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| author |   Ming Lei <ming.lei@redhat.com> | 2017-06-06 23:22:07 +0800 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2017-06-18 14:24:48 -0600 |
| commit | 69e07c4adb8669fd77f3b59abdb436aca9f1bee9 (patch) | |
| tree | 3cb9d1d58028066defca897d75076f7b1d1d6bfd /block | |
| parent | blk-mq: use QUEUE_FLAG_QUIESCED to quiesce queue (diff) | |
| download | wireguard-linux-69e07c4adb8669fd77f3b59abdb436aca9f1bee9.tar.xz wireguard-linux-69e07c4adb8669fd77f3b59abdb436aca9f1bee9.zip | |
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.c | 7 |
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) { |