linux-kernel - [PATCH 5.0 047/346] IB/hfi1: Fix WQ_MEM

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Message-Id: <20190530030543.273964726@linuxfoundation.org>
Date:   Wed, 29 May 2019 20:02:00 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        "Michael J. Ruhl" <michael.j.ruhl@...el.com>,
        Mike Marciniszyn <mike.marciniszyn@...el.com>,
        Dennis Dalessandro <dennis.dalessandro@...el.com>,
        Jason Gunthorpe <jgg@...lanox.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.0 047/346] IB/hfi1: Fix WQ_MEM_RECLAIM warning

[ Upstream commit 4c4b1996b5db688e2dcb8242b0a3bf7b1e845e42 ]

The work_item cancels that occur when a QP is destroyed can elicit the
following trace:

 workqueue: WQ_MEM_RECLAIM ipoib_wq:ipoib_cm_tx_reap [ib_ipoib] is flushing !WQ_MEM_RECLAIM hfi0_0:_hfi1_do_send [hfi1]
 WARNING: CPU: 7 PID: 1403 at kernel/workqueue.c:2486 check_flush_dependency+0xb1/0x100
 Call Trace:
  __flush_work.isra.29+0x8c/0x1a0
  ? __switch_to_asm+0x40/0x70
  __cancel_work_timer+0x103/0x190
  ? schedule+0x32/0x80
  iowait_cancel_work+0x15/0x30 [hfi1]
  rvt_reset_qp+0x1f8/0x3e0 [rdmavt]
  rvt_destroy_qp+0x65/0x1f0 [rdmavt]
  ? _cond_resched+0x15/0x30
  ib_destroy_qp+0xe9/0x230 [ib_core]
  ipoib_cm_tx_reap+0x21c/0x560 [ib_ipoib]
  process_one_work+0x171/0x370
  worker_thread+0x49/0x3f0
  kthread+0xf8/0x130
  ? max_active_store+0x80/0x80
  ? kthread_bind+0x10/0x10
  ret_from_fork+0x35/0x40

Since QP destruction frees memory, hfi1_wq should have the WQ_MEM_RECLAIM.

The hfi1_wq does not allocate memory with GFP_KERNEL or otherwise become
entangled with memory reclaim, so this flag is appropriate.

Fixes: 0a226edd203f ("staging/rdma/hfi1: Use parallel workqueue for SDMA engines")
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@...el.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@...el.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@...el.com>
Signed-off-by: Jason Gunthorpe <jgg@...lanox.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/infiniband/hw/hfi1/init.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/hfi1/init.c b/drivers/infiniband/hw/hfi1/init.c
index c532ceb0bb9af..b66c4fe8151a1 100644
--- a/drivers/infiniband/hw/hfi1/init.c
+++ b/drivers/infiniband/hw/hfi1/init.c
@@ -797,7 +797,8 @@ static int create_workqueues(struct hfi1_devdata *dd)
 			ppd->hfi1_wq =
 				alloc_workqueue(
 				    "hfi%d_%d",
-				    WQ_SYSFS | WQ_HIGHPRI | WQ_CPU_INTENSIVE,
+				    WQ_SYSFS | WQ_HIGHPRI | WQ_CPU_INTENSIVE |
+				    WQ_MEM_RECLAIM,
 				    HFI1_MAX_ACTIVE_WORKQUEUE_ENTRIES,
 				    dd->unit, pidx);
 			if (!ppd->hfi1_wq)
-- 
2.20.1