patches/delayacct-use-raw_spinlocks.patch

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat, 20 May 2017 12:32:23 +0200
Subject: [PATCH] delayacct: use raw_spinlocks

try_to_wake_up() might invoke delayacct_blkio_end() while holding the
pi_lock. The lock is only held for a short amount of time so it should
be safe to make it raw.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 include/linux/delayacct.h |    2 +-
 kernel/delayacct.c        |   14 +++++++-------
 2 files changed, 8 insertions(+), 8 deletions(-)

--- a/include/linux/delayacct.h
+++ b/include/linux/delayacct.h
@@ -29,7 +29,7 @@
 
 #ifdef CONFIG_TASK_DELAY_ACCT
 struct task_delay_info {
-	spinlock_t	lock;
+	raw_spinlock_t	lock;
 	unsigned int	flags;	/* Private per-task flags */
 
 	/* For each stat XXX, add following, aligned appropriately
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -44,7 +44,7 @@ void __delayacct_tsk_init(struct task_st
 {
 	tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
 	if (tsk->delays)
-		spin_lock_init(&tsk->delays->lock);
+		raw_spin_lock_init(&tsk->delays->lock);
 }
 
 /*
@@ -57,10 +57,10 @@ static void delayacct_end(u64 *start, u6
 	unsigned long flags;
 
 	if (ns > 0) {
-		spin_lock_irqsave(&current->delays->lock, flags);
+		raw_spin_lock_irqsave(&current->delays->lock, flags);
 		*total += ns;
 		(*count)++;
-		spin_unlock_irqrestore(&current->delays->lock, flags);
+		raw_spin_unlock_irqrestore(&current->delays->lock, flags);
 	}
 }
 
@@ -119,7 +119,7 @@ int __delayacct_add_tsk(struct taskstats
 
 	/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
 
-	spin_lock_irqsave(&tsk->delays->lock, flags);
+	raw_spin_lock_irqsave(&tsk->delays->lock, flags);
 	tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
 	d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
 	tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
@@ -129,7 +129,7 @@ int __delayacct_add_tsk(struct taskstats
 	d->blkio_count += tsk->delays->blkio_count;
 	d->swapin_count += tsk->delays->swapin_count;
 	d->freepages_count += tsk->delays->freepages_count;
-	spin_unlock_irqrestore(&tsk->delays->lock, flags);
+	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
 
 	return 0;
 }
@@ -139,10 +139,10 @@ int __delayacct_add_tsk(struct taskstats
 	__u64 ret;
 	unsigned long flags;
 
-	spin_lock_irqsave(&tsk->delays->lock, flags);
+	raw_spin_lock_irqsave(&tsk->delays->lock, flags);
 	ret = nsec_to_clock_t(tsk->delays->blkio_delay +
 				tsk->delays->swapin_delay);
-	spin_unlock_irqrestore(&tsk->delays->lock, flags);
+	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
 	return ret;
 }