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From: Peter Lieven <pl@kamp.de>
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Date: Mon, 31 Aug 2015 10:38:17 +0200
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Subject: Re: [Qemu-devel] [PATCH 1/2] block/io: allow AIOCB without callback
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To: Eric Blake <eblake@redhat.com>, qemu-devel@nongnu.org, qemu-block@nongnu.org
Cc: kwolf@redhat.com, stefanha@gmail.com, Jeff Cody <jcody@redhat.com>, Max Reitz <mreitz@redhat.com>, pbonzini@redhat.com, jsnow@redhat.com

Am 21.08.2015 um 08:12 schrieb Eric Blake:
> On 08/20/2015 01:14 AM, Peter Lieven wrote:
>> If the backend storage is unresponsive and we cancel a request due to
>> a timeout we cannot immediately destroy the AIOCB because the storage
>> might complete the original request laster if it is responsive again.
> s/laster/later/
>
>> For this purpose allow to set the callback to NULL and ignore it in
>> this case.
>>
>> Signed-off-by: Peter Lieven <pl@kamp.de>
>> ---
> I'll leave the technical review to others, I'm just pointing out grammar.
>


I am using this one for quite some time now. It seems a good step into solving the deadlock
problem. The issue is we still need to make the ATAPI calls async. The OS is only spending 2-3 Minutes
with DMA cancelling and then issues reads again so we still deadlock at the end.

Peter