Re: [PATCH] arm: mach-tegra: check wether we have debugfs enabled or not

[Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>]

On 10/17/2012 02:12 PM, Russell King - ARM Linux wrote:
> On Wed, Oct 17, 2012 at 03:13:16PM -0400, Devendra Naga wrote:
>> if debugfs is not enabled in kernel it returns -ENODEV, check it
>> with IS_ERR_OR_NULL along with the null return if it fails to
>> create a file in debugfs.
>>
>> Signed-off-by: Devendra Naga <devendra.aaru-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> ---
>>  arch/arm/mach-tegra/powergate.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/mach-tegra/powergate.c b/arch/arm/mach-tegra/powergate.c
>> index de0662d..1809b91d 100644
>> --- a/arch/arm/mach-tegra/powergate.c
>> +++ b/arch/arm/mach-tegra/powergate.c
>> @@ -269,7 +269,7 @@ int __init tegra_powergate_debugfs_init(void)
>>  	if (powergate_name) {
>>  		d = debugfs_create_file("powergate", S_IRUGO, NULL, NULL,
>>  			&powergate_fops);
>> -		if (!d)
>> +		if (IS_ERR_OR_NULL(d))
>>  			return -ENOMEM;
> 
> So, you want to make this function hard-fail if a debugfs error occurs
> _or_ debugfs is not configured?  That doesn't seem to be a clever thing
> to do.

In practice, that quoted chunk of code is inside an #ifdef
CONFIG_DEBUG_FS, so according to the documentation for
debugfs_create_file(), the IS_ERR case of IS_ERR_OR_NULL cannot happen
here. So, the above change is a no-op, so there's not much point
applying it.