[PATCH 2/3] blk-mq: introduce blk_mq_unfreeze_queue_no_drain_io
From: Ming Lei <hidden>
Date: 2018-09-18 10:13:37
Also in:
linux-nvme, lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
This patch introduces blk_mq_unfreeze_queue_no_drain_io() so that it can be used when no necessary to check if IO is drained, such as nvme pci resetting(nvme_reset_work). Cc: Tejun Heo <tj@kernel.org> Cc: Jianchao Wang <redacted> Cc: Kent Overstreet <redacted> Cc: linux-block@vger.kernel.org Cc: Christoph Hellwig <hch@lst.de> Cc: linux-nvme@lists.infradead.org Cc: Keith Busch <redacted> Signed-off-by: Ming Lei <redacted> --- block/blk-mq.c | 25 +++++++++++++++++++++++-- include/linux/blk-mq.h | 1 + 2 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 85a1c1a59c72..a22f82061b93 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c@@ -191,20 +191,41 @@ void blk_mq_freeze_queue(struct request_queue *q) } EXPORT_SYMBOL_GPL(blk_mq_freeze_queue); -void blk_mq_unfreeze_queue(struct request_queue *q) +static void __blk_mq_unfreeze_queue(struct request_queue *q, + bool need_drop_zero) { int freeze_depth; freeze_depth = atomic_dec_return(&q->mq_freeze_depth); WARN_ON_ONCE(freeze_depth < 0); if (!freeze_depth) { - percpu_ref_reinit(&q->q_usage_counter); + if (need_drop_zero) + percpu_ref_reinit(&q->q_usage_counter); + else + percpu_ref_resurge(&q->q_usage_counter); wake_up_all(&q->mq_freeze_wq); } } + +void blk_mq_unfreeze_queue(struct request_queue *q) +{ + __blk_mq_unfreeze_queue(q, true); +} EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); /* + * Compared with blk_mq_unfreeze_queue(), the verion of _no_drain_io + * doesn't require the queue is really frozen, and it is useful in + * case of timeout handling in which IO can't be drained and has to + * be retried after controler is recovered. + */ +void blk_mq_unfreeze_queue_no_drain_io(struct request_queue *q) +{ + __blk_mq_unfreeze_queue(q, false); +} +EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue_no_drain_io); + +/* * FIXME: replace the scsi_internal_device_*block_nowait() calls in the * mpt3sas driver such that this function can be removed. */
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 1da59c16f637..5e0740ec407f 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h@@ -279,6 +279,7 @@ void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset, busy_tag_iter_fn *fn, void *priv); void blk_mq_freeze_queue(struct request_queue *q); void blk_mq_unfreeze_queue(struct request_queue *q); +void blk_mq_unfreeze_queue_no_drain_io(struct request_queue *q); void blk_freeze_queue_start(struct request_queue *q); void blk_mq_freeze_queue_wait(struct request_queue *q); int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
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2.9.5