Re: [PATCH 1/2] virtio: console: Serialise control work

[Amit Shah <amit.shah@xxxxxxxxxx>]

On (Mon) 09 Jan 2012 [13:03:59], Rusty Russell wrote:
> On Fri,  6 Jan 2012 16:19:07 +0530, Amit Shah <amit.shah@xxxxxxxxxx> wrote:
> > We currently allow multiple instances of the control work handler to run
> > in parallel.  This isn't expected to work; serialise access by disabling
> > interrupts on new packets from the Host and enable them when all the
> > existing ones are consumed.
> > 
> > Testcase: hot-plug/unplug a port in a loop.  Without this patch, some
> > sysfs warnings are seen along with freezes.  With the patch, all works
> > fine.
> 
> Wait a sec... This might *work*, but it's not correct.  Remember that
> disabling callbacks is a hint, and it's cetainly not synchronous.
> 
> You need something else to explicitly prevent reentry.

OK, right.  I'll use the nrt workqueue to synchronise then.

		Amit
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