Re: [PATCH v2 5/5] panic_qr: use new #[export] macro

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Fri, Feb 28, 2025 at 12:39:34PM +0000, Alice Ryhl wrote:
> This validates at compile time that the signatures match what is in the
> header file. It highlights one annoyance with the compile-time check,
> which is that it can only be used with functions marked unsafe.
> 
> If the function is not unsafe, then this error is emitted:
> 
> error[E0308]: `if` and `else` have incompatible types
>    --> <linux>/drivers/gpu/drm/drm_panic_qr.rs:987:19
>     |
> 986 | #[export]
>     | --------- expected because of this
> 987 | pub extern "C" fn drm_panic_qr_max_data_size(version: u8, url_len: usize) -> usize {
>     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^ expected unsafe fn, found safe fn
>     |
>     = note: expected fn item `unsafe extern "C" fn(_, _) -> _ {kernel::bindings::drm_panic_qr_max_data_size}`
>                found fn item `extern "C" fn(_, _) -> _ {drm_panic_qr_max_data_size}`

...

> +#if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
> +extern size_t drm_panic_qr_max_data_size(u8 version, size_t url_len);
> +
> +extern u8 drm_panic_qr_generate(const char *url, u8 *data, size_t data_len, size_t data_size,
> +				u8 *tmp, size_t tmp_size);

Is extern needed?

> +#endif

-- 
With Best Regards,
Andy Shevchenko