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@xxxxxxxxxx>
Cc: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: linux-block@xxxxxxxxxxxxxxx
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: linux-nvme@xxxxxxxxxxxxxxxxxxx
Cc: Keith Busch <keith.busch@xxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
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,
--
2.9.5
