linux-kernel - Re: [PATCH] staging: most: usb: Remove variable frame

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Date:   Fri, 24 May 2019 08:03:26 +0000
From:   <Christian.Gromm@...rochip.com>
To:     <gregkh@...uxfoundation.org>, <nishkadg.linux@...il.com>
CC:     <linux-kernel@...r.kernel.org>, <devel@...verdev.osuosl.org>
Subject: Re: [PATCH] staging: most: usb: Remove variable frame_size

On Do, 2019-05-23 at 18:51 +0200, Greg KH wrote:
> External E-Mail
> 
> 
> On Thu, May 23, 2019 at 06:53:34PM +0530, Nishka Dasgupta wrote:
> > 
> > Remove variable frame_size as its multiple usages are all
> > independent of
> > each other and so can be returned separately.
> > Issue found with Coccinelle.
> > 
> > Signed-off-by: Nishka Dasgupta <nishkadg.linux@...il.com>
> > ---
> >  drivers/staging/most/usb/usb.c | 16 ++++++----------
> >  1 file changed, 6 insertions(+), 10 deletions(-)
> > 
> > diff --git a/drivers/staging/most/usb/usb.c
> > b/drivers/staging/most/usb/usb.c
> > index 360cb5b7a10b..751e82cf66c5 100644
> > --- a/drivers/staging/most/usb/usb.c
> > +++ b/drivers/staging/most/usb/usb.c
> > @@ -186,32 +186,28 @@ static inline int start_sync_ep(struct
> > usb_device *usb_dev, u16 ep)
> >   */
> >  static unsigned int get_stream_frame_size(struct
> > most_channel_config *cfg)
> >  {
> > -	unsigned int frame_size = 0;
> >  	unsigned int sub_size = cfg->subbuffer_size;
> >  
> >  	if (!sub_size) {
> >  		pr_warn("Misconfig: Subbuffer size zero.\n");
> > -		return frame_size;
> > +		return 0;
> >  	}
> >  	switch (cfg->data_type) {
> >  	case MOST_CH_ISOC:
> > -		frame_size = AV_PACKETS_PER_XACT * sub_size;
> > -		break;
> > +		return AV_PACKETS_PER_XACT * sub_size;
> >  	case MOST_CH_SYNC:
> >  		if (cfg->packets_per_xact == 0) {
> >  			pr_warn("Misconfig: Packets per XACT
> > zero\n");
> > -			frame_size = 0;
> > +			return 0;
> >  		} else if (cfg->packets_per_xact == 0xFF) {
> > -			frame_size = (USB_MTU / sub_size) *
> > sub_size;
> > +			return (USB_MTU / sub_size) * sub_size;
> >  		} else {
> > -			frame_size = cfg->packets_per_xact *
> > sub_size;
> > +			return cfg->packets_per_xact * sub_size;
> >  		}
> > -		break;
> >  	default:
> >  		pr_warn("Query frame size of non-streaming
> > channel\n");
> > -		break;
> > +		return 0;
> >  	}
> > -	return frame_size;
> >  }
> Now it just feels like you are doing "busy work" :(
> 
> frame_size makes sense here, right?  Why change this code?
> 
> Remember, code is written for developers first, the compiler second.
> Reading this with frame_size makes it much more obvious what this
> code
> does when you read it again in 5-10 years.  Why change this, you have
> not made it faster, or smaller at all.
> 
> So no, I would not accept this, sorry.

I haven't seen this on time. So please ignore my acknowledge I've sent.
Good to know that you favor readability over compactness.

Sorry for the noise,
Chris

> 
> We have so many _real_ things to do in the drivers/staging/ directory
> if
> you are looking for stuff to clean up.  Don't try to micro-optimize
> things that do not matter at the expense of understanding.
> 
> thanks,
> 
> greg k-h
>