From: Maxim Mikityanskiy <maximmi@nvidia.com>
Date: Fri, 15 Apr 2022 16:19:15 +0300
Subject: net/mlx5e: Disable softirq in mlx5e_activate_rq to avoid race
condition
Patch-mainline: v5.19-rc1
Git-commit: 2e642afb61b24401a7ec819d27ddcd69c7c29784
References: jsc#PED-1549
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/ethernet/mellanox/mlx5/core/en.h | 4 ++
drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c | 1
drivers/net/ethernet/mellanox/mlx5/core/en/reporter_rx.c | 6 +++
drivers/net/ethernet/mellanox/mlx5/core/en/trap.c | 1
drivers/net/ethernet/mellanox/mlx5/core/en/xsk/pool.c | 1
drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c | 5 ---
drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 24 ++++++++++-----
7 files changed, 31 insertions(+), 11 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -764,6 +764,7 @@ 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;
@@ -1076,6 +1077,9 @@ 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);
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
@@ -736,6 +736,7 @@ void mlx5e_ptp_activate_channel(struct m
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);
}
}
--- 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_c
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_
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);
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c
@@ -179,6 +179,7 @@ static void mlx5e_activate_trap(struct m
{
napi_enable(&trap->napi);
mlx5e_activate_rq(&trap->rq);
+ mlx5e_trigger_napi_sched(&trap->napi);
}
void mlx5e_deactivate_trap(struct mlx5e_priv *priv)
--- 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(struc
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.
--- 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 mlx5
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_cha
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)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -475,6 +475,7 @@ static int mlx5e_init_rxq_rq(struct mlx5
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;
@@ -1066,13 +1067,6 @@ err_free_rq:
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)
@@ -2227,6 +2221,20 @@ static int mlx5e_channel_stats_alloc(str
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,
@@ -2308,6 +2316,8 @@ static void mlx5e_activate_channel(struc
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)