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[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>
This commit is contained in:
Jesper Juhl 2005-09-06 15:17:37 -07:00 committed by Linus Torvalds
parent 5acd57936c
commit 0730ded5be
1 changed files with 2 additions and 4 deletions
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6
kernel/sys.c
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@ -1711,7 +1711,6 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5) unsigned long arg4, unsigned long arg5)
{ {
long error; long error;
int sig;
error = security_task_prctl(option, arg2, arg3, arg4, arg5); error = security_task_prctl(option, arg2, arg3, arg4, arg5);
if (error) if (error)
@ -1719,12 +1718,11 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
switch (option) { switch (option) {
case PR_SET_PDEATHSIG: case PR_SET_PDEATHSIG:
sig = arg2; if (!valid_signal(arg2)) {
if (!valid_signal(sig)) {
error = -EINVAL; error = -EINVAL;
break; break;
} }
current->pdeath_signal = sig; current->pdeath_signal = arg2;
break; break;
case PR_GET_PDEATHSIG: case PR_GET_PDEATHSIG:
error = put_user(current->pdeath_signal, (int __user *)arg2); error = put_user(current->pdeath_signal, (int __user *)arg2);