linux-kernel - Re: [PATCH 1/3] virtio: use virtio_device_ready() in virtio_device

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Message-ID: <20220324113126.f6f5hfabhqfyutix@sgarzare-redhat>
Date:   Thu, 24 Mar 2022 12:31:26 +0100
From:   Stefano Garzarella <sgarzare@...hat.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>
Cc:     Jason Wang <jasowang@...hat.com>,
        virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, maz@...nel.org, tglx@...utronix.de,
        peterz@...radead.org, keirf@...gle.com
Subject: Re: [PATCH 1/3] virtio: use virtio_device_ready() in
 virtio_device_restore()

On Thu, Mar 24, 2022 at 07:07:09AM -0400, Michael S. Tsirkin wrote:
>On Thu, Mar 24, 2022 at 12:03:07PM +0100, Stefano Garzarella wrote:
>> On Thu, Mar 24, 2022 at 06:48:05AM -0400, Michael S. Tsirkin wrote:
>> > On Thu, Mar 24, 2022 at 04:40:02PM +0800, Jason Wang wrote:
>> > > From: Stefano Garzarella <sgarzare@...hat.com>
>> > >
>> > > This avoids setting DRIVER_OK twice for those drivers that call
>> > > virtio_device_ready() in the .restore
>> >
>> > Is this trying to say it's faster?
>>
>> Nope, I mean, when I wrote the original version, I meant to do the same
>> things that we do in virtio_dev_probe() where we called
>> virtio_device_ready() which not only set the state, but also called
>> .enable_cbs callback.
>>
>> Was this a side effect and maybe more compliant with the spec?
>
>
>Sorry I don't understand the question. it says "avoids setting DRIVER_OK twice" -
>why is that advantageous and worth calling out in the commit log?

I just wanted to say that it seems strange to set DRIVER_OK twice if we 
read the spec. I don't think it's wrong, but weird.

Yes, maybe we should rewrite the commit message saying that we want to 
use virtio_device_ready() everywhere to complete the setup before 
setting DRIVER_OK so we can do all the necessary operations inside (like 
in patch 3 or call enable_cbs).

Jason rewrote the commit log, so I don't know if he agrees.

Thanks,
Stefano