Re: [PATCH 2/2] drm/xe/configfs: fix clang warnings for missing parameter name

[David Laight <david.laight.linux@gmail.com>]

On Fri, 17 Oct 2025 12:46:26 -0700
Ryan Neph <ryanneph@google.com> wrote:

> Fixes warning from clang-17 that look like:
> 
> drivers/gpu/drm/xe/xe_configfs.h:35:97: error: omitting the parameter name in a function definition is a C2x extension [-Werror,-Wc2x-extensions]
>    35 | static inline u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev, enum xe_engine_class,

Why did that become invalid?
It has pretty much always been used - and can be used to avoid -Wshadow warnings.
This looks like a clang bug.
And you'd want a specific -W 'knob' for it as well.

At a guess the C2x extension lets the name be omitted in the function body for
an unused parameter (the same as C++).
I think that is the 'definition' and the ones being changed here are the 'declaration'.
But I might be wrong.

	David

> 
> Signed-off-by: Ryan Neph <ryanneph@google.com>
> ---
>  drivers/gpu/drm/xe/xe_configfs.h | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_configfs.h b/drivers/gpu/drm/xe/xe_configfs.h
> index fed57be0b90e146d57d966bab0e55e1723513997..a0d614b37efd54b89390f04a238aef1a8d4df4e2 100644
> --- a/drivers/gpu/drm/xe/xe_configfs.h
> +++ b/drivers/gpu/drm/xe/xe_configfs.h
> @@ -21,9 +21,9 @@ bool xe_configfs_primary_gt_allowed(struct pci_dev *pdev);
>  bool xe_configfs_media_gt_allowed(struct pci_dev *pdev);
>  u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev);
>  bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev);
> -u32 xe_configfs_get_ctx_restore_mid_bb(struct pci_dev *pdev, enum xe_engine_class,
> +u32 xe_configfs_get_ctx_restore_mid_bb(struct pci_dev *pdev, enum xe_engine_class class,
>  				       const u32 **cs);
> -u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev, enum xe_engine_class,
> +u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev, enum xe_engine_class class,
>  					const u32 **cs);
>  #ifdef CONFIG_PCI_IOV
>  unsigned int xe_configfs_get_max_vfs(struct pci_dev *pdev);
> @@ -37,9 +37,11 @@ static inline bool xe_configfs_primary_gt_allowed(struct pci_dev *pdev) { return
>  static inline bool xe_configfs_media_gt_allowed(struct pci_dev *pdev) { return true; }
>  static inline u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev) { return U64_MAX; }
>  static inline bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev) { return false; }
> -static inline u32 xe_configfs_get_ctx_restore_mid_bb(struct pci_dev *pdev, enum xe_engine_class,
> +static inline u32 xe_configfs_get_ctx_restore_mid_bb(struct pci_dev *pdev,
> +						     enum xe_engine_class class,
>  						     const u32 **cs) { return 0; }
> -static inline u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev, enum xe_engine_class,
> +static inline u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev,
> +						      enum xe_engine_class class,
>  						      const u32 **cs) { return 0; }
>  static inline unsigned int xe_configfs_get_max_vfs(struct pci_dev *pdev) { return UINT_MAX; }
>  #endif
>