linux-kernel - Re: [PATCH 2/8] KVM: x86: cleanup kvm_apic_match

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Date:	Mon, 02 Feb 2015 15:28:35 +0100
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Radim Krčmář <rkrcmar@...hat.com>
CC:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
	Nadav Amit <namit@...technion.ac.il>,
	Gleb Natapov <gleb@...nel.org>
Subject: Re: [PATCH 2/8] KVM: x86: cleanup kvm_apic_match_*()



On 02/02/2015 15:26, Radim Krčmář wrote:
>>> > > +		return ((logical_id >> 4) == (mda >> 4))
>>> > > +		       && (logical_id & mda & 0xf);
> was merged as
> 
> +		return ((logical_id >> 4) == (mda >> 4))
> +		       && (logical_id & mda & 0xf) != 0;
> 
> but it has to be parenthesized ('&&' has lower precedence than '!=').

Lower precedence means that the merged version is right (unless my brain
went bonkers, which I cannot exclude).  "!=" has higher precedence and
thus it is implicitly parenthesized.

In fact the first comparison could have its parentheses removed as well.

Paolo
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