Re: [PATCH v2 1/1] mmc: block: Add write packing control

[Chris Ball <cjb@laptop.org>]

Hi,

On Wed, Jun 13 2012, Muthu Kumar wrote:
> On Wed, Jun 13, 2012 at 12:52 PM,  <merez@codeaurora.org> wrote:
>>
>> On Mon, June 11, 2012 5:28 pm, Muthu Kumar wrote:
>>> On Mon, Jun 11, 2012 at 2:19 PM, Muthu Kumar <muthu.lkml@gmail.com> wrote:
>>>> On Fri, Jun 1, 2012 at 11:55 AM, Maya Erez <merez@codeaurora.org> wrote:
>>>>> trigger
>>>>> the packing can be configured via sysfs by writing the required value
>>>>> to:
>>>>> /sys/block/<block_dev_name>/num_wr_reqs_to_start_packing.
>>>>> The trigger for disabling the write packing is fetching a read request.
>>>>>
>>>>
>>>> If it is applicable only to MMC why do we have this sysfs attr for all
>>>> block devices?
>>>
>>> Just to be clear, please create a directory, say mmc, under
>>> /sys/block/<dev>/ and create the attr inside that.
>>>
>>> You can refer to dm (dm-sysfs.c) for sample implementation.
>> I understand why you think it would be best to distinguish the MMC
>> specific attribute from the general block devices attributes.
>> However, since this attribute is created only for the MMC block device,
>> other block devices won't be aware of it.
>
> I understand its created by the MMC code so will not be there for
> other block devices. But having the device specific attributes inside
> one <device> directory is better/cleaner. And since we are already
> following that model for other devices, why not follow that for MMC
> also?

I've already replied to a later version of the patch, but just to get
this comment in at the appropriate point of the discussion as well:

Even though it would result in a cleaner sysfs, I don't want to do
this now because it will break userspace scripts that are depending
on the current locations of these attributes.

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child