Re: [PATCH] drm/xe: Make p2pdma distance check verbose via dynamic debug

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Unconditional use of the internal `_dynamic_func_call` macro causes a build failure when `CONFIG_DYNAMIC_DEBUG` is disabled.
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commit 6e70a101effbf7ae91a2873e2642ceaadc4900a3
Author: Thomas Hellström <thomas.hellstrom@linux.intel.com>

drm/xe: Make p2pdma distance check verbose via dynamic debug

pci_p2pdma_distance() can optionally print details about how it computed
the ACS/PCIe topology distance between the two devices. Tie the verbose
argument to a dedicated dynamic-debug callsite tagged "xe dma-buf p2p
debug" so the extra p2pdma distance logging can be switched on without a
recompile.

> diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c
> index 5d9f1cd24b7f3..b63fd70fb4de9 100644
> --- a/drivers/gpu/drm/xe/xe_dma_buf.c
> +++ b/drivers/gpu/drm/xe/xe_dma_buf.c
> @@ -22,13 +22,21 @@
>  
>  MODULE_IMPORT_NS("DMA_BUF");
>  
> +static void xe_ddebug_flip_bool(const struct _ddebug *desc, bool *flag)
> +{
> +	*flag = true;
> +}
> +
>  static int xe_dma_buf_attach(struct dma_buf *dmabuf,
>  			     struct dma_buf_attachment *attach)
>  {
>  	struct drm_gem_object *obj = attach->dmabuf->priv;
> +	bool verbose_p2p_dist = drm_debug_enabled(DRM_UT_DRIVER);
> +
> +	_dynamic_func_call("xe dma-buf p2p debug", xe_ddebug_flip_bool, &verbose_p2p_dist);
        ^^^^^^^^^^^^^^^^^^

[Severity: Low]
Does this unconditional use of the internal _dynamic_func_call macro cause a
build failure when CONFIG_DYNAMIC_DEBUG is disabled?

Since _dynamic_func_call has no stub definition in the #else block of
include/linux/dynamic_debug.h, compiling the xe driver with CONFIG_DRM_XE
enabled but CONFIG_DYNAMIC_DEBUG disabled results in an implicit function
declaration error.

If the macro call is guarded by an ifdef, does xe_ddebug_flip_bool() also need
an ifdef guard or __maybe_unused to avoid a -Wunused-function warning?

>  
>  	if (attach->peer2peer &&
> -	    pci_p2pdma_distance(to_pci_dev(obj->dev->dev), attach->dev, false) < 0)
> +	    pci_p2pdma_distance(to_pci_dev(obj->dev->dev), attach->dev, verbose_p2p_dist) < 0)
>  		attach->peer2peer = false;

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Sashiko AI review · https://sashiko.dev/#/patchset/20260914094641.8779-1-thomas.hellstrom@linux.intel.com?part=1