Date:   Wed, 24 Nov 2021 14:27:51 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     cgel.zte@gmail.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, chiminghao <chi.minghao@zte.com.cn>,
        Zeal Robot <zealci@zte.com.cn>
Subject: Re: [PATCH] mm: Use BUG_ON instead of if condition followed by BUG
Message-Id: <20211124142751.e48cdcc3aea9e0ef899f4347@linux-foundation.org>
In-Reply-To: <YZ483gwnwTysPt0G@casper.infradead.org>
References: <20211124030849.34998-1-chi.minghao@zte.com.cn>
        <YZ483gwnwTysPt0G@casper.infradead.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Wed, 24 Nov 2021 13:23:42 +0000 Matthew Wilcox <willy@infradead.org> wrote:

> On Wed, Nov 24, 2021 at 03:08:49AM +0000, cgel.zte@gmail.com wrote:
> > From: chiminghao <chi.minghao@zte.com.cn>
> > 
> > Fix the following coccinelle report:
> > ./mm/memory_hotplug.c:2210:2-5:
> > WARNING  Use BUG_ON instead of if condition followed by BUG.
> 
> What coccinelle script is reporting this?
> 
> > -	if (try_remove_memory(start, size))
> > -		BUG();
> > +	BUG_ON(try_remove_memory(start, size));
> 
> I really, really, really do not like this.  For functions with
> side-effects, this is bad style.  If it's a pure predicate, then
> sure, but this is bad.

I don't like it either.  Yes, BUG() is special but it's such dangerous
practice.  I'd vote to change coccinelle.