From: Kimberly Brown <kimbrownkd@gmail.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Michael Kelley <mikelley@microsoft.com>,
Long Li <longli@microsoft.com>,
Sasha Levin <Alexander.Levin@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Dexuan Cui <decui@microsoft.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] Drivers: hv: vmbus: Expose monitor data only when monitor pages are used
Date: Sun, 3 Mar 2019 16:11:28 -0500 [thread overview]
Message-ID: <20190303211128.GA2071@ubu-Virtual-Machine> (raw)
In-Reply-To: <20190303080543.GA32186@kroah.com>
On Sun, Mar 03, 2019 at 09:05:43AM +0100, Greg KH wrote:
> On Fri, Mar 01, 2019 at 02:18:24PM -0500, Kimberly Brown wrote:
> > +/*
> > + * Channel-level attribute_group callback function. Returns the permission for
> > + * each attribute, and returns 0 if an attribute is not visible.
> > + */
> > +static umode_t vmbus_chan_attr_is_visible(struct kobject *kobj,
> > + struct attribute *attr, int idx)
> > +{
> > + const struct vmbus_channel *channel =
> > + container_of(kobj, struct vmbus_channel, kobj);
> > +
> > + /* Hide the monitor attributes if the monitor mechanism is not used. */
> > + if (!channel->offermsg.monitor_allocated &&
> > + (attr == &chan_attr_pending.attr ||
> > + attr == &chan_attr_latency.attr ||
> > + attr == &chan_attr_monitor_id.attr))
> > + return 0;
> > +
> > + return attr->mode;
> > +}
> > +
> > +static struct attribute_group vmbus_chan_group = {
> > + .attrs = vmbus_chan_attrs,
> > + .is_visible = vmbus_chan_attr_is_visible
> > +};
> > +
> > static struct kobj_type vmbus_chan_ktype = {
> > .sysfs_ops = &vmbus_chan_sysfs_ops,
> > .release = vmbus_chan_release,
> > - .default_attrs = vmbus_chan_attrs,
>
> Why did you remove this line?
I removed the default attributes because vmbus_chan_attrs contains
non-default attributes. You suggested that I use one attribute_group and
an is_visible() callback for the device-level attributes (see
https://lore.kernel.org/lkml/20190226081848.GA15659@kroah.com/). I
assumed (possibly incorrectly) that I should do the same for these
channel-level attributes.
> > };
> >
> > /*
> > @@ -1571,6 +1624,12 @@ 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);
>
> Why are you adding these "by hand"? What was wrong with using the
> default attribute group pointer? You also are not removing the
> attributes :(
Are you referring to default_attrs in kobj_type? It's not an
attribute_group pointer, it's a pointer to an attribute pointer array.
The problem with using default_attrs is that all of the attributes are
visible.
I'm fairly certain that the monitor attributes are being removed.
sysfs_create_group() uses the attribute_group's is_visible() callback to
control the attribute visibility. And, when I look at the sysfs files, I
can see that the monitor sysyfs files are removed.
In v3, I proposed moving the monitor attributes to a special
attribute_group and adding that group manually when needed. Do you
prefer that approach for the channel-level monitor attributes?
Thanks,
Kim
>
> greg k-h
next prev parent reply other threads:[~2019-03-03 21:11 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-08 9:57 [PATCH 0/2] Drivers: hv: vmbus: Fix sysfs functions that display monitor id and page data Kimberly Brown
2019-02-08 9:58 ` [PATCH 1/2] Drivers: hv: vmbus: Change server monitor_pages index to 0 Kimberly Brown
2019-02-08 22:28 ` Stephen Hemminger
2019-02-08 10:01 ` [PATCH 2/2] Drivers: hv: vmbus: Display nothing in sysfs if monitor_allocated not set Kimberly Brown
2019-02-08 22:32 ` Stephen Hemminger
2019-02-11 7:01 ` Kimberly Brown
2019-02-11 18:02 ` Stephen Hemminger
2019-02-14 6:11 ` Kimberly Brown
2019-02-14 19:50 ` Stephen Hemminger
2019-02-19 5:37 ` [PATCH v2 0/2] Drivers: hv: vmbus: Fix sysfs functions that display monitor id and page data Kimberly Brown
2019-02-19 5:38 ` [PATCH v2 1/2] Drivers: hv: vmbus: Change server monitor_pages index to 0 Kimberly Brown
2019-02-20 14:35 ` Michael Kelley
[not found] ` <cover.1550554279.git.kimbrownkd@gmail.com>
2019-02-19 5:38 ` [PATCH v2 2/2] Drivers: hv: vmbus: Return -EINVAL if monitor_allocated not set Kimberly Brown
2019-02-20 16:11 ` Michael Kelley
2019-02-26 5:35 ` [PATCH v3] Drivers: hv: vmbus: Expose monitor data when channel uses monitor pages Kimberly Brown
2019-02-26 8:18 ` Greg KH
2019-03-01 19:18 ` [PATCH v4] Drivers: hv: vmbus: Expose monitor data only when monitor pages are used Kimberly Brown
2019-03-02 18:39 ` Michael Kelley
2019-03-03 21:40 ` Kimberly Brown
2019-03-03 8:05 ` Greg KH
2019-03-03 21:11 ` Kimberly Brown [this message]
2019-03-04 7:38 ` Greg KH
2019-03-08 22:46 ` [PATCH v5] " Kimberly Brown
2019-03-09 7:21 ` Greg KH
2019-03-12 0:04 ` Kimberly Brown
2019-03-19 4:04 ` [PATCH v6] " Kimberly Brown
2019-03-19 9:26 ` Greg KH
2019-03-20 20:18 ` Michael Kelley
2019-03-21 3:57 ` Sasha Levin
2019-03-21 15:55 ` Michael Kelley
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