Re: [PULL 11/33] scsi: only access SCSIDevice->requests from one thread

[Kevin Wolf <kwolf@redhat.com>]

Am 01.02.2024 um 10:43 hat Hanna Czenczek geschrieben:
> On 31.01.24 11:17, Kevin Wolf wrote:
> > Am 29.01.2024 um 17:30 hat Hanna Czenczek geschrieben:
> > > I don’t like using drain as a form of lock specifically against AioContext
> > > changes, but maybe Stefan is right, and we should use it in this specific
> > > case to get just the single problem fixed.  (Though it’s not quite trivial
> > > either.  We’d probably still want to remove the assertion from
> > > blk_get_aio_context(), so we don’t have to require all of its callers to
> > > hold a count in the in-flight counter.)
> > Okay, fair, maybe fixing the specific problem is more important that
> > solving the more generic blk_get_aio_context() race.
> > 
> > In this case, wouldn't it be enough to increase the in-flight counter so
> > that the drain before switching AioContexts would run the BH before
> > anything bad can happen? Does the following work?
> 
> Yes, that’s what I had in mind (Stefan, too, I think), and in testing,
> it looks good.

Oh, sorry, I completely misunderstood then. I thought you were talking
about adding a new drained section somewhere and that sounded a bit more
complicated. :-)

If it works, let's do this. Would you like to pick this up and send it
as a formal patch (possibly in a more polished form), or should I do
that?

Kevin