Re: Kernel patches enabling better POSIX AIO (Was Re: [3/4] kevent: AIO, aio_sendfile)

Sébastien Dugué
2006-09-04T14:36:50Z

On Sat, 2006-08-12 at 12:10 -0700, Ulrich Drepper wrote:
> Suparna Bhattacharya wrote:
> > I am wondering about that too. IIRC, the IO_NOTIFY_* constants are not
> > part of the ABI, but only internal to the kernel implementation. I think
> > Zach had suggested inferring THREAD_ID notification if the pid specified
> > is not zero. But, I don't see why ->sigev_notify couldn't used directly
> > (just like the POSIX timers code does) thus doing away with the
> > new constants altogether. Sebestian/Laurent, do you recall?
>
> I suggest to model the implementation after the timer code which does
> exactly what we need.
>

Will do.

>
> > I'm guessing they are being used for validation of permissions at the time
> > of sending the signal, but maybe saving the task pointer in the iocb instead
> > of the pid would suffice ?
>
> Why should any verification be necessary? The requests are generated in
> the same process which will receive the notification. Even if the POSIX
> process (aka, kernel process group) changes the IDs the notifications
> should be set. The key is that notifications cannot be sent to another
> POSIX process.
>
> Adding this as a feature just makes things so much more complicated.
>

Agreed.

Sébastien.

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Sébastien Dugué BULL/FREC:B1-247
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Linux POSIX AIO: http://www.bullopensource.org/posix
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