From: Maxim Mikityanskiy maximmi@nvidia.com
[ Upstream commit 2e642afb61b24401a7ec819d27ddcd69c7c29784 ]
When the driver activates the channels, it assumes NAPI isn't running yet. mlx5e_activate_rq posts a NOP WQE to ICOSQ to trigger a hardware interrupt and start NAPI, which will run mlx5e_alloc_rx_mpwqe and post UMR WQEs to ICOSQ to be able to receive packets with striding RQ.
Unfortunately, a race condition is possible if NAPI is triggered by something else (for example, TX) at a bad timing, before mlx5e_activate_rq finishes. In this case, mlx5e_alloc_rx_mpwqe may post UMR WQEs to ICOSQ, and with the bad timing, the wqe_info of the first UMR may be overwritten by the wqe_info of the NOP posted by mlx5e_activate_rq.
The consequence is that icosq->db.wqe_info[0].num_wqebbs will be changed from MLX5E_UMR_WQEBBS to 1, disrupting the integrity of the array-based linked list in wqe_info[]. mlx5e_poll_ico_cq will hang in an infinite loop after processing wqe_info[0], because after the corruption, the next item to be processed will be wqe_info[1], which is filled with zeros, and `sqcc += wi->num_wqebbs` will never move further.
This commit fixes this race condition by using async_icosq to post the NOP and trigger the interrupt. async_icosq is always protected with a spinlock, eliminating the race condition.
Fixes: bc77b240b3c5 ("net/mlx5e: Add fragmented memory support for RX multi packet WQE") Signed-off-by: Maxim Mikityanskiy maximmi@nvidia.com Reported-by: Karsten Nielsen karsten@foo-bar.dk Reviewed-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Gal Pressman gal@nvidia.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/en.h | 4 ++++ .../net/ethernet/mellanox/mlx5/core/en/ptp.c | 1 + .../mellanox/mlx5/core/en/reporter_rx.c | 6 +++++ .../net/ethernet/mellanox/mlx5/core/en/trap.c | 1 + .../ethernet/mellanox/mlx5/core/en/xsk/pool.c | 1 + .../mellanox/mlx5/core/en/xsk/setup.c | 5 +--- .../net/ethernet/mellanox/mlx5/core/en_main.c | 24 +++++++++++++------ 7 files changed, 31 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index 5ccd6c634274..4c8c8e4c1ef3 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -730,6 +730,7 @@ struct mlx5e_rq { u8 wq_type; u32 rqn; struct mlx5_core_dev *mdev; + struct mlx5e_channel *channel; u32 umr_mkey; struct mlx5e_dma_info wqe_overflow;
@@ -1044,6 +1045,9 @@ void mlx5e_close_cq(struct mlx5e_cq *cq); int mlx5e_open_locked(struct net_device *netdev); int mlx5e_close_locked(struct net_device *netdev);
+void mlx5e_trigger_napi_icosq(struct mlx5e_channel *c); +void mlx5e_trigger_napi_sched(struct napi_struct *napi); + int mlx5e_open_channels(struct mlx5e_priv *priv, struct mlx5e_channels *chs); void mlx5e_close_channels(struct mlx5e_channels *chs); diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c index 82baafd3c00c..fdb82f2b0130 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c @@ -737,6 +737,7 @@ void mlx5e_ptp_activate_channel(struct mlx5e_ptp *c) if (test_bit(MLX5E_PTP_STATE_RX, c->state)) { mlx5e_ptp_rx_set_fs(c->priv); mlx5e_activate_rq(&c->rq); + mlx5e_trigger_napi_sched(&c->napi); } }
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_rx.c index 2684e9da9f41..fc366e66d0b0 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_rx.c @@ -123,6 +123,8 @@ static int mlx5e_rx_reporter_err_icosq_cqe_recover(void *ctx) xskrq->stats->recover++; }
+ mlx5e_trigger_napi_icosq(icosq->channel); + mutex_unlock(&icosq->channel->icosq_recovery_lock);
return 0; @@ -166,6 +168,10 @@ static int mlx5e_rx_reporter_err_rq_cqe_recover(void *ctx) clear_bit(MLX5E_RQ_STATE_RECOVERING, &rq->state); mlx5e_activate_rq(rq); rq->stats->recover++; + if (rq->channel) + mlx5e_trigger_napi_icosq(rq->channel); + else + mlx5e_trigger_napi_sched(rq->cq.napi); return 0; out: clear_bit(MLX5E_RQ_STATE_RECOVERING, &rq->state); diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c b/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c index a55b066746cb..6dd36e3cf425 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c @@ -172,6 +172,7 @@ static void mlx5e_activate_trap(struct mlx5e_trap *trap) { napi_enable(&trap->napi); mlx5e_activate_rq(&trap->rq); + mlx5e_trigger_napi_sched(&trap->napi); }
void mlx5e_deactivate_trap(struct mlx5e_priv *priv) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/pool.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/pool.c index 279cd8f4e79f..2c520394aa1d 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/pool.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/pool.c @@ -117,6 +117,7 @@ static int mlx5e_xsk_enable_locked(struct mlx5e_priv *priv, goto err_remove_pool;
mlx5e_activate_xsk(c); + mlx5e_trigger_napi_icosq(c);
/* Don't wait for WQEs, because the newer xdpsock sample doesn't provide * any Fill Ring entries at the setup stage. diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c index 25eac9e20342..5a2cd15e245d 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c @@ -64,6 +64,7 @@ static int mlx5e_init_xsk_rq(struct mlx5e_channel *c, rq->clock = &mdev->clock; rq->icosq = &c->icosq; rq->ix = c->ix; + rq->channel = c; rq->mdev = mdev; rq->hw_mtu = MLX5E_SW2HW_MTU(params, params->sw_mtu); rq->xdpsq = &c->rq_xdpsq; @@ -179,10 +180,6 @@ void mlx5e_activate_xsk(struct mlx5e_channel *c) mlx5e_reporter_icosq_resume_recovery(c);
/* TX queue is created active. */ - - spin_lock_bh(&c->async_icosq_lock); - mlx5e_trigger_irq(&c->async_icosq); - spin_unlock_bh(&c->async_icosq_lock); }
void mlx5e_deactivate_xsk(struct mlx5e_channel *c) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index 531fffe1abe3..9730bd96d0de 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -477,6 +477,7 @@ static int mlx5e_init_rxq_rq(struct mlx5e_channel *c, struct mlx5e_params *param rq->clock = &mdev->clock; rq->icosq = &c->icosq; rq->ix = c->ix; + rq->channel = c; rq->mdev = mdev; rq->hw_mtu = MLX5E_SW2HW_MTU(params, params->sw_mtu); rq->xdpsq = &c->rq_xdpsq; @@ -1070,13 +1071,6 @@ int mlx5e_open_rq(struct mlx5e_params *params, struct mlx5e_rq_param *param, void mlx5e_activate_rq(struct mlx5e_rq *rq) { set_bit(MLX5E_RQ_STATE_ENABLED, &rq->state); - if (rq->icosq) { - mlx5e_trigger_irq(rq->icosq); - } else { - local_bh_disable(); - napi_schedule(rq->cq.napi); - local_bh_enable(); - } }
void mlx5e_deactivate_rq(struct mlx5e_rq *rq) @@ -2218,6 +2212,20 @@ static int mlx5e_channel_stats_alloc(struct mlx5e_priv *priv, int ix, int cpu) return 0; }
+void mlx5e_trigger_napi_icosq(struct mlx5e_channel *c) +{ + spin_lock_bh(&c->async_icosq_lock); + mlx5e_trigger_irq(&c->async_icosq); + spin_unlock_bh(&c->async_icosq_lock); +} + +void mlx5e_trigger_napi_sched(struct napi_struct *napi) +{ + local_bh_disable(); + napi_schedule(napi); + local_bh_enable(); +} + static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix, struct mlx5e_params *params, struct mlx5e_channel_param *cparam, @@ -2299,6 +2307,8 @@ static void mlx5e_activate_channel(struct mlx5e_channel *c)
if (test_bit(MLX5E_CHANNEL_STATE_XSK, c->state)) mlx5e_activate_xsk(c); + + mlx5e_trigger_napi_icosq(c); }
static void mlx5e_deactivate_channel(struct mlx5e_channel *c)