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Date: Fri, 16 Nov 2012 18:55:26 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] iscsi: fix deadlock during login
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To: Peter Lieven <pl@dlhnet.de>
Cc: Kevin Wolf <kwolf@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, ronnie sahlberg <ronniesahlberg@gmail.com>

Il 16/11/2012 18:38, Peter Lieven ha scritto:
> Am 16.11.2012 11:38, schrieb Kevin Wolf:
>> Am 15.11.2012 17:37, schrieb Paolo Bonzini:
>>> Il 15/11/2012 17:13, ronnie sahlberg ha scritto:
>>>> On Thu, Nov 15, 2012 at 7:54 AM, Paolo Bonzini <pbonzini@redhat.com>
>>>> wrote:
>>>>> Il 15/11/2012 15:57, ronnie sahlberg ha scritto:
>>>>>> I dont know if we should switch to use synchronous code here.
>>>>>> It is much nicer if all code is async.
>>>>> bdrv_open is generally synchronous, so I think Peter's patch is ok.
>>>> I was thinking about the case where you disconnect/reconnect a device
>>>> at runtime. Like swapping the medium in a CDROM.
>>>> If bdrv_open() is synchronous and blocks for a long time, would that
>>>> not impact the rest of QEMU?
>>> Yes, it's not optimal, but VCPUs would still run until they request I/O.
>>>   But usually iscsi devices should be non-removable, no?  That leaves
>>> hotplug as the only problematic case.
>> I guess we need a bdrv_co_open() for the long term.
> but for now its save to implement iscsi_open (and iscsi_create) completely
> sync?

Yes.

Paolo