[PATCH 4.9 32/33] nfp: TX time stamp packets before HW doorbell is rung

Greg Kroah-Hartman
2018-05-18T08:16:11Z

From: Jakub Kicinski <jakub.kicinski@netronome.com>

commit 46f1c52e66dbc0d7a99f7c2a3c9debb497fe7b7b upstream.

TX completion may happen any time after HW queue was kicked.
We can't access the skb afterwards. Move the time stamping
before ringing the doorbell.

Fixes: 4c3523623dc0 ("net: add driver for Netronome NFP4000/NFP6000 NIC VFs")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/netronome/nfp/nfp_net_common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -854,6 +854,8 @@ static int nfp_net_tx(struct sk_buff *sk

netdev_tx_sent_queue(nd_q, txbuf->real_len);

+ skb_tx_timestamp(skb);
+
tx_ring->wr_p += nr_frags + 1;
if (nfp_net_tx_ring_should_stop(tx_ring))
nfp_net_tx_ring_stop(nd_q, tx_ring);
@@ -866,8 +868,6 @@ static int nfp_net_tx(struct sk_buff *sk
tx_ring->wr_ptr_add = 0;
}

- skb_tx_timestamp(skb);
-
return NETDEV_TX_OK;