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From: Avi Kivity <avi@redhat.com>
To: Liu Ping Fan <qemulist@gmail.com>
Cc: kvm@vger.kernel.org, Jan Kiszka <jan.kiszka@siemens.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	qemu-devel@nongnu.org, Anthony Liguori <anthony@codemonkey.ws>,
	Stefan Hajnoczi <stefanha@gmail.com>
Subject: Re: [Qemu-devel] [PATCH 2/5] exec.c: use refcnt to protect device during dispatching
Date: Wed, 25 Jul 2012 15:27:15 +0300	[thread overview]
Message-ID: <500FE623.8060304@redhat.com> (raw)
In-Reply-To: <500FD13B.7040108@redhat.com>

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

  reply	other threads:[~2012-07-25 13:25 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-25  3:31 [Qemu-devel] [PATCH 0/5] prepare unplug out of protection of global lock Liu Ping Fan
2012-07-25  3:31 ` [Qemu-devel] [PATCH 1/5] qom: adopt rwlock to protect accessing dev from removing it Liu Ping Fan
2012-07-25  9:08   ` Paolo Bonzini
2012-07-26 12:56     ` liu ping fan
2012-07-26 13:00       ` Avi Kivity
2012-07-26 13:14         ` liu ping fan
2012-07-26 13:15           ` Avi Kivity
2012-07-26 13:21             ` liu ping fan
2012-07-26 13:46               ` Avi Kivity
2012-07-25  3:31 ` [Qemu-devel] [PATCH 2/5] exec.c: use refcnt to protect device during dispatching Liu Ping Fan
2012-07-25  7:43   ` Stefan Hajnoczi
2012-07-25  8:12     ` liu ping fan
2012-07-25  9:18       ` Paolo Bonzini
2012-07-26 13:00         ` liu ping fan
2012-07-25 10:58   ` Avi Kivity
2012-07-25 12:27     ` Avi Kivity [this message]
2012-07-26 13:06       ` liu ping fan
2012-07-26 13:13         ` Avi Kivity
2012-07-25  3:31 ` [Qemu-devel] [PATCH 3/5] hotplug: introduce qdev_unplug_ack() to remove device from views Liu Ping Fan
2012-07-25 10:58   ` Avi Kivity
2012-07-25  3:31 ` [Qemu-devel] [PATCH 4/5] qom: delay DeviceState's reclaim to main-loop Liu Ping Fan
2012-07-25  7:03   ` Stefan Hajnoczi
2012-07-25  7:37     ` Paolo Bonzini
2012-07-25  8:16       ` liu ping fan
2012-07-25  8:22         ` Paolo Bonzini
2012-07-25  8:17     ` liu ping fan
2012-07-25  3:31 ` [Qemu-devel] [PATCH 5/5] e1000: using new interface--unmap to unplug Liu Ping Fan
2012-07-25  7:12   ` Stefan Hajnoczi

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