[PATCH] dmaengine: imx-dma: fix missing irq disable in tasklet
From: Dirk Behme <hidden>
Date: 2012-11-09 07:00:04
Subsystem:
dma generic offload engine subsystem, the rest · Maintainers:
Vinod Koul, Linus Torvalds
From: Andreas Pape <redacted> Interrupt handler uses spinlock, too. To avoid deadlock tasklet must disable IRQ. Signed-off-by: Andreas Pape <redacted> CC: Vinod Koul <redacted> CC: Javier Martin <redacted> CC: Sascha Hauer <s.hauer@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,
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1.7.0.4