Re: [PATCH] mm/mmap: replace if (cond) BUG() with BUG_ON()

[Andrew Morton]

On Tue, 5 Jan 2021 20:28:27 -0800 (PST) Hugh Dickins <hughd@xxxxxxxxxx> wrote:

> Alex, please consider why the authors of these lines (whom you
> did not Cc) chose to write them without BUG_ON(): it has always
> been preferred practice to use BUG_ON() on predicates, but not on
> functionally effective statements (sorry, I've forgotten the proper
> term: I'd say statements with side-effects, but here they are not
> just side-effects: they are their main purpose).
> 
> We prefer not to hide those away inside BUG macros

Should we change that?  I find BUG_ON(something_which_shouldnt_fail())
to be quite natural and readable.

As are things like the existing

BUG_ON(mmap_read_trylock(mm));
BUG_ON(wb_domain_init(&global_wb_domain, GFP_KERNEL));

etc.


No strong opinion here, but is current mostly-practice really
useful?