x86/PCI: fixup early quirk probing

On x86, we do early PCI probing to apply some quirks for chipset bugs.
However, in a recent cleanup (7bcbc78dea92fdf0947fa48e248da3c993a5690f) a
thinko was introduced that causes us to probe all subfunctions of even single
function devices (a function was factored out of an inner loop and a "break"
became a "return").  Fix that up by making check_dev_quirk() return a value so
we can keep the factored code intact.

Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

arch/x86/kernel/early-quirks.c

@@ -133,7 +133,18 @@ static struct chipset early_qrk[] __initdata = {
 	{}
 };
 
-static void __init check_dev_quirk(int num, int slot, int func)
+/**
+ * check_dev_quirk - apply early quirks to a given PCI device
+ * @num: bus number
+ * @slot: slot number
+ * @func: PCI function
+ *
+ * Check the vendor & device ID against the early quirks table.
+ *
+ * If the device is single function, let early_quirks() know so we don't
+ * poke at this device again.
+ */
+static int __init check_dev_quirk(int num, int slot, int func)
 {
 	u16 class;
 	u16 vendor;
@@ -144,7 +155,7 @@ static void __init check_dev_quirk(int num, int slot, int func)
 	class = read_pci_config_16(num, slot, func, PCI_CLASS_DEVICE);
 
 	if (class == 0xffff)
-		return;
+		return -1; /* no class, treat as single function */
 
 	vendor = read_pci_config_16(num, slot, func, PCI_VENDOR_ID);
 
@@ -167,7 +178,9 @@ static void __init check_dev_quirk(int num, int slot, int func)
 	type = read_pci_config_byte(num, slot, func,
 				    PCI_HEADER_TYPE);
 	if (!(type & 0x80))
-		return;
+		return -1;
+
+	return 0;
 }
 
 void __init early_quirks(void)
@@ -180,6 +193,9 @@ void __init early_quirks(void)
 	/* Poor man's PCI discovery */
 	for (num = 0; num < 32; num++)
 		for (slot = 0; slot < 32; slot++)
-			for (func = 0; func < 8; func++)
-				check_dev_quirk(num, slot, func);
+			for (func = 0; func < 8; func++) {
+				/* Only probe function 0 on single fn devices */
+				if (check_dev_quirk(num, slot, func))
+					break;
+			}
 }