Date: Mon, 22 Jun 2009 21:32:22 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: Gregory Haskins <gregory.haskins@gmail.com>,
       Gregory Haskins <ghaskins@novell.com>, kvm@vger.kernel.org,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       avi@redhat.com, paulmck@linux.vnet.ibm.com, Ingo Molnar <mingo@elte.hu>,
       Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [KVM PATCH v3 3/3] KVM: Fix races in irqfd using new
	eventfd_kref_get interface
Message-ID: <20090622183222.GF15228@redhat.com>
References: <20090622155504.22967.50532.stgit@dev.haskins.net> <20090622160556.22967.76273.stgit@dev.haskins.net> <20090622165708.GB15228@redhat.com> <4A3FBFF1.8050504@gmail.com> <20090622174506.GD15228@redhat.com> <alpine.DEB.1.10.0906221105500.10952@makko.or.mcafeemobile.com>
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On Mon, Jun 22, 2009 at 11:11:12AM -0700, Davide Libenzi wrote:
> On Mon, 22 Jun 2009, Michael S. Tsirkin wrote:
> 
> > Not really, it's impossible to document all races one have thought
> > about and avoided.
> 
> Well, when some new code has non-trivial locking/racing logics, you better 
> document it as clearly as possible, akpm announced time ago.

Absolutely. But IMO documentation in the form of "fields A B C are
protected by lock X" in a single place near field declaration is better
than "we take lock X here to protect against race with user thread using
fields A B C" sprinkled all over the code.


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