[PATCH] usb: dwc3: meson-g12a: Don't use ret uninitialized in dwc3_meson_g12a_otg_init

[PATCH] usb: dwc3: meson-g12a: Don't use ret uninitialized in dwc3_meson_g12a_otg_init

[Nathan Chancellor]

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)
-- 
2.25.0


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Re: [PATCH] usb: dwc3: meson-g12a: Don't use ret uninitialized in dwc3_meson_g12a_otg_init

[Neil Armstrong]

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>

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Re: [PATCH] usb: dwc3: meson-g12a: Don't use ret uninitialized in dwc3_meson_g12a_otg_init

[patchwork-bot+linux-amlogic]

Hello:

This patch was applied to khilman/linux-amlogic.git (refs/heads/for-next).

On Mon, 10 Feb 2020 15:58:17 -0700 you 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.
> 
> [...]


Here is a summary with links:
  - usb: dwc3: meson-g12a: Don't use ret uninitialized in dwc3_meson_g12a_otg_init
    https://git.kernel.org/khilman/linux-amlogic/c/238d760216541d345ee930e76c781f5cd1d22fba

You are awesome, thank you!

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