Re: [PATCH 0/3] lib/string_helpers: Add a few string helpers

[Jani Nikula]

On Tue, 18 Jan 2022, Lucas De Marchi <lucas.demarchi@xxxxxxxxx> wrote:
> Add some helpers under lib/string_helpers.h so they can be used
> throughout the kernel. When I started doing this there were 2 other
> previous attempts I know of, not counting the iterations each of them
> had:
>
> 1) https://lore.kernel.org/all/20191023131308.9420-1-jani.nikula@xxxxxxxxx/
> 2) https://lore.kernel.org/all/20210215142137.64476-1-andriy.shevchenko@xxxxxxxxxxxxxxx/#t
>
> Going through the comments I tried to find some common ground and
> justification for what is in here, addressing some of the concerns
> raised.
>
> a. This version should be a drop-in replacement for what is currently in
>    the tree, with no change in behavior or binary size. For binary
>    size what I checked wat that the linked objects in the end have the
>    same size (gcc 11). From comments in the previous attempts this seems
>    also the case for earlier compiler versions
>
> b. I didn't change the function name to choice_* as suggested by Andrew
>    Morton in 20191023155619.43e0013f0c8c673a5c508c1e@xxxxxxxxxxxxxxxxxxxx
>    because other people argumented in favor of shorter names for these
>    simple helpers - if they are long and people simply not use due to
>    that, we failed
>
> c. Use string_helper.h for these helpers - pulling string.h in the
>    compilations units was one of the concerns and I think re-using this
>    already existing header is better than creating a new string-choice.h
>
> d. This doesn't bring onoff() helper as there are some places in the
>    kernel with onoff as variable - another name is probably needed for
>    this function in order not to shadow the variable, or those variables
>    could be renamed.  Or if people wanting  <someprefix>
>    try to find a short one
>
> e. One alternative to all of this suggested by Christian König
>    (43456ba7-c372-84cc-4949-dcb817188e21@xxxxxxx) would be to add a
>    printk format. But besides the comment, he also seemed to like
>    the common function. This brought the argument from others that the
>    simple yesno()/enabledisable() already used in the code is easier to
>    remember and use than e.g. %py[DOY]
>
> Last patch also has some additional conversion of open coded cases. I
> preferred starting with drm/ since this is "closer to home".
>
> I hope this is a good summary of the previous attempts and a way we can
> move forward.

Thanks for picking this up again. I agree with the approach here.

Acked-by: Jani Nikula <jani.nikula@xxxxxxxxx>

>
> Andrew Morton, Petr Mladek, Andy Shevchenko: if this is accepted, my
> proposal is to take first 2 patches either through mm tree or maybe
> vsprintf. Last patch can be taken later through drm.
>
> thanks
> Lucas De Marchi
>
> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Cc: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Cc: Ben Skeggs <bskeggs@xxxxxxxxxx>
> Cc: Christian König <christian.koenig@xxxxxxx>
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Daniel Vetter <daniel@xxxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxx>
> Cc: David S. Miller <davem@xxxxxxxxxxxxx>
> Cc: Emma Anholt <emma@xxxxxxxxxx>
> Cc: Eryk Brol <eryk.brol@xxxxxxx>
> Cc: Francis Laniel <laniel_francis@xxxxxxxxxxxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Harry Wentland <harry.wentland@xxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> Cc: Julia Lawall <julia.lawall@xxxxxxx>
> Cc: Kentaro Takeda <takedakn@xxxxxxxxxxxxx>
> Cc: Leo Li <sunpeng.li@xxxxxxx>
> Cc: Mikita Lipski <mikita.lipski@xxxxxxx>
> Cc: Petr Mladek <pmladek@xxxxxxxx>
> Cc: Rahul Lakkireddy <rahul.lakkireddy@xxxxxxxxxxx>
> Cc: Raju Rangoju <rajur@xxxxxxxxxxx>
> Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> Cc: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Vishal Kulkarni <vishal@xxxxxxxxxxx>
>
> Lucas De Marchi (3):
>   lib/string_helpers: Consolidate yesno() implementation
>   lib/string_helpers: Add helpers for enable[d]/disable[d]
>   drm: Convert open yes/no strings to yesno()
>
>  drivers/gpu/drm/amd/amdgpu/atom.c              |  3 ++-
>  .../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c  |  6 +-----
>  drivers/gpu/drm/drm_client_modeset.c           |  3 ++-
>  drivers/gpu/drm/drm_dp_helper.c                |  3 ++-
>  drivers/gpu/drm/drm_gem.c                      |  3 ++-
>  drivers/gpu/drm/i915/i915_utils.h              | 15 ---------------
>  drivers/gpu/drm/nouveau/nvkm/subdev/i2c/aux.c  |  4 +++-
>  drivers/gpu/drm/radeon/atom.c                  |  3 ++-
>  drivers/gpu/drm/v3d/v3d_debugfs.c              | 11 ++++++-----
>  drivers/gpu/drm/virtio/virtgpu_debugfs.c       |  3 ++-
>  .../net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c | 11 -----------
>  include/linux/string_helpers.h                 |  4 ++++
>  security/tomoyo/audit.c                        |  2 +-
>  security/tomoyo/common.c                       | 18 ++++--------------
>  security/tomoyo/common.h                       |  1 -
>  15 files changed, 31 insertions(+), 59 deletions(-)

-- 
Jani Nikula, Intel Open Source Graphics Center