Re: [PATCH] percpu: explain quick paths in pcpu_[de]populate_chunk()

[Cong Wang]

Tejun Heo wrote:
> pcpu_[de]populate_chunk() check whether there's actually any work to
> do at the beginning and exit early if not.  This checking is done by
> seeing whether the first iteration of pcpu_for_each_[un]pop_region()
> covers the whole requested region.  The resulting code is a bit
> unusual in that it's loop-like but never loops which apparently
> confuses people.  Add comments to explain it.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Reported-by: Amerigo Wang <amwang@xxxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
> ---
> Added to percpu#for-next.  This should be clear enough, right?

Nope, comments can never fix bad code.

Since these two break statements are intentional, why not use if?
Logically, the following two are equalent.

for(a1; a2; a3){
    if (a4)
       return;
    break;
}


a1;
if (a2) {
   if (a4)
       return;
}


And the latter is much more readable than the former.
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