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Subject[[PATCH] 3/3] dma: imx-dma: fix callback path in tasklet
Date
We need to free the ld_active list head before jumping into the callback
routine. Otherwise the callback could run into issue_pending and change
our ld_active list head we just going to free. This will run the channel
list into an currupted and undefined state.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
drivers/dma/imx-dma.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
index 247aa7c..55852c0 100644
--- a/drivers/dma/imx-dma.c
+++ b/drivers/dma/imx-dma.c
@@ -627,13 +627,11 @@ static void imxdma_tasklet(unsigned long data)

if (list_empty(&imxdmac->ld_active)) {
/* Someone might have called terminate all */
- goto out;
+ spin_unlock_irqrestore(&imxdma->lock, flags);
+ return;
}
desc = list_first_entry(&imxdmac->ld_active, struct imxdma_desc, node);

- if (desc->desc.callback)
- desc->desc.callback(desc->desc.callback_param);
-
/* If we are dealing with a cyclic descriptor, keep it on ld_active
* and dont mark the descriptor as complete.
* Only in non-cyclic cases it would be marked as complete
@@ -661,6 +659,10 @@ static void imxdma_tasklet(unsigned long data)
}
out:
spin_unlock_irqrestore(&imxdma->lock, flags);
+
+ if (desc->desc.callback)
+ desc->desc.callback(desc->desc.callback_param);
+
}

static int imxdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
--
1.8.4.rc3


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