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Subject: Re: [PATCH] usb: dwc3: meson-g12a: Don't use ret uninitialized in
 dwc3_meson_g12a_otg_init
To:     Nathan Chancellor <natechancellor@gmail.com>,
        Felipe Balbi <balbi@kernel.org>
Cc:     Hanjie Lin <hanjie.lin@amlogic.com>,
        kbuild test robot <lkp@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Yue Wang <yue.wang@amlogic.com>,
        clang-built-linux@googlegroups.com,
        Kevin Hilman <khilman@baylibre.com>,
        linux-amlogic@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org
References: <20200210225816.36598-1-natechancellor@gmail.com>
From:   Neil Armstrong <narmstrong@baylibre.com>
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Organization: Baylibre
Message-ID: <d47c9cb2-9458-afc7-e91b-1a56ad87d1be@baylibre.com>
Date:   Wed, 19 Feb 2020 15:14:06 +0100
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In-Reply-To: <20200210225816.36598-1-natechancellor@gmail.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 10/02/2020 23:58, Nathan Chancellor wrote:
> Clang warns:
> 
> ../drivers/usb/dwc3/dwc3-meson-g12a.c:421:6: warning: variable 'ret' is
> used uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
>         if (priv->otg_mode == USB_DR_MODE_OTG) {
>             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../drivers/usb/dwc3/dwc3-meson-g12a.c:455:9: note: uninitialized use
> occurs here
>         return ret;
>                ^~~
> ../drivers/usb/dwc3/dwc3-meson-g12a.c:421:2: note: remove the 'if' if
> its condition is always true
>         if (priv->otg_mode == USB_DR_MODE_OTG) {
>         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../drivers/usb/dwc3/dwc3-meson-g12a.c:415:9: note: initialize the
> variable 'ret' to silence this warning
>         int ret, irq;
>                ^
>                 = 0
> 1 warning generated.
> 
> It is not wrong, ret is only used when that if statement is true. Just
> directly return 0 at the end to avoid this.
> 
> Fixes: 729149c53f04 ("usb: dwc3: Add Amlogic A1 DWC3 glue")
> Reported-by: kbuild test robot <lkp@intel.com>
> Link: https://groups.google.com/d/msg/clang-built-linux/w5iBENco_m4/PPuXreAxBQAJ
> Link: https://github.com/ClangBuiltLinux/linux/issues/869
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> 
> Note: This patch is against Felipe's testing/next branch.
> 
>  drivers/usb/dwc3/dwc3-meson-g12a.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/dwc3-meson-g12a.c b/drivers/usb/dwc3/dwc3-meson-g12a.c
> index 70d24b98fcad..902553f39889 100644
> --- a/drivers/usb/dwc3/dwc3-meson-g12a.c
> +++ b/drivers/usb/dwc3/dwc3-meson-g12a.c
> @@ -452,7 +452,7 @@ static int dwc3_meson_g12a_otg_init(struct platform_device *pdev,
>  	if (IS_ERR(priv->role_switch))
>  		dev_warn(dev, "Unable to register Role Switch\n");
>  
> -	return ret;
> +	return 0;
>  }
>  
>  static int dwc3_meson_g12a_probe(struct platform_device *pdev)
> 

Acked-by: Neil Armstrong <narmstrong@baylibre.com>