linux-kernel - Re: [PATCH v4 03/13] media: pci: cx18-av-vbi: Replace open-coded parity calculation with parity

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Message-ID: <Z/bDnLzcajzIxey3@visitorckw-System-Product-Name>
Date: Thu, 10 Apr 2025 02:59:40 +0800
From: Kuan-Wei Chiu <visitorckw@...il.com>
To: Arend van Spriel <arend.vanspriel@...adcom.com>
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	Yu-Chun Lin <eleanor15x@...il.com>
Subject: Re: [PATCH v4 03/13] media: pci: cx18-av-vbi: Replace open-coded
 parity calculation with parity_odd()

On Wed, Apr 09, 2025 at 08:43:09PM +0200, Arend van Spriel wrote:
> On 4/9/2025 5:43 PM, Kuan-Wei Chiu wrote:
> > Refactor parity calculations to use the standard parity_odd() helper.
> > This change eliminates redundant implementations.
> > 
> > Co-developed-by: Yu-Chun Lin <eleanor15x@...il.com>
> > Signed-off-by: Yu-Chun Lin <eleanor15x@...il.com>
> > Signed-off-by: Kuan-Wei Chiu <visitorckw@...il.com>
> > ---
> >   drivers/media/pci/cx18/cx18-av-vbi.c | 12 ++----------
> >   1 file changed, 2 insertions(+), 10 deletions(-)
> > 
> > diff --git a/drivers/media/pci/cx18/cx18-av-vbi.c b/drivers/media/pci/cx18/cx18-av-vbi.c
> > index 65281d40c681..15b515b95956 100644
> > --- a/drivers/media/pci/cx18/cx18-av-vbi.c
> > +++ b/drivers/media/pci/cx18/cx18-av-vbi.c
> 
> [...]
> 
> > @@ -278,7 +270,7 @@ int cx18_av_decode_vbi_line(struct v4l2_subdev *sd,
> >   		break;
> >   	case 6:
> >   		sdid = V4L2_SLICED_CAPTION_525;
> > -		err = !odd_parity(p[0]) || !odd_parity(p[1]);
> > +		err = !parity_odd(p[0]) || !parity_odd(p[1]);
> 
> No need to call parity_odd() twice here. Instead you could do:
> 
> 		err = !parity_odd(p[0] ^ p[1]);
> 
> This is orthogonal to the change to parity_odd() though. More specific to
> the new parity_odd() you can now do following as parity_odd() argument is
> u64:
> 
> 		err = !parity_odd(*(u16 *)p);
> 
> 
Thanks for the feedback!
Would you prefer this change to be part of the parity() conversion
patch, or in a separate one?

Regards,
Kuan-Wei