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* [PATCH] staging: media: davinci_vpfe: Replace explicit NULL comparison with ! operator
@ 2016-09-16 16:17 sayli karnik
  2016-09-16 16:32 ` [Outreachy kernel] " Julia Lawall
  0 siblings, 1 reply; 3+ messages in thread
From: sayli karnik @ 2016-09-16 16:17 UTC (permalink / raw)
  To: outreachy-kernel; +Cc: Mauro Carvalho Chehab, Greg Kroah-Hartman

This patch replaces the explicit NULL comparisons with ! operator.
It was found using Coccinelle:

@@
expression e;
@@
- e == NULL
+ !e

Signed-off-by: sayli karnik <karniksayli1995@gmail.com>
---
 drivers/staging/media/davinci_vpfe/vpfe_video.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/media/davinci_vpfe/vpfe_video.c b/drivers/staging/media/davinci_vpfe/vpfe_video.c
index 3319fb8..7483de0 100644
--- a/drivers/staging/media/davinci_vpfe/vpfe_video.c
+++ b/drivers/staging/media/davinci_vpfe/vpfe_video.c
@@ -37,7 +37,7 @@ static struct media_entity *vpfe_get_input_entity
 	struct media_pad *remote;
 
 	remote = media_entity_remote_pad(&vpfe_dev->vpfe_isif.pads[0]);
-	if (remote == NULL) {
+	if (!remote) {
 		pr_err("Invalid media connection to isif/ccdc\n");
 		return NULL;
 	}
@@ -54,7 +54,7 @@ static int vpfe_update_current_ext_subdev(struct vpfe_video_device *video)
 	int i;
 
 	remote = media_entity_remote_pad(&vpfe_dev->vpfe_isif.pads[0]);
-	if (remote == NULL) {
+	if (!remote) {
 		pr_err("Invalid media connection to isif/ccdc\n");
 		return -EINVAL;
 	}
@@ -75,8 +75,7 @@ static int vpfe_update_current_ext_subdev(struct vpfe_video_device *video)
 	}
 	/* find the v4l2 subdev pointer */
 	for (i = 0; i < vpfe_dev->num_ext_subdevs; i++) {
-		if (!strcmp(video->current_ext_subdev->module_name,
-			vpfe_dev->sd[i]->name))
+		if (!strcmp(video->current_ext_subdev->module_name, vpfe_dev->sd[i]->name))
 			video->current_ext_subdev->subdev = vpfe_dev->sd[i];
 	}
 	return 0;
@@ -107,7 +106,7 @@ __vpfe_video_get_format(struct vpfe_video_device *video,
 	int ret;
 
 	subdev = vpfe_video_remote_subdev(video, &pad);
-	if (subdev == NULL)
+	if (!subdev)
 		return -EINVAL;
 
 	fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
@@ -236,7 +235,7 @@ static int vpfe_video_validate_pipeline(struct vpfe_pipeline *pipe)
 	 * format of the connected pad.
 	 */
 	subdev = vpfe_video_remote_subdev(pipe->outputs[0], NULL);
-	if (subdev == NULL)
+	if (!subdev)
 		return -EPIPE;
 
 	while (1) {
@@ -413,7 +412,7 @@ static int vpfe_open(struct file *file)
 	/* Allocate memory for the file handle object */
 	handle = kzalloc(sizeof(struct vpfe_fh), GFP_KERNEL);
 
-	if (handle == NULL)
+	if (!handle)
 		return -ENOMEM;
 
 	v4l2_fh_init(&handle->vfh, &video->video_dev);
@@ -683,14 +682,14 @@ static int vpfe_enum_fmt(struct file *file, void  *priv,
 	}
 	/* get the remote pad */
 	remote = media_entity_remote_pad(&video->pad);
-	if (remote == NULL) {
+	if (!remote) {
 		v4l2_err(&vpfe_dev->v4l2_dev,
 			 "invalid remote pad for video node\n");
 		return -EINVAL;
 	}
 	/* get the remote subdev */
 	subdev = vpfe_video_remote_subdev(video, NULL);
-	if (subdev == NULL) {
+	if (!subdev) {
 		v4l2_err(&vpfe_dev->v4l2_dev,
 			 "invalid remote subdev for video node\n");
 		return -EINVAL;
-- 
2.7.4



^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [Outreachy kernel] [PATCH] staging: media: davinci_vpfe: Replace explicit NULL comparison with ! operator
  2016-09-16 16:17 [PATCH] staging: media: davinci_vpfe: Replace explicit NULL comparison with ! operator sayli karnik
@ 2016-09-16 16:32 ` Julia Lawall
  2016-09-16 17:35   ` sayli karnik
  0 siblings, 1 reply; 3+ messages in thread
From: Julia Lawall @ 2016-09-16 16:32 UTC (permalink / raw)
  To: sayli karnik; +Cc: outreachy-kernel, Mauro Carvalho Chehab, Greg Kroah-Hartman



On Fri, 16 Sep 2016, sayli karnik wrote:

> This patch replaces the explicit NULL comparisons with ! operator.
> It was found using Coccinelle:
>
> @@
> expression e;
> @@
> - e == NULL
> + !e
>
> Signed-off-by: sayli karnik <karniksayli1995@gmail.com>
> ---
>  drivers/staging/media/davinci_vpfe/vpfe_video.c | 17 ++++++++---------
>  1 file changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/staging/media/davinci_vpfe/vpfe_video.c b/drivers/staging/media/davinci_vpfe/vpfe_video.c
> index 3319fb8..7483de0 100644
> --- a/drivers/staging/media/davinci_vpfe/vpfe_video.c
> +++ b/drivers/staging/media/davinci_vpfe/vpfe_video.c
> @@ -37,7 +37,7 @@ static struct media_entity *vpfe_get_input_entity
>  	struct media_pad *remote;
>
>  	remote = media_entity_remote_pad(&vpfe_dev->vpfe_isif.pads[0]);
> -	if (remote == NULL) {
> +	if (!remote) {
>  		pr_err("Invalid media connection to isif/ccdc\n");
>  		return NULL;
>  	}
> @@ -54,7 +54,7 @@ static int vpfe_update_current_ext_subdev(struct vpfe_video_device *video)
>  	int i;
>
>  	remote = media_entity_remote_pad(&vpfe_dev->vpfe_isif.pads[0]);
> -	if (remote == NULL) {
> +	if (!remote) {
>  		pr_err("Invalid media connection to isif/ccdc\n");
>  		return -EINVAL;
>  	}
> @@ -75,8 +75,7 @@ static int vpfe_update_current_ext_subdev(struct vpfe_video_device *video)
>  	}
>  	/* find the v4l2 subdev pointer */
>  	for (i = 0; i < vpfe_dev->num_ext_subdevs; i++) {
> -		if (!strcmp(video->current_ext_subdev->module_name,
> -			vpfe_dev->sd[i]->name))
> +		if (!strcmp(video->current_ext_subdev->module_name, vpfe_dev->sd[i]->name))

Here you reformatted exiting code in an unpleasant way.  Checkpatch should
have complained about this.

You might wonder why Coccielle did this, when there is not == NULL here.
The reason is that Coccinelle has a feature called an "isomorphism" that
makes it consider some forms of code to be pretty much the same as some
other forms of code.  In particular, if you make a pattern with x == NULL,
it will also match !x and NULL == x, because for most purposes they are
all the same.

That is not what you want here, though.  Just put disable is_null in
between the initial @@ of your rule (ie @disable is_null@), and the
problem will go away.  You can find the definition of is_null in the file
standard.iso in your Coccinelle distributions.  You can read more about
isomorphisms in the tutorial:

http://coccinelle.lip6.fr/papers/tutorial.pdf

slide 38 and onwards.

julia

>  			video->current_ext_subdev->subdev = vpfe_dev->sd[i];
>  	}
>  	return 0;
> @@ -107,7 +106,7 @@ __vpfe_video_get_format(struct vpfe_video_device *video,
>  	int ret;
>
>  	subdev = vpfe_video_remote_subdev(video, &pad);
> -	if (subdev == NULL)
> +	if (!subdev)
>  		return -EINVAL;
>
>  	fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> @@ -236,7 +235,7 @@ static int vpfe_video_validate_pipeline(struct vpfe_pipeline *pipe)
>  	 * format of the connected pad.
>  	 */
>  	subdev = vpfe_video_remote_subdev(pipe->outputs[0], NULL);
> -	if (subdev == NULL)
> +	if (!subdev)
>  		return -EPIPE;
>
>  	while (1) {
> @@ -413,7 +412,7 @@ static int vpfe_open(struct file *file)
>  	/* Allocate memory for the file handle object */
>  	handle = kzalloc(sizeof(struct vpfe_fh), GFP_KERNEL);
>
> -	if (handle == NULL)
> +	if (!handle)
>  		return -ENOMEM;
>
>  	v4l2_fh_init(&handle->vfh, &video->video_dev);
> @@ -683,14 +682,14 @@ static int vpfe_enum_fmt(struct file *file, void  *priv,
>  	}
>  	/* get the remote pad */
>  	remote = media_entity_remote_pad(&video->pad);
> -	if (remote == NULL) {
> +	if (!remote) {
>  		v4l2_err(&vpfe_dev->v4l2_dev,
>  			 "invalid remote pad for video node\n");
>  		return -EINVAL;
>  	}
>  	/* get the remote subdev */
>  	subdev = vpfe_video_remote_subdev(video, NULL);
> -	if (subdev == NULL) {
> +	if (!subdev) {
>  		v4l2_err(&vpfe_dev->v4l2_dev,
>  			 "invalid remote subdev for video node\n");
>  		return -EINVAL;
> --
> 2.7.4
>
> --
> You received this message because you are subscribed to the Google Groups "outreachy-kernel" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to outreachy-kernel+unsubscribe@googlegroups.com.
> To post to this group, send email to outreachy-kernel@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/outreachy-kernel/20160916161701.GA25197%40sayli-HP-15-Notebook-PC.
> For more options, visit https://groups.google.com/d/optout.
>


^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [Outreachy kernel] [PATCH] staging: media: davinci_vpfe: Replace explicit NULL comparison with ! operator
  2016-09-16 16:32 ` [Outreachy kernel] " Julia Lawall
@ 2016-09-16 17:35   ` sayli karnik
  0 siblings, 0 replies; 3+ messages in thread
From: sayli karnik @ 2016-09-16 17:35 UTC (permalink / raw)
  To: Julia Lawall; +Cc: outreachy-kernel, Mauro Carvalho Chehab, Greg Kroah-Hartman

On Fri, Sep 16, 2016 at 10:02 PM, Julia Lawall <julia.lawall@lip6.fr> wrote:
>
>
> On Fri, 16 Sep 2016, sayli karnik wrote:
>
>> This patch replaces the explicit NULL comparisons with ! operator.
>> It was found using Coccinelle:
>>
>> @@
>> expression e;
>> @@
>> - e == NULL
>> + !e
>>
>> Signed-off-by: sayli karnik <karniksayli1995@gmail.com>
>> ---
>>  drivers/staging/media/davinci_vpfe/vpfe_video.c | 17 ++++++++---------
>>  1 file changed, 8 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/staging/media/davinci_vpfe/vpfe_video.c b/drivers/staging/media/davinci_vpfe/vpfe_video.c
>> index 3319fb8..7483de0 100644
>> --- a/drivers/staging/media/davinci_vpfe/vpfe_video.c
>> +++ b/drivers/staging/media/davinci_vpfe/vpfe_video.c
>> @@ -37,7 +37,7 @@ static struct media_entity *vpfe_get_input_entity
>>       struct media_pad *remote;
>>
>>       remote = media_entity_remote_pad(&vpfe_dev->vpfe_isif.pads[0]);
>> -     if (remote == NULL) {
>> +     if (!remote) {
>>               pr_err("Invalid media connection to isif/ccdc\n");
>>               return NULL;
>>       }
>> @@ -54,7 +54,7 @@ static int vpfe_update_current_ext_subdev(struct vpfe_video_device *video)
>>       int i;
>>
>>       remote = media_entity_remote_pad(&vpfe_dev->vpfe_isif.pads[0]);
>> -     if (remote == NULL) {
>> +     if (!remote) {
>>               pr_err("Invalid media connection to isif/ccdc\n");
>>               return -EINVAL;
>>       }
>> @@ -75,8 +75,7 @@ static int vpfe_update_current_ext_subdev(struct vpfe_video_device *video)
>>       }
>>       /* find the v4l2 subdev pointer */
>>       for (i = 0; i < vpfe_dev->num_ext_subdevs; i++) {
>> -             if (!strcmp(video->current_ext_subdev->module_name,
>> -                     vpfe_dev->sd[i]->name))
>> +             if (!strcmp(video->current_ext_subdev->module_name, vpfe_dev->sd[i]->name))
>
> Here you reformatted exiting code in an unpleasant way.  Checkpatch should
> have complained about this.
>
> You might wonder why Coccielle did this, when there is not == NULL here.
> The reason is that Coccinelle has a feature called an "isomorphism" that
> makes it consider some forms of code to be pretty much the same as some
> other forms of code.  In particular, if you make a pattern with x == NULL,
> it will also match !x and NULL == x, because for most purposes they are
> all the same.
>
> That is not what you want here, though.  Just put disable is_null in
> between the initial @@ of your rule (ie @disable is_null@), and the
> problem will go away.  You can find the definition of is_null in the file
> standard.iso in your Coccinelle distributions.  You can read more about
> isomorphisms in the tutorial:
>
> http://coccinelle.lip6.fr/papers/tutorial.pdf
>
> slide 38 and onwards.
>

Ah, this is interesting! I'll read up and send a v2.

thanks a lot!

sayli

> julia
>
>>                       video->current_ext_subdev->subdev = vpfe_dev->sd[i];
>>       }
>>       return 0;
>> @@ -107,7 +106,7 @@ __vpfe_video_get_format(struct vpfe_video_device *video,
>>       int ret;
>>
>>       subdev = vpfe_video_remote_subdev(video, &pad);
>> -     if (subdev == NULL)
>> +     if (!subdev)
>>               return -EINVAL;
>>
>>       fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
>> @@ -236,7 +235,7 @@ static int vpfe_video_validate_pipeline(struct vpfe_pipeline *pipe)
>>        * format of the connected pad.
>>        */
>>       subdev = vpfe_video_remote_subdev(pipe->outputs[0], NULL);
>> -     if (subdev == NULL)
>> +     if (!subdev)
>>               return -EPIPE;
>>
>>       while (1) {
>> @@ -413,7 +412,7 @@ static int vpfe_open(struct file *file)
>>       /* Allocate memory for the file handle object */
>>       handle = kzalloc(sizeof(struct vpfe_fh), GFP_KERNEL);
>>
>> -     if (handle == NULL)
>> +     if (!handle)
>>               return -ENOMEM;
>>
>>       v4l2_fh_init(&handle->vfh, &video->video_dev);
>> @@ -683,14 +682,14 @@ static int vpfe_enum_fmt(struct file *file, void  *priv,
>>       }
>>       /* get the remote pad */
>>       remote = media_entity_remote_pad(&video->pad);
>> -     if (remote == NULL) {
>> +     if (!remote) {
>>               v4l2_err(&vpfe_dev->v4l2_dev,
>>                        "invalid remote pad for video node\n");
>>               return -EINVAL;
>>       }
>>       /* get the remote subdev */
>>       subdev = vpfe_video_remote_subdev(video, NULL);
>> -     if (subdev == NULL) {
>> +     if (!subdev) {
>>               v4l2_err(&vpfe_dev->v4l2_dev,
>>                        "invalid remote subdev for video node\n");
>>               return -EINVAL;
>> --
>> 2.7.4
>>
>> --
>> You received this message because you are subscribed to the Google Groups "outreachy-kernel" group.
>> To unsubscribe from this group and stop receiving emails from it, send an email to outreachy-kernel+unsubscribe@googlegroups.com.
>> To post to this group, send email to outreachy-kernel@googlegroups.com.
>> To view this discussion on the web visit https://groups.google.com/d/msgid/outreachy-kernel/20160916161701.GA25197%40sayli-HP-15-Notebook-PC.
>> For more options, visit https://groups.google.com/d/optout.
>>


^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2016-09-16 17:36 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2016-09-16 16:17 [PATCH] staging: media: davinci_vpfe: Replace explicit NULL comparison with ! operator sayli karnik
2016-09-16 16:32 ` [Outreachy kernel] " Julia Lawall
2016-09-16 17:35   ` sayli karnik

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