linux-kernel - Re: [PATCH v6 3/8] tda9950: use cec_notifier_cec_adap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190813113209.GF13294@shell.armlinux.org.uk>
Date:   Tue, 13 Aug 2019 12:32:09 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Dariusz Marcinkiewicz <darekm@...gle.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-media@...r.kernel.org,
        hverkuil-cisco@...all.nl, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Hans Verkuil <hverkuil@...all.nl>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Allison Randal <allison@...utok.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Kees Cook <keescook@...omium.org>,
        Colin Ian King <colin.king@...onical.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 3/8] tda9950: use cec_notifier_cec_adap_(un)register

On Tue, Aug 13, 2019 at 01:02:35PM +0200, Dariusz Marcinkiewicz wrote:
> Use the new cec_notifier_cec_adap_(un)register() functions to
> (un)register the notifier for the CEC adapter.
> 
> Signed-off-by: Dariusz Marcinkiewicz <darekm@...gle.com>
> Signed-off-by: Hans Verkuil <hverkuil-cisco@...all.nl>
> Tested-by: Hans Verkuil <hverkuil-cisco@...all.nl>
> ---
>  drivers/gpu/drm/i2c/tda9950.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i2c/tda9950.c b/drivers/gpu/drm/i2c/tda9950.c
> index 8039fc0d83db4..a5a75bdeb7a5f 100644
> --- a/drivers/gpu/drm/i2c/tda9950.c
> +++ b/drivers/gpu/drm/i2c/tda9950.c
> @@ -420,7 +420,8 @@ static int tda9950_probe(struct i2c_client *client,
>  		priv->hdmi = glue->parent;
>  
>  	priv->adap = cec_allocate_adapter(&tda9950_cec_ops, priv, "tda9950",
> -					  CEC_CAP_DEFAULTS,
> +					  CEC_CAP_DEFAULTS |
> +					  CEC_CAP_CONNECTOR_INFO,
>  					  CEC_MAX_LOG_ADDRS);
>  	if (IS_ERR(priv->adap))
>  		return PTR_ERR(priv->adap);
> @@ -457,13 +458,14 @@ static int tda9950_probe(struct i2c_client *client,
>  	if (ret < 0)
>  		return ret;
>  
> -	priv->notify = cec_notifier_get(priv->hdmi);
> +	priv->notify = cec_notifier_cec_adap_register(priv->hdmi, NULL,
> +						      priv->adap);
>  	if (!priv->notify)
>  		return -ENOMEM;
>  
>  	ret = cec_register_adapter(priv->adap, priv->hdmi);
>  	if (ret < 0) {
> -		cec_notifier_put(priv->notify);
> +		cec_notifier_cec_adap_unregister(priv->notify);
>  		return ret;
>  	}
>  
> @@ -473,8 +475,6 @@ static int tda9950_probe(struct i2c_client *client,
>  	 */
>  	devm_remove_action(dev, tda9950_cec_del, priv);
>  
> -	cec_register_cec_notifier(priv->adap, priv->notify);
> -
>  	return 0;
>  }
>  
> @@ -482,8 +482,8 @@ static int tda9950_remove(struct i2c_client *client)
>  {
>  	struct tda9950_priv *priv = i2c_get_clientdata(client);
>  
> +	cec_notifier_cec_adap_unregister(priv->notify);
>  	cec_unregister_adapter(priv->adap);
> -	cec_notifier_put(priv->notify);

It looks weird to have an unexpectedly different ordering of
unregistration from the registration path - normally, unregistration
is the reverse order of initialisation.

In the initialisation path, it seems that we register the notifier
and _then_ the adapter.  Here, we unregister the notifier and then
the adapter rather than what would normally be expected.  Why is
this?  I suspect there will be drivers created that do this the
"normal" way round, so if this is a requirement, it needs to be made
plainly obvious.

>  
>  	return 0;
>  }
> -- 
> 2.23.0.rc1.153.gdeed80330f-goog
> 
> 

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up