Revert "usbnet: drop unneeded check for NULL"

This reverts commit 5d65878d7031b6c39054b282faceff406bb2fda9.
The upper layers call usbnet_start_xmit() with a valid skb.
However cdc_ncm abuses this method by calling it with NULL
to trigger IO for the aggregated private skb holding erlier
packets. Until cdc_ncm is fixed, the check for NULL must
be reintroduced.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 5234d20..8531c1c 100644 (file)
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1092,7 +1092,8 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
        unsigned long           flags;
        int retval;
 
-       skb_tx_timestamp(skb);
+       if (skb)
+               skb_tx_timestamp(skb);
 
        // some devices want funky USB-level framing, for
        // win32 driver (usually) and/or hardware quirks