Re: [PATCH v8 2/2] rust: add dma coherent allocator abstraction.

Greg KH
2025-01-31T07:47:57Z

On Thu, Jan 30, 2025 at 01:24:37PM -0400, Jason Gunthorpe wrote:
> On Thu, Jan 30, 2025 at 05:11:43PM +0100, Greg KH wrote:
> > On Thu, Jan 30, 2025 at 11:46:46AM -0400, Jason Gunthorpe wrote:
> > > On Thu, Jan 30, 2025 at 02:19:16PM +0100, Philipp Stanner wrote:
> > > > would some sort of official statement by the "entire community"
> > > > reassure you that the burden of keeping Rust abstractions working with
> > > > any changes on the C side rests entirely on the Rust side's
> > > > shoulders?
> > >
> > > You'd have to reconcile that with the recent event where Linus defered
> > > the MM pull request and some C patches were dropped because of rust
> > > kbuild bugs:
> > >
> > > https://lore.kernel.org/linux-mm/CAHk-=whddBhfi5DUi370W3pYs+z3r2E7KYuHjwR=a1eRig5Gxg@mail.gmail.com/
> > >
> > > It seems to me the message is now crystal clear, and the opposite of
> > > what you claim.
> > >
> > > All PRs to Linus must not break the rust build and the responsibilty
> > > for that falls to all the maintainers. If the Rust team is not quick
> > > enough to resolve any issues during the development window then
> > > patches must be dropped before sending PRs, or Linus will refuse the
> > > PR.
> > >
> > > Effectively this seems to imply that patches changing some of the C
> > > API cannot be merged by maintainers unless accompanied by matching
> > > Rust hunks.
> > >
> > > If there are different instructions to maintainers I would be
> > > interested to know.
> >
> > That's not the case, the one you point at above was a tooling issue that
> > people missed due to the holidays. Fixing it up was simple enough and
> > people did so and moved on.
>
> Regardless of holidays, you seem to be saying that Linus should have
> accepted Andrew's PR and left rust with build failures?

I can't answer for Linus, sorry. But a generic "hey, this broke our
working toolchain builds" is something that is much much much different
than "an api changed so I now have to turn off this driver in my build"
issue.

thanks,

greg k-h