Messages in this thread | | | Subject | Re: [PATCH] spi: rockchip: fix warning of static check | From | Vladimir Zapolskiy <> | Date | Tue, 22 Mar 2016 14:56:04 +0200 |
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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 <dan.carpenter@oracle.com> > Cc: Doug Anderson <dianders@chromium.org> > Cc: Dan Carpenter <dan.carpenter@oracle.com> > Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com> > --- > > 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
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