[libvirt PATCH v3 07/21] nodedev: add mdevctl devices to node device list

[Erik Skultety]

On Wed, Jan 06, 2021 at 11:27:09AM +0100, Erik Skultety wrote:
> On Thu, Dec 24, 2020 at 08:14:31AM -0600, Jonathon Jongsma wrote:
> > At startup, query devices that are defined by 'mdevctl' and add them to
> > the node device list.
> > 
> > This adds a complication: we now have two potential sources of
> > information for a node device:
> >  - udev for all devices and for activated mediated devices
> >  - mdevctl for persistent mediated devices
> > 
> > Unfortunately, neither backend returns full information for a mediated
> > device. For example, if a persistent mediated device in the list (with
> > information provided from mdevctl) is 'started', that same device will
> > now be detected by udev. If we simply overwrite the existing device
> > definition with the new one provided by the udev backend, we will lose
> > extra information that was provided by mdevctl (e.g. attributes, etc).
> > To avoid this, make sure to copy the extra information into the new
> > device definition.
> > 
> > Signed-off-by: Jonathon Jongsma <jjongsma at redhat.com>
> > ---
> >  src/node_device/node_device_driver.c | 76 ++++++++++++++++++++++++++++
> >  src/node_device/node_device_driver.h |  3 ++
> >  src/node_device/node_device_udev.c   | 48 ++++++++++++++++++
> >  3 files changed, 127 insertions(+)
> > 
> > diff --git a/src/node_device/node_device_driver.c b/src/node_device/node_device_driver.c
> > index 5309b8abd5..0267005af1 100644
> > --- a/src/node_device/node_device_driver.c
> > +++ b/src/node_device/node_device_driver.c
> > @@ -1144,3 +1144,79 @@ nodeDeviceGenerateName(virNodeDeviceDefPtr def,
> >              *(def->name + i) = '_';
> >      }
> >  }
> > +
> > +
> > +static int
> > +virMdevctlListDefined(virNodeDeviceDefPtr **devs)
> > +{
> > +    int status;
> > +    g_autofree char *output = NULL;
> > +    g_autoptr(virCommand) cmd = nodeDeviceGetMdevctlListCommand(true, &output);
> > +
> > +    if (virCommandRun(cmd, &status) < 0)
> > +        return -1;
> > +
> > +    if (!output)
> > +        return -1;
> > +
> > +    return nodeDeviceParseMdevctlJSON(output, devs);
> > +}
> > +
> > +
> > +int
> > +nodeDeviceUpdateMediatedDevices(void)
> 
> ^This was called mdevctlEnumerateDevices in v2, so I'm wondering why did you
> change the name? I think it was okay the way it was (I double checked that I
> didn't suggest this change in v2 by accident).

In patch 9 I see the reason and it's indeed better to be named this way, so you
can ignore ^this comment, sorry, I was too hasty.

Erik