Re: [PATCH 1/5] sound: SoC: sof: no need to check return value of debugfs_create functions

[Mark Brown <broonie@kernel.org>]

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On Fri, Jun 14, 2019 at 11:47:52AM +0200, 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.

> +++ b/sound/soc/sof/debug.c
> @@ -77,8 +77,7 @@ static ssize_t sof_dfsentry_read(struct file *file, char __user *buffer,
>  		if (!pm_runtime_active(sdev->dev) &&
>  		    dfse->access_type == SOF_DEBUGFS_ACCESS_D0_ONLY) {
>  			dev_err(sdev->dev,
> -				"error: debugfs entry %s cannot be read in DSP D3\n",
> -				dfse->dfsentry->d_name.name);
> +				"error: debugfs entry cannot be read in DSP D3\n");
>  			kfree(buf);
>  			return -EINVAL;
>  		}

This appears to be an unrelated change with no description in the
changelog, please split it out into a separate change with a description
of the change.

> @@ -119,13 +119,8 @@ static int trace_debugfs_create(struct snd_sof_dev *sdev)
>  	dfse->size = sdev->dmatb.bytes;
>  	dfse->sdev = sdev;
>  
> -	dfse->dfsentry = debugfs_create_file("trace", 0444, sdev->debugfs_root,
> -					     dfse, &sof_dfs_trace_fops);
> -	if (!dfse->dfsentry) {
> -		/* can't rely on debugfs, only log error and keep going */
> -		dev_err(sdev->dev,
> -			"error: cannot create debugfs entry for trace\n");
> -	}
> +	debugfs_create_file("trace", 0444, sdev->debugfs_root, dfse,
> +			    &sof_dfs_trace_fops);

I might be missing something but I can't see any error logging in
debugfs_create_file() so this isn't equivalent (though the current code
is broken, it should be using IS_ERR()).  Logging creation failures is
helpful to developers trying to figure out what happened to the trace
files they're trying to use.

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