From ae8799125d565c798e49dcab4bf182dbfc483524 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 8 Nov 2018 09:03:51 -0700 Subject: blk-mq: provide a helper to check if a queue is busy Returns true if the queue currently has requests pending, false if not. DM can use this to replace the atomic_inc/dec they do per device to see if a device is busy. Reviewed-by: Mike Snitzer Reviewed-by: Bart Van Assche Signed-off-by: Jens Axboe --- block/blk-mq.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'block/blk-mq.c') diff --git a/block/blk-mq.c b/block/blk-mq.c index 4a622c832b31..4880e13e2394 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -790,6 +790,32 @@ struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) } EXPORT_SYMBOL(blk_mq_tag_to_rq); +static bool blk_mq_check_busy(struct blk_mq_hw_ctx *hctx, struct request *rq, + void *priv, bool reserved) +{ + /* + * If we find a request, we know the queue is busy. Return false + * to stop the iteration. + */ + if (rq->q == hctx->queue) { + bool *busy = priv; + + *busy = true; + return false; + } + + return true; +} + +bool blk_mq_queue_busy(struct request_queue *q) +{ + bool busy = false; + + blk_mq_queue_tag_busy_iter(q, blk_mq_check_busy, &busy); + return busy; +} +EXPORT_SYMBOL_GPL(blk_mq_queue_busy); + static void blk_mq_rq_timed_out(struct request *req, bool reserved) { req->rq_flags |= RQF_TIMED_OUT; -- cgit