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Diffstat (limited to 'kernel/freezer.c')
-rw-r--r--kernel/freezer.c62
1 files changed, 40 insertions, 22 deletions
diff --git a/kernel/freezer.c b/kernel/freezer.c
index 11e32d4..f53cd5a 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -11,9 +11,41 @@
#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 pm_mutex */
+bool pm_freezing;
+bool pm_nosig_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)
+ return false;
+
+ if (pm_nosig_freezing || cgroup_freezing(p))
+ return true;
+
+ if (pm_freezing && !(p->flags & PF_FREEZER_NOSIG))
+ return true;
+
+ return false;
+}
+EXPORT_SYMBOL(freezing_slow_path);
+
/* Refrigerator is place where frozen processes are stored :-). */
bool __refrigerator(bool check_kthr_stop)
{
@@ -23,17 +55,11 @@ bool __refrigerator(bool check_kthr_stop)
long save;
/*
- * Enter FROZEN. If NOFREEZE, schedule immediate thawing by
- * clearing freezing.
+ * No point in checking freezing() again - the caller already did.
+ * Proceed to enter FROZEN.
*/
spin_lock_irq(&freezer_lock);
repeat:
- if (!freezing(current)) {
- spin_unlock_irq(&freezer_lock);
- return was_frozen;
- }
- if (current->flags & PF_NOFREEZE)
- clear_freeze_flag(current);
current->flags |= PF_FROZEN;
spin_unlock_irq(&freezer_lock);
@@ -99,18 +125,12 @@ static void fake_signal_wake_up(struct task_struct *p)
bool freeze_task(struct task_struct *p, bool sig_only)
{
unsigned long flags;
- bool ret = false;
spin_lock_irqsave(&freezer_lock, flags);
-
- if ((p->flags & PF_NOFREEZE) ||
- (sig_only && !should_send_signal(p)))
- goto out_unlock;
-
- if (frozen(p))
- goto out_unlock;
-
- set_freeze_flag(p);
+ if (!freezing(p) || frozen(p)) {
+ spin_unlock_irqrestore(&freezer_lock, flags);
+ return false;
+ }
if (should_send_signal(p)) {
fake_signal_wake_up(p);
@@ -123,10 +143,9 @@ bool freeze_task(struct task_struct *p, bool sig_only)
} else {
wake_up_state(p, TASK_INTERRUPTIBLE);
}
- ret = true;
-out_unlock:
+
spin_unlock_irqrestore(&freezer_lock, flags);
- return ret;
+ return true;
}
void __thaw_task(struct task_struct *p)
@@ -143,7 +162,6 @@ void __thaw_task(struct task_struct *p)
* avoid leaving dangling TIF_SIGPENDING behind.
*/
spin_lock_irqsave(&freezer_lock, flags);
- clear_freeze_flag(p);
if (frozen(p)) {
wake_up_process(p);
} else {
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