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

Alice Ryhl
2025-02-28T17:06:26Z

On Fri, Feb 28, 2025 at 4:34 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> 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?

I doubt it. I just copied the declaration without changing it.

Alice