Re: [PATCH] debugfs: New debugfs interface for creation of files,directory and symlinks

From: Sasikanth babu
Date: Wed May 02 2012 - 17:58:14 EST


On Wed, May 2, 2012 at 9:01 PM, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, May 02, 2012 at 06:20:54PM +0530, Sasikantha babu wrote:
>> As we know the current debugfs file or directory or symlink creation
>> doesn't return proper error codes to the caller on failure. Because
>> of this caller and user could not able to find the exact reason of
>> the failure.
>
> And what is the problem with this?  Either the file is created or not,
> you really shouldn't care anymore than that.  It's not like you are
> going to retry the creation, or are you?
>
> Who really cares if the file is failed to be created?

In most of cases I had observed caller of debufs_create_file or
debufs_create_dir always returns -ENOMEM on failure, which is not true.
I felt returning proper error code will help in figuring out the actual
reason of the failure (for eg: it can be -EEXISTS based on the error
caller can change the name of the file or dir)

>
>> As Andrew Morton suggested (http://www.spinics.net/lists/linux-mm/msg33617.html)
>> introduced new debugfs interface to create debugfs entries. Newer APIs
>> returns proper error codes(ERR_PTR) on failure.
>
> Again, why?  What root problem are you trying to solve here?

The usage of debugfs throughout the kernel is not uniform especially the
error handling scenarios. Some place it is IS_ERR validations , other place
against NULL and some place ignoring the return value. Just tried to make it
uniform.
>
> thanks,
>
> greg k-h
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