From: Steve Wise <swise@opengridcomputing.com>

Date: Wed, 26 May 2021 13:25:00 +0200

Subject: RDMA/addr: create addr_wq with WQ_MEM_RECLAIM flag

Patch-mainline: Never, no fix yet availabe upstream revert offending change

References: bsc#1183346

While running NVMe/oF wire unplug tests, we hit this warning in

kernel/workqueue.c:check_flush_dependency():

WARN_ONCE(worker && ((worker->current_pwq->wq->flags &

		      (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM),

	  "workqueue: WQ_MEM_RECLAIM %s:%pf is flushing !WQ_MEM_RECLAIM %s:%pf",

	  worker->current_pwq->wq->name, worker->current_func,

	  target_wq->name, target_func);

Which I think means we're flushing a workq that doesn't have

WQ_MEM_RECLAIM set, from workqueue context that does have it set.

Looking at rdma_addr_cancel() which is doing the flushing, it flushes

the addr_wq which doesn't have MEM_RECLAIM set.  Yet rdma_addr_cancel()

is being called by the nvme host connection timeout/reconnect workqueue

thread that does have WQ_MEM_RECLAIM set.

So set WQ_MEM_RECLAIM on the addr_req workqueue.

This is to silence the warning and not fixing the problem at

all. Upstream is aware of this problem but there is no fix yet. To

avoid a lot of support requests undo the offending commit.

Link: https://patchwork.kernel.org/project/linux-rdma/patch/5f5a1e4e90f3625cea57ffa79fc0e5bcb7efe09d.1548963371.git.swise@opengridcomputing.com/

Fixes: 39baf10310e6 ("IB/core: Fix use workqueue without WQ_MEM_RECLAIM")

Signed-off-by: Steve Wise <swise@opengridcomputing.com>

Reviewed-by: Parav Pandit <parav@mellanox.com>

[dwagner: Updated commit message]

Signed-off-by: Daniel Wagner <dwagner@suse.de>

---

 drivers/infiniband/core/addr.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c

index 0abce004a959..c92d25c97ba1 100644

--- a/drivers/infiniband/core/addr.c

+++ b/drivers/infiniband/core/addr.c

@@ -871,7 +871,7 @@ static struct notifier_block nb = {

 int addr_init(void)

 {

-	addr_wq = alloc_ordered_workqueue("ib_addr", 0);

+	addr_wq = alloc_ordered_workqueue("ib_addr", WQ_MEM_RECLAIM);

 	if (!addr_wq)

 		return -ENOMEM;

-- 

2.29.2