diff mbox series

[2/7] dmaengine: sprd: Add validation of current descriptor in irq handler

Message ID e2f3b8f2f5391565d0662d98524acf239ae8da6e.1555330115.git.baolin.wang@linaro.org
State Superseded
Headers show
Series Fix some bugs and add new feature for Spreadtrum DMA engine | expand

Commit Message

(Exiting) Baolin Wang April 15, 2019, 12:14 p.m. UTC
When user terminates one DMA channel to free all its descriptors, but
at the same time one transaction interrupt was triggered possibly, now
we should not handle this interrupt by validating if the 'schan->cur_desc'
was set as NULL to avoid crashing the kernel.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

---
 drivers/dma/sprd-dma.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

-- 
1.7.9.5
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Patch

diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index e29342a..431e289 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -552,12 +552,17 @@  static irqreturn_t dma_irq_handle(int irq, void *dev_id)
 		schan = &sdev->channels[i];
 
 		spin_lock(&schan->vc.lock);
+
+		sdesc = schan->cur_desc;
+		if (!sdesc) {
+			spin_unlock(&schan->vc.lock);
+			return IRQ_HANDLED;
+		}
+
 		int_type = sprd_dma_get_int_type(schan);
 		req_type = sprd_dma_get_req_type(schan);
 		sprd_dma_clear_int(schan);
 
-		sdesc = schan->cur_desc;
-
 		/* cyclic mode schedule callback */
 		cyclic = schan->linklist.phy_addr ? true : false;
 		if (cyclic == true) {