Re: [PATCH] IB/core: Make ib_dealloc_pd return void

[Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>]

On Fri, Aug 14, 2015 at 09:05:07PM -0400, Doug Ledford wrote:

> I'm not sure I like this patch.  I have my concerns that this will
> make debugging and catching problems more difficult.
[..]
> The change you put in here will make note of the driver that fails to
> return a clean return, but the error happens elsewhere.

Eh? I don't understand your comments.

Nothing is lost, in your specific example instead of seeing the little
one line printk from IPoIB, you'd get instead a full blown WARN_ON
with a stack trace from here:

+	   WARN_ON(atomic_read(&pd->usecnt));

The stack trace still fingers IPoIB as the culprit, and a WARN_ON
strongly motivates bug reports.

If the above WARN_ON triggers it unconditionally represents a bug in
the caller. There is no correct way to use the old error return.

> It serves as a final check on the ULP, and to me that has value.

Yes, which is why this patch extends that same basic check to all ~50
call sites and every single ULP instead of only having it in only two
places.

Jason
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