linux-kernel - Re: [PATCH] media: imx7-mipi-csis: Add the missed v4l2_async_notifier_cleanup in remove

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Date:   Thu, 12 Dec 2019 19:08:58 +0000
From:   Rui Miguel Silva <rmfrfs@...il.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>
Cc:     Chuhong Yuan <hslester96@...il.com>, devel@...verdev.osuosl.org,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        linux-kernel@...r.kernel.org, NXP Linux Team <linux-imx@....com>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Steve Longerbeam <slongerbeam@...il.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org
Subject: Re: [PATCH] media: imx7-mipi-csis: Add the missed
 v4l2_async_notifier_cleanup in remove

Hi Dan,
Thanks for the inputs.
On Thu, Dec 12, 2019 at 02:51:34PM +0300, Dan Carpenter wrote:
> On Mon, Dec 09, 2019 at 04:58:28PM +0800, Chuhong Yuan wrote:
> > All drivers in imx call v4l2_async_notifier_cleanup() after
> > unregistering the notifier except this driver.  This should be a
> > miss and we need to add the call to fix it.
> > 
> > Signed-off-by: Chuhong Yuan <hslester96@...il.com> ---
> > drivers/staging/media/imx/imx7-mipi-csis.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/staging/media/imx/imx7-mipi-csis.c
> > b/drivers/staging/media/imx/imx7-mipi-csis.c index
> > 99166afca071..2bfa85bb84e7 100644 ---
> > a/drivers/staging/media/imx/imx7-mipi-csis.c +++
> > b/drivers/staging/media/imx/imx7-mipi-csis.c @@ -1105,6 +1105,7 @@
> > static int mipi_csis_remove(struct platform_device *pdev)
> > mipi_csis_debugfs_exit(state);
> > v4l2_async_unregister_subdev(&state->mipi_sd);
> > v4l2_async_notifier_unregister(&state->subdev_notifier); +
> > v4l2_async_notifier_cleanup(&state->subdev_notifier);
> >  
> 
> In this case the "state->subdev_notifier" was never initialized or
> used so both v4l2_async_notifier_unregister() and
> v4l2_async_notifier_cleanup() are no-ops.

I have applied this patch on top of Steve's series [0], since by the
timeline I was expecting to be applied before this one, that series
adds a bound notifier, even though, it is not named the same, eheh.

That trigged me to think that this cleanup was correct since a
notifier was initialized in probe.

But as you say, it is a no-ops in the end.

@Steve, that said, it looks that in [0], you will need to add some
unregister and cleanup for the notifiers that you are adding in
several places.

A patch to fix this will follow.

------
Cheers,
     Rui

[0]: https://patchwork.kernel.org/project/linux-media/list/?series=207517

> 
> We should just delete "subdev_notifier".
> 
> regards, dan carpenter
> 
> _______________________________________________ devel mailing list
> devel@...uxdriverproject.org
> http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel

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