Re: [alsa-devel] [PATCH] ASoC: fix balance of of_node_get()/of_node_put()

[Kuninori Morimoto]

Hi

> On Hikey target board, enabling CONFIG_OF_DYNAMIC triggers several
> errors at kernel boot, like the following one
> OF: ERROR: Bad of_node_put() on /soc/i2s@f7118000/ports/port@0/endpoint
> each followed by stack dump.
> 
> Fixed by:
> - removing of_node_put() in the body of of_for_each_phandle(){},
>   since already provided at each iteration. Add it in case the
>   loop is break out;
> - adding of_node_get() before calling of_graph_get_port_parent()
>   or asoc_graph_card_dai_link_of().
> 
> Tested with kernel v4.13-rc1 with hikey_defconfig taken from
> https://git.linaro.org/people/john.stultz/android-dev.git
> branch dev/hikey-mainline-WIP
> 
> Signed-off-by: Antonio Borneo <borneo.antonio@xxxxxxxxx>
> ---

I got kernel boot error on my board (= Renesas R-Car Salvator-X) + CONFIG_OF_DYNAMIC.
This patch solved this issue.

Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>

> To: Liam Girdwood <lgirdwood@xxxxxxxxx>
> To: Mark Brown <broonie@xxxxxxxxxx>
> To: Jaroslav Kysela <perex@xxxxxxxx>
> To: Takashi Iwai <tiwai@xxxxxxxx>
> To: alsa-devel@xxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: Wei Xu <xuwei5@xxxxxxxxxxxxx>
> Cc: John Stultz <john.stultz@xxxxxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> ---
>  sound/soc/generic/audio-graph-card.c  | 14 +++++++++-----
>  sound/soc/generic/simple-card-utils.c |  5 +++++
>  sound/soc/soc-core.c                  |  5 +++++
>  3 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
> index c0f08a6..7574c5f 100644
> --- a/sound/soc/generic/audio-graph-card.c
> +++ b/sound/soc/generic/audio-graph-card.c
> @@ -228,10 +228,16 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv)
>  	 */
>  
>  	of_for_each_phandle(&it, rc, node, "dais", NULL, 0) {
> +		/*
> +		 * asoc_graph_card_dai_link_of() will call
> +		 * of_node_put(). So, call of_node_get() here
> +		 */
> +		of_node_get(it.node);
>  		ret = asoc_graph_card_dai_link_of(it.node, priv, idx++);
> -		of_node_put(it.node);
> -		if (ret < 0)
> +		if (ret < 0) {
> +			of_node_put(it.node);
>  			return ret;
> +		}
>  	}
>  
>  	return asoc_simple_card_parse_card_name(card, NULL);
> @@ -244,10 +250,8 @@ static int asoc_graph_get_dais_count(struct device *dev)
>  	int count = 0;
>  	int rc;
>  
> -	of_for_each_phandle(&it, rc, node, "dais", NULL, 0) {
> +	of_for_each_phandle(&it, rc, node, "dais", NULL, 0)
>  		count++;
> -		of_node_put(it.node);
> -	}
>  
>  	return count;
>  }
> diff --git a/sound/soc/generic/simple-card-utils.c b/sound/soc/generic/simple-card-utils.c
> index 26d64fa..144954b 100644
> --- a/sound/soc/generic/simple-card-utils.c
> +++ b/sound/soc/generic/simple-card-utils.c
> @@ -250,6 +250,11 @@ static int asoc_simple_card_get_dai_id(struct device_node *ep)
>  	if (ret != -ENOTSUPP)
>  		return ret;
>  
> +	/*
> +	 * of_graph_get_port_parent() will call
> +	 * of_node_put(). So, call of_node_get() here
> +	 */
> +	of_node_get(ep);
>  	node = of_graph_get_port_parent(ep);
>  
>  	/*
> diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
> index 921622a..a0f39de 100644
> --- a/sound/soc/soc-core.c
> +++ b/sound/soc/soc-core.c
> @@ -4087,6 +4087,11 @@ int snd_soc_get_dai_id(struct device_node *ep)
>  	struct device_node *node;
>  	int ret;
>  
> +	/*
> +	 * of_graph_get_port_parent() will call
> +	 * of_node_put(). So, call of_node_get() here
> +	 */
> +	of_node_get(ep);
>  	node = of_graph_get_port_parent(ep);
>  
>  	/*
> -- 
> 1.9.1
> 
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