Re: [patch 13/13] signal/timer/event fds v9 - KAIO eventfd supportexample ...

From: Davide Libenzi
Date: Sun Apr 01 2007 - 13:31:53 EST


On Sun, 1 Apr 2007, Linus Torvalds wrote:

> On Sun, 1 Apr 2007, Davide Libenzi wrote:
> >
> > > [also, minor nit: sys_eventfd() can legitimately return 0, but you're banning
> > > its use in aio. userspace could easily dup() and close(), but...]
> >
> > Noone said that binary compatibility comes free ;)
> > I'm truly open to other ways of integration, but I thought that binary
> > compatibility is the key here.
>
> I would suggest taking "aio_reserved3" and turning it into
>
> __u32 aio_flags;
> __u32 aio_resfd;
>
> if so. And then some bit in the "flags" field has to be set (say,
> "IOCB_FLAG_RESFB") to enable this codepath, instead of expecting that
> aio_resfd == 0 is special.
>
> It's generally always a good thing to have a "flags" field anyway, exactly
> because it allows for future expansion.

Makes sense. I was actually thinking of using the higher bit to signal
that, but a flags field makes more sense.



- Davide


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