[PATCH 4.5 019/101] net/mlx4_en: fix spurious timestamping callbacks

Greg Kroah-Hartman
2016-05-17T01:24:35Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit fc96256c906362e845d848d0f6a6354450059e81 ]

When multiple skb are TX-completed in a row, we might incorrectly keep
a timestamp of a prior skb and cause extra work.

Fixes: ec693d47010e8 ("net/mlx4_en: Add HW timestamping (TS) support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -402,7 +402,6 @@ static bool mlx4_en_process_tx_cq(struct
u32 packets = 0;
u32 bytes = 0;
int factor = priv->cqe_factor;
- u64 timestamp = 0;
int done = 0;
int budget = priv->tx_work_limit;
u32 last_nr_txbb;
@@ -442,9 +441,12 @@ static bool mlx4_en_process_tx_cq(struct
new_index = be16_to_cpu(cqe->wqe_index) & size_mask;

do {
+ u64 timestamp = 0;
+
txbbs_skipped += last_nr_txbb;
ring_index = (ring_index + last_nr_txbb) & size_mask;
- if (ring->tx_info[ring_index].ts_requested)
+
+ if (unlikely(ring->tx_info[ring_index].ts_requested))
timestamp = mlx4_en_get_cqe_ts(cqe);

/* free next descriptor */