Re: [PATCH RESEND MERGE REQUEST] mm/damon: move damon_rand() definition into damon.h

From: Andrew Morton
Date: Thu Dec 02 2021 - 18:12:20 EST


On Thu, 2 Dec 2021 15:58:59 +0800 Xin Hao <xhao@xxxxxxxxxxxxxxxxx> wrote:

> damon_rand() is called in three files:damon/core.c, damon/
> paddr.c, damon/vaddr.c, i think there is no need to redefine
> this twice, So move it to damon.h will be a good choice.

Fair enough.

> +/* Get a random number in [l, r) */
> +#define damon_rand(l, r) (l + prandom_u32_max(r - l))

This shouldn't be implemented as a macro, for all the usual reasons
(typechecking, side-effects, ugliness, code-documentation site, etc).

In particular, this expression references `l' twice, so calling

damon_rand(a++, b);

will increment `a' twice, surprise surprise.

Can someone please send a followup patch to convert this (and any
similar damon macros) into (probably static inlined) C functions?