Hi Shawn,
On 22.03.2016 13:36, Shawn Lin wrote:
> Let's improve the check with -EPROBE_DEFER, otherwise
> we may pass on null pointer to PTR_ERR. That causes the
> static checker warning: passing zero to 'PTR_ERR'.
>
> Reported-by: Dan Carpenter <[email protected]>
> Cc: Doug Anderson <[email protected]>
> Cc: Dan Carpenter <[email protected]>
> Signed-off-by: Shawn Lin <[email protected]>
> ---
>
> drivers/spi/spi-rockchip.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
> index bfeb0d4..2cb36d9 100644
> --- a/drivers/spi/spi-rockchip.c
> +++ b/drivers/spi/spi-rockchip.c
> @@ -726,20 +726,24 @@ static int rockchip_spi_probe(struct platform_device
> *pdev)
> rs->dma_tx.ch = dma_request_slave_channel(rs->dev, "tx");
> if (IS_ERR_OR_NULL(rs->dma_tx.ch)) {
> /* Check tx to see if we need defer probing driver */
> - if (PTR_ERR(rs->dma_tx.ch) == -EPROBE_DEFER) {
> + if (rs->dma_tx.ch == ERR_PTR(-EPROBE_DEFER)) {
won't it be easier to change dma_request_slave_channel() to
dma_request_chan() or dma_request_slave_channel_reason() and replace strange
IS_ERR_OR_NULL() check with IS_ERR() one?
AFAIU that's almost what has been suggested by Doug and it is a better
fix than this one published.
At the moment check for IS_ERR_OR_NULL() is too aggressive and quite
confusing, because dma_request_slave_channel() never returns NULL.
> ret = -EPROBE_DEFER;
> goto err_get_fifo_len;
> }
> dev_warn(rs->dev, "Failed to request TX DMA channel\n");
> + rs->dma_tx.ch = NULL;
> }
>
> rs->dma_rx.ch = dma_request_slave_channel(rs->dev, "rx");
> - if (!rs->dma_rx.ch) {
> - if (rs->dma_tx.ch) {
> + if (IS_ERR_OR_NULL(rs->dma_rx.ch)) {
> + if (rs->dma_tx.ch == ERR_PTR(-EPROBE_DEFER)) {
Same as above.
> dma_release_channel(rs->dma_tx.ch);
> rs->dma_tx.ch = NULL;
> + ret = -EPROBE_DEFER;
> + goto err_get_fifo_len;
> }
> dev_warn(rs->dev, "Failed to request RX DMA channel\n");
> + rs->dma_rx.ch = NULL;
> }
>
> if (rs->dma_tx.ch && rs->dma_rx.ch) {
>
--
With best wishes,
Vladimir
