The newly added xilinx_dma_prep_dma_cyclic function sometimes causes
a gcc warning about the use of the segment function in case
we never run into the inner loop of the function:
dma/xilinx/xilinx_vdma.c: In function 'xilinx_dma_prep_dma_cyclic':
dma/xilinx/xilinx_vdma.c:1808:23: error: 'segment' may be used uninitialized in
this function [-Werror=maybe-uninitialized]
segment->hw.control |= XILINX_DMA_BD_SOP;
This can only happen if the period len is zero (which would cause other
problems earlier), or if the buffer is shorter than a period. Neither
of them should ever happen, but by adding an explicit check for these two
cases, we can abort in a more controlled way, and the compiler is
able to see that we never use uninitialized data.
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
drivers/dma/xilinx/xilinx_vdma.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/dma/xilinx/xilinx_vdma.c b/drivers/dma/xilinx/xilinx_vdma.c
index 0f5b38a0e46f..2ac3253bc823 100644
--- a/drivers/dma/xilinx/xilinx_vdma.c
+++ b/drivers/dma/xilinx/xilinx_vdma.c
@@ -1745,8 +1745,14 @@ static struct dma_async_tx_descriptor
*xilinx_dma_prep_dma_cyclic(
int i;
u32 reg;
+ if (!period_len)
+ return NULL;
+
num_periods = buf_len / period_len;
+ if (!num_periods)
+ return NULL;
+
if (!is_slave_direction(direction))
return NULL;
--
2.7.0
