| Message ID | 1458646574-12830-1-git-send-email-shawn.lin@rock-chips.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 <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. 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 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, On Tue, Mar 22, 2016 at 4:36 AM, Shawn Lin <shawn.lin@rock-chips.com> 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"); Please change from: dma_request_slave_channel() to: dma_request_chan() The first will never return -EPROBE_DEFER. The second will. > if (IS_ERR_OR_NULL(rs->dma_tx.ch)) { Once you've changed to dma_request_chan(), change IS_ERR_OR_NULL() to just IS_ERR(). dma_request_chan() never returns NULL. > /* 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)) { Once you've changed to use dma_request_chan(), no need to change this line. Leave it as it was. > 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)) { > 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; Same comments apply to the rx path. -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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)) { 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)) { 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) {
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(-)