Subject: block/mq: do not invoke preempt_disable()
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue Jul 14 14:26:34 2015 +0200

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

preempt_disable() and get_cpu() don't play well together with the sleeping
locks it tries to allocate later.
It seems to be enough to replace it with get_cpu_light() and migrate_disable().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>


---
 block/blk-mq.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1559,14 +1559,14 @@ static void __blk_mq_delay_run_hw_queue(
 		return;
 
 	if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
-		int cpu = get_cpu();
+		int cpu = get_cpu_light();
 		if (cpumask_test_cpu(cpu, hctx->cpumask)) {
 			__blk_mq_run_hw_queue(hctx);
-			put_cpu();
+			put_cpu_light();
 			return;
 		}
 
-		put_cpu();
+		put_cpu_light();
 	}
 
 	kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,