mlxsw: spectrum_dpipe: Add missing error path

In case devlink_dpipe_entry_ctx_prepare() failed, release RTNL that was
previously taken and free the memory allocated by
mlxsw_sp_erif_entry_prepare().

Fixes: 2ba5999f ("mlxsw: spectrum: Add Support for erif table entries access")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -215,7 +215,7 @@ mlxsw_sp_dpipe_table_erif_entries_dump(void *priv, bool counters_enabled,
 start_again:
 	err = devlink_dpipe_entry_ctx_prepare(dump_ctx);
 	if (err)
-		return err;
+		goto err_ctx_prepare;
 	j = 0;
 	for (; i < rif_count; i++) {
 		struct mlxsw_sp_rif *rif = mlxsw_sp_rif_by_index(mlxsw_sp, i);
@@ -247,6 +247,7 @@ mlxsw_sp_dpipe_table_erif_entries_dump(void *priv, bool counters_enabled,
 	return 0;
 err_entry_append:
 err_entry_get:
+err_ctx_prepare:
 	rtnl_unlock();
 	devlink_dpipe_entry_clear(&entry);
 	return err;