2019-07-05 10:00:46

by Colin King

[permalink] [raw]
Subject: [PATCH] ALSA: cs4281: remove redundant assignment to variable val and remove a goto

From: Colin Ian King <[email protected]>

The variable val is being assigned with a value that is never
read and it is being updated later with a new value. The
assignment is redundant and can be removed. Also remove a
goto statement and a label and replace with a break statement.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <[email protected]>
---
sound/pci/cs4281.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/sound/pci/cs4281.c b/sound/pci/cs4281.c
index a2cce3ecda6f..04c712647853 100644
--- a/sound/pci/cs4281.c
+++ b/sound/pci/cs4281.c
@@ -694,7 +694,7 @@ static int snd_cs4281_trigger(struct snd_pcm_substream *substream, int cmd)

static unsigned int snd_cs4281_rate(unsigned int rate, unsigned int *real_rate)
{
- unsigned int val = ~0;
+ unsigned int val;

if (real_rate)
*real_rate = rate;
@@ -707,9 +707,8 @@ static unsigned int snd_cs4281_rate(unsigned int rate, unsigned int *real_rate)
case 44100: return 1;
case 48000: return 0;
default:
- goto __variable;
+ break;
}
- __variable:
val = 1536000 / rate;
if (real_rate)
*real_rate = 1536000 / val;
--
2.20.1


2019-07-05 10:13:29

by Takashi Iwai

[permalink] [raw]
Subject: Re: [PATCH] ALSA: cs4281: remove redundant assignment to variable val and remove a goto

On Fri, 05 Jul 2019 11:57:04 +0200,
Colin King wrote:
>
> From: Colin Ian King <[email protected]>
>
> The variable val is being assigned with a value that is never
> read and it is being updated later with a new value. The
> assignment is redundant and can be removed. Also remove a
> goto statement and a label and replace with a break statement.
>
> Addresses-Coverity: ("Unused value")
> Signed-off-by: Colin Ian King <[email protected]>

Applied, thanks.


Takashi

2019-07-05 10:22:11

by walter harms

[permalink] [raw]
Subject: Re: [PATCH] ALSA: cs4281: remove redundant assignment to variable val and remove a goto



Am 05.07.2019 11:57, schrieb Colin King:
> From: Colin Ian King <[email protected]>
>
> The variable val is being assigned with a value that is never
> read and it is being updated later with a new value. The
> assignment is redundant and can be removed. Also remove a
> goto statement and a label and replace with a break statement.
>
> Addresses-Coverity: ("Unused value")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> sound/pci/cs4281.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/sound/pci/cs4281.c b/sound/pci/cs4281.c
> index a2cce3ecda6f..04c712647853 100644
> --- a/sound/pci/cs4281.c
> +++ b/sound/pci/cs4281.c
> @@ -694,7 +694,7 @@ static int snd_cs4281_trigger(struct snd_pcm_substream *substream, int cmd)
>
> static unsigned int snd_cs4281_rate(unsigned int rate, unsigned int *real_rate)
> {
> - unsigned int val = ~0;
> + unsigned int val;
>
> if (real_rate)
> *real_rate = rate;
> @@ -707,9 +707,8 @@ static unsigned int snd_cs4281_rate(unsigned int rate, unsigned int *real_rate)
> case 44100: return 1;
> case 48000: return 0;
> default:
> - goto __variable;
> + break;
> }
> - __variable:
> val = 1536000 / rate;
> if (real_rate)
> *real_rate = 1536000 / val;
^^^^^^^^^^^^^^^^^^^^^^^^^

this is confusing. is
*real_rate = rate
intended here ? (like above)

val could be eliminated by using

return 1536000 / rate ;

re,
wh

2019-07-05 11:28:43

by Takashi Iwai

[permalink] [raw]
Subject: Re: [PATCH] ALSA: cs4281: remove redundant assignment to variable val and remove a goto

On Fri, 05 Jul 2019 12:20:10 +0200,
walter harms wrote:
>
>
>
> Am 05.07.2019 11:57, schrieb Colin King:
> > From: Colin Ian King <[email protected]>
> >
> > The variable val is being assigned with a value that is never
> > read and it is being updated later with a new value. The
> > assignment is redundant and can be removed. Also remove a
> > goto statement and a label and replace with a break statement.
> >
> > Addresses-Coverity: ("Unused value")
> > Signed-off-by: Colin Ian King <[email protected]>
> > ---
> > sound/pci/cs4281.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/sound/pci/cs4281.c b/sound/pci/cs4281.c
> > index a2cce3ecda6f..04c712647853 100644
> > --- a/sound/pci/cs4281.c
> > +++ b/sound/pci/cs4281.c
> > @@ -694,7 +694,7 @@ static int snd_cs4281_trigger(struct snd_pcm_substream *substream, int cmd)
> >
> > static unsigned int snd_cs4281_rate(unsigned int rate, unsigned int *real_rate)
> > {
> > - unsigned int val = ~0;
> > + unsigned int val;
> >
> > if (real_rate)
> > *real_rate = rate;
> > @@ -707,9 +707,8 @@ static unsigned int snd_cs4281_rate(unsigned int rate, unsigned int *real_rate)
> > case 44100: return 1;
> > case 48000: return 0;
> > default:
> > - goto __variable;
> > + break;
> > }
> > - __variable:
> > val = 1536000 / rate;
> > if (real_rate)
> > *real_rate = 1536000 / val;
> ^^^^^^^^^^^^^^^^^^^^^^^^^
>
> this is confusing. is
> *real_rate = rate
> intended here ? (like above)
>
> val could be eliminated by using
>
> return 1536000 / rate ;

No, the current code is correct.
The purpose of this calculation is to consider the truncation by
division.


Takashi