On Thu, 29 Aug 2024, Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> The INTERVAL_TREE_DEFINE() uncoditionally provides a bunch of helper
> functions which in some cases may be not used. This, in particular,
> prevents kernel builds with `make W=1` and CONFIG_WERROR=y:
>
> .../drm/drm_mm.c:152:1: error: unused function 'drm_mm_interval_tree_insert' [-Werror,-Wunused-function]
> 152 | INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 153 | u64, __subtree_last,
> | ~~~~~~~~~~~~~~~~~~~~
> 154 | START, LAST, static inline, drm_mm_interval_tree)
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Fix this by marking drm_mm_interval_tree*() functions with __maybe_unused.
>
> Fixes: 202b52b7fbf7 ("drm: Track drm_mm nodes with an interval tree")
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
As discussed in [1], the key combo is W=1 and Clang, which enables
detection for unused static inlines.
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
BR,
Jani.
[1] https://lore.kernel.org/r/20240829155950.1141978-1-andriy.shevchenko@xxxxxxxxxxxxxxx
> ---
> drivers/gpu/drm/drm_mm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
> index 5ace481c1901..1ed68d3cd80b 100644
> --- a/drivers/gpu/drm/drm_mm.c
> +++ b/drivers/gpu/drm/drm_mm.c
> @@ -151,7 +151,7 @@ static void show_leaks(struct drm_mm *mm) { }
>
> INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,
> u64, __subtree_last,
> - START, LAST, static inline, drm_mm_interval_tree)
> + START, LAST, static inline __maybe_unused, drm_mm_interval_tree)
>
> struct drm_mm_node *
> __drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last)
--
Jani Nikula, Intel
