On Mon, Mar 14, 2016 at 06:21:00PM +0800, Shawn Lin wrote:
> On 2016/3/14 17:48, Dan Carpenter wrote:
> >Hello Shawn Lin,
> >
> >The patch 61cadcf46cfd: "spi: rockchip: check requesting dma channel
> >with EPROBE_DEFER" from Mar 9, 2016, leads to the following static
> >checker warning:
> >
> > drivers/spi/spi-rockchip.c:742 rockchip_spi_probe()
> > warn: passing zero to 'PTR_ERR'
> >
> >drivers/spi/spi-rockchip.c
> > 732
> > 733 rs->dma_tx.ch = dma_request_slave_channel(rs->dev, "tx");
> > 734 if (IS_ERR_OR_NULL(rs->dma_tx.ch)) {
> > 735 /* Check tx to see if we need defer probing driver */
> > 736 if (PTR_ERR(rs->dma_tx.ch) == -EPROBE_DEFER) {
> > 737 ret = -EPROBE_DEFER;
> > 738 goto err_get_fifo_len;
> >
> >What's going on here? Are we planning to change dma_request_slave_channel()
> >to return error pointers? Also what about other error pointers besides
> >EPROBE_DEFER it seems dangerous to leave rs->dma_tx.ch as an error
> >pointer. We probably eventually try to free it if it's non-NULL.
>
> yes, we are plannig to return EPROBE_DEFER/NULL for
> dma_request_slave_channel to make sure we don't decide
> the dma cap based on driver probe sequence.
>
> No any other error pointer will be returned to the caller
It would not be terribly shocking if a couple years from now someone
else adds a new error return without auditing all the caller functions.
regards,
dan carpenter
