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authorMing Lei <ming.lei@redhat.com>2017-06-06 23:22:07 +0800
committerJens Axboe <axboe@kernel.dk>2017-06-18 14:24:48 -0600
commit69e07c4adb8669fd77f3b59abdb436aca9f1bee9 (patch)
tree3cb9d1d58028066defca897d75076f7b1d1d6bfd /block
parentf4560ffe8cec1361b1021d81aca6a4173f8e7c87 (diff)
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blk-mq: update comments on blk_mq_quiesce_queue()
Actually what we want to get from blk_mq_quiesce_queue() isn't only to wait for completion of all ongoing .queue_rq(). In the typical context of canceling requests, we need to make sure that the following is done in the dispatch path before starting to cancel requests: - failed dispatched request is finished - busy dispatched request is requeued, and the STARTED flag is cleared So update comment to keep code, doc and our expection consistent. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 40b22c7f684e..f2a73190f60d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -155,12 +155,13 @@ void blk_mq_unfreeze_queue(struct request_queue *q)
EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
/**
- * blk_mq_quiesce_queue() - wait until all ongoing queue_rq calls have finished
+ * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
* @q: request queue.
*
* Note: this function does not prevent that the struct request end_io()
- * callback function is invoked. Additionally, it is not prevented that
- * new queue_rq() calls occur unless the queue has been stopped first.
+ * callback function is invoked. Once this function is returned, we make
+ * sure no dispatch can happen until the queue is unquiesced via
+ * blk_mq_unquiesce_queue().
*/
void blk_mq_quiesce_queue(struct request_queue *q)
{