Re: [PATCH 1/4] selftests/hid: fix compilation when bpf_wq and hid_device are not exported

[Thomas Weißschuh]

On Fri, Mar 13, 2026 at 08:40:24AM +0100, Benjamin Tissoires wrote:
> This can happen in situations when CONFIG_HID_SUPPORT is set to no, or
> some complex situations where struct bpf_wq is not exported.
> 
> So do the usual dance of hiding them before including vmlinux.h, and
> then redefining them and make use of CO-RE to have the correct offsets.
> 
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202603111558.KLCIxsZB-lkp@xxxxxxxxx/
> Cc: stable@xxxxxxxxxxxxxxx

'Fixes' missing? Also for patch 2 in the series.

> Signed-off-by: Benjamin Tissoires <bentiss@xxxxxxxxxx>

Reviewed-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>

(Some nits below, feel free to ignore them)

> ---
>  tools/testing/selftests/hid/progs/hid_bpf_helpers.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/tools/testing/selftests/hid/progs/hid_bpf_helpers.h b/tools/testing/selftests/hid/progs/hid_bpf_helpers.h
> index 80ab60905865..2c6ec907dd05 100644
> --- a/tools/testing/selftests/hid/progs/hid_bpf_helpers.h
> +++ b/tools/testing/selftests/hid/progs/hid_bpf_helpers.h
> @@ -8,9 +8,11 @@
>  /* "undefine" structs and enums in vmlinux.h, because we "override" them below */
>  #define hid_bpf_ctx hid_bpf_ctx___not_used
>  #define hid_bpf_ops hid_bpf_ops___not_used
> +#define hid_device hid_device___not_used
>  #define hid_report_type hid_report_type___not_used
>  #define hid_class_request hid_class_request___not_used
>  #define hid_bpf_attach_flags hid_bpf_attach_flags___not_used
> +#define bpf_wq bpf_wq___not_used

'bpf' would sort before 'hid' alphabetically.

>  #define HID_INPUT_REPORT         HID_INPUT_REPORT___not_used
>  #define HID_OUTPUT_REPORT        HID_OUTPUT_REPORT___not_used
>  #define HID_FEATURE_REPORT       HID_FEATURE_REPORT___not_used
> @@ -29,9 +31,11 @@
>  
>  #undef hid_bpf_ctx
>  #undef hid_bpf_ops
> +#undef hid_device
>  #undef hid_report_type
>  #undef hid_class_request
>  #undef hid_bpf_attach_flags
> +#undef bpf_wq
>  #undef HID_INPUT_REPORT
>  #undef HID_OUTPUT_REPORT
>  #undef HID_FEATURE_REPORT
> @@ -55,6 +59,14 @@ enum hid_report_type {
>  	HID_REPORT_TYPES,
>  };
>  
> +struct hid_device {
> +	unsigned int id;
> +} __attribute__((preserve_access_index));
> +
> +struct bpf_wq {
> +	__u64 __opaque[2];
> +};

The fields are never used, would a forward-declaration be sufficient?

struct bpf_wq;

Then you could also avoid the #define dance for that struct.

> +
>  struct hid_bpf_ctx {
>  	struct hid_device *hid;
>  	__u32 allocated_size;
> 
> -- 
> 2.52.0
>