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From: Roland Dreier <rdreier@cisco.com>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Oliver Neukum <oliver@neukum.org>, Ingo Oeser <ioe-lkml@rameria.de>,
       Linus Torvalds <torvalds@linux-foundation.org>,
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       Bart Van Assche <bart.vanassche@gmail.com>, Ingo Molnar <mingo@elte.hu>,
       Daniel Walker <dwalker@mvista.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Replace completions with semaphores
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	<20080416163413.GL9191@parisc-linux.org>
	<200804161842.52739.oliver@neukum.org>
	<20080416164404.GM9191@parisc-linux.org>
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 > The cookies aren't checked by the kcounter implementation if
 > CONFIG_DEBUG_KCOUNTER isn't set.  So you can avoid storing them if it's
 > *really* that important to shrink your data structures.

I guess if anyone cared we could have something analogous to
DECLARE_PCI_UNMAP_ADDR() et al that compiles to nothing if
CONFIG_DEBUG_KCOUNTER isn't set.  But I'm not sure it's worth it.
Certainly for the mthca/mlx4 cases of semaphore use there's no problem
holding onto a cookie.

 - R.