Re: [PATCH v2] signal: add procfd_signal() syscall

[Andy Lutomirski]

On Fri, Nov 30, 2018 at 3:40 PM Christian Brauner <christian@xxxxxxxxxx> wrote:
>
> On December 1, 2018 12:12:53 PM GMT+13:00, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> >On Sat, Dec 1, 2018 at 12:05 AM Daniel Colascione <dancol@xxxxxxxxxx>
> >wrote:
> >> On Fri, Nov 30, 2018 at 2:26 PM Christian Brauner
> ><christian@xxxxxxxxxx> wrote:
> >> > On December 1, 2018 11:09:58 AM GMT+13:00, Arnd Bergmann
> ><arnd@xxxxxxxx> wrote:
> >> >
> >> > One humble point I would like to make is that what I care about
> >most is a sensible way forward without having to redo essential parts
> >of how syscalls work.
> >> > I don't want to introduce a sane, small syscall that ends up
> >breaking all over the place because we decided to fix past mistakes
> >that technically have nothing to do with the patch itself.
> >> > However, I do sympathize and understand these concerns.
> >>
> >> IMHO, it's fine to just replicate all the splits we have for the
> >> existing signal system calls. It's ugly, but once it's done, it'll be
> >> done for a long time. I can't see a need to add even more signal
> >> system calls after this one.
> >
> >We definitely need waitid_time64() and rt_sigtimedwait_time64()
> >in the very near future.
>
> Right, I remember you pointing this out in a prior mail.
> Thanks for working on this for such a long time now, Arnd!
> Can we agree to move on with the procfd syscall given the current constraints?
> I just don't want to see the syscall being
> blocked by a generic problem whose
> ultimate solution is to get rid of weird
> architectural constraints.

Creating and using a copy_siginfo_from_user64() function would work
for everyone, no?