Re: [Qemu-devel] [PATCH v2 for-4.0 1/7] chardev: Add disconnected option for chardev socket

[Daniel P . Berrangé]

On Tue, Dec 18, 2018 at 04:24:26PM +0400, Marc-André Lureau wrote:
> Hi
> 
> On Tue, Dec 18, 2018 at 2:01 PM <address@hidden> wrote:
> >
> > From: Xie Yongji <address@hidden>
> >
> > New option "disconnected" is added to init the chardev socket
> > in disconnected state. Then we can use qemu_chr_fe_wait_connected()
> > to connect when necessary. Now it would be used for unix domain
> > socket of vhost-user-blk device to support reconnect.
> 
> What difference does that make if you wait for connection in
> qemu_chr_fe_wait_connected(), or during chardev setup?
> 
> "disconnected" is misleading, would it be possible to reuse
> "wait/nowait" instead?

Currently we default to doing a blocking connect in foreground,
except if reconnect is non-zero, in which case we do a connect
async in the background. This "disconnected" proposal effectively
does a blocking connect, but delayed to later in startup.

IOW, this could already be achieved if "reconnect" were set to
non-zero. If the usage doesn't want reconnect though, I tend
to agree that we should use the exisiting wait/nowait options
to let it be controlled. I don't see that this "disconnected"
option gives a compelling benefit over using wait/nowait.


Regards,
Daniel
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