net/mlx5: Drain fw_reset when removing device

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: 41097260c786 ("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>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
index ca1aba845dd6da173c3f172d8daed199d8c40503..81eb67fb95b04a1157dbe9765154907f4726f0aa 100644 (file)
--- 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 {
@@ -208,7 +209,10 @@ 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;
        }
 
@@ -433,9 +437,12 @@ 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);
@@ -479,6 +486,18 @@ 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 694fc7cb268457e460374c7d014fc530f524b549..dc141c7e641a307b9579c1509a650538c7371c06 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.h
@@ -16,6 +16,7 @@ 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 c6737720bf3a2b1df06f8411fe27acf09030546b..ef196cb764e2a3edaf640c29e928954f1c1d1475 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -1627,6 +1627,10 @@ 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_sriov_disable(pdev);
        mlx5_crdump_disable(dev);