1 files changed, 153 insertions, 205 deletions

diff --git a/kernel/power/process.c b/kernel/power/process.c
index f1d0b345c9b..4ee194eb524 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -9,272 +9,220 @@
 #undef DEBUG
 
 #include <linux/interrupt.h>
+#include <linux/oom.h>
 #include <linux/suspend.h>
 #include <linux/module.h>
 #include <linux/syscalls.h>
 #include <linux/freezer.h>
+#include <linux/delay.h>
+#include <linux/workqueue.h>
+#include <linux/kmod.h>
+#include <trace/events/power.h>
 
 /* 
  * Timeout for stopping processes
  */
-#define TIMEOUT	(20 * HZ)
+unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC;
 
-#define FREEZER_KERNEL_THREADS 0
-#define FREEZER_USER_SPACE 1
-
-static inline int freezeable(struct task_struct * p)
-{
-	if ((p == current) ||
-	    (p->flags & PF_NOFREEZE) ||
-	    (p->exit_state != 0))
-		return 0;
-	return 1;
-}
-
-/*
- * freezing is complete, mark current process as frozen
- */
-static inline void frozen_process(void)
-{
-	if (!unlikely(current->flags & PF_NOFREEZE)) {
-		current->flags |= PF_FROZEN;
-		wmb();
-	}
-	clear_freeze_flag(current);
-}
-
-/* Refrigerator is place where frozen processes are stored :-). */
-void refrigerator(void)
-{
-	/* Hmm, should we be allowed to suspend when there are realtime
-	   processes around? */
-	long save;
-
-	task_lock(current);
-	if (freezing(current)) {
-		frozen_process();
-		task_unlock(current);
-	} else {
-		task_unlock(current);
-		return;
-	}
-	save = current->state;
-	pr_debug("%s entered refrigerator\n", current->comm);
-
-	spin_lock_irq(&current->sighand->siglock);
-	recalc_sigpending(); /* We sent fake signal, clean it up */
-	spin_unlock_irq(&current->sighand->siglock);
-
-	for (;;) {
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		if (!frozen(current))
-			break;
-		schedule();
-	}
-	pr_debug("%s left refrigerator\n", current->comm);
-	__set_current_state(save);
-}
-
-static void fake_signal_wake_up(struct task_struct *p)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&p->sighand->siglock, flags);
-	signal_wake_up(p, 0);
-	spin_unlock_irqrestore(&p->sighand->siglock, flags);
-}
-
-static int has_mm(struct task_struct *p)
-{
-	return (p->mm && !(p->flags & PF_BORROWED_MM));
-}
-
-/**
- *	freeze_task - send a freeze request to given task
- *	@p: task to send the request to
- *	@with_mm_only: if set, the request will only be sent if the task has its
- *		own mm
- *	Return value: 0, if @with_mm_only is set and the task has no mm of its
- *		own or the task is frozen, 1, otherwise
- *
- *	The freeze request is sent by seting the tasks's TIF_FREEZE flag and
- *	either sending a fake signal to it or waking it up, depending on whether
- *	or not it has its own mm (ie. it is a user land task).  If @with_mm_only
- *	is set and the task has no mm of its own (ie. it is a kernel thread),
- *	its TIF_FREEZE flag should not be set.
- *
- *	The task_lock() is necessary to prevent races with exit_mm() or
- *	use_mm()/unuse_mm() from occuring.
- */
-static int freeze_task(struct task_struct *p, int with_mm_only)
-{
-	int ret = 1;
-
-	task_lock(p);
-	if (freezing(p)) {
-		if (has_mm(p)) {
-			if (!signal_pending(p))
-				fake_signal_wake_up(p);
-		} else {
-			if (with_mm_only)
-				ret = 0;
-			else
-				wake_up_state(p, TASK_INTERRUPTIBLE);
-		}
-	} else {
-		rmb();
-		if (frozen(p)) {
-			ret = 0;
-		} else {
-			if (has_mm(p)) {
-				set_freeze_flag(p);
-				fake_signal_wake_up(p);
-			} else {
-				if (with_mm_only) {
-					ret = 0;
-				} else {
-					set_freeze_flag(p);
-					wake_up_state(p, TASK_INTERRUPTIBLE);
-				}
-			}
-		}
-	}
-	task_unlock(p);
-	return ret;
-}
-
-static void cancel_freezing(struct task_struct *p)
-{
-	unsigned long flags;
-
-	if (freezing(p)) {
-		pr_debug("  clean up: %s\n", p->comm);
-		clear_freeze_flag(p);
-		spin_lock_irqsave(&p->sighand->siglock, flags);
-		recalc_sigpending_and_wake(p);
-		spin_unlock_irqrestore(&p->sighand->siglock, flags);
-	}
-}
-
-static int try_to_freeze_tasks(int freeze_user_space)
+static int try_to_freeze_tasks(bool user_only)
 {
 	struct task_struct *g, *p;
 	unsigned long end_time;
 	unsigned int todo;
+	bool wq_busy = false;
 	struct timeval start, end;
-	s64 elapsed_csecs64;
-	unsigned int elapsed_csecs;
+	u64 elapsed_msecs64;
+	unsigned int elapsed_msecs;
+	bool wakeup = false;
+	int sleep_usecs = USEC_PER_MSEC;
 
 	do_gettimeofday(&start);
 
-	end_time = jiffies + TIMEOUT;
-	do {
+	end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs);
+
+	if (!user_only)
+		freeze_workqueues_begin();
+
+	while (true) {
 		todo = 0;
 		read_lock(&tasklist_lock);
 		do_each_thread(g, p) {
-			if (frozen(p) || !freezeable(p))
-				continue;
-
-			if (!freeze_task(p, freeze_user_space))
+			if (p == current || !freeze_task(p))
 				continue;
 
-			/*
-			 * Now that we've done set_freeze_flag, don't
-			 * perturb a task in TASK_STOPPED or TASK_TRACED.
-			 * It is "frozen enough".  If the task does wake
-			 * up, it will immediately call try_to_freeze.
-			 */
-			if (!task_is_stopped_or_traced(p) &&
-			    !freezer_should_skip(p))
+			if (!freezer_should_skip(p))
 				todo++;
 		} while_each_thread(g, p);
 		read_unlock(&tasklist_lock);
-		yield();			/* Yield is okay here */
-		if (time_after(jiffies, end_time))
+
+		if (!user_only) {
+			wq_busy = freeze_workqueues_busy();
+			todo += wq_busy;
+		}
+
+		if (!todo || time_after(jiffies, end_time))
 			break;
-	} while (todo);
+
+		if (pm_wakeup_pending()) {
+			wakeup = true;
+			break;
+		}
+
+		/*
+		 * We need to retry, but first give the freezing tasks some
+		 * time to enter the refrigerator.  Start with an initial
+		 * 1 ms sleep followed by exponential backoff until 8 ms.
+		 */
+		usleep_range(sleep_usecs / 2, sleep_usecs);
+		if (sleep_usecs < 8 * USEC_PER_MSEC)
+			sleep_usecs *= 2;
+	}
 
 	do_gettimeofday(&end);
-	elapsed_csecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);
-	do_div(elapsed_csecs64, NSEC_PER_SEC / 100);
-	elapsed_csecs = elapsed_csecs64;
+	elapsed_msecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);
+	do_div(elapsed_msecs64, NSEC_PER_MSEC);
+	elapsed_msecs = elapsed_msecs64;
 
 	if (todo) {
-		/* This does not unfreeze processes that are already frozen
-		 * (we have slightly ugly calling convention in that respect,
-		 * and caller must call thaw_processes() if something fails),
-		 * but it cleans up leftover PF_FREEZE requests.
-		 */
 		printk("\n");
-		printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds "
-				"(%d tasks refusing to freeze):\n",
-				elapsed_csecs / 100, elapsed_csecs % 100, todo);
-		show_state();
-		read_lock(&tasklist_lock);
-		do_each_thread(g, p) {
-			task_lock(p);
-			if (freezing(p) && !freezer_should_skip(p))
-				printk(KERN_ERR " %s\n", p->comm);
-			cancel_freezing(p);
-			task_unlock(p);
-		} while_each_thread(g, p);
-		read_unlock(&tasklist_lock);
+		printk(KERN_ERR "Freezing of tasks %s after %d.%03d seconds "
+		       "(%d tasks refusing to freeze, wq_busy=%d):\n",
+		       wakeup ? "aborted" : "failed",
+		       elapsed_msecs / 1000, elapsed_msecs % 1000,
+		       todo - wq_busy, wq_busy);
+
+		if (!wakeup) {
+			read_lock(&tasklist_lock);
+			do_each_thread(g, p) {
+				if (p != current && !freezer_should_skip(p)
+				    && freezing(p) && !frozen(p))
+					sched_show_task(p);
+			} while_each_thread(g, p);
+			read_unlock(&tasklist_lock);
+		}
 	} else {
-		printk("(elapsed %d.%02d seconds) ", elapsed_csecs / 100,
-			elapsed_csecs % 100);
+		printk("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000,
+			elapsed_msecs % 1000);
 	}
 
 	return todo ? -EBUSY : 0;
 }
 
 /**
- *	freeze_processes - tell processes to enter the refrigerator
+ * freeze_processes - Signal user space processes to enter the refrigerator.
+ * The current thread will not be frozen.  The same process that calls
+ * freeze_processes must later call thaw_processes.
+ *
+ * On success, returns 0.  On failure, -errno and system is fully thawed.
  */
 int freeze_processes(void)
 {
 	int error;
 
+	error = __usermodehelper_disable(UMH_FREEZING);
+	if (error)
+		return error;
+
+	/* Make sure this task doesn't get frozen */
+	current->flags |= PF_SUSPEND_TASK;
+
+	if (!pm_freezing)
+		atomic_inc(&system_freezing_cnt);
+
 	printk("Freezing user space processes ... ");
-	error = try_to_freeze_tasks(FREEZER_USER_SPACE);
+	pm_freezing = true;
+	error = try_to_freeze_tasks(true);
+	if (!error) {
+		printk("done.");
+		__usermodehelper_set_disable_depth(UMH_DISABLED);
+		oom_killer_disable();
+	}
+	printk("\n");
+	BUG_ON(in_atomic());
+
 	if (error)
-		goto Exit;
-	printk("done.\n");
+		thaw_processes();
+	return error;
+}
+
+/**
+ * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
+ *
+ * On success, returns 0.  On failure, -errno and only the kernel threads are
+ * thawed, so as to give a chance to the caller to do additional cleanups
+ * (if any) before thawing the userspace tasks. So, it is the responsibility
+ * of the caller to thaw the userspace tasks, when the time is right.
+ */
+int freeze_kernel_threads(void)
+{
+	int error;
 
 	printk("Freezing remaining freezable tasks ... ");
-	error = try_to_freeze_tasks(FREEZER_KERNEL_THREADS);
-	if (error)
-		goto Exit;
-	printk("done.");
- Exit:
-	BUG_ON(in_atomic());
+	pm_nosig_freezing = true;
+	error = try_to_freeze_tasks(false);
+	if (!error)
+		printk("done.");
+
 	printk("\n");
+	BUG_ON(in_atomic());
+
+	if (error)
+		thaw_kernel_threads();
 	return error;
 }
 
-static void thaw_tasks(int thaw_user_space)
+void thaw_processes(void)
 {
 	struct task_struct *g, *p;
+	struct task_struct *curr = current;
 
-	read_lock(&tasklist_lock);
-	do_each_thread(g, p) {
-		if (!freezeable(p))
-			continue;
+	trace_suspend_resume(TPS("thaw_processes"), 0, true);
+	if (pm_freezing)
+		atomic_dec(&system_freezing_cnt);
+	pm_freezing = false;
+	pm_nosig_freezing = false;
+
+	oom_killer_enable();
+
+	printk("Restarting tasks ... ");
 
-		if (!p->mm == thaw_user_space)
-			continue;
+	__usermodehelper_set_disable_depth(UMH_FREEZING);
+	thaw_workqueues();
 
-		thaw_process(p);
+	read_lock(&tasklist_lock);
+	do_each_thread(g, p) {
+		/* No other threads should have PF_SUSPEND_TASK set */
+		WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK));
+		__thaw_task(p);
 	} while_each_thread(g, p);
 	read_unlock(&tasklist_lock);
+
+	WARN_ON(!(curr->flags & PF_SUSPEND_TASK));
+	curr->flags &= ~PF_SUSPEND_TASK;
+
+	usermodehelper_enable();
+
+	schedule();
+	printk("done.\n");
+	trace_suspend_resume(TPS("thaw_processes"), 0, false);
 }
 
-void thaw_processes(void)
+void thaw_kernel_threads(void)
 {
-	printk("Restarting tasks ... ");
-	thaw_tasks(FREEZER_KERNEL_THREADS);
-	thaw_tasks(FREEZER_USER_SPACE);
+	struct task_struct *g, *p;
+
+	pm_nosig_freezing = false;
+	printk("Restarting kernel threads ... ");
+
+	thaw_workqueues();
+
+	read_lock(&tasklist_lock);
+	do_each_thread(g, p) {
+		if (p->flags & (PF_KTHREAD | PF_WQ_WORKER))
+			__thaw_task(p);
+	} while_each_thread(g, p);
+	read_unlock(&tasklist_lock);
+
 	schedule();
 	printk("done.\n");
 }
-
-EXPORT_SYMBOL(refrigerator);