linux-kernel - Re: Re: [PATCH v6 1/8] x86: allow to handle errors in text

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Date:	Wed, 22 Jan 2014 09:52:03 +0900
From:	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Petr Mladek <pmladek@...e.cz>,
	Frederic Weisbecker <fweisbec@...il.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Jiri Kosina <jkosina@...e.cz>, linux-kernel@...r.kernel.org,
	x86@...nel.org
Subject: Re: Re: [PATCH v6 1/8] x86: allow to handle errors in text_poke
 function family

(2014/01/21 23:02), Steven Rostedt wrote:
> On Tue, 21 Jan 2014 14:00:37 +0100
> Petr Mladek <pmladek@...e.cz> wrote:
> 
>>>> There are some situations where it is hard to recover from an error. Masami
>>>> Hiramatsu <masami.hiramatsu.pt@...achi.com> suggested to create
>>>> text_poke*_or_die() variants for this purpose.
>>>
>>> I don't like the "_or_die()". Although I don't care much about it, I'm
>>> thinking the x86 maintainers might not like it either.
>>>
>>> What about just doing the test in the places that would call "or_die"?
>>>
>>> 	ret = text_poke*();
>>> 	BUG_ON(ret);
>>
>> Exactly this solution has been used in v5 of this patch set, see 
>> https://lkml.org/lkml/2013/12/3/258
>>
>> Masami suggested to use the "or_die()" because BUG_ON() was used on most
>> locations, see https://lkml.org/lkml/2013/12/6/1107
> 
> If BUG_ON() is used in most locations, then we can make text_poke()
> default to bug, and the just have a text_poke_safe() function that does
> not bug. Or some similar name.

Unfortunately, since still there is BUG_ON() in text_poke() when
we failed to modify text, I think text_poke_safe() is not a good
name too.

> The "_die" has a bad taste in several developers mouth ;-)

What about using text_poke() for BUG_ON and __text_poke()
for returning an error ? This may not change caller sites.

Thank you,

-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@...achi.com


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