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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, Hauke Mehrtens <hauke@hauke-m.de>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 154/270] spi: lantiq-ssc: Fix warning by using WQ_MEM_RECLAIM
Date:   Mon, 17 Aug 2020 17:15:55 +0200
Message-Id: <20200817143803.501300258@linuxfoundation.org>
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From: Hauke Mehrtens <hauke@hauke-m.de>

[ Upstream commit ba3548cf29616b58c93bbaffc3d636898d009858 ]

The lantiq-ssc driver uses internally an own workqueue to wait till the
data is not only written out of the FIFO but really written to the wire.
This workqueue is flushed while the SPI subsystem is working in some
other system workqueue.

The system workqueue is marked as WQ_MEM_RECLAIM, but the workqueue in
the lantiq-ssc driver does not use WQ_MEM_RECLAIM for now. Add this flag
too to prevent this warning.

This fixes the following warning:
[    2.975956] WARNING: CPU: 1 PID: 17 at kernel/workqueue.c:2614 check_flush_dependency+0x168/0x184
[    2.984752] workqueue: WQ_MEM_RECLAIM kblockd:blk_mq_run_work_fn is flushing !WQ_MEM_RECLAIM 1e100800.spi:0x0

Fixes: 891b7c5fbf61 ("mtd_blkdevs: convert to blk-mq")
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Link: https://lore.kernel.org/r/20200717215648.20522-1-hauke@hauke-m.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-lantiq-ssc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-lantiq-ssc.c b/drivers/spi/spi-lantiq-ssc.c
index 55394bdbc5a30..f9bc1705c0d4d 100644
--- a/drivers/spi/spi-lantiq-ssc.c
+++ b/drivers/spi/spi-lantiq-ssc.c
@@ -917,7 +917,7 @@ static int lantiq_ssc_probe(struct platform_device *pdev)
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 8) |
 				     SPI_BPW_MASK(16) | SPI_BPW_MASK(32);
 
-	spi->wq = alloc_ordered_workqueue(dev_name(dev), 0);
+	spi->wq = alloc_ordered_workqueue(dev_name(dev), WQ_MEM_RECLAIM);
 	if (!spi->wq) {
 		err = -ENOMEM;
 		goto err_clk_put;
-- 
2.25.1