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From: Chen Gang <gang.chen@asianux.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	"'Jiri Kosina'" <trivial@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] kernel/itimer.c: beautify code, not need check 'value', so save one instruction, simpler and easier for readers.
Date: Thu, 20 Jun 2013 20:02:57 +0800	[thread overview]
Message-ID: <51C2EF71.4010308@asianux.com> (raw)
In-Reply-To: <51C2E6F9.80107@asianux.com>


Oh, sorry, maybe it is a trivial patch, also need send to
trivial@kernel.org.


On 06/20/2013 07:26 PM, Chen Gang wrote:
> 
> Since copy_to_user() will check 'value', we do not need check it outside
> again,  so can save one comparing instruction at least.
> 
> Also can let code simpler and easier for readers: if checking parameter
> 'value', it will easily lead readers to think about why not return
> -EINVAL instead of -EFAULT, when checking parameter failed.
> 
> Signed-off-by: Chen Gang <gang.chen@asianux.com>
> ---
>  kernel/itimer.c |   13 ++++++-------
>  1 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/itimer.c b/kernel/itimer.c
> index 8d262b4..3b12271 100644
> --- a/kernel/itimer.c
> +++ b/kernel/itimer.c
> @@ -102,15 +102,14 @@ int do_getitimer(int which, struct itimerval *value)
>  
>  SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
>  {
> -	int error = -EFAULT;
> +	int error;
>  	struct itimerval get_buffer;
>  
> -	if (value) {
> -		error = do_getitimer(which, &get_buffer);
> -		if (!error &&
> -		    copy_to_user(value, &get_buffer, sizeof(get_buffer)))
> -			error = -EFAULT;
> -	}
> +	error = do_getitimer(which, &get_buffer);
> +	if (!error &&
> +	    copy_to_user(value, &get_buffer, sizeof(get_buffer)))
> +		error = -EFAULT;
> +
>  	return error;
>  }
>  
> 


-- 
Chen Gang

Asianux Corporation

  reply	other threads:[~2013-06-20 12:03 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-20 11:26 [PATCH v2] kernel/itimer.c: beautify code, not need check 'value', so save one instruction, simpler and easier for readers Chen Gang
2013-06-20 12:02 ` Chen Gang [this message]
2013-06-20 12:55   ` Thomas Gleixner
2013-06-21  1:24     ` Chen Gang
2013-06-20 13:42 ` Thomas Gleixner
2013-06-21  2:04   ` Chen Gang
2013-06-21 10:31     ` [PATCH v3] kernel/itimer.c: remove the checking 'value' statement Chen Gang
2013-06-24 23:28     ` [PATCH v2] kernel/itimer.c: beautify code, not need check 'value', so save one instruction, simpler and easier for readers.t Thomas Gleixner
2013-06-25  0:58       ` Chen Gang
2013-06-25  1:16         ` [PATH v4] itimers: Remove bogus NULL pointer check in sys_getitimer() Chen Gang
2013-07-05  1:28           ` Chen Gang
2013-07-22  2:45             ` Chen Gang

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