ch9200: use skb_cow_head() to deal with cloned skbs

We need to ensure there is enough headroom to push extra header, but we also need to check if we are allowed to change headers. skb_cow_head() is the proper helper to deal with this. Fixes: 4a476bd ("usbnet: New driver for QinHeng CH9200 devices") Signed-off-by: Eric Dumazet <[email protected]> Cc: James Hughes <[email protected]> Cc: Matthew Garrett <[email protected]> Signed-off-by: David S. Miller <[email protected]>
raspberrypi · Apr 21, 2017 · 6bc6895 · 6bc6895
1 parent d4ca735
commit 6bc6895
Showing 1 changed file with 2 additions and 7 deletions.
diff --git a/drivers/net/usb/ch9200.c b/drivers/net/usb/ch9200.c
@@ -254,14 +254,9 @@ static struct sk_buff *ch9200_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 	tx_overhead = 0x40;
 
 	len = skb->len;
-	if (skb_headroom(skb) < tx_overhead) {
-		struct sk_buff *skb2;
-
-		skb2 = skb_copy_expand(skb, tx_overhead, 0, flags);
+	if (skb_cow_head(skb, tx_overhead)) {
 		dev_kfree_skb_any(skb);
-		skb = skb2;
-		if (!skb)
-			return NULL;
+		return NULL;
 	}
 
 	__skb_push(skb, tx_overhead);