Because of the possible failure of the platform_get_irq(), it should be
better to check it to avoid the use of error irq.
Fixes: 041f031def33 ("serial: mps2-uart: add MPS2 UART driver")
Signed-off-by: Jiasheng Jiang <[email protected]>
---
Changelog:
v2 -> v3
*Change 1. Using error variable to check.
*Change 2. Add new commit message.
---
drivers/tty/serial/mps2-uart.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c
index 587b42f754cb..24a52300d8d9 100644
--- a/drivers/tty/serial/mps2-uart.c
+++ b/drivers/tty/serial/mps2-uart.c
@@ -584,11 +584,29 @@ static int mps2_init_port(struct platform_device *pdev,
if (mps_port->flags & UART_PORT_COMBINED_IRQ) {
- mps_port->port.irq = platform_get_irq(pdev, 0);
+ ret = platform_get_irq(pdev, 0);
+ if (ret < 0)
+ return ret;
+
+ mps_port->port.irq = ret;
} else {
- mps_port->rx_irq = platform_get_irq(pdev, 0);
- mps_port->tx_irq = platform_get_irq(pdev, 1);
- mps_port->port.irq = platform_get_irq(pdev, 2);
+ ret = platform_get_irq(pdev, 0);
+ if (ret < 0)
+ return ret;
+
+ mps_port->rx_irq = ret;
+
+ ret = platform_get_irq(pdev, 1);
+ if (ret < 0)
+ return ret;
+
+ mps_port->tx_irq = ret;
+
+ ret = platform_get_irq(pdev, 2);
+ if (ret < 0)
+ return ret;
+
+ mps_port->port.irq = ret;
}
return ret;
--
2.25.1
On 2021-12-23 12:14, Jiasheng Jiang wrote:
> Because of the possible failure of the platform_get_irq(), it should be
> better to check it to avoid the use of error irq.
As far as I can see, the only "use" of error values is that they will be
passed to request_irq(), which will then return -EINVAL because they are
not valid IRQ numbers, and that error will be handled appropriately. I
think that's a relatively common pattern, so your commit message should
really describe why you think it's a problem and why this addition is a
meaningful improvement.
Robin.
> Fixes: 041f031def33 ("serial: mps2-uart: add MPS2 UART driver")
> Signed-off-by: Jiasheng Jiang <[email protected]>
> ---
> Changelog:
>
> v2 -> v3
>
> *Change 1. Using error variable to check.
> *Change 2. Add new commit message.
> ---
> drivers/tty/serial/mps2-uart.c | 26 ++++++++++++++++++++++----
> 1 file changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c
> index 587b42f754cb..24a52300d8d9 100644
> --- a/drivers/tty/serial/mps2-uart.c
> +++ b/drivers/tty/serial/mps2-uart.c
> @@ -584,11 +584,29 @@ static int mps2_init_port(struct platform_device *pdev,
>
>
> if (mps_port->flags & UART_PORT_COMBINED_IRQ) {
> - mps_port->port.irq = platform_get_irq(pdev, 0);
> + ret = platform_get_irq(pdev, 0);
> + if (ret < 0)
> + return ret;
> +
> + mps_port->port.irq = ret;
> } else {
> - mps_port->rx_irq = platform_get_irq(pdev, 0);
> - mps_port->tx_irq = platform_get_irq(pdev, 1);
> - mps_port->port.irq = platform_get_irq(pdev, 2);
> + ret = platform_get_irq(pdev, 0);
> + if (ret < 0)
> + return ret;
> +
> + mps_port->rx_irq = ret;
> +
> + ret = platform_get_irq(pdev, 1);
> + if (ret < 0)
> + return ret;
> +
> + mps_port->tx_irq = ret;
> +
> + ret = platform_get_irq(pdev, 2);
> + if (ret < 0)
> + return ret;
> +
> + mps_port->port.irq = ret;
> }
>
> return ret;
On 2021-12-23 12:54, Robin Murphy wrote:
>> Because of the possible failure of the platform_get_irq(), it should be
>> better to check it to avoid the use of error irq.
>
> As far as I can see, the only "use" of error values is that they will be
> passed to request_irq(), which will then return -EINVAL because they are
> not valid IRQ numbers, and that error will be handled appropriately. I
> think that's a relatively common pattern, so your commit message should
> really describe why you think it's a problem and why this addition is a
> meaningful improvement.
Thanks for your reminder, and I correct my commit message as follow.
If that's ok, I will correct my other patches like this.
For the possible failure of the platform_get_irq(), the returned irq
could be error number and will finally cause the failure of the request_irq().
So it might be better to check just now in order to avoid the waste of
later processes.
Sincerely thanks,
Jiasheng
On 2021-12-23 13:27, Jiasheng Jiang wrote:
> On 2021-12-23 12:54, Robin Murphy wrote:
>>> Because of the possible failure of the platform_get_irq(), it should be
>>> better to check it to avoid the use of error irq.
>>
>> As far as I can see, the only "use" of error values is that they will be
>> passed to request_irq(), which will then return -EINVAL because they are
>> not valid IRQ numbers, and that error will be handled appropriately. I
>> think that's a relatively common pattern, so your commit message should
>> really describe why you think it's a problem and why this addition is a
>> meaningful improvement.
>
> Thanks for your reminder, and I correct my commit message as follow.
> If that's ok, I will correct my other patches like this.
>
> For the possible failure of the platform_get_irq(), the returned irq
> could be error number and will finally cause the failure of the request_irq().
> So it might be better to check just now in order to avoid the waste of
> later processes.
Even better, consider that platform_get_irq() can now in certain cases
return -EPROBE_DEFER, and the consequences of letting request_irq()
effectively convert that into -EINVAL, even at probe time rather than
later on ;)
Cheers,
Robin.
>
> Sincerely thanks,
> Jiasheng
>