Commit 7a54f46b authored by Joel Stanley's avatar Joel Stanley Committed by Linus Torvalds
Browse files

kernel/reboot.c: add orderly_reboot for graceful reboot 



The kernel has orderly_poweroff which allows the kernel to initiate a
graceful shutdown of userspace, by running /sbin/poweroff.  This adds
orderly_reboot that will cause userspace to shut itself down by calling
/sbin/reboot.

This will be used for shutdown initiated by a system controller on
platforms that do not use ACPI.

orderly_reboot() should be used when the system wants to allow userspace
to gracefully shut itself down.  For cases where the system may imminently
catch on fire, the existing emergency_restart() provides an immediate
reboot without involving userspace.

Signed-off-by: default avatarJoel Stanley <joel@jms.id.au>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7975a9b7

include/linux/reboot.h

+2 −1
Original line number Diff line number Diff line
@@ -70,7 +70,8 @@ void ctrl_alt_del(void); 
#define POWEROFF_CMD_PATH_LEN	256

extern char poweroff_cmd[POWEROFF_CMD_PATH_LEN];



extern int orderly_poweroff(bool force);

extern void orderly_poweroff(bool force);

extern void orderly_reboot(void);



/*

 * Emergency restart, callable from an interrupt handler.

kernel/reboot.c

+48 −5
Original line number Diff line number Diff line
@@ -387,8 +387,9 @@ void ctrl_alt_del(void) 
}



char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";

static const char reboot_cmd[] = "/sbin/reboot";



static int __orderly_poweroff(bool force)

static int run_cmd(const char *cmd)

{

	char **argv;

	static char *envp[] = {
@@ -397,8 +398,7 @@ static int __orderly_poweroff(bool force) 
		NULL

	};

	int ret;



	argv = argv_split(GFP_KERNEL, poweroff_cmd, NULL);

	argv = argv_split(GFP_KERNEL, cmd, NULL);

	if (argv) {

		ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);

		argv_free(argv);
@@ -406,8 +406,33 @@ static int __orderly_poweroff(bool force) 
		ret = -ENOMEM;

	}



	return ret;

}



static int __orderly_reboot(void)

{

	int ret;



	ret = run_cmd(reboot_cmd);



	if (ret) {

		pr_warn("Failed to start orderly reboot: forcing the issue\n");

		emergency_sync();

		kernel_restart(NULL);

	}



	return ret;

}



static int __orderly_poweroff(bool force)

{

	int ret;



	ret = run_cmd(poweroff_cmd);



	if (ret && force) {

		pr_warn("Failed to start orderly shutdown: forcing the issue\n");



		/*

		 * I guess this should try to kick off some daemon to sync and

		 * poweroff asap.  Or not even bother syncing if we're doing an
@@ -436,15 +461,33 @@ static DECLARE_WORK(poweroff_work, poweroff_work_func); 
 * This may be called from any context to trigger a system shutdown.

 * If the orderly shutdown fails, it will force an immediate shutdown.

 */

int orderly_poweroff(bool force)

void orderly_poweroff(bool force)

{

	if (force) /* do not override the pending "true" */

		poweroff_force = true;

	schedule_work(&poweroff_work);

	return 0;

}

EXPORT_SYMBOL_GPL(orderly_poweroff);



static void reboot_work_func(struct work_struct *work)

{

	__orderly_reboot();

}



static DECLARE_WORK(reboot_work, reboot_work_func);



/**

 * orderly_reboot - Trigger an orderly system reboot

 *

 * This may be called from any context to trigger a system reboot.

 * If the orderly reboot fails, it will force an immediate reboot.

 */

void orderly_reboot(void)

{

	schedule_work(&reboot_work);

}

EXPORT_SYMBOL_GPL(orderly_reboot);



static int __init reboot_setup(char *str)

{

	for (;;) {

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