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[PATCH 0/2] ALSA: compress: Fine-tuning for snd_compr_set_params()

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  [PATCH 0/2] ALSA: compress: Fine-tuning for snd_compr_set_params() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-08-21 21:50 +0200
    [PATCH 1/2] ALSA: compress: Use memdup_user() rather than duplicating  its implementation SF Markus Elfring <elfring@users.sourceforge.net> - 2016-08-21 21:50 +0200
      Re: [PATCH 1/2] ALSA: compress: Use memdup_user() rather than  duplicating its implementation Vinod Koul <vinod.koul@intel.com> - 2016-08-22 07:00 +0200
      Re: [alsa-devel] [PATCH 1/2] ALSA: compress: Use memdup_user() rather than duplicating its implementation Takashi Iwai <tiwai@suse.de> - 2016-08-22 14:10 +0200
        Re: [alsa-devel] [PATCH 1/2] ALSA: compress: Use memdup_user()  rather than duplicating its implementation Vinod Koul <vinod.koul@intel.com> - 2016-08-23 05:50 +0200
    [PATCH 2/2] ALSA: compress: Reduce the scope for two variables in  snd_compr_set_params() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-08-21 21:50 +0200
      Re: [PATCH 2/2] ALSA: compress: Reduce the scope for two variables  in snd_compr_set_params() Joe Perches <joe@perches.com> - 2016-08-21 22:00 +0200
        [PATCH v2 0/2] ALSA: compress: Fine-tuning for snd_compr_set_params() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-08-22 10:40 +0200
          [PATCH v2 1/2] ALSA: compress: Restructure source code around an if  statement in snd_compr_set_params() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-08-22 10:40 +0200
          [PATCH v2 2/2] ALSA: compress: Use memdup_user() rather than  duplicating its implementation SF Markus Elfring <elfring@users.sourceforge.net> - 2016-08-22 10:50 +0200
          Re: [PATCH v2 0/2] ALSA: compress: Fine-tuning for  snd_compr_set_params() Vinod Koul <vinod.koul@intel.com> - 2016-08-23 06:00 +0200
      Re: [PATCH 2/2] ALSA: compress: Reduce the scope for two variables  in snd_compr_set_params() Julia Lawall <julia.lawall@lip6.fr> - 2016-08-21 22:40 +0200
        Re: [PATCH 2/2] ALSA: compress: Reduce the scope for two variables  in snd_compr_set_params() Vinod Koul <vinod.koul@intel.com> - 2016-08-22 07:00 +0200
      Re: [PATCH 2/2] ALSA: compress: Reduce the scope for two variables  in snd_compr_set_params() walter harms <wharms@bfs.de> - 2016-08-22 09:30 +0200

#1467223 — [PATCH 0/2] ALSA: compress: Fine-tuning for snd_compr_set_params()

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 21 Aug 2016 21:35:43 +0200

A few update suggestions were taken into account
from static source code analysis.

Markus Elfring (2):
  Use memdup_user()
  Reduce the scope for two variables

 sound/core/compress_offload.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

-- 
2.9.3

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#1467224 — [PATCH 1/2] ALSA: compress: Use memdup_user() rather than duplicating its implementation

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 21 Aug 2016 21:02:06 +0200

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 sound/core/compress_offload.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index 2c49848..583d407 100644
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -553,13 +553,9 @@ snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
 		 * we should allow parameter change only when stream has been
 		 * opened not in other cases
 		 */
-		params = kmalloc(sizeof(*params), GFP_KERNEL);
-		if (!params)
-			return -ENOMEM;
-		if (copy_from_user(params, (void __user *)arg, sizeof(*params))) {
-			retval = -EFAULT;
-			goto out;
-		}
+		params = memdup_user((void __user *)arg, sizeof(*params));
+		if (IS_ERR(params))
+			return PTR_ERR(params);
 
 		retval = snd_compress_check_input(params);
 		if (retval)
-- 
2.9.3

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#1467369 — Re: [PATCH 1/2] ALSA: compress: Use memdup_user() rather than duplicating its implementation

On Sun, Aug 21, 2016 at 09:43:22PM +0200, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 21 Aug 2016 21:02:06 +0200
> 
> Reuse existing functionality from memdup_user() instead of keeping
> duplicate source code.
> 
> This issue was detected by using the Coccinelle software.

It usually helps to have Coccinelle script in changelog.

But nevertheless

Acked-by: Vinod Koul <vinod.koul@intel.com>

> 
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>  sound/core/compress_offload.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
> index 2c49848..583d407 100644
> --- a/sound/core/compress_offload.c
> +++ b/sound/core/compress_offload.c
> @@ -553,13 +553,9 @@ snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
>  		 * we should allow parameter change only when stream has been
>  		 * opened not in other cases
>  		 */
> -		params = kmalloc(sizeof(*params), GFP_KERNEL);
> -		if (!params)
> -			return -ENOMEM;
> -		if (copy_from_user(params, (void __user *)arg, sizeof(*params))) {
> -			retval = -EFAULT;
> -			goto out;
> -		}
> +		params = memdup_user((void __user *)arg, sizeof(*params));
> +		if (IS_ERR(params))
> +			return PTR_ERR(params);
>  
>  		retval = snd_compress_check_input(params);
>  		if (retval)
> -- 
> 2.9.3
> 

-- 
~Vinod

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#1467574 — Re: [alsa-devel] [PATCH 1/2] ALSA: compress: Use memdup_user() rather than duplicating its implementation

On Sun, 21 Aug 2016 21:43:22 +0200,
SF Markus Elfring wrote:
> 
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 21 Aug 2016 21:02:06 +0200
> 
> Reuse existing functionality from memdup_user() instead of keeping
> duplicate source code.
> 
> This issue was detected by using the Coccinelle software.
> 
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>

Applied this one, but the second patch won't be, since other people
seem to disagree with the usefulness.


thanks,

Takashi

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#1468257 — Re: [alsa-devel] [PATCH 1/2] ALSA: compress: Use memdup_user() rather than duplicating its implementation

On Mon, Aug 22, 2016 at 02:05:43PM +0200, Takashi Iwai wrote:
> On Sun, 21 Aug 2016 21:43:22 +0200,
> SF Markus Elfring wrote:
> > 
> > From: Markus Elfring <elfring@users.sourceforge.net>
> > Date: Sun, 21 Aug 2016 21:02:06 +0200
> > 
> > Reuse existing functionality from memdup_user() instead of keeping
> > duplicate source code.
> > 
> > This issue was detected by using the Coccinelle software.
> > 
> > Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> 
> Applied this one, but the second patch won't be, since other people
> seem to disagree with the usefulness.

I see a v2 as well discarding patch 2 here and some other changes

-- 
~Vinod

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#1467225 — [PATCH 2/2] ALSA: compress: Reduce the scope for two variables in snd_compr_set_params()

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 21 Aug 2016 21:26:18 +0200

Reduce the scope for the local variables to an if branch.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 sound/core/compress_offload.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index 583d407..b43aec5 100644
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -545,14 +545,14 @@ static int snd_compress_check_input(struct snd_compr_params *params)
 static int
 snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
 {
-	struct snd_compr_params *params;
-	int retval;
-
 	if (stream->runtime->state == SNDRV_PCM_STATE_OPEN) {
 		/*
 		 * we should allow parameter change only when stream has been
 		 * opened not in other cases
 		 */
+		int retval;
+		struct snd_compr_params *params;
+
 		params = memdup_user((void __user *)arg, sizeof(*params));
 		if (IS_ERR(params))
 			return PTR_ERR(params);
@@ -578,12 +578,12 @@ snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
 			stream->runtime->state = SNDRV_PCM_STATE_SETUP;
 		else
 			stream->runtime->state = SNDRV_PCM_STATE_PREPARED;
+out:
+		kfree(params);
+		return retval;
 	} else {
 		return -EPERM;
 	}
-out:
-	kfree(params);
-	return retval;
 }
 
 static int
-- 
2.9.3

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#1467231 — Re: [PATCH 2/2] ALSA: compress: Reduce the scope for two variables in snd_compr_set_params()

On Sun, 2016-08-21 at 21:45 +0200, SF Markus Elfring wrote:
> Reduce the scope for the local variables to an if branch.
[]
> diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
[]
> @@ -545,14 +545,14 @@ static int snd_compress_check_input(struct snd_compr_params *params)
>  static int
>  snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
>  {
> -	struct snd_compr_params *params;
> -	int retval;
> -
>  	if (stream->runtime->state == SNDRV_PCM_STATE_OPEN) {

Likely better not reducing variable scope but changing:

 	if (stream->runtime->state == SNDRV_PCM_STATE_OPEN)

to

	if (stream->runtime->state != SNDRV_PCM_STATE_OPEN)
		return -EPERM;

and unindenting the remainder of the code one level instead.

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#1467458 — [PATCH v2 0/2] ALSA: compress: Fine-tuning for snd_compr_set_params()

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 22 Aug 2016 10:27:01 +0200

A few update suggestions were taken into account
from static source code analysis.

Markus Elfring (2):
  Restructure source code around an if statement
  Use memdup_user()

 sound/core/compress_offload.c | 58 +++++++++++++++++++------------------------
 1 file changed, 26 insertions(+), 32 deletions(-)

-- 
2.9.3

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#1467459 — [PATCH v2 1/2] ALSA: compress: Restructure source code around an if statement in snd_compr_set_params()

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 22 Aug 2016 10:01:52 +0200

* Reverse a condition check.

* Reduce the indentation one level then for some source code
  from a previous if branch.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 sound/core/compress_offload.c | 62 +++++++++++++++++++++----------------------
 1 file changed, 30 insertions(+), 32 deletions(-)

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index 2c49848..a10d139 100644
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -548,43 +548,41 @@ snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
 	struct snd_compr_params *params;
 	int retval;
 
-	if (stream->runtime->state == SNDRV_PCM_STATE_OPEN) {
-		/*
-		 * we should allow parameter change only when stream has been
-		 * opened not in other cases
-		 */
-		params = kmalloc(sizeof(*params), GFP_KERNEL);
-		if (!params)
-			return -ENOMEM;
-		if (copy_from_user(params, (void __user *)arg, sizeof(*params))) {
-			retval = -EFAULT;
-			goto out;
-		}
+	if (stream->runtime->state != SNDRV_PCM_STATE_OPEN)
+		return -EPERM;
+	/*
+	 * we should allow parameter change only when stream has been
+	 * opened not in other cases
+	 */
+	params = kmalloc(sizeof(*params), GFP_KERNEL);
+	if (!params)
+		return -ENOMEM;
+	if (copy_from_user(params, (void __user *)arg, sizeof(*params))) {
+		retval = -EFAULT;
+		goto out;
+	}
 
-		retval = snd_compress_check_input(params);
-		if (retval)
-			goto out;
+	retval = snd_compress_check_input(params);
+	if (retval)
+		goto out;
 
-		retval = snd_compr_allocate_buffer(stream, params);
-		if (retval) {
-			retval = -ENOMEM;
-			goto out;
-		}
+	retval = snd_compr_allocate_buffer(stream, params);
+	if (retval) {
+		retval = -ENOMEM;
+		goto out;
+	}
 
-		retval = stream->ops->set_params(stream, params);
-		if (retval)
-			goto out;
+	retval = stream->ops->set_params(stream, params);
+	if (retval)
+		goto out;
 
-		stream->metadata_set = false;
-		stream->next_track = false;
+	stream->metadata_set = false;
+	stream->next_track = false;
 
-		if (stream->direction == SND_COMPRESS_PLAYBACK)
-			stream->runtime->state = SNDRV_PCM_STATE_SETUP;
-		else
-			stream->runtime->state = SNDRV_PCM_STATE_PREPARED;
-	} else {
-		return -EPERM;
-	}
+	if (stream->direction == SND_COMPRESS_PLAYBACK)
+		stream->runtime->state = SNDRV_PCM_STATE_SETUP;
+	else
+		stream->runtime->state = SNDRV_PCM_STATE_PREPARED;
 out:
 	kfree(params);
 	return retval;
-- 
2.9.3

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#1467474 — [PATCH v2 2/2] ALSA: compress: Use memdup_user() rather than duplicating its implementation

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 22 Aug 2016 10:12:37 +0200

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 sound/core/compress_offload.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index a10d139..786989b 100644
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -554,13 +554,9 @@ snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
 	 * we should allow parameter change only when stream has been
 	 * opened not in other cases
 	 */
-	params = kmalloc(sizeof(*params), GFP_KERNEL);
-	if (!params)
-		return -ENOMEM;
-	if (copy_from_user(params, (void __user *)arg, sizeof(*params))) {
-		retval = -EFAULT;
-		goto out;
-	}
+	params = memdup_user((void __user *)arg, sizeof(*params));
+	if (IS_ERR(params))
+		return PTR_ERR(params);
 
 	retval = snd_compress_check_input(params);
 	if (retval)
-- 
2.9.3

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#1468260 — Re: [PATCH v2 0/2] ALSA: compress: Fine-tuning for snd_compr_set_params()

On Mon, Aug 22, 2016 at 10:34:19AM +0200, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Mon, 22 Aug 2016 10:27:01 +0200
> 
> A few update suggestions were taken into account
> from static source code analysis.

Both:

Acked-by: Vinod Koul <vinod.koul@intel.com>

-- 
~Vinod

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#1467241 — Re: [PATCH 2/2] ALSA: compress: Reduce the scope for two variables in snd_compr_set_params()

On Sun, 21 Aug 2016, SF Markus Elfring wrote:

> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 21 Aug 2016 21:26:18 +0200
>
> Reduce the scope for the local variables to an if branch.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>  sound/core/compress_offload.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
> index 583d407..b43aec5 100644
> --- a/sound/core/compress_offload.c
> +++ b/sound/core/compress_offload.c
> @@ -545,14 +545,14 @@ static int snd_compress_check_input(struct snd_compr_params *params)
>  static int
>  snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
>  {
> -	struct snd_compr_params *params;
> -	int retval;
> -
>  	if (stream->runtime->state == SNDRV_PCM_STATE_OPEN) {
>  		/*
>  		 * we should allow parameter change only when stream has been
>  		 * opened not in other cases
>  		 */
> +		int retval;
> +		struct snd_compr_params *params;

I don't like this at all.  Local variables should be at the top of the
function, not hiding under 4 lines of comments in the middle of the code.

julia


> +
>  		params = memdup_user((void __user *)arg, sizeof(*params));
>  		if (IS_ERR(params))
>  			return PTR_ERR(params);
> @@ -578,12 +578,12 @@ snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
>  			stream->runtime->state = SNDRV_PCM_STATE_SETUP;
>  		else
>  			stream->runtime->state = SNDRV_PCM_STATE_PREPARED;
> +out:
> +		kfree(params);
> +		return retval;
>  	} else {
>  		return -EPERM;
>  	}
> -out:
> -	kfree(params);
> -	return retval;
>  }
>
>  static int
> --
> 2.9.3
>
>

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#1467368 — Re: [PATCH 2/2] ALSA: compress: Reduce the scope for two variables in snd_compr_set_params()

On Sun, Aug 21, 2016 at 04:36:22PM -0400, Julia Lawall wrote:
> 
> 
> On Sun, 21 Aug 2016, SF Markus Elfring wrote:
> 
> > From: Markus Elfring <elfring@users.sourceforge.net>
> > Date: Sun, 21 Aug 2016 21:26:18 +0200
> >
> > Reduce the scope for the local variables to an if branch.
> >
> > Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> > ---
> >  sound/core/compress_offload.c | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
> > index 583d407..b43aec5 100644
> > --- a/sound/core/compress_offload.c
> > +++ b/sound/core/compress_offload.c
> > @@ -545,14 +545,14 @@ static int snd_compress_check_input(struct snd_compr_params *params)
> >  static int
> >  snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
> >  {
> > -	struct snd_compr_params *params;
> > -	int retval;
> > -
> >  	if (stream->runtime->state == SNDRV_PCM_STATE_OPEN) {
> >  		/*
> >  		 * we should allow parameter change only when stream has been
> >  		 * opened not in other cases
> >  		 */
> > +		int retval;
> > +		struct snd_compr_params *params;
> 
> I don't like this at all.  Local variables should be at the top of the
> function, not hiding under 4 lines of comments in the middle of the code.

I agree with you this, it doesn't help IMO as well

-- 
~Vinod

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#1467416 — Re: [PATCH 2/2] ALSA: compress: Reduce the scope for two variables in snd_compr_set_params()

Am 21.08.2016 21:45, schrieb SF Markus Elfring:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 21 Aug 2016 21:26:18 +0200
> 
> Reduce the scope for the local variables to an if branch.
> 
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>  sound/core/compress_offload.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
> index 583d407..b43aec5 100644
> --- a/sound/core/compress_offload.c
> +++ b/sound/core/compress_offload.c
> @@ -545,14 +545,14 @@ static int snd_compress_check_input(struct snd_compr_params *params)
>  static int
>  snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
>  {
> -	struct snd_compr_params *params;
> -	int retval;
> -
>  	if (stream->runtime->state == SNDRV_PCM_STATE_OPEN) {
>  		/*
>  		 * we should allow parameter change only when stream has been
>  		 * opened not in other cases
>  		 */
> +		int retval;
> +		struct snd_compr_params *params;
> +
>  		params = memdup_user((void __user *)arg, sizeof(*params));
>  		if (IS_ERR(params))
>  			return PTR_ERR(params);
> @@ -578,12 +578,12 @@ snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
>  			stream->runtime->state = SNDRV_PCM_STATE_SETUP;
>  		else
>  			stream->runtime->state = SNDRV_PCM_STATE_PREPARED;
> +out:
> +		kfree(params);
> +		return retval;
>  	} else {
>  		return -EPERM;
>  	}
> -out:
> -	kfree(params);
> -	return retval;
>  }
>  
>  static int


if would make sense to have

if (stream->runtime->state != SNDRV_PCM_STATE_OPEN)
	return -EPERM;

and read adjust the indent.

just my 2 cents
re,
 wh

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