Re: [PATCH v2 1/4] MicroSemi Switchtec management interface driver

From: Greg Kroah-Hartman
Date: Fri Feb 10 2017 - 11:58:18 EST


On Fri, Feb 10, 2017 at 09:48:37AM -0700, Logan Gunthorpe wrote:
> Hey Greg,
>
> Thanks so much for the review.
>
> On 10/02/17 07:51 AM, Greg Kroah-Hartman wrote:
> > On Thu, Feb 02, 2017 at 11:06:00AM -0700, Logan Gunthorpe wrote:
> >> + cdev = &stdev->cdev;
> >> + cdev_init(cdev, &switchtec_fops);
> >> + cdev->owner = THIS_MODULE;
> >> + cdev->kobj.parent = &dev->kobj;
> >
> > Minor nit, the kobject in a cdev is unlike any other kobject you have
> > ever seen, don't mess with it, it's not doing anything like you think it
> > is doing. So no need to set the parent field.
>
> Ok, that makes sense. I'll do a v3 shortly.
>
> I copied this from drivers/dax/dax.c so when I have a spare moment I'll
> submit a patch to remove it from there as well.
>
> Just to make sure I get this right without extra churn: does this look
> correct?
>
>
> cdev = &stdev->cdev;
> cdev_init(cdev, &switchtec_fops);
> cdev->owner = THIS_MODULE;
>
> rc = cdev_add(&stdev->cdev, dev->devt, 1);
> if (rc)
> goto err_cdev;
>
> dev = &stdev->dev;
> dev->devt = MKDEV(MAJOR(switchtec_devt), minor);
> dev->class = switchtec_class;
> dev->parent = &pdev->dev;
> dev->groups = switchtec_device_groups;
> dev->release = stdev_release;
> dev_set_name(dev, "switchtec%d", minor);
>
> rc = device_register(dev);
> if (rc) {
> cdev_del(&stdev->cdev);
> put_device(dev);
> return ERR_PTR(rc);
> }
>

Yes, but try it yourself to verify it really is correct :)

And it can just be an add-on patch, no need to respin a whole new
version for just that simple change, it doesn't hurt anything as-is,
it's just "not needed".

thanks,

greg k-h