public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Li Zefan <lizf@cn.fujitsu.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] tracing/events: clean up for ftrace_set_clr_event()
Date: Fri, 08 May 2009 11:03:28 +0800	[thread overview]
Message-ID: <4A03A100.5020308@cn.fujitsu.com> (raw)
In-Reply-To: <alpine.DEB.2.00.0905072248180.28378@gandalf.stny.rr.com>

>> @@ -500,30 +505,16 @@ system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
>>  	if (ret < 0)
>>  		return ret;
>>  
>> -	switch (val) {
>> -	case 0:
>> -	case 1:
>> -		break;
>> -
>> -	default:
>> +	if (val != 0 && val != 1)
> 
> What about "if (val & ~1UL)"?
> 

I tried it just now:

   text    data     bss     dec     hex filename
   7480     104       8    7592    1da8 kernel/trace/trace_events.o.orig
   text    data     bss     dec     hex filename
   7482     104       8    7594    1daa kernel/trace/trace_events.o

It increased text size by 2 bytes, gcc did a better work. ;)

And it's not so intuitive what's the limit of val.



  reply	other threads:[~2009-05-08  3:06 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-08  2:31 [PATCH 1/2] tracing/events: clean up for ftrace_set_clr_event() Li Zefan
2009-05-08  2:32 ` [PATCH 2/2] tracing/events: simplify system_enable_read() Li Zefan
2009-05-08  2:44   ` Steven Rostedt
2009-05-08 11:03   ` Frederic Weisbecker
2009-05-08 18:27   ` [tip:tracing/core] " tip-bot for Li Zefan
2009-05-08 22:52   ` [PATCH 2/2] " Andrew Morton
2009-05-11 12:40     ` Ingo Molnar
2009-05-08  2:52 ` [PATCH 1/2] tracing/events: clean up for ftrace_set_clr_event() Steven Rostedt
2009-05-08  3:03   ` Li Zefan [this message]
2009-05-08 10:50 ` Frederic Weisbecker
2009-05-08 11:16   ` Li Zefan
2009-05-08 11:27     ` Frederic Weisbecker
2009-05-08 12:05       ` Ingo Molnar
2009-05-08 12:01     ` Steven Rostedt
2009-05-08 11:35   ` Steven Rostedt
2009-05-08 11:47     ` Frederic Weisbecker
2009-05-08 18:27 ` [tip:tracing/core] " tip-bot for Li Zefan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4A03A100.5020308@cn.fujitsu.com \
    --to=lizf@cn.fujitsu.com \
    --cc=fweisbec@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=rostedt@goodmis.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox