linux-kernel - Re: [PATCH 3/3] staging: r8188eu: Reorganize error handling in rtw_drv

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Message-ID: <CAA=Fs0k00kWr-e+40uMVQy9gNfnYy+znaQ4OS5XqE4ouc4fpmg@mail.gmail.com>
Date:   Thu, 12 Aug 2021 22:15:58 +0100
From:   Phillip Potter <phil@...lpotter.co.uk>
To:     Nathan Chancellor <nathan@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Larry Finger <Larry.Finger@...inger.net>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        linux-staging@...ts.linux.dev,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        clang-built-linux@...glegroups.com
Subject: Re: [PATCH 3/3] staging: r8188eu: Reorganize error handling in rtw_drv_init()

On Thu, 12 Aug 2021 at 21:40, Nathan Chancellor <nathan@...nel.org> wrote:
>
> After commit 987219ad34a6 ("staging: r8188eu: remove lines from Makefile
> that silence build warnings"), clang warns:
>
> drivers/staging/r8188eu/os_dep/usb_intf.c:726:6: warning: variable
> 'status' is used uninitialized whenever 'if' condition is true
> [-Wsometimes-uninitialized]
>         if (!if1) {
>             ^~~~
> drivers/staging/r8188eu/os_dep/usb_intf.c:741:6: note: uninitialized use
> occurs here
>         if (status != _SUCCESS)
>             ^~~~~~
> drivers/staging/r8188eu/os_dep/usb_intf.c:726:2: note: remove the 'if'
> if its condition is always false
>         if (!if1) {
>         ^~~~~~~~~~~
> drivers/staging/r8188eu/os_dep/usb_intf.c:714:12: note: initialize the
> variable 'status' to silence this warning
>         int status;
>                   ^
>                    = 0
> 1 warning generated.
>
> status is not initialized if the call to usb_dvobj_init() or
> rtw_usb_if1_init() fails.
>
> Looking at the error function as a whole, the error handling is odd
> compared to the rest of the kernel, which prefers to set error codes on
> goto paths, rather than a global "status" variable which determines the
> error code at the end of the function and function calls in the case of
> error.
>
> Rearrange the error handling of this function to bring it more inline
> with how the kernel does it in most cases, which helps readability.
>
> The call to rtw_usb_if1_deinit() is eliminated because it is not
> possible to ever hit it; if rtw_usb_if1_init() fails, the goto call
> jumps over the call to rtw_usb_if1_deinit() and in the success case,
> status is set to _SUCCESS.
>
> Signed-off-by: Nathan Chancellor <nathan@...nel.org>
> ---
>  drivers/staging/r8188eu/os_dep/usb_intf.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/staging/r8188eu/os_dep/usb_intf.c b/drivers/staging/r8188eu/os_dep/usb_intf.c
> index a462cb6f3005..667f41125a87 100644
> --- a/drivers/staging/r8188eu/os_dep/usb_intf.c
> +++ b/drivers/staging/r8188eu/os_dep/usb_intf.c
> @@ -704,20 +704,23 @@ static void rtw_usb_if1_deinit(struct adapter *if1)
>  static int rtw_drv_init(struct usb_interface *pusb_intf, const struct usb_device_id *pdid)
>  {
>         struct adapter *if1 = NULL;
> -       int status;
>         struct dvobj_priv *dvobj;
> +       int ret;
>
>         /* step 0. */
>         process_spec_devid(pdid);
>
>         /* Initialize dvobj_priv */
>         dvobj = usb_dvobj_init(pusb_intf);
> -       if (!dvobj)
> -               goto exit;
> +       if (!dvobj) {
> +               ret = -ENODEV;
> +               goto err;
> +       }
>
>         if1 = rtw_usb_if1_init(dvobj, pusb_intf);
>         if (!if1) {
>                 DBG_88E("rtw_init_primarystruct adapter Failed!\n");
> +               ret = -ENODEV;
>                 goto free_dvobj;
>         }
>
> @@ -726,15 +729,12 @@ static int rtw_drv_init(struct usb_interface *pusb_intf, const struct usb_device
>                 rtw_signal_process(ui_pid[1], SIGUSR2);
>         }
>
> -       status = _SUCCESS;
> +       return 0;
>
> -       if (status != _SUCCESS && if1)
> -               rtw_usb_if1_deinit(if1);
>  free_dvobj:
> -       if (status != _SUCCESS)
> -               usb_dvobj_deinit(pusb_intf);
> -exit:
> -       return status == _SUCCESS ? 0 : -ENODEV;
> +       usb_dvobj_deinit(pusb_intf);
> +err:
> +       return ret;
>  }
>
>  /*
> --
> 2.33.0.rc2
>

Looks good as far as I can see, nicely done. Thanks.

Acked-by: Phillip Potter <phil@...lpotter.co.uk>

Regards,
Phil