[PATCH] staging: most: usb: Remove variable frame_size

[PATCH] staging: most: usb: Remove variable frame_size

[Nishka Dasgupta]

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@gmail.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;
 }
 
 /**
-- 
2.19.1

Re: [PATCH] staging: most: usb: Remove variable frame_size

[Greg KH]

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@gmail.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.

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

Re: [PATCH] staging: most: usb: Remove variable frame_size

[Christian.Gromm]

On Do, 2019-05-23 at 18:53 +0530, Nishka Dasgupta wrote:
> External E-Mail
> 
> 
> 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@gmail.com>

Acked-by: Christian Gromm <christian.gromm@microchip.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;
>  }
>  
>  /**

Re: [PATCH] staging: most: usb: Remove variable frame_size

[Christian.Gromm]

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@gmail.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
>