[Intel-gfx] [PATCH v9 09/10] vfio/pci: Copy hot-reset device info to userspace in the devices loop

[Liu, Yi L]

> From: Jason Gunthorpe <jgg at nvidia.com>
> Sent: Friday, July 14, 2023 9:37 PM
> 
> On Mon, Jul 10, 2023 at 07:31:25PM -0700, Yi Liu wrote:
> 
> > @@ -1311,29 +1296,17 @@ static int vfio_pci_ioctl_get_pci_hot_reset_info(
> >  	ret = vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_fill_devs,
> >  					    &fill, slot);
> >  	mutex_unlock(&vdev->vdev.dev_set->lock);
> > +	if (ret)
> > +		return ret;
> >
> > -	/*
> > -	 * If a device was removed between counting and filling, we may come up
> > -	 * short of fill.max.  If a device was added, we'll have a return of
> > -	 * -EAGAIN above.
> > -	 */
> > -	if (!ret) {
> > -		hdr.count = fill.cur;
> > -		hdr.flags = fill.flags;
> > -	}
> > -
> > -reset_info_exit:
> > +	hdr.count = fill.count;
> > +	hdr.flags = fill.flags;
> >  	if (copy_to_user(arg, &hdr, minsz))
> > -		ret = -EFAULT;
> > -
> > -	if (!ret) {
> > -		if (copy_to_user(&arg->devices, devices,
> > -				 hdr.count * sizeof(*devices)))
> > -			ret = -EFAULT;
> > -	}
> > +		return -EFAULT;
> >
> > -	kfree(devices);
> > -	return ret;
> > +	if (fill.count != fill.devices - arg->devices)
> > +		return -ENOSPC;
> 
> This should be > right? The previous code returned ENOSPC only if
> their were more devices than requested, not less.

Yes. it is.

Regards,
Yi Liu