Re: [PATCH] hwmon: Fix WARN_ON() always called from devm_hwmon_device_unregister()

[Guenter Roeck]

On 9/12/24 23:40, PJ Waskiewicz wrote:
> On Thu, 2024-09-12 at 07:13 -0700, Guenter Roeck wrote:
> > On 9/12/24 02:14, Matthew Sanders wrote:
> > > devm_hwmon_device_unregister() only takes parent of a devres-
> > > managed
> > > hwmon device as an argument. This always fails, as devres can't
> > > find
> > > the hwmon device it needs to unregister with the parent device
> > > alone.
> > > Without this patch, the WARN_ON() in devm_hwmon_device_unregister()
> > > will
> > > always be displayed unconditionally:
> > >
> > > [    7.969746] WARNING: CPU: 1 PID: 224 at
> > > drivers/hwmon/hwmon.c:1205 devm_hwmon_device_unregister+0x28/0x30
> > >
> > > This patch adds an extra argument to
> > > devm_hwmon_device_unregister(), a
> > > pointer to a hwmon device which was previously registered to the
> > > parent using devres.
> > >
> > > There aren't any drivers which currently make use of this function,
> > > so
> > > any existing users of devm_hwmon_* shouldn't require any changes as
> > > a
> > > result of this patch.
> >
> > If there are no users, there is no need to keep the function. We
> > should drop
> > it instead.
>
> There aren't any direct in-tree users of the function.  But some out-
> of-tree drivers can find it useful to use, hence Matt hitting this
> issue.
>
> If there's a desire to just remove it, that's fine.  But it would
> remove a handy hook for out-of-tree stuff.

Any use of this function is most likely wrong. Out-of-tree code is
completely irrelevant for the upstream kernel. On the contrary - it
is another reason for removing this function. I'll do that myself.

Guenter