From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH 2/5] exec.c: use refcnt to protect device during dispatching
Date: Wed, 25 Jul 2012 15:27:15 +0300
Message-ID: <500FE623.8060304@redhat.com>
References: <1343187070-27371-1-git-send-email-qemulist@gmail.com> <1343187070-27371-3-git-send-email-qemulist@gmail.com> <500FD13B.7040108@redhat.com>
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Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org,
	Anthony Liguori <anthony@codemonkey.ws>,
	Jan Kiszka <jan.kiszka@siemens.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Stefan Hajnoczi <stefanha@gmail.com>
To: Liu Ping Fan <qemulist@gmail.com>
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On 07/25/2012 01:58 PM, Avi Kivity wrote:
>>      while (len > 0) {
>>          page = addr & TARGET_PAGE_MASK;
>>          l = (page + TARGET_PAGE_SIZE) - addr;
>>          if (l > len)
>>              l = len;
>> +
>> +        qemu_rwlock_rdlock_devtree();
>>          section = phys_page_find(page >> TARGET_PAGE_BITS);
> 
> Does the devtree lock also protect the data structures accessed by
> phys_page_find()?  Seems wrong.

The right way is to object_ref() in core_region_add() and object_unref()
in core_region_del().  We're guaranteed that mr->object is alive during
_add(), and DeviceClass::unmap() ensures that the extra ref doesn't
block destruction.

-- 
error compiling committee.c: too many arguments to function