blk-mq: add non_owner variant of start_freeze/unfreeze queue APIs

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.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241025003722.3630252-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index aae9a112c913898ab4b762cccd4ea11c3e681315..77027681550700650348bec3499ef7c93a008f0f 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -196,6 +196,26 @@ void blk_mq_unfreeze_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
 
+/*
+ * non_owner variant of blk_freeze_queue_start
+ *
+ * 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.
+ */
+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 59e9adf815a491ace0e02e8215e7aea5511d5b4f..2035fad3131fb60781957095ce8a3a941dd104be 100644 (file)
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -919,6 +919,8 @@ 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);