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

[ Upstream commit 8acdd0e7bfadda6b5103f2960d293581954454ed ]

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>
Stable-dep-of: 3802f73bd807 ("block: fix uaf for flush rq while iterating tags")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index f2c7fe2dc7aacbc519bf110b45cb63a39ac6d50c..a2c40a97328b69215e8b04091b84453b6308b41c 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 8d304b1d16b15aeac3024be1d6babd2cb4f75c2b..a2d27a4d7b6c7d535ee0955211f611d9acc57307 100644 (file)
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -928,6 +928,8 @@ 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);