devlink: convert occ_get op to separate registration
authorJiri Pirko <jiri@mellanox.com>
Thu, 5 Apr 2018 20:13:21 +0000 (22:13 +0200)
committerDavid S. Miller <davem@davemloft.net>
Sun, 8 Apr 2018 16:45:57 +0000 (12:45 -0400)
commitfc56be47da8cb111add373c36230b0139139898f
treedb38258b8c93ea6920c61702fbd43d5840584b1c
parent5571196135abb6d51e01592812997403c136067c
devlink: convert occ_get op to separate registration

This resolves race during initialization where the resources with
ops are registered before driver and the structures used by occ_get
op is initialized. So keep occ_get callbacks registered only when
all structs are initialized.

The example flows, as it is in mlxsw:
1) driver load/asic probe:
   mlxsw_core
      -> mlxsw_sp_resources_register
        -> mlxsw_sp_kvdl_resources_register
          -> devlink_resource_register IDX
   mlxsw_spectrum
      -> mlxsw_sp_kvdl_init
        -> mlxsw_sp_kvdl_parts_init
          -> mlxsw_sp_kvdl_part_init
            -> devlink_resource_size_get IDX (to get the current setup
                                              size from devlink)
        -> devlink_resource_occ_get_register IDX (register current
                                                  occupancy getter)
2) reload triggered by devlink command:
  -> mlxsw_devlink_core_bus_device_reload
    -> mlxsw_sp_fini
      -> mlxsw_sp_kvdl_fini
-> devlink_resource_occ_get_unregister IDX
    (struct mlxsw_sp *mlxsw_sp is freed at this point, call to occ get
     which is using mlxsw_sp would cause use-after free)
    -> mlxsw_sp_init
      -> mlxsw_sp_kvdl_init
        -> mlxsw_sp_kvdl_parts_init
          -> mlxsw_sp_kvdl_part_init
            -> devlink_resource_size_get IDX (to get the current setup
                                              size from devlink)
        -> devlink_resource_occ_get_register IDX (register current
                                                  occupancy getter)

Fixes: d9f9b9a4d05f ("devlink: Add support for resource abstraction")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/mellanox/mlxsw/spectrum.c
drivers/net/ethernet/mellanox/mlxsw/spectrum.h
drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
drivers/net/netdevsim/devlink.c
include/net/devlink.h
net/core/devlink.c