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Date: Sat, 15 Sep 2012 12:25:12 -0300
From: Marcelo Tosatti <mtosatti@redhat.com>
To: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Avi Kivity <avi@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
        KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 4/5] KVM: MMU: introduce page_fault_start and
 page_fault_end
Message-ID: <20120915152512.GB3037@amt.cnet>
References: <5052FF61.3070600@linux.vnet.ibm.com>
 <5052FFEA.1040607@linux.vnet.ibm.com>
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On Fri, Sep 14, 2012 at 05:59:06PM +0800, Xiao Guangrong wrote:
> Wrap the common operations into these two functions
> 
> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>

Why? I think people are used to 

spin_lock(lock)
sequence
spin_unlock(lock)

So its easy to verify whether access to data structures are protected.

Unrelated to this patch, one opportunity i see to simplify this
code is:

- error pfn / mmio pfn / invalid pfn relation

Have the meaning of this bits unified in a single function/helper, see
comment to patch 1 (perhaps you can further improve).