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

[Greg Kroah-Hartman]

On Fri, Mar 19, 2021 at 12:04:58PM +0100, Ahmad Fatoum 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
> arguably easier to read, so add one.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
> ---
> 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);

No error checking?

:(