linux-imx

/*

 * kernel/freezer.c - Function to freeze a process

 *

 * Originally from kernel/power/process.c

 */

​

#include <linux/interrupt.h>

#include <linux/suspend.h>

#include <linux/export.h>

#include <linux/syscalls.h>

#include <linux/freezer.h>

#include <linux/kthread.h>

​

/* total number of freezing conditions in effect */

atomic_t system_freezing_cnt = ATOMIC_INIT(0);

EXPORT_SYMBOL(system_freezing_cnt);

​

/* indicate whether PM freezing is in effect, protected by

 * system_transition_mutex

 */

bool pm_freezing;

bool pm_nosig_freezing;

​

/*

 * Temporary export for the deadlock workaround in ata_scsi_hotplug().

 * Remove once the hack becomes unnecessary.

 */

EXPORT_SYMBOL_GPL(pm_freezing);

​

/* protects freezing and frozen transitions */

static DEFINE_SPINLOCK(freezer_lock);

​

/**

 * freezing_slow_path - slow path for testing whether a task needs to be frozen

 * @p: task to be tested

 *

 * This function is called by freezing() if system_freezing_cnt isn't zero

 * and tests whether @p needs to enter and stay in frozen state.  Can be

 * called under any context.  The freezers are responsible for ensuring the

 * target tasks see the updated state.

 */

bool freezing_slow_path(struct task_struct *p)

{

    if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK))

        return false;

​

    if (test_tsk_thread_flag(p, TIF_MEMDIE))

        return false;

​

    if (pm_nosig_freezing || cgroup_freezing(p))

        return true;

​

    if (pm_freezing && !(p->flags & PF_KTHREAD))

        return true;

​

    return false;

}

EXPORT_SYMBOL(freezing_slow_path);

​

/* Refrigerator is place where frozen processes are stored :-). */

bool __refrigerator(bool check_kthr_stop)

{

    /* Hmm, should we be allowed to suspend when there are realtime