[PATCH] dmaengine: ensure dmaengine helpers check valid callback

[Vinod Koul <vinod.koul@xxxxxxxxx>]

dmaengine has various device callbacks and exposes helper
functions to invoke these. These helpers should check if channel,
device and callback is valid or not before invoking them.

Reported-by: Jon Hunter <jonathanh@xxxxxxxxxx>
Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
---
 include/linux/dmaengine.h | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 017433712833..30de0197263a 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -804,6 +804,9 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_slave_single(
 	sg_dma_address(&sg) = buf;
 	sg_dma_len(&sg) = len;
 
+	if (!chan || !chan->device || !chan->device->device_prep_slave_sg)
+		return NULL;
+
 	return chan->device->device_prep_slave_sg(chan, &sg, 1,
 						  dir, flags, NULL);
 }
@@ -812,6 +815,9 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_slave_sg(
 	struct dma_chan *chan, struct scatterlist *sgl,	unsigned int sg_len,
 	enum dma_transfer_direction dir, unsigned long flags)
 {
+	if (!chan || !chan->device || !chan->device->device_prep_slave_sg)
+		return NULL;
+
 	return chan->device->device_prep_slave_sg(chan, sgl, sg_len,
 						  dir, flags, NULL);
 }
@@ -823,6 +829,9 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_rio_sg(
 	enum dma_transfer_direction dir, unsigned long flags,
 	struct rio_dma_ext *rio_ext)
 {
+	if (!chan || !chan->device || !chan->device->device_prep_slave_sg)
+		return NULL;
+
 	return chan->device->device_prep_slave_sg(chan, sgl, sg_len,
 						  dir, flags, rio_ext);
 }
@@ -833,6 +842,9 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_cyclic(
 		size_t period_len, enum dma_transfer_direction dir,
 		unsigned long flags)
 {
+	if (!chan || !chan->device || !chan->device->device_prep_dma_cyclic)
+		return NULL;
+
 	return chan->device->device_prep_dma_cyclic(chan, buf_addr, buf_len,
 						period_len, dir, flags);
 }
@@ -841,6 +853,9 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_interleaved_dma(
 		struct dma_chan *chan, struct dma_interleaved_template *xt,
 		unsigned long flags)
 {
+	if (!chan || !chan->device || !chan->device->device_prep_interleaved_dma)
+		return NULL;
+
 	return chan->device->device_prep_interleaved_dma(chan, xt, flags);
 }
 
@@ -848,7 +863,7 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memset(
 		struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
 		unsigned long flags)
 {
-	if (!chan || !chan->device)
+	if (!chan || !chan->device || !chan->device->device_prep_dma_memset)
 		return NULL;
 
 	return chan->device->device_prep_dma_memset(chan, dest, value,
@@ -861,6 +876,9 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_sg(
 		struct scatterlist *src_sg, unsigned int src_nents,
 		unsigned long flags)
 {
+	if (!chan || !chan->device || !chan->device->device_prep_dma_sg)
+		return NULL;
+
 	return chan->device->device_prep_dma_sg(chan, dst_sg, dst_nents,
 			src_sg, src_nents, flags);
 }
-- 
1.9.1

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