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From: Roland Dreier <rdreier@cisco.com>
To: Stefan Roscher <ossrosch@linux.vnet.ibm.com>
Subject: Re: [PATCH] IB/ehca: Allocate event queue size depending on max
	number of CQs and QPs
References: <200804291744.17235.ossrosch@linux.vnet.ibm.com>
Date: Tue, 29 Apr 2008 09:43:42 -0700
In-Reply-To: <200804291744.17235.ossrosch@linux.vnet.ibm.com> (Stefan
	Roscher's message of "Tue, 29 Apr 2008 17:44:15 +0200")
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 > 
 > Signed-off-by: Stefan Roscher <stefan.roscher at de.ibm.com>

Kind of an inadequate changelog ;)

Is this a fix or an enhancement or what?

 > +	if (atomic_read(&shca->num_cqs) >= ehca_max_cq) {

 > +	if (atomic_read(&shca->num_qps) >= ehca_max_qp) {

These are racy in the sense that multiple simultaneous calls to
create_cq/create_qp might end up exceeding the ehca_max_cq limit.  Is
that an issue?

You could close the race by using atomic_add_unless() and testing the
return value (and being careful to do atomic_dec() on error paths after
you bump num_cqs/num_qps).

 - R.