From: Paolo Bonzini <pbonzini@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>, Wen Congyang <wency@cn.fujitsu.com>
Cc: qemu-devl <qemu-devel@nongnu.org>, Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] quorum: don't share qiov
Date: Tue, 03 Feb 2015 12:01:49 +0100 [thread overview]
Message-ID: <54D0AA9D.7040404@redhat.com> (raw)
In-Reply-To: <20150203092153.GA4488@noname.redhat.com>
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.
Paolo
next prev parent reply other threads:[~2015-02-03 11:02 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 [this message]
2015-02-09 2:10 ` Wen Congyang
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