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Date: Tue, 02 Jul 2013 14:00:20 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Liu Ping Fan <pingfank@linux.vnet.ibm.com>, =?ISO-8859-1?Q?Andreas_F=E4rber?= <afaerber@suse.de>, qemu-devel <qemu-devel@nongnu.org>

Il 02/07/2013 13:52, Jan Kiszka ha scritto:
>>> But then atomic_dec_and_test or so. Letting the inc/dec return some
>>> >> value leaves room for interpretations (value of before or after the
>>> >> modification?).
>> > 
>> > In qemu, I made all atomic_* functions return the old value.  This is
>> > consistent with atomic_cmpxchg and atomic_xchg (where returning the new
>> > value makes no sense).
> Please avoid this ambiguity by naming the functions properly. That xchg
> returns old values is known, that dec and inc do, is surely not.

IMO the ambiguity is resolved simply by looking at the docs or existing
code, but I can rename them to atomic_fetch_{add,sub,and,or,inc,dec} and
add void versions without "fetch".

Paolo