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Date: Fri, 02 Sep 2011 10:37:23 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH] monitor: Protect outbuf from concurrent
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, Luiz Capitulino <lcapitulino@redhat.com>, Marian Krcmarik <mkrcmari@redhat.com>, Alon Levy <alevy@redhat.com>, Gerd Hoffmann <kraxel@redhat.com>, spice-devel <spice-devel@freedesktop.org>

On 09/02/2011 10:31 AM, Paolo Bonzini wrote:
> On 09/02/2011 05:18 PM, Gerd Hoffmann wrote:
>>
>>> Can you just use a bottom half to defer this work to the I/O thread?
>>> Bottom half scheduling has to be signal safe which means it will also be
>>> thread safe.
>>
>> Not that straight forward as I would have to pass arguments to the
>> bottom half.
>
> Can you add a variant of qemu_bh_new that accepts a sizeof for the new
> bottom half? Then the bottom half itself can be passed as the opaque and
> used for the arguments.

Bottom halves are opaque to the caller.

Passing arguments would require careful consideration of locking too.  I 
think the best way to resolve this is to fix libspice and not try to 
work around the problem in QEMU.

Regards,

Anthony Liguori

>
> Paolo