From dce56a4ce05f5033a340ecd6383eec77537eefd7 Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@redhat.com>
Date: Mon, 28 Jun 2021 10:55:26 +0800
Subject: [PATCH] Revert "block: Fix a lockdep complaint triggered by request
 queue flushing"

mainline inclusion
from mainline-5.11-rc1
commit 7aa390ec2d9db0cd6677d95d0b8f307f9c086770
category: bugfix
bugzilla: 108493
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7aa390ec2d9db0cd6677d95d0b8f307f9c086770

---------------------------

This reverts commit b3c6a59975415bde29cfd76ff1ab008edbf614a9.

Now we can avoid nvme-loop lockdep warning of 'lockdep possible recursive locking'
by nvme-loop's lock class, no need to apply dynamically allocated lock class key,
so revert commit b3c6a5997541("block: Fix a lockdep complaint triggered by request
queue flushing").

This way fixes horrible SCSI probe delay issue on megaraid_sas, and it is reported
the whole probe may take more than half an hour.

Tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Reported-by: Qian Cai <cai@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
---
 block/blk-flush.c | 5 -----
 block/blk.h       | 1 -
 2 files changed, 6 deletions(-)

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 18a5f75aa4f5..23124d60cffe 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -69,7 +69,6 @@
 #include <linux/blkdev.h>
 #include <linux/gfp.h>
 #include <linux/blk-mq.h>
-#include <linux/lockdep.h>
 
 #include "blk.h"
 #include "blk-mq.h"
@@ -474,9 +473,6 @@ struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size,
 	INIT_LIST_HEAD(&fq->flush_queue[1]);
 	INIT_LIST_HEAD(&fq->flush_data_in_flight);
 
-	lockdep_register_key(&fq->key);
-	lockdep_set_class(&fq->mq_flush_lock, &fq->key);
-
 	return fq;
 
  fail_rq:
@@ -491,7 +487,6 @@ void blk_free_flush_queue(struct blk_flush_queue *fq)
 	if (!fq)
 		return;
 
-	lockdep_unregister_key(&fq->key);
 	kfree(fq->flush_rq);
 	kfree(fq);
 }
diff --git a/block/blk.h b/block/blk.h
index dfab98465db9..806fd6537295 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -25,7 +25,6 @@ struct blk_flush_queue {
 	struct list_head	flush_data_in_flight;
 	struct request		*flush_rq;
 
-	struct lock_class_key	key;
 	spinlock_t		mq_flush_lock;
 };
 
-- 
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