| From | Ben Hutchings <> | Date | Mon, 13 Jun 2016 19:36:37 +0100 | Subject | [PATCH 3.16 051/114] net/mlx4_en: fix spurious timestamping callbacks |
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3.16.36-rc1 review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
commit fc96256c906362e845d848d0f6a6354450059e81 upstream.
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> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- 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 @@ -371,7 +371,6 @@ 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; @@ -405,9 +404,12 @@ static bool mlx4_en_process_tx_cq(struct new_index = be16_to_cpu(cqe->wqe_index) & size_mask; do { + u64 timestamp = 0; + txbbs_skipped += ring->last_nr_txbb; ring_index = (ring_index + ring->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 */
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