On Mon, May 15, 2017 at 04:06:49PM -0700, Linus Torvalds wrote:
> On Mon, May 15, 2017 at 3:37 PM, Al Viro <v...@zeniv.linux.org.uk> wrote:
> >
> > +struct waitid_info {
> > + pid_t pid;
> > + uid_t uid;
> > + int status;
> > + int why;
> > +};
>
> Ugh. Could we please just name those with what they are actually used for?
>
> Even if you hate the "si_" previx for some reason, I really don't see
> why we'd continue call it "why", when it's written to "si_code"
>
> Yes, yes, I see the historical reason, and how "si_code" is just the
> low 16 bits of "why", and the high 16 bits is something else.
__SI_CHLD, and AFAICS it only matters for copy_siginfo_to_user() and its
relatives - basically, "how much of kernel-side struct siginfo do we have
initialized"...
> But now that there is a structure for that, could we not just make
> that explicit in the structure instead? Those games with "why" look
> really odd.
OK...
> So I can see why you'd like to keep this patch as "minimal
> conversion", but it would be really nice to have a followup patch that
> gets rid of the odd "why" games.
The thing is, we lack convenient defines for those constants. We could
turn this "why" thing into u16 si_code, but then gcc will scream about
integer constant truncation ;-/ Suggestions?
BTW, I wonder if making those stores conditional is actually a win -
sure, for put_user() it used to be, but for plain stores... Not sure.
