From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 4/5] qom: delay DeviceState's reclaim to main-loop
Date: Wed, 25 Jul 2012 09:37:19 +0200
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Cc: Liu Ping Fan <qemulist@gmail.com>, qemu-devel@nongnu.org,
	kvm@vger.kernel.org, Anthony Liguori <anthony@codemonkey.ws>,
	Avi Kivity <avi@redhat.com>,
	Jan Kiszka <jan.kiszka@siemens.com>,
	Marcelo Tosatti <mtosatti@redhat.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
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Il 25/07/2012 09:03, Stefan Hajnoczi ha scritto:
> From: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
>
> iohandler/bh/timer may use DeviceState when its refcnt=0,

It's not clear how to me.  The only reference to devices from an
iohandler/bh/timer can be in the opaque.  Now, if you have a
iohandler/bh/timer whose opaque is a DeviceState, you should bump the
refcount before setting it up, and unref after tearing it down.

See for example how hw/scsi-disk.c bumps the refcount of a request
before starting asynchronous I/O and calls unref at the end of the
asynchronous I/O callback.

Paolo