Re: [PATCH v5] Drivers: hv: vmbus: Expose monitor data only when monitor pages are used

From: Greg KH
Date: Sat Mar 09 2019 - 02:21:40 EST


On Fri, Mar 08, 2019 at 05:46:11PM -0500, Kimberly Brown wrote:
> static struct kobj_type vmbus_chan_ktype = {
> .sysfs_ops = &vmbus_chan_sysfs_ops,
> .release = vmbus_chan_release,
> - .default_attrs = vmbus_chan_attrs,

As discussed on IRC, a kobj_type needs to get an attribute group one of
these days, not just a attribute list :)

So thanks for persisting with this, sorry for the earlier review
comments, you were totally right about this, nice work.

Minor review comments below:

> };
>
> /*
> @@ -1571,11 +1624,34 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
> if (ret)
> return ret;
>
> + ret = sysfs_create_group(kobj, &vmbus_chan_group);
> + channel->sysfs_group_ready = !ret;

Why do you need this flag?

> +
> + if (ret) {
> + /*
> + * If an error is returned to the calling functions, those
> + * functions will call kobject_put() on the channel kobject,
> + * which will cleanup the empty channel directory created by
> + * kobject_init_and_add().

Why is this comment needed?

> + */
> + pr_err("Unable to set up channel sysfs files\n");

dev_err() to show who had the problem with the files?

> + return ret;
> + }
> +
> kobject_uevent(kobj, KOBJ_ADD);
>
> return 0;
> }
>
> +/*
> + * vmbus_remove_channel_attr_group - remove the channel's attribute group
> + */
> +void vmbus_remove_channel_attr_group(struct vmbus_channel *channel)
> +{
> + if (channel->sysfs_group_ready)
> + sysfs_remove_group(&channel->kobj, &vmbus_chan_group);

You should be able to just always remove these, no need for a flag to
say you have created them or not, right?

thanks,

greg k-h