Re: [PATCH v3] kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE

[Emil Velikov]

On Fri, 12 Feb 2021 at 14:01, Michel Dänzer <michel@xxxxxxxxxxx> wrote:
>
> On 2021-02-12 1:57 p.m., Emil Velikov wrote:
> > On Fri, 5 Feb 2021 at 22:01, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:
> >>
> >> Userspace has discovered the functionality offered by SYS_kcmp and has
> >> started to depend upon it. In particular, Mesa uses SYS_kcmp for
> >> os_same_file_description() in order to identify when two fd (e.g. device
> >> or dmabuf)
> >
> > As you rightfully point out, SYS_kcmp is a bit of a two edged sword.
> > While you mention the CONFIG issue, there is also a portability aspect
> > (mesa runs on more than just linux) and as well as sandbox filtering
> > of the extra syscall.
> >
> > Last time I looked, the latter was still an issue and mesa was using
> > SYS_kcmp to compare device node fds.
> > A far shorter and more portable solution is possible, so let me
> > prepare a Mesa patch.
>
> Make sure to read my comments on
> https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6881 first. :)
>
Much appreciated. I might have been "slightly" off - pardon for the noise o/

-Emil