[PATCH v5 03/13] PCI: pci_scan_slot() returns newly found devices

[Alex Chiang <achiang@hp.com>]

From: Trent Piepho <xyzzy@speakeasy.org>

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.

[achiang@hp.com: fix checkpatch errors]
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Reviewed-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
---

 drivers/pci/probe.c |   40 ++++++++++++++++------------------------
 1 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b89a86e..f261741 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1037,35 +1037,27 @@ 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++) {
-		struct pci_dev *dev;
-
-		dev = pci_scan_single_device(bus, devfn);
-		if (dev) {
-			nr++;
+	int fn, nr = 0;
+	struct pci_dev *dev;
 
-			/*
-		 	 * If this is a single function device,
-		 	 * don't scan past the first function.
-		 	 */
-			if (!dev->multifunction) {
-				if (func > 0) {
-					dev->multifunction = 1;
-				} else {
- 					break;
-				}
+	dev = pci_scan_single_device(bus, devfn);
+	if (dev && !dev->is_added)	/* new device? */
+		nr++;
+
+	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 {
-			if (func == 0 && !scan_all_fns)
-				break;
 		}
 	}