Re: [Outreachy kernel] [PATCH] staging : media : atomisp : input_system.c : fixes the error of control reaches end of non-void function [-Werror=return-type]

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

On Friday, October 15, 2021 12:30:09 AM CEST Kushal Kothari wrote:
> The compiler cannot tell from that code if the function will ever reach
> the end and still return something. To make that clear, replaced the last
> line with just "else" which fixes the error of "error: control reaches end 
of non-void function [-Werror=return-type]"
> 
> Signed-off-by: Kushal Kothari <kushalkothari285@gmail.com>
> ---
>  .../media/atomisp/pci/hive_isp_css_common/host/input_system.c    | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/staging/media/atomisp/pci/hive_isp_css_common/host/
input_system.c b/drivers/staging/media/atomisp/pci/hive_isp_css_common/host/
input_system.c
> index 8e085dda0c18..91bad8f34efc 100644
> --- a/drivers/staging/media/atomisp/pci/hive_isp_css_common/host/
input_system.c
> +++ b/drivers/staging/media/atomisp/pci/hive_isp_css_common/host/
input_system.c
> @@ -1587,6 +1587,7 @@ static input_system_err_t 
input_system_configure_channel_sensor(
>  	status = set_source_type(&config.source_type, 
channel.source_type,
>  				 &config.source_type_flags);
>  	if (status != INPUT_SYSTEM_ERR_NO_ERROR) return status;
> +	else return status;

Hi Kushal,

Aside from what Alison said about not accepting patches in this driver this 
round, please note that this is not the correct way to address that compiler 
warning.

Think about it: now, whatever "state" you get from set_source_type(), you 
always return it to the caller of input_system_configure_channel_sensor().

By doing so, you change the logic of the function and get dead code. This 
change makes the rest of the function code unreachable and introduces a huge 
bug.

While the patch cannot be accepted for Outreachy, think of a better solution 
as you may need to make similar changes in future patches.

Thanks and welcome,

Fabio M. De Francesco

>  
>  	// Check for conflicts on source (implicitly on multicast, 
capture unit and input buffer).
>  
> -- 
> 2.25.1
> 
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