Re: [openib-general] ipoib lockdep warning

From: Roland Dreier
Date: Tue Jul 11 2006 - 20:04:28 EST


> > So, ugh... maybe the best thing to do is change lib/idr.c to use
> > spin_lock_irqsave() internally?
>
> I dunno, it seems to have had _irq() locking in the past? From the
> comment at the top:
>
> * Modified by George Anzinger to reuse immediately and to use
> * find bit instructions. Also removed _irq on spinlocks.

Well, _irq would be no good, because we might want to call idr stuff
with interrupts disabled. But making idr internally _irqsave seems
like the right fix to me.

I think the real issue here is that the sa_query.c stuff wants to use
the idr mechanism to assign "query ids", and other modules want to be
able to start queries from any context. So if idr uses bare spin_lock
internally, then sa_query.c has no choice but to wrap all idr calls
inside spin_lock_irqsave and do all allocation with GFP_ATOMIC, which
doesn't seem very nice.

- R.
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