Re: [Qemu-devel] [PATCH 11/12] nbd: switch to asynchronous operation

[Paolo Bonzini]

On 09/09/2011 04:52 PM, Nicholas Thomas wrote:
> I'm a bit unsure here, actually. So you lock a mutex, send a request,
> wait for a response, then unlock the mutex. Surely this code doesn't
> allow more than one request to be in flight at a time?

No, it doesn't.  It shouldn't be hard to do it though. You could have 
two mutexes, one for sending and one for receiving.  You yield after 
sending, and let nbd_coroutine_restart read the reply.  It can then 
reenter that reply's coroutine based on the handle in the reply.  I 
still prefer to do it in a separate patch.

Paolo