netdev - Re: [PATCH v3 1/2] pm: runtime: Simplify pm_runtime_get_if

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Date: Tue, 23 Jan 2024 07:45:03 +0000
From: Sakari Ailus <sakari.ailus@...ux.intel.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: Bjorn Helgaas <helgaas@...nel.org>, linux-pm@...r.kernel.org,
	linux-pci@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	Jaroslav Kysela <perex@...ex.cz>,
	Stanislaw Gruszka <stanislaw.gruszka@...ux.intel.com>,
	laurent.pinchart@...asonboard.com, David Airlie <airlied@...il.com>,
	Paul Elder <paul.elder@...asonboard.com>,
	linux-media@...r.kernel.org,
	Thomas Hellström <thomas.hellstrom@...ux.intel.com>,
	intel-gfx@...ts.freedesktop.org,
	Lucas De Marchi <lucas.demarchi@...el.com>,
	Mark Brown <broonie@...nel.org>,
	Jacek Lawrynowicz <jacek.lawrynowicz@...ux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	intel-xe@...ts.freedesktop.org,
	Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
	Alex Elder <elder@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-sound@...r.kernel.org, Takashi Iwai <tiwai@...e.com>,
	Daniel Vetter <daniel@...ll.ch>, netdev@...r.kernel.org
Subject: Re: [PATCH v3 1/2] pm: runtime: Simplify pm_runtime_get_if_active()
 usage

Hi Rafael, Björn,

Thanks for the review.

On Mon, Jan 22, 2024 at 07:16:54PM +0100, Rafael J. Wysocki wrote:
> On Mon, Jan 22, 2024 at 7:12 PM Bjorn Helgaas <helgaas@...nel.org> wrote:
> >
> > On Mon, Jan 22, 2024 at 01:41:21PM +0200, Sakari Ailus wrote:
> > > There are two ways to opportunistically increment a device's runtime PM
> > > usage count, calling either pm_runtime_get_if_active() or
> > > pm_runtime_get_if_in_use(). The former has an argument to tell whether to
> > > ignore the usage count or not, and the latter simply calls the former with
> > > ign_usage_count set to false. The other users that want to ignore the
> > > usage_count will have to explitly set that argument to true which is a bit
> > > cumbersome.
> >
> > s/explitly/explicitly/
> >
> > > To make this function more practical to use, remove the ign_usage_count
> > > argument from the function. The main implementation is renamed as
> > > pm_runtime_get_conditional().
> > >
> > > Signed-off-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
> > > Reviewed-by: Alex Elder <elder@...aro.org> # drivers/net/ipa/ipa_smp2p.c
> > > Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> > > Acked-by: Takashi Iwai <tiwai@...e.de> # sound/
> > > Reviewed-by: Jacek Lawrynowicz <jacek.lawrynowicz@...ux.intel.com> # drivers/accel/ivpu/
> > > Acked-by: Rodrigo Vivi <rodrigo.vivi@...el.com> # drivers/gpu/drm/i915/
> > > Reviewed-by: Rodrigo Vivi <rodrigo.vivi@...el.com>
> >
> > Acked-by: Bjorn Helgaas <bhelgaas@...gle.com> # drivers/pci/
> >
> > > -EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
> > > +EXPORT_SYMBOL_GPL(pm_runtime_get_conditional);
> >
> > If pm_runtime_get_conditional() is exported, shouldn't it also be
> > documented in Documentation/power/runtime_pm.rst?
> >
> > But I'm dubious about exporting it because
> > __intel_runtime_pm_get_if_active() is the only caller, and you end up
> > with the same pattern there that we have before this series in the PM
> > core.  Why can't intel_runtime_pm.c be updated to use
> > pm_runtime_get_if_active() or pm_runtime_get_if_in_use() directly, and
> > make pm_runtime_get_conditional() static?
> 
> Sounds like a good suggestion to me.

The i915 driver uses both but I guess it's not too much different to check
ignore_usecount separately than passing it to the API function?

I'll add another patch to do this and moving
pm_runtime_get_if_{active,in_use} implementations to runtime.c.

-- 
Regards,

Sakari Ailus