[PATCH net] net/mlx5e: Order ICOSQ cc update after CQ doorbell
lirongqing <[email protected]>
| Newsgroups | org.kernel.vger.linux-rdma,org.kernel.vger.linux-kernel,org.kernel.vger.netdev |
|---|---|
| Message-ID | <[email protected]> |
From: Li RongQing <[email protected]> mlx5e_poll_ico_cq() requires sq->cc to be updated only after mlx5_cqwq_update_db_record(), otherwise a CQ overrun may occur. The current implementation updates sq->cc before the CQ doorbell record, violating this ordering requirement. Update the CQ doorbell record first and use dma_wmb() before updating sq->cc. This ensures that the CQ space is released to the device before the corresponding ICOSQ consumer index is updated by software. Fixes: fd9b4be8002c ("net/mlx5e: RX, Support multiple outstanding UMR posts") Signed-off-by: Li RongQing <[email protected]> --- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c index f6eff03..01867dd 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -905,10 +905,12 @@ int mlx5e_poll_ico_cq(struct mlx5e_cq *cq) } while (!last_wqe); } while ((++i < MLX5E_TX_CQ_POLL_BUDGET) && (cqe = mlx5_cqwq_get_cqe(&cq->wq))); - sq->cc = sqcc; - mlx5_cqwq_update_db_record(&cq->wq); + /* ensure cq space is freed before enabling more cqes */ + dma_wmb(); + + sq->cc = sqcc; return i; } -- 2.9.4