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From: Wen Congyang <wency@cn.fujitsu.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	qemu-devl <qemu-devel@nongnu.org>,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] quorum: don't share qiov
Date: Mon, 9 Feb 2015 10:10:46 +0800	[thread overview]
Message-ID: <54D81726.9060000@cn.fujitsu.com> (raw)
In-Reply-To: <54D0AA9D.7040404@redhat.com>

On 02/03/2015 07:01 PM, Paolo Bonzini wrote:
> 
> 
> On 03/02/2015 10:22, Kevin Wolf wrote:
>> Paolo, I think it's rather surprising that iov_send_recv() modifies its
>> iov. The modification is undone at the end, so you seem to have
>> considered that a caller might be reusing it after and you can't "use it
>> up", but we still get problems with concurrent accesses.
> 
> Yes, I wasn't thinking of concurrent accesses indeed.  But I wasn't the
> author of iov_send_recv(), I just took it from sheepdog. :)
> 
>> Was it an intentional design decision that iov_send_recv() is the sole
>> owner of the iov and the caller must duplicate it if it's used elsewhere
>> concurrently?
>>
>> Otherwise I would suggest to fix iov_send_recv(), and possibly try and
>> make all the qiov/iov arguments in the block layer const.
> 
> I agree.  However, it's not a small change.  I think Wen's patch is okay
> with a FIXME comment added.

Hi, kevin

What should I do next? Add a comment and resend it?

Thanks
Wen Congyang

> 
> Paolo
> .
> 

      reply	other threads:[~2015-02-09  2:08 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-30  8:07 [Qemu-devel] [PATCH] quorum: don't share qiov Wen Congyang
2015-01-30 13:39 ` Kevin Wolf
2015-02-02  1:19   ` Wen Congyang
2015-02-03  9:22     ` Kevin Wolf
2015-02-03 11:01       ` Paolo Bonzini
2015-02-09  2:10         ` Wen Congyang [this message]

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