From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965400Ab3FUKcN (ORCPT ); Fri, 21 Jun 2013 06:32:13 -0400 Received: from intranet.asianux.com ([58.214.24.6]:17825 "EHLO intranet.asianux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752119Ab3FUKcM (ORCPT ); Fri, 21 Jun 2013 06:32:12 -0400 X-Spam-Score: -100.8 Message-ID: <51C42B75.7040204@asianux.com> Date: Fri, 21 Jun 2013 18:31:17 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Thomas Gleixner CC: "linux-kernel@vger.kernel.org" Subject: [PATCH v3] kernel/itimer.c: remove the checking 'value' statement References: <51C2E6F9.80107@asianux.com> <51C3B4B4.90603@asianux.com> In-Reply-To: <51C3B4B4.90603@asianux.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since copy_to_user() will process "bad address" internally, we need not check 'value' again, then can save one comparing instruction at least. For some embedded system with NOMMU, 'NULL' may not mean "bad address" (EFAULT), so recommend to let copy_to_user() to check 'EFAULT' in this case, completely. Removing the checking code, also can let it simpler and clearer to readers. Signed-off-by: Chen Gang --- 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; } -- 1.7.7.6