net: correct comment on where to place transmit time stamp hook.

The comment for the skb_tx_timestamp() function suggests calling it just
after a buffer is released to the hardware for transmission. However,
for drivers that free the buffer in an ISR, this produces a race between
the time stamp code and the ISR. This commit changes the comment to advise
placing the call just before handing the buffer over to the hardware.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index e8b78ce144741fda866f79bd32ce3c96ba0c4096..f3af147c211d40f99f03918de5416969580bc284 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2023,8 +2023,7 @@ static inline void sw_tx_timestamp(struct sk_buff *skb)
  * skb_tx_timestamp() - Driver hook for transmit timestamping
  *
  * Ethernet MAC Drivers should call this function in their hard_xmit()
- * function as soon as possible after giving the sk_buff to the MAC
- * hardware, but before freeing the sk_buff.
+ * function immediately before giving the sk_buff to the MAC hardware.
  *
  * @skb: A socket buffer.
  */