[PATCH v2] staging: greybus: audio: check sscanf() result directly

[PATCH v2] staging: greybus: audio: check sscanf() result directly

[abdelnasser hussein]

Smatch warns:

  drivers/staging/greybus/audio_codec.c:335 gbaudio_module_update()
  warn: sscanf doesn't return error codes

sscanf() returns the number of successfully matched input items, not a
negative error code. Compare the return value directly with the expected
number of conversions instead of storing it in ret as an error code.

Also remove the redundant else-if check for snd_soc_dapm_aif_out. The
widget id is validated earlier in the function, so the remaining branch
can only handle snd_soc_dapm_aif_out. This avoids a compiler warning
about a potentially uninitialized variable.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202606140347.gGVWDnbi-lkp@intel.com/

Signed-off-by: abdelnasser hussein <abdelnasserhussein11@gmail.com>
---
 drivers/staging/greybus/audio_codec.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/greybus/audio_codec.c b/drivers/staging/greybus/audio_codec.c
index 720aa752e17e..6daa4e706792 100644
--- a/drivers/staging/greybus/audio_codec.c
+++ b/drivers/staging/greybus/audio_codec.c
@@ -311,8 +311,7 @@ int gbaudio_module_update(struct gbaudio_codec_info *codec,
 	}
 
 	/* parse dai_id from AIF widget's stream_name */
-	ret = sscanf(w->sname, "%s %d %s", intf_name, &dai_id, dir);
-	if (ret < 3) {
+	if (sscanf(w->sname, "%s %d %s", intf_name, &dai_id, dir) != 3) {
 		dev_err(codec->dev, "Error while parsing dai_id for %s\n", w->name);
 		return -EINVAL;
 	}
@@ -323,7 +322,7 @@ int gbaudio_module_update(struct gbaudio_codec_info *codec,
 			ret = gbaudio_module_enable_tx(codec, module, dai_id);
 		else
 			ret = gbaudio_module_disable_tx(module, dai_id);
-	} else if (w->id == snd_soc_dapm_aif_out) {
+	} else {
 		if (enable)
 			ret = gbaudio_module_enable_rx(codec, module, dai_id);
 		else
-- 
2.54.0

Re: [PATCH v2] staging: greybus: audio: check sscanf() result directly

[Greg Kroah-Hartman]

On Sun, Jun 14, 2026 at 09:08:57AM +0300, abdelnasser hussein wrote:
> Smatch warns:
> 
>   drivers/staging/greybus/audio_codec.c:335 gbaudio_module_update()
>   warn: sscanf doesn't return error codes
> 
> sscanf() returns the number of successfully matched input items, not a
> negative error code. Compare the return value directly with the expected
> number of conversions instead of storing it in ret as an error code.
> 
> Also remove the redundant else-if check for snd_soc_dapm_aif_out. The
> widget id is validated earlier in the function, so the remaining branch
> can only handle snd_soc_dapm_aif_out. This avoids a compiler warning
> about a potentially uninitialized variable.

When you say "also" that implies it should be a separate patch.

> 
> Reported-by: kernel test robot <lkp@intel.com>

lkp didn't report the smatch warning :(

> Closes: https://lore.kernel.org/oe-kbuild-all/202606140347.gGVWDnbi-lkp@intel.com/
> 
> Signed-off-by: abdelnasser hussein <abdelnasserhussein11@gmail.com>
> ---
>  drivers/staging/greybus/audio_codec.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)

No list of what changed from previous versions?

thanks,

greg k-h

Re: [PATCH v2] staging: greybus: audio: check sscanf() result directly

[nasser]

Hi Greg,

Thanks for the review and the feedback.

On Sun, Jun 14, 2026 at 06:15:00AM +0000, Greg Kroah-Hartman wrote:
> When you say "also" that implies it should be a separate patch.

Understood. I will split these changes into a two-patch series in v3.

> lkp didn't report the smatch warning :(

My mistake. I will fix the Reported-by and Closes tags in the next
version to correctly reflect the source of the warning.

> No list of what changed from previous versions?

I apologize for missing that. I will make sure to include a proper
changelog below the '---' line for v3.

I will send the v3 patch series shortly.

Thanks,
Abdelnasser


On Sun, Jun 14, 2026 at 9:17 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Sun, Jun 14, 2026 at 09:08:57AM +0300, abdelnasser hussein wrote:
> > Smatch warns:
> >
> >   drivers/staging/greybus/audio_codec.c:335 gbaudio_module_update()
> >   warn: sscanf doesn't return error codes
> >
> > sscanf() returns the number of successfully matched input items, not a
> > negative error code. Compare the return value directly with the expected
> > number of conversions instead of storing it in ret as an error code.
> >
> > Also remove the redundant else-if check for snd_soc_dapm_aif_out. The
> > widget id is validated earlier in the function, so the remaining branch
> > can only handle snd_soc_dapm_aif_out. This avoids a compiler warning
> > about a potentially uninitialized variable.
>
> When you say "also" that implies it should be a separate patch.
>
> >
> > Reported-by: kernel test robot <lkp@intel.com>
>
> lkp didn't report the smatch warning :(
>
> > Closes: https://lore.kernel.org/oe-kbuild-all/202606140347.gGVWDnbi-lkp@intel.com/
> >
> > Signed-off-by: abdelnasser hussein <abdelnasserhussein11@gmail.com>
> > ---
> >  drivers/staging/greybus/audio_codec.c | 5 ++---
> >  1 file changed, 2 insertions(+), 3 deletions(-)
>
> No list of what changed from previous versions?
>
> thanks,
>
> greg k-h