[PATCH] dmaengine: imx-dma: fix missing irq disable in tasklet
Dirk Behme
dirk.behme at de.bosch.com
Fri Nov 9 02:00:04 EST 2012
From: Andreas Pape <external.Andreas.Pape at de.bosch.com>
Interrupt handler uses spinlock, too.
To avoid deadlock tasklet must disable IRQ.
Signed-off-by: Andreas Pape <external.Andreas.Pape at de.bosch.com>
CC: Vinod Koul <vinod.koul at linux.intel.com>
CC: Javier Martin <javier.martin at vista-silicon.com>
CC: Sascha Hauer <s.hauer at pengutronix.de>
---
I'm no DMA expert, so sorry if it's wrong ;)
And btw.: While looking at this code, we wonder if imxdma_xfer_desc() can
get the spin lock recursively, e.g. from imxdma_tasklet()? Or what ensures
that the lock is always taken from an other DMA engine than the one already
holding the lock?
drivers/dma/imx-dma.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
index 7d9554c..bce30e8 100644
--- a/drivers/dma/imx-dma.c
+++ b/drivers/dma/imx-dma.c
@@ -562,8 +562,9 @@ static void imxdma_tasklet(unsigned long data)
struct imxdma_channel *imxdmac = (void *)data;
struct imxdma_engine *imxdma = imxdmac->imxdma;
struct imxdma_desc *desc;
+ unsigned long flags;
- spin_lock(&imxdma->lock);
+ spin_lock_irqsave(&imxdma->lock, flags);
if (list_empty(&imxdmac->ld_active)) {
/* Someone might have called terminate all */
@@ -600,7 +601,7 @@ static void imxdma_tasklet(unsigned long data)
__func__, imxdmac->channel);
}
out:
- spin_unlock(&imxdma->lock);
+ spin_unlock_irqrestore(&imxdma->lock, flags);
}
static int imxdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
--
1.7.0.4
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