From f3ec5d11554778c24ac8915e847223ed71d104fc Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@redhat.com>
Date: Mon, 11 Jul 2022 17:08:08 +0800
Subject: [PATCH] blk-mq: don't create hctx debugfs dir until q->debugfs_dir is
 created
Git-commit: f3ec5d11554778c24ac8915e847223ed71d104fc
Patch-mainline: v6.0-rc1
References: git-fixes

blk_mq_debugfs_register_hctx() can be called by blk_mq_update_nr_hw_queues
when gendisk isn't added yet, such as nvme tcp.

Fixes the warning of 'debugfs: Directory 'hctx0' with parent '/' already present!'
which can be observed reliably when running blktests nvme/005.

Fixes: 6cfc0081b046 ("blk-mq: no need to check return value of debugfs_create functions")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220711090808.259682-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Coly Li <colyli@suse.de>

---
 block/blk-mq-debugfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index b11add9a95e2..7ee1b13380d0 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -728,6 +728,9 @@ void blk_mq_debugfs_register_hctx(struct request_queue *q,
 	char name[20];
 	int i;
 
+	if (!q->debugfs_dir)
+		return;
+
 	snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
 	hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
 
-- 
2.35.3