On 22.03.2016 14:56, Vladimir Zapolskiy wrote:
> 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.
Sorry for a typo, never returns IS_ERR() of course.
>> 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
