linux-kernel - [PATCH v3] kernel/itimer.c: remove the checking 'value' statement

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Message-ID: <51C42B75.7040204@asianux.com>
Date:	Fri, 21 Jun 2013 18:31:17 +0800
From:	Chen Gang <gang.chen@...anux.com>
To:	Thomas Gleixner <tglx@...utronix.de>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH v3] kernel/itimer.c: remove the checking 'value' statement


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 <gang.chen@...anux.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;
 }
 
-- 
1.7.7.6

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