net/mlx5e: Extend SKB room check to include PTP-SQ

When tx_port_ts is set, the driver diverts all UPD traffic over PTP port
to a dedicated PTP-SQ. The SKBs are cached until the wire-CQE arrives.
When the packet size is greater then MTU, the firmware might drop it and
the packet won't be transmitted to the wire, hence the wire-CQE won't
reach the driver. In this case the SKBs are accumulated in the SKB fifo.
Add room check to consider the PTP-SQ SKB fifo, when the SKB fifo is
full, driver stops the queue resulting in a TX timeout. Devlink
TX-reporter can recover from it.

Fixes: 1880bc4e4a96 ("net/mlx5e: Add TX port timestamp support")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Link: https://lore.kernel.org/r/20221026135153.154807-5-saeed@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h b/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h
index 4456ad5cedf1..cb164b62f543 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h
@@ -58,6 +58,12 @@ bool mlx5e_poll_tx_cq(struct mlx5e_cq *cq, int napi_budget);
 void mlx5e_free_txqsq_descs(struct mlx5e_txqsq *sq);
 
 static inline bool
+mlx5e_skb_fifo_has_room(struct mlx5e_skb_fifo *fifo)
+{
+	return (*fifo->pc - *fifo->cc) < fifo->mask;
+}
+
+static inline bool
 mlx5e_wqc_has_room_for(struct mlx5_wq_cyc *wq, u16 cc, u16 pc, u16 n)
 {
 	return (mlx5_wq_cyc_ctr2ix(wq, cc - pc) >= n) || (cc == pc);