linux-kernel - Re: [PATCH] staging: emxx_udc: Fix incorrectly defined global

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Message-ID: <CAMuHMdVE+a4gMwa206=CWCUzAPD9N5nnvsPa1avWq_t1isfizQ@mail.gmail.com>
Date:   Mon, 8 Feb 2021 11:18:01 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Kumar Kartikeya Dwivedi <memxor@...il.com>
Cc:     Stephen Rothwell <sfr@...b.auug.org.au>,
        driverdevel <devel@...verdev.osuosl.org>,
        Greg KH <gregkh@...uxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Nishad Kamdar <nishadkamdar@...il.com>,
        Magnus Damm <magnus.damm@...il.com>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH] staging: emxx_udc: Fix incorrectly defined global

Hi Kumar,

CC Nishad, Magnus, linux-renesas-soc,

On Sun, Feb 7, 2021 at 8:40 AM Kumar Kartikeya Dwivedi <memxor@...il.com> wrote:
> On Sun, Feb 07, 2021 at 12:04:41PM IST, Stephen Rothwell wrote:
> > Given that drivers/staging/emxx_udc/emxx_udc.h is only included by
> > drivers/staging/emxx_udc/emxx_udc.c, shouldn't these variables just be
> > declared static in emxx_udc.c and removed from emxx_udc.h?
> >
>
> Either would be correct. I went this way because it was originally trying to
> (incorrectly) define a global variable instead. I guess they can be static now
> and when more users are added, the linkage can be adjusted as needed.
>
> Here's another version of the patch:
>
> --
> From 5835ad916ceeba620c85bc32f52ecd69f21f8dab Mon Sep 17 00:00:00 2001
> From: Kumar Kartikeya Dwivedi <memxor@...il.com>
> Date: Sun, 7 Feb 2021 12:53:39 +0530
> Subject: [PATCH] staging: emxx_udc: Make incorrectly defined global static
>
> The global gpio_desc pointer and int vbus_irq were defined in the header,
> instead put the definitions in the translation unit and make them static as
> there's only a single consumer in emxx_udc.c.
>
> This fixes the following sparse warnings for this driver:
> drivers/staging/emxx_udc/emxx_udc.c: note: in included file:
> drivers/staging/emxx_udc/emxx_udc.h:23:18: warning: symbol 'vbus_gpio' was not
> declared. Should it be static?
> drivers/staging/emxx_udc/emxx_udc.h:24:5: warning: symbol 'vbus_irq' was not
> declared. Should it be static?
>
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@...il.com>

Thanks for your patch!

> --- a/drivers/staging/emxx_udc/emxx_udc.c
> +++ b/drivers/staging/emxx_udc/emxx_udc.c
> @@ -34,6 +34,9 @@
>  #define        DRIVER_DESC     "EMXX UDC driver"
>  #define        DMA_ADDR_INVALID        (~(dma_addr_t)0)
>
> +static struct gpio_desc *vbus_gpio;
> +static int vbus_irq;

While I agree these must be static, I expect the driver to be still
broken, as vbus_gpio is never set?

Commit 48101806c52203f6 ("Staging: emxx_udc: Switch to the gpio
descriptor interface") introduced both variables, which was presumably
never tested.

Magnus: perhaps we should just remove this driver?

> +
>  static const char      driver_name[] = "emxx_udc";
>  static const char      driver_desc[] = DRIVER_DESC;
>
> diff --git a/drivers/staging/emxx_udc/emxx_udc.h b/drivers/staging/emxx_udc/emxx_udc.h
> index bca614d69..c9e37a1b8 100644
> --- a/drivers/staging/emxx_udc/emxx_udc.h
> +++ b/drivers/staging/emxx_udc/emxx_udc.h
> @@ -20,8 +20,6 @@
>  /* below hacked up for staging integration */
>  #define GPIO_VBUS 0 /* GPIO_P153 on KZM9D */
>  #define INT_VBUS 0 /* IRQ for GPIO_P153 */
> -struct gpio_desc *vbus_gpio;
> -int vbus_irq;

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds