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Subject[patch 09/28] sys: Remove BKL from sys_reboot
Serialization of sys_reboot can be done local. The BKL is not
protecting anything else.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/sys.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

Index: linux-2.6-tip/kernel/sys.c
===================================================================
--- linux-2.6-tip.orig/kernel/sys.c
+++ linux-2.6-tip/kernel/sys.c
@@ -8,7 +8,6 @@
#include <linux/mm.h>
#include <linux/utsname.h>
#include <linux/mman.h>
-#include <linux/smp_lock.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/prctl.h>
@@ -349,6 +348,9 @@ void kernel_power_off(void)
machine_power_off();
}
EXPORT_SYMBOL_GPL(kernel_power_off);
+
+static DEFINE_MUTEX(reboot_mutex);
+
/*
* Reboot system call: for obvious reasons only root may call it,
* and even root needs to set up some magic numbers in the registers
@@ -381,7 +383,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int
if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
cmd = LINUX_REBOOT_CMD_HALT;

- lock_kernel();
+ mutex_lock(&reboot_mutex);
switch (cmd) {
case LINUX_REBOOT_CMD_RESTART:
kernel_restart(NULL);
@@ -397,20 +399,18 @@ SYSCALL_DEFINE4(reboot, int, magic1, int

case LINUX_REBOOT_CMD_HALT:
kernel_halt();
- unlock_kernel();
do_exit(0);
panic("cannot halt");

case LINUX_REBOOT_CMD_POWER_OFF:
kernel_power_off();
- unlock_kernel();
do_exit(0);
break;

case LINUX_REBOOT_CMD_RESTART2:
if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
- unlock_kernel();
- return -EFAULT;
+ ret = -EFAULT;
+ break;
}
buffer[sizeof(buffer) - 1] = '\0';

@@ -433,7 +433,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int
ret = -EINVAL;
break;
}
- unlock_kernel();
+ mutex_unlock(&reboot_mutex);
return ret;
}




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