From 7b33aaeaae1acfec01cbb0cf41fa8c07aea55609 Mon Sep 17 00:00:00 2001 From: Tariq Toukan Date: Sun, 2 Jul 2017 12:56:12 +0300 Subject: [PATCH] net/mlx5e: Use kernel's mechanism to avoid missing NAPIs We used a channel state bit MLX5E_CHANNEL_NAPI_SCHED to make sure no NAPI is missed when a channel's napi_schedule() is called for completion events of the different channel's resources/rings while NAPI is currently running. Now, as similar mechanism is implemented in kernel, ("39e6c8208d7b net: solve a NAPI race"), we obsolete our own implementation and rely on the return value of napi_complete_done(). This patch removes a redundant overhead of atomic bit operations. Signed-off-by: Tariq Toukan Cc: Eric Dumazet Signed-off-by: Saeed Mahameed --- drivers/net/ethernet/mellanox/mlx5/core/en.h | 5 ----- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 1 - drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c | 10 +--------- 3 files changed, 1 insertion(+), 15 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index 9c0c07f..7c046ae 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -570,10 +570,6 @@ struct mlx5e_rq { struct mlx5_core_mkey umr_mkey; } ____cacheline_aligned_in_smp; -enum channel_flags { - MLX5E_CHANNEL_NAPI_SCHED = 1, -}; - struct mlx5e_channel { /* data path */ struct mlx5e_rq rq; @@ -585,7 +581,6 @@ struct mlx5e_channel { struct net_device *netdev; __be32 mkey_be; u8 num_tc; - unsigned long flags; /* control */ struct mlx5e_priv *priv; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index 2da2ea2..b2f689e 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -3697,7 +3697,6 @@ static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog) set_bit(MLX5E_RQ_STATE_ENABLED, &c->rq.state); /* napi_schedule in case we have missed anything */ - set_bit(MLX5E_CHANNEL_NAPI_SCHED, &c->flags); napi_schedule(&c->napi); if (old_prog) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c index 439ba1f..92d9aa1 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c @@ -40,8 +40,6 @@ int mlx5e_napi_poll(struct napi_struct *napi, int budget) int work_done; int i; - clear_bit(MLX5E_CHANNEL_NAPI_SCHED, &c->flags); - for (i = 0; i < c->num_tc; i++) busy |= mlx5e_poll_tx_cq(&c->sq[i].cq, budget); @@ -56,13 +54,8 @@ int mlx5e_napi_poll(struct napi_struct *napi, int budget) if (busy) return budget; - napi_complete_done(napi, work_done); - - /* avoid losing completion event during/after polling cqs */ - if (test_bit(MLX5E_CHANNEL_NAPI_SCHED, &c->flags)) { - napi_schedule(napi); + if (unlikely(!napi_complete_done(napi, work_done))) return work_done; - } for (i = 0; i < c->num_tc; i++) mlx5e_cq_arm(&c->sq[i].cq); @@ -81,7 +74,6 @@ void mlx5e_completion_event(struct mlx5_core_cq *mcq) struct mlx5e_cq *cq = container_of(mcq, struct mlx5e_cq, mcq); cq->event_ctr++; - set_bit(MLX5E_CHANNEL_NAPI_SCHED, &cq->channel->flags); napi_schedule(cq->napi); } -- 2.7.4