* [PATCH AUTOSEL 5.0 76/99] dmaengine: bcm2835: Avoid GFP_KERNEL in device_prep_slave_sg
[not found] <20190507053235.29900-1-sashal@kernel.org>
@ 2019-05-07 5:32 ` Sasha Levin
0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2019-05-07 5:32 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Stefan Wahren, Aaro Koskinen, Vinod Koul, Sasha Levin, dmaengine
From: Stefan Wahren <stefan.wahren@i2se.com>
[ Upstream commit f147384774a7b24dda4783a3dcd61af272757ea8 ]
The commit af19b7ce76ba ("mmc: bcm2835: Avoid possible races on
data requests") introduces a possible circular locking dependency,
which is triggered by swapping to the sdhost interface.
So instead of reintroduce the race condition again, we could also
avoid this situation by using GFP_NOWAIT for the allocation of the
DMA buffer descriptors.
Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Fixes: af19b7ce76ba ("mmc: bcm2835: Avoid possible races on data requests")
Link: http://lists.infradead.org/pipermail/linux-rpi-kernel/2019-March/008615.html
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/bcm2835-dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index ae10f5614f95..bf5119203637 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -674,7 +674,7 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg(
d = bcm2835_dma_create_cb_chain(chan, direction, false,
info, extra,
frames, src, dst, 0, 0,
- GFP_KERNEL);
+ GFP_NOWAIT);
if (!d)
return NULL;
--
2.20.1
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