From: Tariq Toukan <tar...@mellanox.com>
With the MLX5E_CQ_HAS_CQES optimization flag, the following buggy
flow might occur:
- Suppose RX is always busy, TX has a single packet every second.
- We poll a single TX cqe and clear its flag.
- We never arm it again as RX is always busy.
- TX CQ flag is never changed, and new TX cqes are not polled.
We revert this optimization.
Fixes: e586b3b0baee ('net/mlx5: Ethernet Datapath files')
Signed-off-by: Tariq Toukan <tar...@mellanox.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en.h | 5 -----
drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 7 -------
drivers/net/ethernet/mellanox/mlx5/core/en_tx.c | 10 +---------
drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c | 1 -
4 files changed, 1 insertions(+), 22 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h
b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index aac071a..614a602 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -304,14 +304,9 @@ enum {
MLX5E_RQ_STATE_POST_WQES_ENABLE,
};
-enum cq_flags {
- MLX5E_CQ_HAS_CQES = 1,
-};
-
struct mlx5e_cq {
/* data path - accessed per cqe */
struct mlx5_cqwq wq;
- unsigned long flags;
/* data path - accessed per napi poll */
struct napi_struct *napi;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index dd959d9..3fd6a58 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -230,10 +230,6 @@ int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget)
struct mlx5e_rq *rq = container_of(cq, struct mlx5e_rq, cq);
int work_done;
- /* avoid accessing cq (dma coherent memory) if not needed */
- if (!test_and_clear_bit(MLX5E_CQ_HAS_CQES, &cq->flags))
- return 0;
-
for (work_done = 0; work_done < budget; work_done++) {
struct mlx5e_rx_wqe *wqe;
struct mlx5_cqe64 *cqe;
@@ -279,8 +275,5 @@ wq_ll_pop:
/* ensure cq space is freed before enabling more cqes */
wmb();
- if (work_done == budget)
- set_bit(MLX5E_CQ_HAS_CQES, &cq->flags);
-
return work_done;
}
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
index 2c3fba0..2beea8c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
@@ -335,10 +335,6 @@ bool mlx5e_poll_tx_cq(struct mlx5e_cq *cq)
u16 sqcc;
int i;
- /* avoid accessing cq (dma coherent memory) if not needed */
- if (!test_and_clear_bit(MLX5E_CQ_HAS_CQES, &cq->flags))
- return false;
-
sq = container_of(cq, struct mlx5e_sq, cq);
npkts = 0;
@@ -422,10 +418,6 @@ bool mlx5e_poll_tx_cq(struct mlx5e_cq *cq)
netif_tx_wake_queue(sq->txq);
sq->stats.wake++;
}
- if (i == MLX5E_TX_CQ_POLL_BUDGET) {
- set_bit(MLX5E_CQ_HAS_CQES, &cq->flags);
- return true;
- }
- return false;
+ return (i == MLX5E_TX_CQ_POLL_BUDGET);
}
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c
b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c
index 4ac8d71..66d51a7 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c
@@ -88,7 +88,6 @@ void mlx5e_completion_event(struct mlx5_core_cq *mcq)
{
struct mlx5e_cq *cq = container_of(mcq, struct mlx5e_cq, mcq);
- set_bit(MLX5E_CQ_HAS_CQES, &cq->flags);
set_bit(MLX5E_CHANNEL_NAPI_SCHED, &cq->channel->flags);
barrier();
napi_schedule(cq->napi);
--
1.7.1
