From: Jesper Juhl <jesper.juhl@gmail.com>
Date: Tue, 6 Sep 2005 22:17:37 +0000 (-0700)
Subject: [PATCH] remove a redundant variable in sys_prctl()
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=0730ded5be28653675ed314fdd878b8db5f88aa4;p=openwrt%2Fstaging%2Fblogic.git

[PATCH] remove a redundant variable in sys_prctl()

The patch removes a redundant variable `sig' from sys_prctl().

For some reason, when sys_prctl is called with option == PR_SET_PDEATHSIG
then the value of arg2 is assigned to an int variable named sig.  Then sig
is tested with valid_signal() and later used to set the value of
current->pdeath_signal .

There is no reason to use this intermediate variable since valid_signal()
takes a unsigned long argument, so it can handle being passed arg2
directly, and if the call to valid_signal is OK, then we know the value of
arg2 is in the range zero to _NSIG and thus it'll easily fit in a plain int
and thus there's no problem assigning it later to current->pdeath_signal
(which is an int).

The patch gets rid of the pointless variable `sig'.
This reduces the size of kernel/sys.o in 2.6.13-rc6-mm1 by 32 bytes on my
system.

Patch has been compile tested, boot tested, and just to make damn sure I
didn't break anything I wrote a quick test app that calls
prctl(PR_SET_PDEATHSIG ...) with the entire range of values for a
unsigned long, and it behaves as expected with and without the patch.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/kernel/sys.c b/kernel/sys.c
index 0bcaed6560ac..c80412be2302 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1711,7 +1711,6 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
 			  unsigned long arg4, unsigned long arg5)
 {
 	long error;
-	int sig;
 
 	error = security_task_prctl(option, arg2, arg3, arg4, arg5);
 	if (error)
@@ -1719,12 +1718,11 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
 
 	switch (option) {
 		case PR_SET_PDEATHSIG:
-			sig = arg2;
-			if (!valid_signal(sig)) {
+			if (!valid_signal(arg2)) {
 				error = -EINVAL;
 				break;
 			}
-			current->pdeath_signal = sig;
+			current->pdeath_signal = arg2;
 			break;
 		case PR_GET_PDEATHSIG:
 			error = put_user(current->pdeath_signal, (int __user *)arg2);