Re: [PATCHv6 3/3] mmc_test: collect data and show it via sysfs by demand

[Greg KH <greg@kroah.com>]

On Tue, Sep 07, 2010 at 11:58:43PM +0100, Chris Ball wrote:
> On Tue, Sep 07, 2010 at 03:27:53PM -0700, Andrew Morton wrote:
> > So what we end up with is extremely thin.  Something about adding
> > something to sysfs.
> > 
> > This is not enough!  You're proposing an addition to the kernel->user
> > ABI.  Please fully describe this interface so that we can understand
> > and review it.  What are the names of these sysfs files?  What do they
> > do?  Provide us with example output in the changelog so we can see for
> > ourselves.
> 
> Hoping Andy doesn't mind me jumping in, here's an attempt at a better
> changelog:
> 
> ---
> 
> Prior to this patch, the "test" file under each card's sysfs node was
> write-only, and results were obtained by looking at dmesg.  This patch
> improves programmatic access to the test results, making them available
> by reading back from the same "test" file:
> 
> [root@host mmc0:e624]# echo 6 > test
> [root@host mmc0:e624]# cat test
> Test 6: 2

Ick, no.

Why is this in sysfs at all anyway?

Why not put it in debugfs?

And for every sysfs file, you need to have a Documenation/ABI/ entry.

Remember, sysfs is "one value per file".  Does that work with this file?
At first glance, it doesn't look like it.

Please use debugfs instead.

thanks,

greg k-h