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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, Jack Wang <jinpu.wang@cloud.ionos.com>,
        Md Haris Iqbal <haris.iqbal@cloud.ionos.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.8 321/464] RDMA/rtrs: remove WQ_MEM_RECLAIM for rtrs_wq
Date:   Mon, 17 Aug 2020 17:14:34 +0200
Message-Id: <20200817143849.172844464@linuxfoundation.org>
In-Reply-To: <20200817143833.737102804@linuxfoundation.org>
References: <20200817143833.737102804@linuxfoundation.org>
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From: Jack Wang <jinpu.wang@cloud.ionos.com>

[ Upstream commit 03ed5a8cda659e3c71d106b0dd4ce6520e4dcd6e ]

lockdep triggers a warning from time to time when running a regression
test:

 rnbd_client L685: </dev/nullb0@bla> Device disconnected.
 rnbd_client L1756: Unloading module

 workqueue: WQ_MEM_RECLAIM rtrs_client_wq:rtrs_clt_reconnect_work [rtrs_client] is flushing !WQ_MEM_RECLAIM ib_addr:process_one_req [ib_core]
 WARNING: CPU: 2 PID: 18824 at kernel/workqueue.c:2517 check_flush_dependency+0xad/0x130

The root cause is workqueue core expect flushing should not be done for a
!WQ_MEM_RECLAIM wq from a WQ_MEM_RECLAIM workqueue.

In above case ib_addr workqueue without WQ_MEM_RECLAIM, but rtrs_wq
WQ_MEM_RECLAIM.

To avoid the warning, remove the WQ_MEM_RECLAIM flag.

Fixes: 9cb837480424 ("RDMA/rtrs: server: main functionality")
Fixes: 6a98d71daea1 ("RDMA/rtrs: client: main functionality")
Link: https://lore.kernel.org/r/20200724111508.15734-4-haris.iqbal@cloud.ionos.com
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@cloud.ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/ulp/rtrs/rtrs-clt.c | 2 +-
 drivers/infiniband/ulp/rtrs/rtrs-srv.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index 5b31d3b03737c..776e89231c52f 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -2982,7 +2982,7 @@ static int __init rtrs_client_init(void)
 		pr_err("Failed to create rtrs-client dev class\n");
 		return PTR_ERR(rtrs_clt_dev_class);
 	}
-	rtrs_wq = alloc_workqueue("rtrs_client_wq", WQ_MEM_RECLAIM, 0);
+	rtrs_wq = alloc_workqueue("rtrs_client_wq", 0, 0);
 	if (!rtrs_wq) {
 		class_destroy(rtrs_clt_dev_class);
 		return -ENOMEM;
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv.c b/drivers/infiniband/ulp/rtrs/rtrs-srv.c
index 0d9241f5d9e68..a219bd1bdbc26 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c
@@ -2150,7 +2150,7 @@ static int __init rtrs_server_init(void)
 		err = PTR_ERR(rtrs_dev_class);
 		goto out_chunk_pool;
 	}
-	rtrs_wq = alloc_workqueue("rtrs_server_wq", WQ_MEM_RECLAIM, 0);
+	rtrs_wq = alloc_workqueue("rtrs_server_wq", 0, 0);
 	if (!rtrs_wq) {
 		err = -ENOMEM;
 		goto out_dev_class;
-- 
2.25.1