Jose R. Santos wrote:
> On Tue, 05 Jun 2007 15:26:53 +0200 Laurent Vivier <Laurent.Vivier@xxxxxxxx>
> wrote:
>
>> Dave Kleikamp wrote:
>>> Jose is right. The endian conversion is unnecessary.
>>>
>>> Shaggy
>> But by using le32_to_cpu(es->s_blocks_count_hi) you explicitly mark the
>> variable as a little-endian. So if someone reads the code, he knows this is
>> a little-endian value and this allows to avoid errors if later variable
>> must be tested for other value than 0.
>>
>> For instance, you have :
>>
>> if(es->s_blocks_count_hi)
>>
>> and later the value should be compared to 10, how do you know easily you
>> should use:
>>
>> if (le32_to_cpu(es->s_blocks_count_hi) == 10)
>>
>> instead of
>>
>> if(es->s_blocks_count_hi == 10)
>>
>> I think writing like Mingming asks should allow to avoid errors later.
>>
>> (and code becomes really self-explicit...)
>>
>> Regards, Laurent
>
> Hi Laurent,
>
> In this particular case though, the value of s_blocks_count_hi should not be
> uses on its own. The correct way would be to use ext4_blocks_count() which
> already does the endian conversion. If you think the code could confuse
> people as to how to access the data in s_blocks_count_hi, wouldn't hiding it
> through the use of a macro make more sense than doing an unnecessary endian
> conversion?
>
Yes, I think the code could confuse people, but I don't think defining "Yet
Another Macro" is a good choice (IMHO).
I think we can resolve this (non-)issue by two ways:
- using le32_to_cpu() (but I agree it does an unnecessary endian conversion on
big-endian systems)
- put a comment on the line (but are we allowed to put comments in kernel source
code... ;-) )
Regards
Laurent
--
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