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;