Re: [RFC PATCH] mmc: support background operation

[J Freyensee <james_p_freyensee@linux.intel.com>]

On 08/17/2011 07:11 PM, Jaehoon Chung wrote:
> Hi Jay..
>
> I didn't know the tool 'sparse'. i will check the tool for your advice.
> Thank you a lot for your help.. :)

here, I'll provide it from a write-up I did within my department. 
Unfortunately, finding documentation how to use it is pretty hard 
because very little is provided.

-------------------------------------------------
Step 9 in SubmitChecklist documentation in preparing to submit a device 
driver upstream to Linus's kernel is:

9: Check cleanly with sparse.

Sparse is a tool written by Linus that contains built-in checks
for known problematic and a set of annotations in the Linux kernel
designed to convey semantic information about types, such as what
address space pointers point to, or what locks a function acquires or
releases.  It does appear to be a useful tool to make your code that
much more tight.

The #1 problem with this tool is there is little documentation how to 
use it.  I think I figured it out how to use it, basic-wise,
with the help of searching on-line forums.

To set up and use for the first time:
1. git clone git://git.kernel.org/pub/scm/devel/sparse/sparse.git
2. cd to the sparse directory
3. make; sudo make install
4. cd to your linux kernel
5. 'make C=1 >& sparse.log' if you have not built your kernel,
OR
'make C=2 >& sparse.log' if you have already built your kernel

I HIGHLY recommend the file redirection operator because a LOT OF STUFF
GETS SPIT OUT.

6. To use other macros, do something like:

make C=1 CF=
example:
make C=2 CF="-D__CHECK_ENDIAN__" (to check endianess)

Further info:
http://en.wikipedia.org/wiki/Sparse
-------------------------------------------------

>
>> Unfortunately, I am still a little new to this area of the Linux kernel
>> so I don't quite have the background to give an intelligent answer
>> w/respect to eMMC 4.41 and BKOPS.  I just have 3 device driver accepts
>> in the TTY space, so my contributions to patches are mainly basic code
>> functionality and Linux kernel/device-driver gotchas.
>>
>> Do you know the tool 'sparse'?  It's a good thing to try once, before
>> submitting upstream, if you haven't done it.
>>
>>>
>>> Regards,
>>> Jaehoon Chung
>>>
>>>
>>>
>>
>>
>


-- 
J (James/Jay) Freyensee
Storage Technology Group
Intel Corporation