NVMe calls freeze/unfreeze in different contexts, and controller removal
may break in-progress error recovery, then leave queues in frozen state.
So cause IO hang in del_gendisk() because pending writeback IOs are
still waited in bio_queue_enter().
Prepare for fixing this issue by calling the added
blk_mq_unfreeze_queue_force when removing device.
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/blk-mq.c | 25 ++++++++++++++++++++++---
block/blk.h | 3 ++-
block/genhd.c | 2 +-
include/linux/blk-mq.h | 1 +
4 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 24dc8fe0a9d2..6ac58dc9e648 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -185,12 +185,16 @@ 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, bool force_atomic)
+void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic,
+ bool force)
{
mutex_lock(&q->mq_freeze_lock);
if (force_atomic)
q->q_usage_counter.data->force_atomic = true;
- q->mq_freeze_depth--;
+ if (force)
+ q->mq_freeze_depth = 0;
+ else
+ q->mq_freeze_depth--;
WARN_ON_ONCE(q->mq_freeze_depth < 0);
if (!q->mq_freeze_depth) {
percpu_ref_resurrect(&q->q_usage_counter);
@@ -201,10 +205,25 @@ void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic)
void blk_mq_unfreeze_queue(struct request_queue *q)
{
- __blk_mq_unfreeze_queue(q, false);
+ __blk_mq_unfreeze_queue(q, false, false);
}
EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
+/*
+ * Force to unfreeze queue
+ *
+ * Be careful: this API should only be used for avoiding IO hang in
+ * bio_queue_enter() when going to remove disk which needs to drain pending
+ * writeback IO.
+ *
+ * Please don't use it for other cases.
+ */
+void blk_mq_unfreeze_queue_force(struct request_queue *q)
+{
+ __blk_mq_unfreeze_queue(q, false, true);
+}
+EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue_force);
+
/*
* FIXME: replace the scsi_internal_device_*block_nowait() calls in the
* mpt3sas driver such that this function can be removed.
diff --git a/block/blk.h b/block/blk.h
index 768852a84fef..5c9f99051837 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -33,7 +33,8 @@ struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size,
void blk_free_flush_queue(struct blk_flush_queue *q);
void blk_freeze_queue(struct request_queue *q);
-void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic);
+void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic, bool
+ force);
void blk_queue_start_drain(struct request_queue *q);
int __bio_queue_enter(struct request_queue *q, struct bio *bio);
void submit_bio_noacct_nocheck(struct bio *bio);
diff --git a/block/genhd.c b/block/genhd.c
index f71f82991434..184aa968b453 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -708,7 +708,7 @@ void del_gendisk(struct gendisk *disk)
*/
if (!test_bit(GD_OWNS_QUEUE, &disk->state)) {
blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
- __blk_mq_unfreeze_queue(q, true);
+ __blk_mq_unfreeze_queue(q, true, false);
} else {
if (queue_is_mq(q))
blk_mq_exit_queue(q);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index f401067ac03a..fa265e85d753 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -890,6 +890,7 @@ void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset);
void blk_mq_freeze_queue(struct request_queue *q);
void blk_mq_unfreeze_queue(struct request_queue *q);
+void blk_mq_unfreeze_queue_force(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,
--
2.40.1
