Re: [PATCH v2 2/3] mm/memory_hotplug: Drop mem_blk check from unregister_mem_sect_under_nodes

David Hildenbrand
2018-08-14T10:09:22Z

On 14.08.2018 12:06, Oscar Salvador wrote:
> On Tue, Aug 14, 2018 at 11:44:50AM +0200, David Hildenbrand wrote:
>>
>> Yes I know, as I said, if it would be local to a file I would not care.
>> Making this functions never return an error is nice, though (and as you
>> noted, the return value is never checked).
>>
>> I am a friend of stating which conditions a function expects to hold if
>> a function can be called from other parts of the system. Usually I
>> prefer to use BUG_ONs for that (whoever decides to call it can directly
>> see what he as to check before calling) or comments. But comments tend
>> to become obsolete.
>
> Uhm, I think a BUG_ON is too much here.
> We could replace the check with a WARN_ON, just in case
> a new function decides to call unregister_mem_sect_under_nodes() in the future.
>
> Something like:
>
> WARN_ON(!mem_blk)
> return;
>
> In that case, we should get a nice splat in the logs that should tell us
> who is calling it with an invalid mem_blk.
>

Whatever you think is best. I have no idea what the general rules in MM
code are. Maybe dropping this check is totally fine.

--

Thanks,

David / dhildenb