mlxsw: spectrum: Remove RTNL where possible

After introducing the router lock in previous patches and making sure it
protects internal router structures, we no longer need to rely on RTNL
to serialize access to these structures.

Remove RTNL from call sites that no longer require it.

Two calls sites that keep taking the lock are
mlxsw_sp_router_fibmr_event_work() and mlxsw_sp_inet6addr_event_work().
The first calls into ACL code that still assumes RTNL is taken. The
second potentially calls into the FID code that also relies on RTNL.
Removing RTNL from these two call sites is the subject of future work.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_dpipe.c

@@ -211,7 +211,6 @@ mlxsw_sp_dpipe_table_erif_entries_dump(void *priv, bool counters_enabled,
 		return err;
 
 	rif_count = MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_RIFS);
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	i = 0;
 start_again:
@@ -244,7 +243,6 @@ mlxsw_sp_dpipe_table_erif_entries_dump(void *priv, bool counters_enabled,
 	if (i != rif_count)
 		goto start_again;
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 
 	devlink_dpipe_entry_clear(&entry);
 	return 0;
@@ -252,7 +250,6 @@ mlxsw_sp_dpipe_table_erif_entries_dump(void *priv, bool counters_enabled,
 err_entry_get:
 err_ctx_prepare:
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 	devlink_dpipe_entry_clear(&entry);
 	return err;
 }
@@ -262,7 +259,6 @@ static int mlxsw_sp_dpipe_table_erif_counters_update(void *priv, bool enable)
 	struct mlxsw_sp *mlxsw_sp = priv;
 	int i;
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	for (i = 0; i < MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_RIFS); i++) {
 		struct mlxsw_sp_rif *rif = mlxsw_sp_rif_by_index(mlxsw_sp, i);
@@ -277,7 +273,6 @@ static int mlxsw_sp_dpipe_table_erif_counters_update(void *priv, bool enable)
 						  MLXSW_SP_RIF_COUNTER_EGRESS);
 	}
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 	return 0;
 }
 
@@ -552,7 +547,6 @@ mlxsw_sp_dpipe_table_host_entries_get(struct mlxsw_sp *mlxsw_sp,
 	int i, j;
 	int err;
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	i = 0;
 	rif_count = MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_RIFS);
@@ -610,13 +604,11 @@ mlxsw_sp_dpipe_table_host_entries_get(struct mlxsw_sp *mlxsw_sp,
 		goto start_again;
 
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 	return 0;
 
 err_ctx_prepare:
 err_entry_append:
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 	return err;
 }
 
@@ -671,7 +663,6 @@ mlxsw_sp_dpipe_table_host_counters_update(struct mlxsw_sp *mlxsw_sp,
 {
 	int i;
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	for (i = 0; i < MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_RIFS); i++) {
 		struct mlxsw_sp_rif *rif = mlxsw_sp_rif_by_index(mlxsw_sp, i);
@@ -695,7 +686,6 @@ mlxsw_sp_dpipe_table_host_counters_update(struct mlxsw_sp *mlxsw_sp,
 		}
 	}
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 }
 
 static int mlxsw_sp_dpipe_table_host4_counters_update(void *priv, bool enable)
@@ -712,7 +702,6 @@ mlxsw_sp_dpipe_table_host_size_get(struct mlxsw_sp *mlxsw_sp, int type)
 	u64 size = 0;
 	int i;
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	for (i = 0; i < MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_RIFS); i++) {
 		struct mlxsw_sp_rif *rif = mlxsw_sp_rif_by_index(mlxsw_sp, i);
@@ -734,7 +723,6 @@ mlxsw_sp_dpipe_table_host_size_get(struct mlxsw_sp *mlxsw_sp, int type)
 		}
 	}
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 
 	return size;
 }
@@ -1106,7 +1094,6 @@ mlxsw_sp_dpipe_table_adj_entries_get(struct mlxsw_sp *mlxsw_sp,
 	int j;
 	int err;
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	nh_count_max = mlxsw_sp_dpipe_table_adj_size(mlxsw_sp);
 start_again:
@@ -1145,14 +1132,12 @@ mlxsw_sp_dpipe_table_adj_entries_get(struct mlxsw_sp *mlxsw_sp,
 	if (nh_count != nh_count_max)
 		goto start_again;
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 
 	return 0;
 
 err_ctx_prepare:
 err_entry_append:
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 	return err;
 }
 
@@ -1222,11 +1207,9 @@ mlxsw_sp_dpipe_table_adj_size_get(void *priv)
 	struct mlxsw_sp *mlxsw_sp = priv;
 	u64 size;
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	size = mlxsw_sp_dpipe_table_adj_size(mlxsw_sp);
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 
 	return size;
 }

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -2307,7 +2307,6 @@ __mlxsw_sp_router_neighs_update_rauhtd(struct mlxsw_sp *mlxsw_sp,
 	int i, num_rec;
 	int err;
 
-	rtnl_lock();
 	/* Ensure the RIF we read from the device does not change mid-dump. */
 	mutex_lock(&mlxsw_sp->router->lock);
 	do {
@@ -2324,7 +2323,6 @@ __mlxsw_sp_router_neighs_update_rauhtd(struct mlxsw_sp *mlxsw_sp,
 							  i);
 	} while (mlxsw_sp_router_rauhtd_is_full(rauhtd_pl));
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 
 	return err;
 }
@@ -2355,7 +2353,6 @@ static void mlxsw_sp_router_neighs_update_nh(struct mlxsw_sp *mlxsw_sp)
 {
 	struct mlxsw_sp_neigh_entry *neigh_entry;
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	list_for_each_entry(neigh_entry, &mlxsw_sp->router->nexthop_neighs_list,
 			    nexthop_neighs_list_node)
@@ -2364,7 +2361,6 @@ static void mlxsw_sp_router_neighs_update_nh(struct mlxsw_sp *mlxsw_sp)
 		 */
 		neigh_event_send(neigh_entry->key.n, NULL);
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 }
 
 static void
@@ -2405,14 +2401,12 @@ static void mlxsw_sp_router_probe_unresolved_nexthops(struct work_struct *work)
 	 * but it wouldn't get resolved ever in case traffic is flowing in HW
 	 * using different nexthop.
 	 */
-	rtnl_lock();
 	mutex_lock(&router->lock);
 	list_for_each_entry(neigh_entry, &router->nexthop_neighs_list,
 			    nexthop_neighs_list_node)
 		if (!neigh_entry->connected)
 			neigh_event_send(neigh_entry->key.n, NULL);
 	mutex_unlock(&router->lock);
-	rtnl_unlock();
 
 	mlxsw_core_schedule_dw(&router->nexthop_probe_dw,
 			       MLXSW_SP_UNRESOLVED_NH_PROBE_INTERVAL);
@@ -2550,7 +2544,6 @@ static void mlxsw_sp_router_neigh_event_work(struct work_struct *work)
 	dead = n->dead;
 	read_unlock_bh(&n->lock);
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	mlxsw_sp_span_respin(mlxsw_sp);
 
@@ -2574,7 +2567,6 @@ static void mlxsw_sp_router_neigh_event_work(struct work_struct *work)
 
 out:
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 	neigh_release(n);
 	kfree(net_work);
 }
@@ -5981,7 +5973,6 @@ static void mlxsw_sp_router_fib4_event_work(struct work_struct *work)
 	struct mlxsw_sp *mlxsw_sp = fib_work->mlxsw_sp;
 	int err;
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	mlxsw_sp_span_respin(mlxsw_sp);
 
@@ -6005,7 +5996,6 @@ static void mlxsw_sp_router_fib4_event_work(struct work_struct *work)
 		break;
 	}
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 	kfree(fib_work);
 }
 
@@ -6016,7 +6006,6 @@ static void mlxsw_sp_router_fib6_event_work(struct work_struct *work)
 	struct mlxsw_sp *mlxsw_sp = fib_work->mlxsw_sp;
 	int err;
 
-	rtnl_lock();
 	mutex_lock(&mlxsw_sp->router->lock);
 	mlxsw_sp_span_respin(mlxsw_sp);
 
@@ -6045,7 +6034,6 @@ static void mlxsw_sp_router_fib6_event_work(struct work_struct *work)
 		break;
 	}
 	mutex_unlock(&mlxsw_sp->router->lock);
-	rtnl_unlock();
 	kfree(fib_work);
 }