Re: [dpdk-dev] [PATCH v8 03/10] drivers: relax dependency order

[David Marchand <david.marchand@redhat.com>]

On Thu, Jul 23, 2020 at 10:10 PM Parav Pandit <parav@mellanox.com> wrote:
>
> From: Thomas Monjalon <thomas@monjalon.net>
>
> Drivers dependencies are evaluated in the order defined per
> their parent directory (also called class).
> This strict ordering prevent from having 2 different drivers
> of the same class with different dependencies ordering.
> This problem occurs if drivers/common/mlx5 depends on drivers/bus/pci,
> while drivers/bus/dpaa depends on drivers/common/dpaax.
> Having a strict ordering between directories bus and common
> is too much restrictive.
>
> That's why it is made possible to have a more fine-grain directory list,
> adding a driver sub-directory in the list.
> In this case, the isolated driver must be removed from its class list,
> and added directly in drivers/meson.build.
> Also, the per-class variables must be duplicated in the isolated driver,
> because the call "subdir(class)" is skipped in the isolated driver case.
>
> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> ---
>  drivers/meson.build | 28 +++++++++++++++++++++-------
>  1 file changed, 21 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/meson.build b/drivers/meson.build
> index e2aeba931..e6d0409aa 100644
> --- a/drivers/meson.build
> +++ b/drivers/meson.build
> @@ -1,8 +1,8 @@
>  # SPDX-License-Identifier: BSD-3-Clause
>  # Copyright(c) 2017-2019 Intel Corporation
>
> -# Defines the order in which the drivers are buit.
> -dpdk_driver_classes = [
> +# Defines the order of dependencies evaluation
> +subdirs = [
>         'common',
>         'bus',
>         'mempool', # depends on common and bus.
> @@ -27,7 +27,7 @@ if cc.has_argument('-Wno-format-truncation')
>         default_cflags += '-Wno-format-truncation'
>  endif
>
> -foreach class:dpdk_driver_classes
> +foreach subpath:subdirs
>         drivers = []
>         std_deps = []
>         config_flag_fmt = '' # format string used to set the value in dpdk_conf
> @@ -35,8 +35,22 @@ foreach class:dpdk_driver_classes
>                              # the library, the dependency and to find the
>                              # version file for linking
>
> -       subdir(class)
> -       class_drivers = []
> +       # subpath can be either "class" or "class/driver"
> +       if subpath.contains('/')
> +               driver_path = subpath.split('/')
> +               class = driver_path[0]
> +               drivers += driver_path[1]
> +       else
> +               class = subpath
> +               subdir(class)
> +       endif
> +
> +       # save class name on first occurence
> +       if not dpdk_driver_classes.contains(class)
> +               dpdk_driver_classes += class
> +       endif
> +       # get already enabled drivers of the same class
> +       enabled_drivers = get_variable(class + '_drivers', [])
>
>         foreach drv:drivers
>                 drv_path = join_paths(class, drv)
> @@ -96,7 +110,7 @@ foreach class:dpdk_driver_classes
>                                                 '_disable_reason', reason)
>                         endif
>                 else
> -                       class_drivers += name
> +                       enabled_drivers += name
>
>                         if fmt_name == ''
>                                 fmt_name = name
> @@ -203,5 +217,5 @@ foreach class:dpdk_driver_classes
>                 endif # build
>         endforeach
>
> -       set_variable(class + '_drivers', class_drivers)
> +       set_variable(class + '_drivers', enabled_drivers)
>  endforeach
> --
> 2.25.4
>

Reviewed-by: David Marchand <david.marchand@redhat.com>


-- 
David Marchand