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

[Davide Libenzi <davidel@xmailserver.org>]

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