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

Oscar Salvador
2018-08-14T10:06:49Z

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.

--
Oscar Salvador
SUSE L3