diff mbox series

[1/3] blk-mq: add non_owner variant of start_freeze/unfreeze queue APIs

Message ID 20241023095438.3451156-2-ming.lei@redhat.com (mailing list archive)
State New
Headers show
Series block: model freeze/enter queue as lock for lockdep | expand

Commit Message

Ming Lei Oct. 23, 2024, 9:54 a.m. UTC 
Add non_owner variant of start_freeze/unfreeze queue APIs, so that the
caller knows that what they are doing, and we can skip lockdep support
for non_owner variant in per-call level.

Prepare for supporting lockdep for freezing/unfreezing queue.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-mq.c         | 19 +++++++++++++++++++
 include/linux/blk-mq.h |  2 ++
 2 files changed, 21 insertions(+)

Comments

Christoph Hellwig Oct. 23, 2024, 12:19 p.m. UTC | #1 
> +/*
> + * non_owner variant of blk_freeze_queue_start
> + *
> + * The queue needn't to be unfreeze in current task, and non-owner use is
> + * fragile and easy to cause race, please try your best to avoid it

Maybe say:

 Unlike blk_freeze_queue_start, the queue doesn't need to be unfrozen
 by the same task.  This is fragile and should not be used if at all
 possible.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4b2c8e940f59..2c84c2d2510d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -196,6 +196,25 @@  void blk_mq_unfreeze_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
 
+/*
+ * non_owner variant of blk_freeze_queue_start
+ *
+ * The queue needn't to be unfreeze in current task, and non-owner use is
+ * fragile and easy to cause race, please try your best to avoid it
+ */
+void blk_freeze_queue_start_non_owner(struct request_queue *q)
+{
+	blk_freeze_queue_start(q);
+}
+EXPORT_SYMBOL_GPL(blk_freeze_queue_start_non_owner);
+
+/* non_owner variant of blk_mq_unfreeze_queue */
+void blk_mq_unfreeze_queue_non_owner(struct request_queue *q)
+{
+	__blk_mq_unfreeze_queue(q, false);
+}
+EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue_non_owner);
+
 /*
  * 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 4fecf46ef681..c5063e0a38a0 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -925,6 +925,8 @@  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,
 				     unsigned long timeout);
+void blk_mq_unfreeze_queue_non_owner(struct request_queue *q);
+void blk_freeze_queue_start_non_owner(struct request_queue *q);
 
 void blk_mq_map_queues(struct blk_mq_queue_map *qmap);
 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);