patches/block-mq-drop-preempt-disable.patch

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

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>
---
 block/blk-mq.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -341,7 +341,7 @@ static void blk_mq_ipi_complete_request(
 		return;
 	}
 
-	cpu = get_cpu();
+	cpu = get_cpu_light();
 	if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags))
 		shared = cpus_share_cache(cpu, ctx->cpu);
 
@@ -353,7 +353,7 @@ static void blk_mq_ipi_complete_request(
 	} else {
 		rq->q->softirq_done_fn(rq);
 	}
-	put_cpu();
+	put_cpu_light();
 }
 
 static void __blk_mq_complete_request(struct request *rq)
@@ -868,14 +868,14 @@ void blk_mq_run_hw_queue(struct blk_mq_h
 		return;
 
 	if (!async) {
-		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_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx),