RE: [PATCH v2 1/3] hv: hv_util: move vmbus_open() to a later place

[Jason Wang]

On Tue, Feb 3, 2015 at 11:40 AM, KY Srinivasan <kys@xxxxxxxxxxxxx> 
wrote:
> >  -----Original Message-----
> >  From: Jason Wang [mailto:jasowang@xxxxxxxxxx]
> >  Sent: Monday, February 2, 2015 7:38 PM
> >  To: KY Srinivasan
> >  Cc: Dexuan Cui; gregkh@xxxxxxxxxxxxxxxxxxx; 
> > linux-kernel@xxxxxxxxxxxxxxx;
> >  driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx;
> >  apw@xxxxxxxxxxxxx; vkuznets@xxxxxxxxxx; Haiyang Zhang
> >  Subject: RE: [PATCH v2 1/3] hv: hv_util: move vmbus_open() to a 
> > later place
> >  
> >  
> >  
> >  On Tue, Feb 3, 2015 at 11:30 AM, KY Srinivasan <kys@xxxxxxxxxxxxx>
> >  wrote:
> >  >
> >  >
> >  >>  -----Original Message-----
> >  >>  From: Jason Wang [mailto:jasowang@xxxxxxxxxx]
> >  >>  Sent: Monday, February 2, 2015 7:09 PM
> >  >>  To: Dexuan Cui
> >  >>  Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> >  >> driverdev-
> >  >>  devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx; 
> > apw@xxxxxxxxxxxxx; KY
> >  >> Srinivasan; vkuznets@xxxxxxxxxx; Haiyang Zhang
> >  >>  Subject: RE: [PATCH v2 1/3] hv: hv_util: move vmbus_open() to a
> >  >> later place
> >  >>
> >  >>
> >  >>
> >  >>  On Mon, Feb 2, 2015 at 6:09 PM, Dexuan Cui <decui@xxxxxxxxxxxxx>
> >  >> wrote:
> >  >>  >>  -----Original Message-----
> >  >>  >>  From: Jason Wang [mailto:jasowang@xxxxxxxxxx]  >>  Sent: 
> > Monday,
> >  >> February 2, 2015 17:36 PM  >>  To: Dexuan Cui  >>  Cc:
> >  >> gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;  >>
> >  >> driverdev-  >>  devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx;
> >  >> apw@xxxxxxxxxxxxx; KY  >> Srinivasan; vkuznets@xxxxxxxxxx; 
> > Haiyang
> >  >> Zhang  >>  Subject: Re: [PATCH v2 1/3] hv: hv_util: move 
> > vmbus_open()
> >  >> to a  >> later place  >>  >>  >>  >>  On Mon, Feb 2, 2015 at 
> > 12:35
> >  >> PM, Dexuan Cui <decui@xxxxxxxxxxxxx>  >> wrote:
> >  >>  >>  > Before the line vmbus_open() returns, srv->util_cb can be
> >  >> already  >> > running  > and the variables, like 
> > util_fw_version, are
> >  >> needed by  >> the  > srv->util_cb.
> >  >>  >>
> >  >>  >>  A questions is why we do this for util only? Can callbacks 
> > of
> >  >> other  >> devices be called before vmbus_open() returns?
> >  >>  > The variables are used in vmbus_prep_negotiate_resp(), which 
> > is
> >  >> only  > for the util devices.
> >  >>  >
> >  >>  > I think the other devices should already handle the similar 
> > issue
> >  >> > properly.
> >  >>  > If this is not the case, we need to fix them too.
> >  >>
> >  >>  Better to check all the others, e.g in balloon_probe(), it call
> >  >>  hv_set_drvdata() after vmbus_open() and dose several datas 
> > setups in
> >  >> the  middle. If balloon_onchannelcallback() could be called 
> > before
> >  >> hv_set_drvdata(), the code looks wrong.
> >  >
> >  > Jason,
> >  >
> >  > For all other device types, the guest initiates the communication 
> > with
> >  > the host and potentially negotiates appropriate (supported) 
> > version
> >  > with the host. For the services packaged in the util driver, the 
> > flow
> >  > is a little different - the host pushes the version information 
> > into
> >  > the guest. So, the fix Dexuan made is only needed in the util 
> > driver.
> >  >
> >  > Regards,
> >  >
> >  > K. Y
> >  
> >  Thanks, so you mean for other device, it won't get any interrupt 
> > before guest
> >  negotiate the version with host?
>
> Yes, the guest initiates the version negotiation. Are you seeing 
> something different?
>
> K. Y

No, thanks.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/