sys: Remove BKL from sys_reboot

Serialization of sys_reboot can be done local. The BKL is not
protecting anything else.

LKML-Reference: <20091010153349.405590702@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 7 insertions, 7 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index 255475d163e0..22ea9553c3bc 100644
--- a/kernel/sys.c
+++ b/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, magic2, unsigned int, cmd,
         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, magic2, unsigned int, cmd,
 
         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, magic2, unsigned int, cmd,
                 ret = -EINVAL;
                 break;
         }
-        unlock_kernel();
+        mutex_unlock(&reboot_mutex);
         return ret;
 }