Re: [Xen-devel] [PATCH] blkfront: Move blkif_interrupt into a tasklet.

[Daniel Stodden <daniel.stodden@xxxxxxxxxx>]

On Tue, 2010-09-07 at 22:03 -0400, Jeremy Fitzhardinge wrote:
> On 09/03/2010 09:08 AM, Daniel Stodden wrote:
> > We clearly spin_lock_irqsave all through the blkif_do_interrupt frame.
> >
> > It follows that something underneath quite unconditionally chose to
> > reenable them again (?)
> >
> > Either: Can you add a bunch of similar WARN_ONs along that path?
> >
> > Or: This lock is quite coarse-grained. The lock only matters for queue
> > access, and we know irqs are reenabled, so no need for flags. In fact we
> > only need to spin_lock_irq around the __blk_end_ calls and
> > kick_pending_.
> >
> > But I don't immediately see what's to blame, so I'd be curious.
> 
> It looks like __blk_end_request_all(req, error); (line 743) is returning
> with interrupts enabled sometimes (not consistently).  I had a quick
> look through the code, but I couldn't see where it touches the interrupt
> state at all.

Oha. Was this found on 2.6.32 or later?

Thanks,
Daniel


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