[PATCH] system_state splitup

Split the system_state state `SYSTEM_SHUTDOWN' into SYSTEM_HALT,
SYSTEM_POWER_OFF and SYSTEM_RESTART and export system_state to modules.

This allows driver shutdown routines to know why they are being shutdown.  The
IDE subsystem wants this so that it knows to not spin the disks down across a
reboot.

include/linux/kernel.h

@@ -109,14 +109,17 @@ static inline void console_verbose(void)
 extern void bust_spinlocks(int yes);
 extern int oops_in_progress;		/* If set, an oops, panic(), BUG() or die() is in progress */
 extern int panic_on_oops;
-extern int system_state;		/* See values below */
 extern int tainted;
 extern const char *print_tainted(void);
 
 /* Values used for system_state */
-#define SYSTEM_BOOTING 0
-#define SYSTEM_RUNNING 1
-#define SYSTEM_SHUTDOWN 2
+extern enum system_states {
+	SYSTEM_BOOTING,
+	SYSTEM_RUNNING,
+	SYSTEM_HALT,
+	SYSTEM_POWER_OFF,
+	SYSTEM_RESTART,
+} system_state;
 
 #define TAINT_PROPRIETARY_MODULE	(1<<0)
 #define TAINT_FORCED_MODULE		(1<<1)

init/main.c

@@ -95,7 +95,8 @@ extern void prepare_namespace(void);
 extern void tc_init(void);
 #endif
 
-int system_state;	/* SYSTEM_BOOTING/RUNNING/SHUTDOWN */
+enum system_states system_state;
+EXPORT_SYMBOL(system_state);
 
 /*
  * Boot command-line arguments

kernel/sys.c

@@ -451,7 +451,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user
 	switch (cmd) {
 	case LINUX_REBOOT_CMD_RESTART:
 		notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
-		system_state = SYSTEM_SHUTDOWN;
+		system_state = SYSTEM_RESTART;
 		device_shutdown();
 		printk(KERN_EMERG "Restarting system.\n");
 		machine_restart(NULL);
@@ -467,7 +467,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user
 
 	case LINUX_REBOOT_CMD_HALT:
 		notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
-		system_state = SYSTEM_SHUTDOWN;
+		system_state = SYSTEM_HALT;
 		device_shutdown();
 		printk(KERN_EMERG "System halted.\n");
 		machine_halt();
@@ -477,7 +477,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user
 
 	case LINUX_REBOOT_CMD_POWER_OFF:
 		notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
-		system_state = SYSTEM_SHUTDOWN;
+		system_state = SYSTEM_POWER_OFF;
 		device_shutdown();
 		printk(KERN_EMERG "Power down.\n");
 		machine_power_off();
@@ -493,7 +493,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user
 		buffer[sizeof(buffer) - 1] = '\0';
 
 		notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
-		system_state = SYSTEM_SHUTDOWN;
+		system_state = SYSTEM_RESTART;
 		device_shutdown();
 		printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
 		machine_restart(buffer);