linux-kernel - Re: [PATCH v2 2/2] driver core: add helper for deferred probe reason setting

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Message-ID: <CAHp75VdjefJHMu2ot7RoZZZis0aNyV097J34wxDSwLgh3bQ8Pg@mail.gmail.com>
Date:   Fri, 19 Mar 2021 13:13:53 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Ahmad Fatoum <a.fatoum@...gutronix.de>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] driver core: add helper for deferred probe reason setting

On Fri, Mar 19, 2021 at 1:05 PM Ahmad Fatoum <a.fatoum@...gutronix.de> wrote:
>
> We now have three places within the same file doing the same operation
> of freeing this pointer and setting it anew. A helper make this

makes

> arguably easier to read, so add one.

FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>

Now I'm wondering why deferred_probe_reason is not defined with const.

Can you check and maybe squeeze a patch in the middle (before these
two of this series) to move to const?

> Signed-off-by: Ahmad Fatoum <a.fatoum@...gutronix.de>
> ---
> v1 -> v2:
>  - no change
> ---
>  drivers/base/dd.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index e2cf3b29123e..4201baa1cc13 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -69,6 +69,12 @@ static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
>   */
>  static bool defer_all_probes;
>
> +static void __device_set_deferred_probe_reason(const struct device *dev, char *reason)
> +{
> +       kfree(dev->p->deferred_probe_reason);
> +       dev->p->deferred_probe_reason = reason;
> +}
> +
>  /*
>   * deferred_probe_work_func() - Retry probing devices in the active list.
>   */
> @@ -97,8 +103,7 @@ static void deferred_probe_work_func(struct work_struct *work)
>
>                 get_device(dev);
>
> -               kfree(dev->p->deferred_probe_reason);
> -               dev->p->deferred_probe_reason = NULL;
> +               __device_set_deferred_probe_reason(dev, NULL);
>
>                 /*
>                  * Drop the mutex while probing each device; the probe path may
> @@ -140,8 +145,7 @@ void driver_deferred_probe_del(struct device *dev)
>         if (!list_empty(&dev->p->deferred_probe)) {
>                 dev_dbg(dev, "Removed from deferred list\n");
>                 list_del_init(&dev->p->deferred_probe);
> -               kfree(dev->p->deferred_probe_reason);
> -               dev->p->deferred_probe_reason = NULL;
> +               __device_set_deferred_probe_reason(dev, NULL);
>         }
>         mutex_unlock(&deferred_probe_mutex);
>  }
> @@ -220,11 +224,12 @@ void device_unblock_probing(void)
>  void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf)
>  {
>         const char *drv = dev_driver_string(dev);
> +       char *reason;
>
>         mutex_lock(&deferred_probe_mutex);
>
> -       kfree(dev->p->deferred_probe_reason);
> -       dev->p->deferred_probe_reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
> +       reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
> +       __device_set_deferred_probe_reason(dev, reason);
>
>         mutex_unlock(&deferred_probe_mutex);
>  }
> --
> 2.29.2
>


-- 
With Best Regards,
Andy Shevchenko