linux-kernel - Re: [PATCH 2/3] ACPI / PM: Split acpi_device

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Date:   Fri, 21 Jul 2017 22:49:06 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Linux PCI <linux-pci@...r.kernel.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH 2/3] ACPI / PM: Split acpi_device_wakeup()

On Friday, July 21, 2017 06:27:39 PM Andy Shevchenko wrote:
> On Fri, Jul 21, 2017 at 3:40 PM, Rafael J. Wysocki <rjw@...ysocki.net> wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > To prepare for a subsequent change and make the code somewhat easier
> > to follow, do the following in the ACPI device wakeup handling code:
> >
> >  * Replace wakeup.flags.enabled under struct acpi_device with
> >    wakeup.enable_count as that will be necessary going forward.
> >
> >    For now, wakeup.enable_count is not allowed to grow beyond 1,
> >    so the current behavior is retained.
> >
> >  * Split acpi_device_wakeup() into acpi_device_wakeup_enable()
> >    and acpi_device_wakeup_disable() and modify the callers of
> >    it accordingly.
> >
> >  * Introduce a new acpi_wakeup_lock mutex to protect the wakeup
> >    enabling/disabling code from races in case it is executed
> >    more than once in parallel for the same device (which may
> >    happen for bridges theoretically).
> 
> I prefer more self-explaining labels, though it's minor here

Well, I prefer shorter ones.

> To be constructive:
> out -> err_unlock
> out -> out_unlock or err_unlock (depends on context)
> 
> 
> > +out:
> > +       mutex_unlock(&acpi_wakeup_lock);
> > +       return error;
> 
> > +out:
> > +       mutex_unlock(&acpi_wakeup_lock);
> 
> 

So while I don't have a particular problem with appending the "_unlock" to the
"out", I'm not exactly sure why this would be an improvement.

If that's just a matter of personal preference, then I would prefer to follow
my personal preference here, with all due respect.  [And besides, it follows
the general style of this file which matters too IMO.]

But if there's more to it, just please let me know. :-)

Thanks,
Rafael