linux-kernel - Re: [PATCH] fw_cfg: avoid unused function warning

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Message-ID: <CAMxuvayxXG2526Z6p7-fEJM_sVefn8EkjWnY=ZozuiS_UiJS2Q@mail.gmail.com>
Date:   Wed, 28 Feb 2018 15:22:51 +0100
From:   Marc-André Lureau <marcandre.lureau@...hat.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Gabriel Somlo <somlo@....edu>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Vasyl Gomonovych <gomonovych@...il.com>,
        qemu-devel <qemu-devel@...gnu.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] fw_cfg: avoid unused function warning

Hi

On Wed, Feb 28, 2018 at 2:33 PM, Arnd Bergmann <arnd@...db.de> wrote:
> The newly introduced fw_cfg_dma_transfer() function is unused when
> CONFIG_CRASH_CORE is disabled:
>
> drivers/firmware/qemu_fw_cfg.c:89:16: error: 'fw_cfg_dma_transfer' defined but not used [-Werror=unused-function]
>  static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control)
>
> This moves it into the #ifdef section that hides its caller to avoid the
> warning.
>
> Fixes: 47e78bfb5426 ("fw_cfg: write vmcoreinfo details")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

I don't know from which tree you found this, I suppose from
mst/linux-next (which btw, I don't know which version got partially
applied).

This is a regression in v13, because dma read is last patch now, as RFC.
Fixed in upcoming v16.

thanks

> ---
>  drivers/firmware/qemu_fw_cfg.c | 60 +++++++++++++++++++++---------------------
>  1 file changed, 30 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index 3015e77aebca..f002bb40519b 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -66,6 +66,36 @@ static void fw_cfg_sel_endianness(u16 key)
>                 iowrite16(key, fw_cfg_reg_ctrl);
>  }
>
> +/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
> +static ssize_t fw_cfg_read_blob(u16 key,
> +                               void *buf, loff_t pos, size_t count)
> +{
> +       u32 glk = -1U;
> +       acpi_status status;
> +
> +       /* If we have ACPI, ensure mutual exclusion against any potential
> +        * device access by the firmware, e.g. via AML methods:
> +        */
> +       status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
> +       if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
> +               /* Should never get here */
> +               WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n");
> +               memset(buf, 0, count);
> +               return -EINVAL;
> +       }
> +
> +       mutex_lock(&fw_cfg_dev_lock);
> +       fw_cfg_sel_endianness(key);
> +       while (pos-- > 0)
> +               ioread8(fw_cfg_reg_data);
> +       ioread8_rep(fw_cfg_reg_data, buf, count);
> +       mutex_unlock(&fw_cfg_dev_lock);
> +
> +       acpi_release_global_lock(glk);
> +       return count;
> +}
> +
> +#ifdef CONFIG_CRASH_CORE
>  static inline bool fw_cfg_dma_enabled(void)
>  {
>         return (fw_cfg_rev & FW_CFG_VERSION_DMA) && fw_cfg_reg_dma;
> @@ -124,36 +154,6 @@ static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control)
>         return ret;
>  }
>
> -/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
> -static ssize_t fw_cfg_read_blob(u16 key,
> -                               void *buf, loff_t pos, size_t count)
> -{
> -       u32 glk = -1U;
> -       acpi_status status;
> -
> -       /* If we have ACPI, ensure mutual exclusion against any potential
> -        * device access by the firmware, e.g. via AML methods:
> -        */
> -       status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
> -       if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
> -               /* Should never get here */
> -               WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n");
> -               memset(buf, 0, count);
> -               return -EINVAL;
> -       }
> -
> -       mutex_lock(&fw_cfg_dev_lock);
> -       fw_cfg_sel_endianness(key);
> -       while (pos-- > 0)
> -               ioread8(fw_cfg_reg_data);
> -       ioread8_rep(fw_cfg_reg_data, buf, count);
> -       mutex_unlock(&fw_cfg_dev_lock);
> -
> -       acpi_release_global_lock(glk);
> -       return count;
> -}
> -
> -#ifdef CONFIG_CRASH_CORE
>  /* write chunk of given fw_cfg blob (caller responsible for sanity-check) */
>  static ssize_t fw_cfg_write_blob(u16 key,
>                                  void *buf, loff_t pos, size_t count)
> --
> 2.9.0
>