[PATCH] NET: r8169: fix past rtl_chip_info arraysize for unknown chipsets

[Roel Kluin <12o3l@tiscali.nl>]

i is unsigned, so, with an unknown chip, for (;i >= 0;) fails and i
just keeps decrementing, underflowing past ARRAY_SIZE(rtl_chip_info).

Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
---
diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index 3acfeea..7d6be1b 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -1702,21 +1702,19 @@ rtl8169_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	/* Identify chip attached to board */
 	rtl8169_get_mac_version(tp, ioaddr);
-
 	rtl8169_print_mac_version(tp);
 
-	for (i = ARRAY_SIZE(rtl_chip_info) - 1; i >= 0; i--) {
-		if (tp->mac_version == rtl_chip_info[i].mac_version)
+	for (i = ARRAY_SIZE(rtl_chip_info) - 1;
+			tp->mac_version != rtl_chip_info[i].mac_version; i--) {
+		if (i == 0) {
+			/* Unknown chip: assume chipset 0: original RTL-8169 */
+			if (netif_msg_probe(tp)) {
+				dev_printk(KERN_DEBUG, &pdev->dev,
+					"unknown chip version, assuming %s\n",
+					rtl_chip_info[0].name);
+			}
 			break;
-	}
-	if (i < 0) {
-		/* Unknown chip: assume array element #0, original RTL-8169 */
-		if (netif_msg_probe(tp)) {
-			dev_printk(KERN_DEBUG, &pdev->dev,
-				"unknown chip version, assuming %s\n",
-				rtl_chip_info[0].name);
 		}
-		i++;
 	}
 	tp->chipset = i;