From: Lukas Wunner <lukas@wunner.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: gregkh@linuxfoundation.org,
Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
Marc Herbert <marc.herbert@intel.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-coco@lists.linux.dev, alsa-devel@alsa-project.org
Subject: Re: [PATCH 1/3] sysfs: Fix crash on empty group attributes array
Date: Sat, 27 Apr 2024 23:14:28 +0200 [thread overview]
Message-ID: <Zi1qtKNwcyydP4c2@wunner.de> (raw)
In-Reply-To: <662d2ca522cc6_b6e02942d@dwillia2-mobl3.amr.corp.intel.com.notmuch>
On Sat, Apr 27, 2024 at 09:49:41AM -0700, Dan Williams wrote:
> Lukas Wunner wrote:
> > But I want to raise awareness that the inability to hide
> > empty attribute groups feels awkward.
>
> That is fair, it was definitely some gymnastics to only change user
> visible behavior for new "invisible aware" attribute groups that opt-in
> while leaving all the legacy cases alone.
>
> The concern is knowing when it is ok to call an is_visible() callback
> with a NULL @attr argument, or knowing when an empty array actually
> means "hide the group directory".
>
> We could add a sentinel value to indicate "I am an empty attribute list
> *AND* I want my directory hidden by default". However, that's almost
> identical to requiring a placeholder attribute in the list just to make
> __first_visible() happy.
>
> Other ideas?
Perhaps an optional ->is_group_visible() callback in struct attribute_group
which gets passed only the struct kobject pointer?
At least for PCI device authentication, that would be sufficient.
I could get from the kobject to the corresponding struct device,
then determine whether the device supports authentication or not.
Because it's a new, optional callback, there should be no compatibility
issues. The SYSFS_GROUP_INVISIBLE return code from the ->is_visible()
call for individual attributes would not be needed then, at least in my
use case.
Thanks,
Lukas
next prev parent reply other threads:[~2024-04-27 21:14 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-22 20:40 [PATCH 0/3] sysfs: Group visibility fixups Dan Williams
2024-02-22 20:40 ` [PATCH 1/3] sysfs: Fix crash on empty group attributes array Dan Williams
2024-02-22 21:14 ` Rafael J. Wysocki
2024-02-22 22:03 ` Dan Williams
2024-02-22 23:15 ` Dan Williams
2024-04-22 9:20 ` Lukas Wunner
2024-04-26 17:59 ` Dan Williams
2024-04-26 19:18 ` Lukas Wunner
2024-04-27 11:05 ` Greg KH
2024-04-27 16:49 ` Dan Williams
2024-04-27 21:14 ` Lukas Wunner [this message]
2024-04-27 21:33 ` Dan Williams
2024-04-27 22:39 ` Dan Williams
2024-04-27 23:09 ` Dan Williams
2024-04-28 10:08 ` Lukas Wunner
2024-04-29 17:47 ` Dan Williams
2024-02-22 20:41 ` [PATCH 2/3] sysfs: Document new "group visible" helpers Dan Williams
2024-02-22 20:41 ` [PATCH 3/3] sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE() Dan Williams
2024-02-23 6:33 ` [PATCH 0/3] sysfs: Group visibility fixups Greg KH
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