From: Chen Gang <gang.chen@asianux.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: [PATCH v3] kernel/itimer.c: remove the checking 'value' statement
Date: Fri, 21 Jun 2013 18:31:17 +0800 [thread overview]
Message-ID: <51C42B75.7040204@asianux.com> (raw)
In-Reply-To: <51C3B4B4.90603@asianux.com>
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@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;
}
--
1.7.7.6
next prev parent reply other threads:[~2013-06-21 10:32 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
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 ` Chen Gang [this message]
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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