3 files changed, 48 insertions, 20 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 65fe40f55d84..416ab6b6da97 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -1665,11 +1665,9 @@ bool mlx5e_tc_is_vf_tunnel(struct net_device *out_dev, struct net_device *route_
 int mlx5e_tc_query_route_vport(struct net_device *out_dev, struct net_device *route_dev, u16 *vport)
 {
 	struct mlx5e_priv *out_priv, *route_priv;
-	struct mlx5_devcom *devcom = NULL;
 	struct mlx5_core_dev *route_mdev;
 	struct mlx5_eswitch *esw;
 	u16 vhca_id;
-	int err;
 
 	out_priv = netdev_priv(out_dev);
 	esw = out_priv->mdev->priv.eswitch;
@@ -1678,6 +1676,9 @@ int mlx5e_tc_query_route_vport(struct net_device *out_dev, struct net_device *ro
 
 	vhca_id = MLX5_CAP_GEN(route_mdev, vhca_id);
 	if (mlx5_lag_is_active(out_priv->mdev)) {
+		struct mlx5_devcom *devcom;
+		int err;
+
 		/* In lag case we may get devices from different eswitch instances.
 		 * If we failed to get vport num, it means, mostly, that we on the wrong
 		 * eswitch.
@@ -1686,16 +1687,16 @@ int mlx5e_tc_query_route_vport(struct net_device *out_dev, struct net_device *ro
 		if (err != -ENOENT)
 			return err;
 
+		rcu_read_lock();
 		devcom = out_priv->mdev->priv.devcom;
-		esw = mlx5_devcom_get_peer_data(devcom, MLX5_DEVCOM_ESW_OFFLOADS);
-		if (!esw)
-			return -ENODEV;
+		esw = mlx5_devcom_get_peer_data_rcu(devcom, MLX5_DEVCOM_ESW_OFFLOADS);
+		err = esw ? mlx5_eswitch_vhca_id_to_vport(esw, vhca_id, vport) : -ENODEV;
+		rcu_read_unlock();
+
+		return err;
 	}
 
-	err = mlx5_eswitch_vhca_id_to_vport(esw, vhca_id, vport);
-	if (devcom)
-		mlx5_devcom_release_peer_data(devcom, MLX5_DEVCOM_ESW_OFFLOADS);
-	return err;
+	return mlx5_eswitch_vhca_id_to_vport(esw, vhca_id, vport);
 }
 
 static int
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c
index adefde3ea941..070d55f13419 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c
@@ -13,7 +13,7 @@ static LIST_HEAD(devcom_list);
 
 struct mlx5_devcom_component {
 	struct {
-		void *data;
+		void __rcu *data;
 	} device[MLX5_DEVCOM_PORTS_SUPPORTED];
 
 	mlx5_devcom_event_handler_t handler;
@@ -162,7 +162,7 @@ void mlx5_devcom_register_component(struct mlx5_devcom *devcom,
 	comp = &devcom->priv->components[id];
 	down_write(&comp->sem);
 	comp->handler = handler;
-	comp->device[devcom->idx].data = data;
+	rcu_assign_pointer(comp->device[devcom->idx].data, data);
 	up_write(&comp->sem);
 }
 
@@ -176,8 +176,9 @@ void mlx5_devcom_unregister_component(struct mlx5_devcom *devcom,
 
 	comp = &devcom->priv->components[id];
 	down_write(&comp->sem);
-	comp->device[devcom->idx].data = NULL;
+	RCU_INIT_POINTER(comp->device[devcom->idx].data, NULL);
 	up_write(&comp->sem);
+	synchronize_rcu();
 }
 
 int mlx5_devcom_send_event(struct mlx5_devcom *devcom,
@@ -193,12 +194,15 @@ int mlx5_devcom_send_event(struct mlx5_devcom *devcom,
 
 	comp = &devcom->priv->components[id];
 	down_write(&comp->sem);
-	for (i = 0; i < MLX5_DEVCOM_PORTS_SUPPORTED; i++)
-		if (i != devcom->idx && comp->device[i].data) {
-			err = comp->handler(event, comp->device[i].data,
-					    event_data);
+	for (i = 0; i < MLX5_DEVCOM_PORTS_SUPPORTED; i++) {
+		void *data = rcu_dereference_protected(comp->device[i].data,
+						       lockdep_is_held(&comp->sem));
+
+		if (i != devcom->idx && data) {
+			err = comp->handler(event, data, event_data);
 			break;
 		}
+	}
 
 	up_write(&comp->sem);
 	return err;
@@ -213,7 +217,7 @@ void mlx5_devcom_set_paired(struct mlx5_devcom *devcom,
 	comp = &devcom->priv->components[id];
 	WARN_ON(!rwsem_is_locked(&comp->sem));
 
-	comp->paired = paired;
+	WRITE_ONCE(comp->paired, paired);
 }
 
 bool mlx5_devcom_is_paired(struct mlx5_devcom *devcom,
@@ -222,7 +226,7 @@ bool mlx5_devcom_is_paired(struct mlx5_devcom *devcom,
 	if (IS_ERR_OR_NULL(devcom))
 		return false;
 
-	return devcom->priv->components[id].paired;
+	return READ_ONCE(devcom->priv->components[id].paired);
 }
 
 void *mlx5_devcom_get_peer_data(struct mlx5_devcom *devcom,
@@ -236,7 +240,7 @@ void *mlx5_devcom_get_peer_data(struct mlx5_devcom *devcom,
 
 	comp = &devcom->priv->components[id];
 	down_read(&comp->sem);
-	if (!comp->paired) {
+	if (!READ_ONCE(comp->paired)) {
 		up_read(&comp->sem);
 		return NULL;
 	}
@@ -245,7 +249,29 @@ void *mlx5_devcom_get_peer_data(struct mlx5_devcom *devcom,
 		if (i != devcom->idx)
 			break;
 
-	return comp->device[i].data;
+	return rcu_dereference_protected(comp->device[i].data, lockdep_is_held(&comp->sem));
+}
+
+void *mlx5_devcom_get_peer_data_rcu(struct mlx5_devcom *devcom, enum mlx5_devcom_components id)
+{
+	struct mlx5_devcom_component *comp;
+	int i;
+
+	if (IS_ERR_OR_NULL(devcom))
+		return NULL;
+
+	for (i = 0; i < MLX5_DEVCOM_PORTS_SUPPORTED; i++)
+		if (i != devcom->idx)
+			break;
+
+	comp = &devcom->priv->components[id];
+	/* This can change concurrently, however 'data' pointer will remain
+	 * valid for the duration of RCU read section.
+	 */
+	if (!READ_ONCE(comp->paired))
+		return NULL;
+
+	return rcu_dereference(comp->device[i].data);
 }
 
 void mlx5_devcom_release_peer_data(struct mlx5_devcom *devcom,
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.h b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.h
index 94313c18bb64..9a496f4722da 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.h
@@ -41,6 +41,7 @@ bool mlx5_devcom_is_paired(struct mlx5_devcom *devcom,
 
 void *mlx5_devcom_get_peer_data(struct mlx5_devcom *devcom,
 				enum mlx5_devcom_components id);
+void *mlx5_devcom_get_peer_data_rcu(struct mlx5_devcom *devcom, enum mlx5_devcom_components id);
 void mlx5_devcom_release_peer_data(struct mlx5_devcom *devcom,
 				   enum mlx5_devcom_components id);