linux-kernel - Re: [PATCH] ALSA: hda: fix unused variable warning

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Message-ID: <s5hbm941law.wl-tiwai@suse.de>
Date:   Tue, 11 Sep 2018 10:37:59 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     "Anders Roxell" <anders.roxell@...aro.org>
Cc:     <perex@...ex.cz>, <alsa-devel@...a-project.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ALSA: hda: fix unused variable warning

On Tue, 11 Sep 2018 10:25:59 +0200,
Anders Roxell wrote:
> 
> When CONFIG_X86=n function azx_snoop doesn't use the variable chip it
> only returns true.
> 
> sound/pci/hda/hda_intel.c: In function ‘dma_alloc_pages’:
> sound/pci/hda/hda_intel.c:2002:14: warning: unused variable ‘chip’ [-Wunused-variable]
>   struct azx *chip = bus_to_azx(bus);
>               ^~~~
> 
> Create a inline function of azx_snoop.
> 
> Fixes: a41d122449be ("ALSA: hda - Embed bus into controller object")
> Signed-off-by: Anders Roxell <anders.roxell@...aro.org>
> ---
>  sound/pci/hda/hda_controller.h | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/sound/pci/hda/hda_controller.h b/sound/pci/hda/hda_controller.h
> index 0053b704ddc4..aa20048742d0 100644
> --- a/sound/pci/hda/hda_controller.h
> +++ b/sound/pci/hda/hda_controller.h
> @@ -170,11 +170,10 @@ struct azx {
>  #define azx_bus(chip)	(&(chip)->bus.core)
>  #define bus_to_azx(_bus)	container_of(_bus, struct azx, bus.core)
>  
> -#ifdef CONFIG_X86
> -#define azx_snoop(chip)		((chip)->snoop)
> -#else
> -#define azx_snoop(chip)		true
> -#endif
> +static inline bool azx_snoop(struct azx *chip)
> +{
> +	return IS_ENABLED(CONFIG_X86) || (chip->snoop);
> +}

The idea is good, but the patch is obviously wrong; it should be
!IS_ENABLED() :)

Also, please remove the parentheses around chip->snoop.


thanks,

Takashi