Re: AGP bogosities

[Dave Jones]

On Fri, Mar 11, 2005 at 01:40:24PM +1100, Benjamin Herrenschmidt wrote:
 > 
 > > After it does that pci_dev_put on the from, it does another pci_dev_get
 > > on 'dev', which is what my put was releasing.
 > > 
 > > Or am I terribly confused ?
 > 
 > Well, pci_get_class() put's the passed-in device and get's() the
 > returned one. So if you run it in a loop, you should never have to
 > either get or put. When you exit the loop with a valid pci_dev, though,
 > you should definitely put() it after you're done with it, but this is
 > something that should be done only for that specific instance and after
 > you are finished with it...

Yeah. Makes perfect sense now I've had it spelled out for me :-)
I think Linus is right though that some extra bullet-proofing in kref_put
to BUG() if it goes negative would've caught this.  I wonder if anyone
else has fallen into this trap.

		Dave
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