linux-kernel - [PATCH V2 1/3] blk-mq: add non_owner variant of start

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Message-ID: <20241025003722.3630252-2-ming.lei@redhat.com>
Date: Fri, 25 Oct 2024 08:37:18 +0800
From: Ming Lei <ming.lei@...hat.com>
To: Jens Axboe <axboe@...nel.dk>,
	linux-block@...r.kernel.org
Cc: Christoph Hellwig <hch@....de>,
	Peter Zijlstra <peterz@...radead.org>,
	Waiman Long <longman@...hat.com>,
	Boqun Feng <boqun.feng@...il.com>,
	Ingo Molnar <mingo@...hat.com>,
	Will Deacon <will@...nel.org>,
	linux-kernel@...r.kernel.org,
	Bart Van Assche <bvanassche@....org>,
	Ming Lei <ming.lei@...hat.com>
Subject: [PATCH V2 1/3] 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@....de>
Suggested-by: Christoph Hellwig <hch@....de>
Signed-off-by: Ming Lei <ming.lei@...hat.com>
---
 block/blk-mq.c         | 20 ++++++++++++++++++++
 include/linux/blk-mq.h |  2 ++
 2 files changed, 22 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4b2c8e940f59..96858fb3b9ff 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 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);
-- 
2.46.0