From 9ef4d0209cbadb63656a7aa29fde49c27ab2b9bf Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 9 Nov 2021 15:11:41 +0800 Subject: blk-mq: add one API for waiting until quiesce is done Some drivers(NVMe, SCSI) need to call quiesce and unquiesce in pair, but it is hard to switch to this style, so these drivers need one atomic flag for helping to balance quiesce and unquiesce. When quiesce is in-progress, the driver still needs to wait until the quiesce is done, so add API of blk_mq_wait_quiesce_done() for these drivers. Signed-off-by: Ming Lei Reviewed-by: Martin K. Petersen Link: https://lore.kernel.org/r/20211109071144.181581-2-ming.lei@redhat.com Signed-off-by: Jens Axboe --- block/blk-mq.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) (limited to 'block') diff --git a/block/blk-mq.c b/block/blk-mq.c index 5a9cd9fe8da3..d3e5fcbc943b 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -251,22 +251,18 @@ void blk_mq_quiesce_queue_nowait(struct request_queue *q) EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); /** - * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished + * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done * @q: request queue. * - * Note: this function does not prevent that the struct request end_io() - * 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(). + * Note: it is driver's responsibility for making sure that quiesce has + * been started. */ -void blk_mq_quiesce_queue(struct request_queue *q) +void blk_mq_wait_quiesce_done(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; unsigned int i; bool rcu = false; - blk_mq_quiesce_queue_nowait(q); - queue_for_each_hw_ctx(q, hctx, i) { if (hctx->flags & BLK_MQ_F_BLOCKING) synchronize_srcu(hctx->srcu); @@ -276,6 +272,22 @@ void blk_mq_quiesce_queue(struct request_queue *q) if (rcu) synchronize_rcu(); } +EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done); + +/** + * 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. 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) +{ + blk_mq_quiesce_queue_nowait(q); + blk_mq_wait_quiesce_done(q); +} EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); /* -- cgit v1.2.3