RE: [PATCH] virtio_pci: modify ENOENT to EINVAL

[Angus Chen]

Hi Jason.

> -----Original Message-----
> From: Jason Wang <jasowang@xxxxxxxxxx>
> Sent: Wednesday, November 2, 2022 1:34 PM
> To: Angus Chen <angus.chen@xxxxxxxxxxxxxxx>
> Cc: mst@xxxxxxxxxx; virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; lingshan.zhu@xxxxxxxxx
> Subject: Re: [PATCH] virtio_pci: modify ENOENT to EINVAL
> 
> On Tue, Nov 1, 2022 at 7:17 PM Angus Chen <angus.chen@xxxxxxxxxxxxxxx>
> wrote:
> >
> > Virtio_crypto use max_data_queues+1 to setup vqs,
> > we use vp_modern_get_num_queues to protect the vq range in setup_vq.
> > We could enter index >= vp_modern_get_num_queues(mdev) in setup_vq
> > if common->num_queues is not set well,and it return -ENOENT.
> > It is better to use -EINVAL instead.
> 
> I'm not sure I get this. It would be better to describe:
> 
> 1) what kind of issues can we see if we return -ENOENT
> 2) why -EINVAL can help in this case
> 
> Thanks
Thank you for your reply.
We use a robot to test our dpu to get the return value of probe.
 We often get ENOENT form ' setup_vq ' function because of device error.
Most of time, my device can't handle queue_enable well.
This time,we get 'ENOENT' because the device set max_data_queues bigger than num_queues.

I think EINVAL is used when the value of some parameter is wrong.
Btw,it not a big deal,I can modify the robot to workaround.

> 
> >
> > Signed-off-by: Angus Chen <angus.chen@xxxxxxxxxxxxxxx>
> > ---
> >  drivers/virtio/virtio_pci_modern.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/virtio/virtio_pci_modern.c
> b/drivers/virtio/virtio_pci_modern.c
> > index c3b9f2761849..edf2e18014cd 100644
> > --- a/drivers/virtio/virtio_pci_modern.c
> > +++ b/drivers/virtio/virtio_pci_modern.c
> > @@ -303,7 +303,7 @@ static struct virtqueue *setup_vq(struct
> virtio_pci_device *vp_dev,
> >         int err;
> >
> >         if (index >= vp_modern_get_num_queues(mdev))
> > -               return ERR_PTR(-ENOENT);
> > +               return ERR_PTR(-EINVAL);
> >
> >         /* Check if queue is either not available or already active. */
> >         num = vp_modern_get_queue_size(mdev, index);
> > --
> > 2.25.1
> >