Re: [linux-safety] [PATCH] misc: hisi_hikey_usb: use PTR_ERR_OR_ZERO

[Lukas Bulwahn]

On Mon, 26 Oct 2020, Sudip Mukherjee wrote:

> Coccinelle suggested using PTR_ERR_OR_ZERO() and looking at the code,
> we can use PTR_ERR_OR_ZERO() instead of checking IS_ERR() and then
> doing 'return 0'.
> 
> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>

A nice small local clean up.

Here is my test report:

Build requires HISI_HIKEY_USB in config:

Symbol: HISI_HIKEY_USB [=n]
Type: tristate
Defined at drivers/misc/Kconfig:459
Prompt: USB GPIO Hub on HiSilicon Hikey 960/970 Platform
Depends on: (OF [=n] && GPIOLIB [=n] || COMPILE_TEST [=n]) && 
USB_ROLE_SWITCH [=n]

Build Preparation:

make defconfig
./scripts/config -e CONFIG_OF
./scripts/config -e CONFIG_GPIOLIB
./scripts/config -e CONFIG_USB_ROLE_SWITCH
./scripts/config -e CONFIG_HISI_HIKEY_USB
make olddefconfig

Build on next-20201027:

make
md5sum ./drivers/misc/hisi_hikey_usb.o
770db9ff0c1ca193eda2207a28deee4a  ./drivers/misc/hisi_hikey_usb.o
objdump -d ./drivers/misc/hisi_hikey_usb.o > hisi_hikey_usb.next-20201027.objdump

Build with patch on next-20201027:

make clean && make
md5sum ./drivers/misc/hisi_hikey_usb.o
770db9ff0c1ca193eda2207a28deee4a  ./drivers/misc/hisi_hikey_usb.o

objdump -d ./drivers/misc/hisi_hikey_usb.o > hisi_hikey_usb.cleanup-on-next-20201027.objdump

Compare objdump:

diff hisi_hikey_usb.next-20201027.objdump hisi_hikey_usb.cleanup-on-next-20201027.objdump

Summary:

'{md5sum,objdump -d} ./drivers/misc/hisi_hikey_usb.o' are identical before 
and after patch.

So, no functional change and no change in object code.

Tested-by: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>

> ---
>  drivers/misc/hisi_hikey_usb.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/misc/hisi_hikey_usb.c b/drivers/misc/hisi_hikey_usb.c
> index cc93569e601c..989d7d129469 100644
> --- a/drivers/misc/hisi_hikey_usb.c
> +++ b/drivers/misc/hisi_hikey_usb.c
> @@ -168,10 +168,7 @@ static int hisi_hikey_usb_parse_kirin970(struct platform_device *pdev,
>  
>  	hisi_hikey_usb->reset = devm_gpiod_get(&pdev->dev, "hub_reset_en_gpio",
>  					       GPIOD_OUT_HIGH);
> -	if (IS_ERR(hisi_hikey_usb->reset))
> -		return PTR_ERR(hisi_hikey_usb->reset);
> -
> -	return 0;
> +	return PTR_ERR_OR_ZERO(hisi_hikey_usb->reset);
>  }
>  
>  static int hisi_hikey_usb_probe(struct platform_device *pdev)
> -- 
> 2.11.0
> 
> 
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