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

From: Chris Ball
Date: Tue Jul 17 2012 - 18:50:39 EST

Hi Muthu,

On Mon, Jul 16 2012, Muthu Kumar wrote:
> On Sun, Jul 15, 2012 at 7:46 PM, Chris Ball <cjb@xxxxxxxxxx> wrote:
>> Hi,
>> On Sun, Jul 15 2012, Muthu Kumar wrote:
>>>> 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.
>>> Maya is adding a new sysfs attribute with that patch. So, there should
>>> not be any user space stuff that depends on it.
>> In the later patchset, Maya's "[PATCH v4 1/2] mmc: card: Move MMC
>> specific attributes to mmc sub-directory" moves the existing attributes
>> into the mmc/ directory.
>> It's that move that I'm objecting to, rather than the creation of a new
>> directory -- although since we're going to leave the current attributes
>> where they are, it might not make sense to add the new directory.
>> We'd be creating two places that people have to look for mmc-related
>> attributes, which is arguably less clean than having one place to look
>> even though it's mixed in with the other block device attributes.
> So, what is the plan for fixing the user land tools and cleaning this up?

At the moment I don't have any plan to do that, because the cure
(potentially breaking userland scripts that are writing to some
read/write attributes, by breaking ABI to move everything into a
new directory) seems worse than the disease (having some attributes
in a directory that isn't the ideal one).

I'd be willing to explore something like Venkat's idea if the block
layer maintainers insist, though.

- Chris.
Chris Ball <cjb@xxxxxxxxxx> <>
One Laptop Per Child
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