Re: [PATCH 05/17] media: atomisp: pci: fix inverted error check for ia_css_mipi_is_source_port_valid()

[Tsuchiya Yuto]

On Tue, 2021-11-02 at 14:33 +0300, Dan Carpenter wrote:
> On Mon, Oct 18, 2021 at 01:19:45AM +0900, Tsuchiya Yuto wrote:
> > The function ia_css_mipi_is_source_port_valid() returns true if the port
> > is valid. So, we can't use the existing err variable as is.
> > 
> > To fix this issue while reusing that variable, invert the return value
> > when assigning it to the variable.
> > 
> > Fixes: 3c0538fbad9f ("media: atomisp: get rid of most checks for ISP2401 version")
> > Signed-off-by: Tsuchiya Yuto <kitakar@xxxxxxxxx>
> > ---
> >  .../staging/media/atomisp/pci/sh_css_mipi.c   | 24 ++++++++++++-------
> >  1 file changed, 15 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/staging/media/atomisp/pci/sh_css_mipi.c b/drivers/staging/media/atomisp/pci/sh_css_mipi.c
> > index 65fc93c5d56b..c1f2f6151c5f 100644
> > --- a/drivers/staging/media/atomisp/pci/sh_css_mipi.c
> > +++ b/drivers/staging/media/atomisp/pci/sh_css_mipi.c
> > @@ -423,10 +423,12 @@ allocate_mipi_frames(struct ia_css_pipe *pipe,
> >  		return 0; /* AM TODO: Check  */
> >  	}
> >  
> > -	if (!IS_ISP2401)
> > +	if (!IS_ISP2401) {
> >  		port = (unsigned int)pipe->stream->config.source.port.port;
> > -	else
> > -		err = ia_css_mipi_is_source_port_valid(pipe, &port);
> > +	} else {
> > +		/* Returns true if port is valid. So, invert it */
> > +		err = !ia_css_mipi_is_source_port_valid(pipe, &port);
> 
> Don't invert it...  This isn't supposed to return 1 on failure it's
> supposed to return negative error codes.

You mean I should instead modify the return value of
ia_css_mipi_is_source_port_valid() ?

Yeah, I also thought that the current true/false return value was a little
bit confusing.

In another words, should the function return:

    - negative values (maybe -EINVAL for this case) for invalid case
    - 0 for valid case

instead? and if we go this way, we should also rename the function name
like

    - check_ia_css_mipi_source_port_validity

or something. How does this sound?

Regards,
Tsuchiya Yuto