On Fri, 2026-03-06 at 21:40 +0100, Danilo Krummrich wrote:
> On Fri Mar 6, 2026 at 8:35 PM CET, Markus Probst wrote:
> > + extern "C" fn receive_buf_callback(
> > + sdev: *mut bindings::serdev_device,
> > + buf: *const u8,
> > + length: usize,
> > + ) -> usize {
> > + // SAFETY: The serial device bus only ever calls the receive buf
> > callback with a valid
> > + // pointer to a `struct serdev_device`.
> > + //
> > + // INVARIANT: `sdev` is valid for the duration of
> > `receive_buf_callback()`.
> > + let sdev = unsafe { &*sdev.cast::<Device<device::CoreInternal>>()
> > };
> > +
> > + // SAFETY: `receive_buf_callback` is only ever called after a
> > successful call to
> > + // `probe_callback`, hence it's guaranteed that
> > `Device::set_drvdata()` has been called
> > + // and stored a `Pin<KBox<T>>`.
> > + let data = unsafe { sdev.as_ref().drvdata_borrow::<T>() };
> > +
> > + // SAFETY:
> > + // - The serial device bus only ever calls the receive buf
> > callback with a valid pointer to
> > + // a `struct serdev_device`.
> > + // - `receive_buf_callback` is only ever called after a successful
> > call to
> > + // `probe_callback`, hence it's guaranteed that
> > `sdev.private_data` is a pointer
> > + // to a valid `PrivateData`.
> > + let private_data = unsafe {
> > &*(*sdev.as_raw()).private_data.cast::<PrivateData>() };
> > +
> > + private_data.probe_complete.complete_all();
>
> Will do a full review pass later on, but one quick question in advance:
>
> What is this used for? It is completed here and in probe(), but I don't see
> it ever
> being used to actually wait.
Uh, thats a typo. It is supposed to wait here in receive_buf_callback.
Thanks
- Markus Probst
>
> > +
> > + // SAFETY: No one has exclusive access to `private_data.error`.
> > + if unsafe { *private_data.error.get() } {
> > + return length;
> > + }
> > +
> > + // SAFETY: `buf` is guaranteed to be non-null and has the size of
> > `length`.
> > + let buf = unsafe { core::slice::from_raw_parts(buf, length) };
> > +
> > + T::receive(sdev, data, buf)
> > + }
> > +}
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