Re: [RFC][PATCH -mmotm 1/4] Add static function calls of pstore tokexec path

From: Matthew Garrett
Date: Tue Jul 19 2011 - 15:40:49 EST

On Tue, Jul 19, 2011 at 08:27:54PM +0100, Matthew Garrett wrote:
> On Tue, Jul 19, 2011 at 03:14:22PM -0400, Seiji Aguchi wrote:
> >
> > >And how does that handle the case where we're halfway through a pstore
> > >access when the NMI arrives? ERST, at least, has a complex state
> > >machine. You can't guarantee what starting one transaction without
> > >completing one that was in process will do.
> >
> > As for ERST, write access is protected by raw_spin_trylock_irqsave(&erst_lock).
> > Are there anything I'm missing?
> If there's already locking involved, what benefit does removing the lock
> in the pstore code give? You'll just hang when you hit the erst code
> instead of the pstore code.

I'm sorry, you're right, this is a trylock so we won't hang in this
case. We should probably document that in the pstore documentation to
ensure that any future backends have the same behaviour.

Matthew Garrett | mjg59@xxxxxxxxxxxxx
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