Re: [PATCH v5 4/5] rust_binder: consolidate transaction failure prints

[Greg Kroah-Hartman]

On Tue, Sep 01, 2026 at 06:15:52PM +0200, Miguel Ojeda wrote:
> On Mon, Aug 3, 2026 at 9:30 AM Alice Ryhl <aliceryhl@xxxxxxxxxx> wrote:
> >
> > diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
> > index a56ba6309594..380cd3f7276b 100644
> > --- a/rust/kernel/error.rs
> > +++ b/rust/kernel/error.rs
> > @@ -135,7 +135,7 @@ pub fn from_errno(errno: crate::ffi::c_int) -> Error {
> >      /// Creates an [`Error`] from a kernel error code.
> >      ///
> >      /// Returns [`None`] if `errno` is out-of-range.
> > -    const fn try_from_errno(errno: crate::ffi::c_int) -> Option<Error> {
> > +    pub const fn try_from_errno(errno: crate::ffi::c_int) -> Option<Error> {
> >          if errno < -(bindings::MAX_ERRNO as i32) || errno >= 0 {
> >              return None;
> >          }
> 
> Generally speaking, one should know from the context whether an
> integer is supposed to be an error or not, and thus it is rare to need
> this function instead of the public one (this one is private, and the
> two callers are here, not elsewhere in `kernel`).
> 
> So I wondered if Binder needs this -- I noticed the change when doing
> my usual go-through-the-ML exercise and asked Alice about it, since it
> seemed to me like Binder could perhaps avoid using the fallible
> operation (and maybe even define an `enum` for `BinderError` instead
> of a `struct` to be more precise about when a `source` is needed).
> 
> Alice told me that the `Option` in `BinderError` is just meant for the
> zero case, i.e. the raw integer there should not be a random value.
> Thus, since the `if` already covers the zero case, it does look like
> this could use the infallible operation since we do know statically it
> should be an error (modulo a bug).
> 
> So it sounds like the change can indeed be avoided, which should also
> improve the code.
> 
> In any case, if we keep it, then the `error.rs` change should be
> mentioned in the commit message.
> 
> By the way, I am still happy to take the first three patches unless
> Binder is picking this up.

I'll just take them all now, thanks.

greg k-h