linux-kernel - Re: [PATCH 1/2] memblock: add assertion for zero allocation size

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Date:	Fri, 22 Feb 2013 01:13:53 +0530
From:	Vineet Gupta <Vineet.Gupta1@...opsys.com>
To:	Tejun Heo <tj@...nel.org>
CC:	Yinghai Lu <yinghai@...nel.org>, "H. Peter Anvin" <hpa@...or.com>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	Chris Zankel <chris@...kel.net>,
	"Max Filippov" <jcmvbkbc@...il.com>,
	Marc Gauthier <marc@...silica.com>,
	Wanpeng Li <liwanp@...ux.vnet.ibm.com>,
	Ingo Molnar <mingo@...nel.org>, <linux-mm@...ck.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] memblock: add assertion for zero allocation size

On Friday 22 February 2013 01:06 AM, Tejun Heo wrote:
> On Fri, Feb 22, 2013 at 01:03:41AM +0530, Vineet Gupta wrote:
>> Where - you mean if user passes 0, just make it 1. Nah - it's better to complain
>> and get the call site fixed !
>>
>>> or BUG_ON(!align) instead?
>> That could be done too but you would also need BUG_ON(!size) - to catch another
>> API abuse.
>> BUG_ON(!size) however catches both the cases.
> How about "if (WARN_ON(!align)) align = __alignof__(long long);"?
> Early BUG_ON()s can be painful to debug depending on setup.

Totally agree - been there - seen that :-)
Also for caller passing zero, the panic will force the caller to fix it.
I'll respin the patch.

Thx,
-Vineet

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