Re: aio_down() patch series -- cancellation support added

From: Suparna Bhattacharya
Date: Thu Jun 23 2005 - 08:30:42 EST


On Mon, Jun 20, 2005 at 05:46:14PM -0400, Benjamin LaHaise wrote:
> Add linux-kernel to the Cc list...
>
> On Mon, Jun 20, 2005 at 05:38:35PM -0400, Benjamin LaHaise wrote:
> > Hello all,
> >
> > The patch series at http://www.kvack.org/~bcrl/patches/aio-2.6.12-A1/
> > now adds support for cancellation of an aio_down() operation. The
> > races should be correctly handled by introducing per-kiocb locking
> > that serialises ->ki_cancel() and ->ki_retry(). The interesting patch
> > additions are 40_lock_kiocb 50_aio_down_cancel.diff. Comments?
> >
> > -ben
> > --

One quick question.
Since lock_kiocb() may block, does that mean that the aio worker thread
could be put to sleep while an iocb cancellation is in progress, even though
there may be other iocbs/ioctx's to process ?

Looking at the rest a little more closely in terms of how everything
will fit together, a few questions come to mind - need to think
about it a little more. I guess the main reason you need the aio_down_wait
callback is to make sure the semaphore is grabbed right in the context
of the wakeup rather than at retry time, is that correct ?

Regards
Suparna

--
Suparna Bhattacharya (suparna@xxxxxxxxxx)
Linux Technology Center
IBM Software Lab, India

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