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 <arnd@xxxxxxxx> --- 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 -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
