From 8e67fdab6758c6e047316f6406ac28a2935acd1b Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat, 3 May 2014 11:00:29 +0200
Subject: [PATCH 163/398] blk-mq: revert raw locks, post pone notifier to
 POST_DEAD

The blk_mq_cpu_notify_lock should be raw because some CPU down levels
are called with interrupts off. The notifier itself calls currently one
function that is blk_mq_hctx_notify().
That function acquires the ctx->lock lock which is sleeping and I would
prefer to keep it that way. That function only moves IO-requests from
the CPU that is going offline to another CPU and it is currently the
only one. Therefore I revert the list lock back to sleeping spinlocks
and let the notifier run at POST_DEAD time.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 block/blk-mq-cpu.c | 17 ++++++++++-------
 block/blk-mq.c     |  2 +-
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/block/blk-mq-cpu.c b/block/blk-mq-cpu.c
index bb3ed488f7b5..628c6c13c482 100644
--- a/block/blk-mq-cpu.c
+++ b/block/blk-mq-cpu.c
@@ -16,7 +16,7 @@
 #include "blk-mq.h"
 
 static LIST_HEAD(blk_mq_cpu_notify_list);
-static DEFINE_RAW_SPINLOCK(blk_mq_cpu_notify_lock);
+static DEFINE_SPINLOCK(blk_mq_cpu_notify_lock);
 
 static int blk_mq_main_cpu_notify(struct notifier_block *self,
 				  unsigned long action, void *hcpu)
@@ -25,7 +25,10 @@ static int blk_mq_main_cpu_notify(struct notifier_block *self,
 	struct blk_mq_cpu_notifier *notify;
 	int ret = NOTIFY_OK;
 
-	raw_spin_lock(&blk_mq_cpu_notify_lock);
+	if (action != CPU_POST_DEAD)
+		return NOTIFY_OK;
+
+	spin_lock(&blk_mq_cpu_notify_lock);
 
 	list_for_each_entry(notify, &blk_mq_cpu_notify_list, list) {
 		ret = notify->notify(notify->data, action, cpu);
@@ -33,7 +36,7 @@ static int blk_mq_main_cpu_notify(struct notifier_block *self,
 			break;
 	}
 
-	raw_spin_unlock(&blk_mq_cpu_notify_lock);
+	spin_unlock(&blk_mq_cpu_notify_lock);
 	return ret;
 }
 
@@ -41,16 +44,16 @@ void blk_mq_register_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
 {
 	BUG_ON(!notifier->notify);
 
-	raw_spin_lock(&blk_mq_cpu_notify_lock);
+	spin_lock(&blk_mq_cpu_notify_lock);
 	list_add_tail(&notifier->list, &blk_mq_cpu_notify_list);
-	raw_spin_unlock(&blk_mq_cpu_notify_lock);
+	spin_unlock(&blk_mq_cpu_notify_lock);
 }
 
 void blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
 {
-	raw_spin_lock(&blk_mq_cpu_notify_lock);
+	spin_lock(&blk_mq_cpu_notify_lock);
 	list_del(&notifier->list);
-	raw_spin_unlock(&blk_mq_cpu_notify_lock);
+	spin_unlock(&blk_mq_cpu_notify_lock);
 }
 
 void blk_mq_init_cpu_notifier(struct blk_mq_cpu_notifier *notifier,
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 223218ee55fd..b7bbb647b304 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1639,7 +1639,7 @@ static int blk_mq_hctx_notify(void *data, unsigned long action,
 {
 	struct blk_mq_hw_ctx *hctx = data;
 
-	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
+	if (action == CPU_POST_DEAD)
 		return blk_mq_hctx_cpu_offline(hctx, cpu);
 
 	/*
-- 
2.14.4

