net: Add some clarification to skb_tx_timestamp() comment.
We've seen so many instances of people invoking skb_tx_timestamp()
after the device already has been given the packet, that it's worth
being a little bit more verbose and explicit in this comment.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6aae838..6f69b3f 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2531,6 +2531,10 @@
* Ethernet MAC Drivers should call this function in their hard_xmit()
* function immediately before giving the sk_buff to the MAC hardware.
*
+ * Specifically, one should make absolutely sure that this function is
+ * called before TX completion of this packet can trigger. Otherwise
+ * the packet could potentially already be freed.
+ *
* @skb: A socket buffer.
*/
static inline void skb_tx_timestamp(struct sk_buff *skb)