The function blk_queue_stopped() allows to test whether or not a
non-mq queue has been stopped. Introduce a helper function that
allows block drivers to query easily whether or not one or more
hardware contexts of a blk-mq queue have been stopped.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
---
block/blk-mq.c | 17 +++++++++++++++++
include/linux/blk-mq.h | 1 +
2 files changed, 18 insertions(+)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0dcafa6..6929a52 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -965,6 +965,23 @@ void blk_mq_run_hw_queues(struct request_queue *q, bool async)
}
EXPORT_SYMBOL(blk_mq_run_hw_queues);
+/*
+ * The caller is responsible for serializing this function against
+ * blk_mq_{start,stop}_hw_queue().
+ */
+bool blk_mq_queue_stopped(struct request_queue *q)
+{
+ struct blk_mq_hw_ctx *hctx;
+ int i;
+
+ queue_for_each_hw_ctx(q, hctx, i)
+ if (test_bit(BLK_MQ_S_STOPPED, &hctx->state))
+ return true;
+
+ return false;
+}
+EXPORT_SYMBOL(blk_mq_queue_stopped);
+
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
{
cancel_delayed_work(&hctx->run_work);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index e43bbff..bd677bc 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -235,6 +235,7 @@ void blk_mq_kick_requeue_list(struct request_queue *q);
void blk_mq_abort_requeue_list(struct request_queue *q);
void blk_mq_complete_request(struct request *rq, int error);
+bool blk_mq_queue_stopped(struct request_queue *q);
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);
void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx);
void blk_mq_stop_hw_queues(struct request_queue *q);
--
2.9.3
--
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