Re: [patch] usb: gadget: gr_udc: debugfs functions return NULL on error

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Jan 09, 2014 at 08:39:37AM +0300, Dan Carpenter wrote:
> Debugfs functions return NULL on error.  They return an ERR_PTR if you
> don't have debugfs configured.
> 
> The way it's designed is that normally you are only supposed to test for
> NULL.  In this code, if "dev->dfs_root" is an ERR_PTR then passing it to
> debugfs_create_file() will not cause a problem because
> debugfs_create_file() would also just a stub.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/usb/gadget/gr_udc.c b/drivers/usb/gadget/gr_udc.c
> index 5f9c65959dd2..b34a52171568 100644
> --- a/drivers/usb/gadget/gr_udc.c
> +++ b/drivers/usb/gadget/gr_udc.c
> @@ -226,13 +226,13 @@ static void gr_dfs_create(struct gr_udc *dev)
>  	const char *name = "gr_udc_state";
>  
>  	dev->dfs_root = debugfs_create_dir(dev_name(dev->dev), NULL);
> -	if (IS_ERR(dev->dfs_root)) {
> +	if (!dev->dfs_root) {
>  		dev_err(dev->dev, "Failed to create debugfs directory\n");
>  		return;
>  	}
>  	dev->dfs_state = debugfs_create_file(name, 0444, dev->dfs_root,
>  					     dev, &gr_dfs_fops);
> -	if (IS_ERR(dev->dfs_state))
> +	if (!dev->dfs_state)
>  		dev_err(dev->dev, "Failed to create debugfs file %s\n", name);
>  }

Don't even check the return value of the calls, I don't think it
matters, right?

greg k-h