netdev - Re: [PATCH 17/17] ieee802154: no need to check return value of debugfs

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Date:   Tue, 6 Aug 2019 21:22:43 +0200
From:   Stefan Schmidt <stefan@...enfreihafen.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        netdev@...r.kernel.org
Cc:     Michael Hennerich <michael.hennerich@...log.com>,
        Alexander Aring <alex.aring@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Harry Morris <h.morris@...coda.com>, linux-wpan@...r.kernel.org
Subject: Re: [PATCH 17/17] ieee802154: no need to check return value of
 debugfs_create functions

Hello.

On 06.08.19 18:11, Greg Kroah-Hartman wrote:
> When calling debugfs functions, there is no need to ever check the
> return value.  The function can work or not, but the code logic should
> never do something different based on this.
> 
> Cc: Michael Hennerich <michael.hennerich@...log.com>
> Cc: Alexander Aring <alex.aring@...il.com>
> Cc: Stefan Schmidt <stefan@...enfreihafen.org>
> Cc: "David S. Miller" <davem@...emloft.net>
> Cc: Harry Morris <h.morris@...coda.com>
> Cc: linux-wpan@...r.kernel.org
> Cc: netdev@...r.kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> ---
>  drivers/net/ieee802154/adf7242.c   | 12 +++---------
>  drivers/net/ieee802154/at86rf230.c | 20 +++++---------------
>  drivers/net/ieee802154/ca8210.c    |  9 +--------
>  3 files changed, 9 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/net/ieee802154/adf7242.c b/drivers/net/ieee802154/adf7242.c
> index c9392d70e639..7b95add2235a 100644
> --- a/drivers/net/ieee802154/adf7242.c
> +++ b/drivers/net/ieee802154/adf7242.c
> @@ -1158,7 +1158,7 @@ static int adf7242_stats_show(struct seq_file *file, void *offset)
>  	return 0;
>  }
>  
> -static int adf7242_debugfs_init(struct adf7242_local *lp)
> +static void adf7242_debugfs_init(struct adf7242_local *lp)
>  {
>  	char debugfs_dir_name[DNAME_INLINE_LEN + 1] = "adf7242-";
>  	struct dentry *stats;

A quick look over the code indicates that the stats variable can go as
well now as it is only used in the now removed code.

> @@ -1166,15 +1166,9 @@ static int adf7242_debugfs_init(struct adf7242_local *lp)
>  	strncat(debugfs_dir_name, dev_name(&lp->spi->dev), DNAME_INLINE_LEN);
>  
>  	lp->debugfs_root = debugfs_create_dir(debugfs_dir_name, NULL);
> -	if (IS_ERR_OR_NULL(lp->debugfs_root))
> -		return PTR_ERR_OR_ZERO(lp->debugfs_root);
>  
> -	stats = debugfs_create_devm_seqfile(&lp->spi->dev, "status",
> -					    lp->debugfs_root,
> -					    adf7242_stats_show);
> -	return PTR_ERR_OR_ZERO(stats);
> -
> -	return 0;
> +	debugfs_create_devm_seqfile(&lp->spi->dev, "status", lp->debugfs_root,
> +				    adf7242_stats_show);
>  }
>  
>  static const s32 adf7242_powers[] = {
> diff --git a/drivers/net/ieee802154/at86rf230.c b/drivers/net/ieee802154/at86rf230.c
> index 595cf7e2a651..7d67f41387f5 100644
> --- a/drivers/net/ieee802154/at86rf230.c
> +++ b/drivers/net/ieee802154/at86rf230.c
> @@ -1626,24 +1626,16 @@ static int at86rf230_stats_show(struct seq_file *file, void *offset)
>  }
>  DEFINE_SHOW_ATTRIBUTE(at86rf230_stats);
>  
> -static int at86rf230_debugfs_init(struct at86rf230_local *lp)
> +static void at86rf230_debugfs_init(struct at86rf230_local *lp)
>  {
>  	char debugfs_dir_name[DNAME_INLINE_LEN + 1] = "at86rf230-";
> -	struct dentry *stats;
>  
>  	strncat(debugfs_dir_name, dev_name(&lp->spi->dev), DNAME_INLINE_LEN);
>  
>  	at86rf230_debugfs_root = debugfs_create_dir(debugfs_dir_name, NULL);
> -	if (!at86rf230_debugfs_root)
> -		return -ENOMEM;
> -
> -	stats = debugfs_create_file("trac_stats", 0444,
> -				    at86rf230_debugfs_root, lp,
> -				    &at86rf230_stats_fops);
> -	if (!stats)
> -		return -ENOMEM;
>  
> -	return 0;
> +	debugfs_create_file("trac_stats", 0444, at86rf230_debugfs_root, lp,
> +			    &at86rf230_stats_fops);
>  }
>  
>  static void at86rf230_debugfs_remove(void)
> @@ -1651,7 +1643,7 @@ static void at86rf230_debugfs_remove(void)
>  	debugfs_remove_recursive(at86rf230_debugfs_root);
>  }
>  #else
> -static int at86rf230_debugfs_init(struct at86rf230_local *lp) { return 0; }
> +static void at86rf230_debugfs_init(struct at86rf230_local *lp) { }
>  static void at86rf230_debugfs_remove(void) { }
>  #endif
>  
> @@ -1751,9 +1743,7 @@ static int at86rf230_probe(struct spi_device *spi)
>  	/* going into sleep by default */
>  	at86rf230_sleep(lp);
>  
> -	rc = at86rf230_debugfs_init(lp);
> -	if (rc)
> -		goto free_dev;
> +	at86rf230_debugfs_init(lp);
>  
>  	rc = ieee802154_register_hw(lp->hw);
>  	if (rc)
> diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
> index b188fce3f641..11402dc347db 100644
> --- a/drivers/net/ieee802154/ca8210.c
> +++ b/drivers/net/ieee802154/ca8210.c
> @@ -3019,14 +3019,7 @@ static int ca8210_test_interface_init(struct ca8210_priv *priv)
>  		priv,
>  		&test_int_fops
>  	);
> -	if (IS_ERR(test->ca8210_dfs_spi_int)) {
> -		dev_err(
> -			&priv->spi->dev,
> -			"Error %ld when creating debugfs node\n",
> -			PTR_ERR(test->ca8210_dfs_spi_int)
> -		);
> -		return PTR_ERR(test->ca8210_dfs_spi_int);
> -	}
> +
>  	debugfs_create_symlink("ca8210", NULL, node_name);
>  	init_waitqueue_head(&test->readq);
>  	return kfifo_alloc(
> 

With a fix for the above included you can have my


Acked-by: Stefan Schmidt <stefan@...enfreihafen.org>

for version 2.

regards
Stefan Schmidt