blk-mq/cpu-notif: Convert to new hotplug state machine

Replace the block-mq notifier list management with the multi instance
facility in the cpu hotplug state machine.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-block@vger.kernel.org
Cc: rt@linutronix.de
Cc: Christoph Hellwing <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index fbcfdf3..b3d1a7f 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -7,12 +7,6 @@
 struct blk_mq_tags;
 struct blk_flush_queue;
 
-struct blk_mq_cpu_notifier {
-	struct list_head list;
-	void *data;
-	int (*notify)(void *data, unsigned long action, unsigned int cpu);
-};
-
 struct blk_mq_hw_ctx {
 	struct {
 		spinlock_t		lock;
@@ -53,7 +47,7 @@
 
 	struct delayed_work	delay_work;
 
-	struct blk_mq_cpu_notifier	cpu_notifier;
+	struct hlist_node	cpuhp_dead;
 	struct kobject		kobj;
 
 	unsigned long		poll_considered;