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Date:   Thu, 2 Dec 2021 15:12:13 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Xin Hao <xhao@linux.alibaba.com>
Cc:     sj@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND MERGE REQUEST] mm/damon: move damon_rand()
 definition into damon.h
Message-Id: <20211202151213.6ec830863342220da4141bc5@linux-foundation.org>
In-Reply-To: <20211202075859.51341-1-xhao@linux.alibaba.com>
References: <20211202075859.51341-1-xhao@linux.alibaba.com>
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On Thu,  2 Dec 2021 15:58:59 +0800 Xin Hao <xhao@linux.alibaba.com> 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?