_all_fns)
-				break;
-		}
 	}
 
 	/* only one slot has pcie device */