[lustre-devel] [PATCH 01/12] staging: lustre: fid: Use !x to check for kzalloc failure

Simmons, James A. simmonsja at ornl.gov
Wed Jun 24 13:14:04 PDT 2015

>> Yes.  I know Al's thoughts and kernel style.
>> But Alan Cox and Andreas have both said they think (x == NULL) can help
>> you avoid some kind of boolean vs pointer bugs.  I've had co-workers who
>> did massive seds changing !foo to foo == NULL on our code base.  But
>> I've never seen a real life example of a bug this fixes.
>> To be honest, I've never seen a real life proof that (!foo) code is less
>> buggy.  I should look through the kbuild mailbox...  Hm...  But my other
>> idea of setting up code style readability testing website is also a good
>> one.
>> Linux kernel style is based on Joe Perches finding that 80% of the code
>> prefers one way or the other.  That's a valid method for determining
>> code style.  I bet it normally picks the more readable style but it
>> would be interesting to measure it more formally.
>On today's linux-next, I find 3218 tests on the result of kmalloc etc
>using NULL and 14429 without, making 82% without.  The complete semantic
>patch is shown below.

Most people doing something a certain way is not a technical argument. Usually
people do what they are taught. From most people's comments their seems to 
be no technical reason to us one over another. I do have one technical reason not
to accept these patches. It is too easy to make a mistake and break things very badly.
I don't think it is worth the risk for a non-hard requirement.

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