[PATCH 3/6] staging: comedi: comedi_fops: Remove useless statements

[PATCH 3/6] staging: comedi: comedi_fops: Remove useless statements

[Amitoj Kaur Chawla]

Drop if conditions that have an unrequired return in a void function.

Found using Coccinelle. The semantic patch used to find this is as
follows:

//<smpl>
@@
statement S;
expression e,x;
@@

* if(e)
(
{ ... return ...; }
&
S
)

* if(x)
(
{ ... return ...; }
&
S
)
//</smpl>

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
---
 drivers/staging/comedi/comedi_fops.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index d6bcf73..35e79d7 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2811,12 +2811,6 @@ void comedi_free_subdevice_minor(struct comedi_subdevice *s)
 {
 	unsigned int i;
 
-	if (!s)
-		return;
-	if (s->minor < COMEDI_NUM_BOARD_MINORS ||
-	    s->minor >= COMEDI_NUM_MINORS)
-		return;
-
 	i = s->minor - COMEDI_NUM_BOARD_MINORS;
 	mutex_lock(&comedi_subdevice_minor_table_lock);
 	if (s == comedi_subdevice_minor_table[i])
-- 
1.9.1

Re: [Outreachy kernel] [PATCH 3/6] staging: comedi: comedi_fops: Remove useless statements

[Julia Lawall]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1774 bytes --]

On Wed, 10 Feb 2016, Amitoj Kaur Chawla wrote:

> Drop if conditions that have an unrequired return in a void function.

The return is needed if it doesn´t come at the end of the function.  You
want to skip over the rest of the code.

julia

>
> Found using Coccinelle. The semantic patch used to find this is as
> follows:
>
> //<smpl>
> @@
> statement S;
> expression e,x;
> @@
>
> * if(e)
> (
> { ... return ...; }
> &
> S
> )
>
> * if(x)
> (
> { ... return ...; }
> &
> S
> )
> //</smpl>
>
> Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
> ---
>  drivers/staging/comedi/comedi_fops.c | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
> index d6bcf73..35e79d7 100644
> --- a/drivers/staging/comedi/comedi_fops.c
> +++ b/drivers/staging/comedi/comedi_fops.c
> @@ -2811,12 +2811,6 @@ void comedi_free_subdevice_minor(struct comedi_subdevice *s)
>  {
>  	unsigned int i;
>
> -	if (!s)
> -		return;
> -	if (s->minor < COMEDI_NUM_BOARD_MINORS ||
> -	    s->minor >= COMEDI_NUM_MINORS)
> -		return;
> -
>  	i = s->minor - COMEDI_NUM_BOARD_MINORS;
>  	mutex_lock(&comedi_subdevice_minor_table_lock);
>  	if (s == comedi_subdevice_minor_table[i])
> --
> 1.9.1
>
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Re: [Outreachy kernel] [PATCH 3/6] staging: comedi: comedi_fops: Remove useless statements

[Greg KH]

On Wed, Feb 10, 2016 at 02:29:22PM +0530, Amitoj Kaur Chawla wrote:
> Drop if conditions that have an unrequired return in a void function.
> 
> Found using Coccinelle. The semantic patch used to find this is as
> follows:
> 
> //<smpl>
> @@
> statement S;
> expression e,x;
> @@
> 
> * if(e)
> (
> { ... return ...; }
> &
> S
> )
> 
> * if(x)
> (
> { ... return ...; }
> &
> S
> )
> //</smpl>
> 
> Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
> ---
>  drivers/staging/comedi/comedi_fops.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
> index d6bcf73..35e79d7 100644
> --- a/drivers/staging/comedi/comedi_fops.c
> +++ b/drivers/staging/comedi/comedi_fops.c
> @@ -2811,12 +2811,6 @@ void comedi_free_subdevice_minor(struct comedi_subdevice *s)
>  {
>  	unsigned int i;
>  
> -	if (!s)
> -		return;
> -	if (s->minor < COMEDI_NUM_BOARD_MINORS ||
> -	    s->minor >= COMEDI_NUM_MINORS)
> -		return;
> -

And you just crashed the kernel :(

not good...

Please be more careful.

greg k-h