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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yi Zhang <yi.zhang@redhat.com>,
        Sagi Grimberg <sagi@grimberg.me>,
        Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 365/389] nvmet-tcp: fix lockdep complaint on nvmet_tcp_wq flush during queue teardown
Date:   Tue, 23 Aug 2022 10:27:23 +0200
Message-Id: <20220823080130.791698452@linuxfoundation.org>
In-Reply-To: <20220823080115.331990024@linuxfoundation.org>
References: <20220823080115.331990024@linuxfoundation.org>
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From: Sagi Grimberg <sagi@grimberg.me>

[ Upstream commit 533d2e8b4d5e4c89772a0adce913525fb86cbbee ]

We probably need nvmet_tcp_wq to have MEM_RECLAIM as we are
sending/receiving for the socket from works on this workqueue.
Also this eliminates lockdep complaints:
--
[ 6174.010200] workqueue: WQ_MEM_RECLAIM
nvmet-wq:nvmet_tcp_release_queue_work [nvmet_tcp] is flushing
!WQ_MEM_RECLAIM nvmet_tcp_wq:nvmet_tcp_io_work [nvmet_tcp]
[ 6174.010216] WARNING: CPU: 20 PID: 14456 at kernel/workqueue.c:2628
check_flush_dependency+0x110/0x14c

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/target/tcp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index 4341c7244662..e9512d077b8a 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1762,7 +1762,8 @@ static int __init nvmet_tcp_init(void)
 {
 	int ret;
 
-	nvmet_tcp_wq = alloc_workqueue("nvmet_tcp_wq", WQ_HIGHPRI, 0);
+	nvmet_tcp_wq = alloc_workqueue("nvmet_tcp_wq",
+				WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
 	if (!nvmet_tcp_wq)
 		return -ENOMEM;
 
-- 
2.35.1