[PATCH] blk-mq: fix blk_mq_start_stopped_hw_queues from irq context

From: Christoph Hellwig
Date: Sun Oct 06 2013 - 13:10:29 EST


The only caller of blk_mq_start_stopped_hw_queues is in irq context,
leading to lockdep splat when it actually gets called. Fix this by
deferring the hw queue run to workqueue context.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 2b85029..923e9e1 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -686,7 +686,8 @@ void blk_mq_start_stopped_hw_queues(struct request_queue *q)
if (!test_bit(BLK_MQ_S_STOPPED, &hctx->state))
continue;

- blk_mq_start_hw_queue(hctx);
+ clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
+ blk_mq_run_hw_queue(hctx, true);
}
}
EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
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