From: Maxim Mikityanskiy maximmi@mellanox.com
commit e7e0004abdd6f83ae4be5613b29ed396beff576c upstream.
XSK wakeup function triggers NAPI by posting a NOP WQE to a special XSK ICOSQ. When the application floods the driver with wakeup requests by calling sendto() in a certain pattern that ends up in mlx5e_trigger_irq, the XSK ICOSQ may overflow.
Multiple NOPs are not required and won't accelerate the process, so avoid posting a second NOP if there is one already on the way. This way we also avoid increasing the queue size (which might not help anyway).
Fixes: db05815b36cb ("net/mlx5e: Add XSK zero-copy support") Signed-off-by: Maxim Mikityanskiy maximmi@mellanox.com Reviewed-by: Tariq Toukan tariqt@mellanox.com Signed-off-by: Saeed Mahameed saeedm@mellanox.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/net/ethernet/mellanox/mlx5/core/en.h | 3 ++- drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c | 3 +++ drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 8 +++++--- drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c | 6 +++++- 4 files changed, 15 insertions(+), 5 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -367,6 +367,7 @@ enum { MLX5E_SQ_STATE_AM, MLX5E_SQ_STATE_TLS, MLX5E_SQ_STATE_VLAN_NEED_L2_INLINE, + MLX5E_SQ_STATE_PENDING_XSK_TX, };
struct mlx5e_sq_wqe_info { @@ -950,7 +951,7 @@ void mlx5e_page_release_dynamic(struct m void mlx5e_handle_rx_cqe(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe); void mlx5e_handle_rx_cqe_mpwrq(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe); bool mlx5e_post_rx_wqes(struct mlx5e_rq *rq); -void mlx5e_poll_ico_cq(struct mlx5e_cq *cq); +int mlx5e_poll_ico_cq(struct mlx5e_cq *cq); bool mlx5e_post_rx_mpwqes(struct mlx5e_rq *rq); void mlx5e_dealloc_rx_wqe(struct mlx5e_rq *rq, u16 ix); void mlx5e_dealloc_rx_mpwqe(struct mlx5e_rq *rq, u16 ix); --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c @@ -33,6 +33,9 @@ int mlx5e_xsk_wakeup(struct net_device * if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &c->xskicosq.state))) return 0;
+ if (test_and_set_bit(MLX5E_SQ_STATE_PENDING_XSK_TX, &c->xskicosq.state)) + return 0; + spin_lock(&c->xskicosq_lock); mlx5e_trigger_irq(&c->xskicosq); spin_unlock(&c->xskicosq_lock); --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -587,7 +587,7 @@ bool mlx5e_post_rx_wqes(struct mlx5e_rq return !!err; }
-void mlx5e_poll_ico_cq(struct mlx5e_cq *cq) +int mlx5e_poll_ico_cq(struct mlx5e_cq *cq) { struct mlx5e_icosq *sq = container_of(cq, struct mlx5e_icosq, cq); struct mlx5_cqe64 *cqe; @@ -595,11 +595,11 @@ void mlx5e_poll_ico_cq(struct mlx5e_cq * int i;
if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &sq->state))) - return; + return 0;
cqe = mlx5_cqwq_get_cqe(&cq->wq); if (likely(!cqe)) - return; + return 0;
/* sq->cc must be updated only after mlx5_cqwq_update_db_record(), * otherwise a cq overrun may occur @@ -648,6 +648,8 @@ void mlx5e_poll_ico_cq(struct mlx5e_cq * sq->cc = sqcc;
mlx5_cqwq_update_db_record(&cq->wq); + + return i; }
bool mlx5e_post_rx_mpwqes(struct mlx5e_rq *rq) --- a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c @@ -145,7 +145,11 @@ int mlx5e_napi_poll(struct napi_struct *
busy |= rq->post_wqes(rq); if (xsk_open) { - mlx5e_poll_ico_cq(&c->xskicosq.cq); + if (mlx5e_poll_ico_cq(&c->xskicosq.cq)) + /* Don't clear the flag if nothing was polled to prevent + * queueing more WQEs and overflowing XSKICOSQ. + */ + clear_bit(MLX5E_SQ_STATE_PENDING_XSK_TX, &c->xskicosq.state); busy |= mlx5e_poll_xdpsq_cq(&xsksq->cq); busy_xsk |= mlx5e_napi_xsk_post(xsksq, xskrq); }