The function blk_queue_stopped() allows to test whether or not a
traditional request 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.vanass...@sandisk.com>
Reviewed-by: Hannes Reinecke <h...@suse.com>
Reviewed-by: Johannes Thumshirn <jthumsh...@suse.de>
Cc: Christoph Hellwig <h...@lst.de>
---
block/blk-mq.c | 20 ++++++++++++++++++++
include/linux/blk-mq.h | 1 +
2 files changed, 21 insertions(+)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index dc5f47f..d8c45de 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -950,6 +950,26 @@ void blk_mq_run_hw_queues(struct request_queue *q, bool
async)
}
EXPORT_SYMBOL(blk_mq_run_hw_queues);
+/**
+ * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
+ * @q: request queue.
+ *
+ * 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_work(&hctx->run_work);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 5daa0ef..368c460d 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -233,6 +233,7 @@ void blk_mq_delay_kick_requeue_list(struct request_queue
*q, unsigned long msecs
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);
--
2.10.0
--
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