Patch "blk-mq: add non_owner variant of start_freeze/unfreeze queue APIs" has been added to the 6.12-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 6.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     blk-mq-add-non_owner-variant-of-start_freeze-unfreez.patch
and it can be found in the queue-6.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 628076bce8184bce7bc854bc43ec42dc8ba50240
Author: Ming Lei <ming.lei@xxxxxxxxxx>
Date:   Fri Oct 25 08:37:18 2024 +0800

    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@xxxxxx>
    Suggested-by: Christoph Hellwig <hch@xxxxxx>
    Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20241025003722.3630252-2-ming.lei@xxxxxxxxxx
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Stable-dep-of: 3802f73bd807 ("block: fix uaf for flush rq while iterating tags")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index fbd63d189c740..0beed0ae0aeba 100644
--- 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 4fecf46ef681b..c5063e0a38a05 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);