Re: [PATCH 02/25] staging: media: imx7-mipi-csis: fix pm_runtime_get_sync() usage count

From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
To: "Rui Miguel Silva" <rmfrfs@gmail.com>
Cc: "Jonathan Cameron" <Jonathan.Cameron@Huawei.com>,
	<linuxarm@huawei.com>, <mauro.chehab@huawei.com>,
	"Fabio Estevam" <festevam@gmail.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"NXP Linux Team" <linux-imx@nxp.com>,
	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	"Philipp Zabel" <p.zabel@pengutronix.de>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Steve Longerbeam" <slongerbeam@gmail.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <linux-media@vger.kernel.org>,
	<linux-staging@lists.linux.dev>
Subject: Re: [PATCH 02/25] staging: media: imx7-mipi-csis: fix pm_runtime_get_sync() usage count
Date: Wed, 5 May 2021 16:23:28 +0200	[thread overview]
Message-ID: <20210505162328.1e5fff80@coco.lan> (raw)
In-Reply-To: <CB5D4B64QTP4.GBH80G3VX3B6@arch-thunder>

Em Wed, 05 May 2021 14:56:40 +0100
"Rui Miguel Silva" <rmfrfs@gmail.com> escreveu:

> Hi,
> On Wed May 5, 2021 at 12:06 PM WEST, Jonathan Cameron wrote:
> 
> > On Wed, 5 May 2021 11:41:52 +0200
> > Mauro Carvalho Chehab <mchehab+huawei@kernel.org> wrote:
> >  
> > > The pm_runtime_get_sync() internally increments the
> > > dev->power.usage_count without decrementing it, even on errors.
> > > Replace it by the new pm_runtime_resume_and_get(), introduced by:
> > > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > > in order to properly decrement the usage counter, avoiding
> > > a potential PM usage counter leak.
> > > 
> > > Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
> > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>  
> >
> > Not a fix as far as I can see, just a cleanup - so perhaps not this set?  
> 
> yes, the original changelog of this patch, that I acked,  made it
> clear it was a cleanup:
> 
> "
> Commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to
> deal with usage counter")                                                                                                                                         
> added pm_runtime_resume_and_get() in order to automatically handle 
> dev->power.usage_count decrement on errors.
> 
> Use the new API, in order to cleanup the error check logic.
> "
> 
> This one above is new, but I saw Mauro is going change it.

Yes, I'll change the subject/description to the
"use pm_runtime_resume_and_get()" one on this patch, as there's
no issue to be fixed here, just a cleanup ;-)

Sorry for the mess. I did lots of rebase on ~80 patch series
over the last couple of days, based on the reviews (and my own
internal reviews)...

See, the current patchset has ~80 patches with ~30% contained
fixes. It shows that writing a balanced PM runtime code is not
so trivial ;-)

Thanks,
Mauro