[PATCH 5.17 109/158] net/mlx5: Drain fw_reset when removing device

Greg Kroah-Hartman
2022-05-23T18:13:16Z

From: Shay Drory <shayd@nvidia.com>

[ Upstream commit 16d42d313350946f4b9a8b74a13c99f0461a6572 ]

In case fw sync reset is called in parallel to device removal, device
might stuck in the following deadlock:
CPU 0 CPU 1
----- -----
remove_one
uninit_one (locks intf_state_mutex)
mlx5_sync_reset_now_event()
work in fw_reset->wq.
mlx5_enter_error_state()
mutex_lock (intf_state_mutex)
cleanup_once
fw_reset_cleanup()
destroy_workqueue(fw_reset->wq)

Drain the fw_reset WQ, and make sure no new work is being queued, before
entering uninit_one().
The Drain is done before devlink_unregister() since fw_reset, in some
flows, is using devlink API devlink_remote_reload_actions_performed().

Fixes: 38b9f903f22b ("net/mlx5: Handle sync reset request event")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../ethernet/mellanox/mlx5/core/fw_reset.c | 25 ++++++++++++++++---
.../ethernet/mellanox/mlx5/core/fw_reset.h | 1 +
.../net/ethernet/mellanox/mlx5/core/main.c | 4 +++
3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
index 862f5b7cb210..1c771287bee5 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
@@ -8,7 +8,8 @@
enum {
MLX5_FW_RESET_FLAGS_RESET_REQUESTED,
MLX5_FW_RESET_FLAGS_NACK_RESET_REQUEST,
- MLX5_FW_RESET_FLAGS_PENDING_COMP
+ MLX5_FW_RESET_FLAGS_PENDING_COMP,
+ MLX5_FW_RESET_FLAGS_DROP_NEW_REQUESTS
};

struct mlx5_fw_reset {
@@ -165,7 +166,10 @@ static void poll_sync_reset(struct timer_list *t)

if (fatal_error) {
mlx5_core_warn(dev, "Got Device Reset\n");
- queue_work(fw_reset->wq, &fw_reset->reset_reload_work);
+ if (!test_bit(MLX5_FW_RESET_FLAGS_DROP_NEW_REQUESTS, &fw_reset->reset_flags))
+ queue_work(fw_reset->wq, &fw_reset->reset_reload_work);
+ else
+ mlx5_core_err(dev, "Device is being removed, Drop new reset work\n");
return;
}

@@ -390,9 +394,12 @@ static int fw_reset_event_notifier(struct notifier_block *nb, unsigned long acti
struct mlx5_fw_reset *fw_reset = mlx5_nb_cof(nb, struct mlx5_fw_reset, nb);
struct mlx5_eqe *eqe = data;

+ if (test_bit(MLX5_FW_RESET_FLAGS_DROP_NEW_REQUESTS, &fw_reset->reset_flags))
+ return NOTIFY_DONE;
+
switch (eqe->sub_type) {
case MLX5_GENERAL_SUBTYPE_FW_LIVE_PATCH_EVENT:
- queue_work(fw_reset->wq, &fw_reset->fw_live_patch_work);
+ queue_work(fw_reset->wq, &fw_reset->fw_live_patch_work);
break;
case MLX5_GENERAL_SUBTYPE_PCI_SYNC_FOR_FW_UPDATE_EVENT:
mlx5_sync_reset_events_handle(fw_reset, eqe);
@@ -436,6 +443,18 @@ void mlx5_fw_reset_events_stop(struct mlx5_core_dev *dev)
mlx5_eq_notifier_unregister(dev, &dev->priv.fw_reset->nb);
}

+void mlx5_drain_fw_reset(struct mlx5_core_dev *dev)
+{
+ struct mlx5_fw_reset *fw_reset = dev->priv.fw_reset;
+
+ set_bit(MLX5_FW_RESET_FLAGS_DROP_NEW_REQUESTS, &fw_reset->reset_flags);
+ cancel_work_sync(&fw_reset->fw_live_patch_work);
+ cancel_work_sync(&fw_reset->reset_request_work);
+ cancel_work_sync(&fw_reset->reset_reload_work);
+ cancel_work_sync(&fw_reset->reset_now_work);
+ cancel_work_sync(&fw_reset->reset_abort_work);
+}
+
int mlx5_fw_reset_init(struct mlx5_core_dev *dev)
{
struct mlx5_fw_reset *fw_reset = kzalloc(sizeof(*fw_reset), GFP_KERNEL);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.h b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.h
index 7761ee5fc7d0..372046e173e7 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.h
@@ -15,6 +15,7 @@ int mlx5_fw_reset_set_live_patch(struct mlx5_core_dev *dev);
int mlx5_fw_reset_wait_reset_done(struct mlx5_core_dev *dev);
void mlx5_fw_reset_events_start(struct mlx5_core_dev *dev);
void mlx5_fw_reset_events_stop(struct mlx5_core_dev *dev);
+void mlx5_drain_fw_reset(struct mlx5_core_dev *dev);
int mlx5_fw_reset_init(struct mlx5_core_dev *dev);
void mlx5_fw_reset_cleanup(struct mlx5_core_dev *dev);

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index f1437b6d4418..4e49dca94bc3 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -1628,6 +1628,10 @@ static void remove_one(struct pci_dev *pdev)
struct mlx5_core_dev *dev = pci_get_drvdata(pdev);
struct devlink *devlink = priv_to_devlink(dev);

+ /* mlx5_drain_fw_reset() is using devlink APIs. Hence, we must drain
+ * fw_reset before unregistering the devlink.
+ */
+ mlx5_drain_fw_reset(dev);
devlink_unregister(devlink);
mlx5_crdump_disable(dev);
mlx5_drain_health_wq(dev);
--
2.35.1