tegrakernel/kernel/kernel-4.9/rt-patches/0193-completion-Use-simple-wait-queues.patch

From d852cd8bdf95687090cde35fc56c3a13cebccf9d Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 11 Jan 2013 11:23:51 +0100
Subject: [PATCH 193/365] completion: Use simple wait queues

Completions have no long lasting callbacks and therefor do not need
the complex waitqueue variant. Use simple waitqueues which reduces the
contention on the waitqueue lock.

Change-Id: I9345d2ae7c277c755c400c850adbef8ec4251485
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 .../wireless/intersil/orinoco/orinoco_usb.c   |  2 +-
 drivers/usb/gadget/function/f_fs.c            |  2 +-
 drivers/usb/gadget/legacy/inode.c             |  4 +--
 include/linux/completion.h                    |  9 +++---
 include/linux/suspend.h                       |  6 ++++
 include/linux/swait.h                         |  1 +
 include/linux/uprobes.h                       |  1 +
 kernel/power/hibernate.c                      |  7 ++++
 kernel/power/suspend.c                        |  4 +++
 kernel/sched/completion.c                     | 32 +++++++++----------
 kernel/sched/core.c                           | 10 ++++--
 kernel/sched/swait.c                          | 20 ++++++++++++
 12 files changed, 71 insertions(+), 27 deletions(-)

diff --git a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
index de928938c7a1..b8984b3f009f 100644
--- a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
+++ b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
@@ -697,7 +697,7 @@ static void ezusb_req_ctx_wait(struct ezusb_priv *upriv,
 			while (!ctx->done.done && msecs--)
 				udelay(1000);
 		} else {
-			wait_event_interruptible(ctx->done.wait,
+			swait_event_interruptible(ctx->done.wait,
 						 ctx->done.done);
 		}
 		break;
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index aac010b466bf..0d897481c595 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1611,7 +1611,7 @@ static void ffs_data_put(struct ffs_data *ffs)
 		pr_info("%s(): freeing\n", __func__);
 		ffs_data_clear(ffs);
 		BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
-		       waitqueue_active(&ffs->ep0req_completion.wait));
+		       swait_active(&ffs->ep0req_completion.wait));
 		kfree(ffs->dev_name);
 		kfree(ffs);
 	}
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index de0f3c2c9f6f..d706d2e134d9 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -347,7 +347,7 @@ ep_io (struct ep_data *epdata, void *buf, unsigned len)
 	spin_unlock_irq (&epdata->dev->lock);
 
 	if (likely (value == 0)) {
-		value = wait_event_interruptible (done.wait, done.done);
+		value = swait_event_interruptible (done.wait, done.done);
 		if (value != 0) {
 			spin_lock_irq (&epdata->dev->lock);
 			if (likely (epdata->ep != NULL)) {
@@ -356,7 +356,7 @@ ep_io (struct ep_data *epdata, void *buf, unsigned len)
 				usb_ep_dequeue (epdata->ep, epdata->req);
 				spin_unlock_irq (&epdata->dev->lock);
 
-				wait_event (done.wait, done.done);
+				swait_event (done.wait, done.done);
 				if (epdata->status == -ECONNRESET)
 					epdata->status = -EINTR;
 			} else {
diff --git a/include/linux/completion.h b/include/linux/completion.h
index 5d5aaae3af43..3bca1590e29f 100644
--- a/include/linux/completion.h
+++ b/include/linux/completion.h
@@ -7,8 +7,7 @@
  * Atomic wait-for-completion handler data structures.
  * See kernel/sched/completion.c for details.
  */
-
-#include <linux/wait.h>
+#include <linux/swait.h>
 
 /*
  * struct completion - structure used to maintain state for a "completion"
@@ -24,11 +23,11 @@
  */
 struct completion {
 	unsigned int done;
-	wait_queue_head_t wait;
+	struct swait_queue_head wait;
 };
 
 #define COMPLETION_INITIALIZER(work) \
-	{ 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
+	{ 0, __SWAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
 
 #define COMPLETION_INITIALIZER_ONSTACK(work) \
 	({ init_completion(&work); work; })
@@ -73,7 +72,7 @@ struct completion {
 static inline void init_completion(struct completion *x)
 {
 	x->done = 0;
-	init_waitqueue_head(&x->wait);
+	init_swait_queue_head(&x->wait);
 }
 
 /**
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 98a4bcd28157..9c04639ea4b7 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -193,6 +193,12 @@ struct platform_freeze_ops {
 	void (*end)(void);
 };
 
+#if defined(CONFIG_SUSPEND) || defined(CONFIG_HIBERNATION)
+extern bool pm_in_action;
+#else
+# define pm_in_action false
+#endif
+
 #ifdef CONFIG_SUSPEND
 /**
  * suspend_set_ops - set platform dependent suspend operations
diff --git a/include/linux/swait.h b/include/linux/swait.h
index c1f9c62a8a50..83f004a72320 100644
--- a/include/linux/swait.h
+++ b/include/linux/swait.h
@@ -87,6 +87,7 @@ static inline int swait_active(struct swait_queue_head *q)
 extern void swake_up(struct swait_queue_head *q);
 extern void swake_up_all(struct swait_queue_head *q);
 extern void swake_up_locked(struct swait_queue_head *q);
+extern void swake_up_all_locked(struct swait_queue_head *q);
 
 extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
 extern void prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait, int state);
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 4a29c75b146e..0a294e950df8 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -27,6 +27,7 @@
 #include <linux/errno.h>
 #include <linux/rbtree.h>
 #include <linux/types.h>
+#include <linux/wait.h>
 
 struct vm_area_struct;
 struct mm_struct;
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 73ddd8143753..18f3162a9d39 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -692,6 +692,10 @@ static int load_image_and_restore(void)
 	return error;
 }
 
+#ifndef CONFIG_SUSPEND
+bool pm_in_action;
+#endif
+
 /**
  * hibernate - Carry out system hibernation, including saving the image.
  */
@@ -705,6 +709,8 @@ int hibernate(void)
 		return -EPERM;
 	}
 
+	pm_in_action = true;
+
 	lock_system_sleep();
 	/* The snapshot device should not be opened while we're running */
 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
@@ -782,6 +788,7 @@ int hibernate(void)
 	atomic_inc(&snapshot_device_available);
  Unlock:
 	unlock_system_sleep();
+	pm_in_action = false;
 	return error;
 }
 
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 880c5a2d48b9..fe37a261a126 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -559,6 +559,7 @@ static void pm_suspend_marker(char *annotation)
 		annotation, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 		tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec);
 }
+bool pm_in_action;
 
 /**
  * pm_suspend - Externally visible function for suspending the system.
@@ -575,6 +576,8 @@ int pm_suspend(suspend_state_t state)
 		return -EINVAL;
 
 	pm_suspend_marker("entry");
+	pm_in_action = true;
+
 	error = enter_state(state);
 	if (error) {
 		suspend_stats.fail++;
@@ -583,6 +586,7 @@ int pm_suspend(suspend_state_t state)
 		suspend_stats.success++;
 	}
 	pm_suspend_marker("exit");
+	pm_in_action = false;
 	return error;
 }
 EXPORT_SYMBOL(pm_suspend);
diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c
index 8d0f35debf35..b62cf6400fe0 100644
--- a/kernel/sched/completion.c
+++ b/kernel/sched/completion.c
@@ -30,10 +30,10 @@ void complete(struct completion *x)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&x->wait.lock, flags);
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
 	x->done++;
-	__wake_up_locked(&x->wait, TASK_NORMAL, 1);
-	spin_unlock_irqrestore(&x->wait.lock, flags);
+	swake_up_locked(&x->wait);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
 }
 EXPORT_SYMBOL(complete);
 
@@ -50,10 +50,10 @@ void complete_all(struct completion *x)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&x->wait.lock, flags);
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
 	x->done += UINT_MAX/2;
-	__wake_up_locked(&x->wait, TASK_NORMAL, 0);
-	spin_unlock_irqrestore(&x->wait.lock, flags);
+	swake_up_all_locked(&x->wait);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
 }
 EXPORT_SYMBOL(complete_all);
 
@@ -62,20 +62,20 @@ do_wait_for_common(struct completion *x,
 		   long (*action)(long), long timeout, int state)
 {
 	if (!x->done) {
-		DECLARE_WAITQUEUE(wait, current);
+		DECLARE_SWAITQUEUE(wait);
 
-		__add_wait_queue_tail_exclusive(&x->wait, &wait);
+		__prepare_to_swait(&x->wait, &wait);
 		do {
 			if (signal_pending_state(state, current)) {
 				timeout = -ERESTARTSYS;
 				break;
 			}
 			__set_current_state(state);
-			spin_unlock_irq(&x->wait.lock);
+			raw_spin_unlock_irq(&x->wait.lock);
 			timeout = action(timeout);
-			spin_lock_irq(&x->wait.lock);
+			raw_spin_lock_irq(&x->wait.lock);
 		} while (!x->done && timeout);
-		__remove_wait_queue(&x->wait, &wait);
+		__finish_swait(&x->wait, &wait);
 		if (!x->done)
 			return timeout;
 	}
@@ -89,9 +89,9 @@ __wait_for_common(struct completion *x,
 {
 	might_sleep();
 
-	spin_lock_irq(&x->wait.lock);
+	raw_spin_lock_irq(&x->wait.lock);
 	timeout = do_wait_for_common(x, action, timeout, state);
-	spin_unlock_irq(&x->wait.lock);
+	raw_spin_unlock_irq(&x->wait.lock);
 	return timeout;
 }
 
@@ -277,12 +277,12 @@ bool try_wait_for_completion(struct completion *x)
 	if (!READ_ONCE(x->done))
 		return 0;
 
-	spin_lock_irqsave(&x->wait.lock, flags);
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
 	if (!x->done)
 		ret = 0;
 	else
 		x->done--;
-	spin_unlock_irqrestore(&x->wait.lock, flags);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL(try_wait_for_completion);
@@ -311,7 +311,7 @@ bool completion_done(struct completion *x)
 	 * after it's acquired the lock.
 	 */
 	smp_rmb();
-	spin_unlock_wait(&x->wait.lock);
+	raw_spin_unlock_wait(&x->wait.lock);
 	return true;
 }
 EXPORT_SYMBOL(completion_done);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c0b0aa0411a6..d939f247c67f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3449,7 +3449,10 @@ void migrate_disable(void)
 	}
 
 #ifdef CONFIG_SCHED_DEBUG
-	WARN_ON_ONCE(p->migrate_disable_atomic);
+	if (unlikely(p->migrate_disable_atomic)) {
+		tracing_off();
+		WARN_ON_ONCE(1);
+	}
 #endif
 
 	if (p->migrate_disable) {
@@ -3476,7 +3479,10 @@ void migrate_enable(void)
 	}
 
 #ifdef CONFIG_SCHED_DEBUG
-	WARN_ON_ONCE(p->migrate_disable_atomic);
+	if (unlikely(p->migrate_disable_atomic)) {
+		tracing_off();
+		WARN_ON_ONCE(1);
+	}
 #endif
 	WARN_ON_ONCE(p->migrate_disable <= 0);
 
diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
index 9c2da06a8869..a26906faf07e 100644
--- a/kernel/sched/swait.c
+++ b/kernel/sched/swait.c
@@ -1,5 +1,6 @@
 #include <linux/sched.h>
 #include <linux/swait.h>
+#include <linux/suspend.h>
 
 void __init_swait_queue_head(struct swait_queue_head *q, const char *name,
 			     struct lock_class_key *key)
@@ -29,6 +30,25 @@ void swake_up_locked(struct swait_queue_head *q)
 }
 EXPORT_SYMBOL(swake_up_locked);
 
+void swake_up_all_locked(struct swait_queue_head *q)
+{
+	struct swait_queue *curr;
+	int wakes = 0;
+
+	while (!list_empty(&q->task_list)) {
+
+		curr = list_first_entry(&q->task_list, typeof(*curr),
+					task_list);
+		wake_up_process(curr->task);
+		list_del_init(&curr->task_list);
+		wakes++;
+	}
+	if (pm_in_action)
+		return;
+	WARN(wakes > 2, "complete_all() with %d waiters\n", wakes);
+}
+EXPORT_SYMBOL(swake_up_all_locked);
+
 void swake_up(struct swait_queue_head *q)
 {
 	unsigned long flags;
-- 
2.28.0