Re: [PATCH v1] i2c: core: Protect acpi_match_device() against NULL

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Sun, 2017-07-09 at 16:16 +0300, Andy Shevchenko wrote:
> The commit 09b3b246acba
> 	("i2c: core: Allow empty id_table in ACPI case as well")
> brought an additional check for ACPI match table entry, though missed
> NULL check for table itself.
> 
> Do it here by introducing a helper i2c_acpi_match_device().
> 
> Note, we rename some static function in i2c-core-acpi.c to distinguish
> with public API.
> 

Wolfram, feel free to squash it into the original commit if it looks
better. 

> Fixes: 09b3b246acba ("i2c: core: Allow empty id_table in ACPI case as
> well")
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/i2c/i2c-core-acpi.c | 19 +++++++++++++++----
>  drivers/i2c/i2c-core-base.c |  2 +-
>  drivers/i2c/i2c-core.h      |  9 +++++++++
>  3 files changed, 25 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
> index 4842ec3a5451..a9126b3cda61 100644
> --- a/drivers/i2c/i2c-core-acpi.c
> +++ b/drivers/i2c/i2c-core-acpi.c
> @@ -230,6 +230,16 @@ void i2c_acpi_register_devices(struct i2c_adapter
> *adap)
>  		dev_warn(&adap->dev, "failed to enumerate I2C
> slaves\n");
>  }
>  
> +const struct acpi_device_id *
> +i2c_acpi_match_device(const struct acpi_device_id *matches,
> +		      struct i2c_client *client)
> +{
> +	if (!(client && matches))
> +		return NULL;
> +
> +	return acpi_match_device(matches, &client->dev);
> +}
> +
>  static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32
> level,
>  					   void *data, void
> **return_value)
>  {
> @@ -289,7 +299,7 @@ u32 i2c_acpi_find_bus_speed(struct device *dev)
>  }
>  EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
>  
> -static int i2c_acpi_match_adapter(struct device *dev, void *data)
> +static int i2c_acpi_find_match_adapter(struct device *dev, void
> *data)
>  {
>  	struct i2c_adapter *adapter = i2c_verify_adapter(dev);
>  
> @@ -299,7 +309,7 @@ static int i2c_acpi_match_adapter(struct device
> *dev, void *data)
>  	return ACPI_HANDLE(dev) == (acpi_handle)data;
>  }
>  
> -static int i2c_acpi_match_device(struct device *dev, void *data)
> +static int i2c_acpi_find_match_device(struct device *dev, void *data)
>  {
>  	return ACPI_COMPANION(dev) == data;
>  }
> @@ -309,7 +319,7 @@ static struct i2c_adapter
> *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
>  	struct device *dev;
>  
>  	dev = bus_find_device(&i2c_bus_type, NULL, handle,
> -			      i2c_acpi_match_adapter);
> +			      i2c_acpi_find_match_adapter);
>  	return dev ? i2c_verify_adapter(dev) : NULL;
>  }
>  
> @@ -317,7 +327,8 @@ static struct i2c_client
> *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
>  {
>  	struct device *dev;
>  
> -	dev = bus_find_device(&i2c_bus_type, NULL, adev,
> i2c_acpi_match_device);
> +	dev = bus_find_device(&i2c_bus_type, NULL, adev,
> +			      i2c_acpi_find_match_device);
>  	return dev ? i2c_verify_client(dev) : NULL;
>  }
>  
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 45231d2257ad..ba51551c3077 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -357,7 +357,7 @@ static int i2c_device_probe(struct device *dev)
>  	 * Tree or ACPI match table entry is supplied for the probing
> device.
>  	 */
>  	if (!driver->id_table &&
> -	    !acpi_match_device(dev->driver->acpi_match_table,
> &client->dev) &&
> +	    !i2c_acpi_match_device(dev->driver->acpi_match_table,
> client) &&
>  	    !i2c_of_match_device(dev->driver->of_match_table,
> client))
>  		return -ENODEV;
>  
> diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
> index 3b63f5e5b89c..3d3d9bf02101 100644
> --- a/drivers/i2c/i2c-core.h
> +++ b/drivers/i2c/i2c-core.h
> @@ -31,9 +31,18 @@ int i2c_check_addr_validity(unsigned addr, unsigned
> short flags);
>  int i2c_check_7bit_addr_validity_strict(unsigned short addr);
>  
>  #ifdef CONFIG_ACPI
> +const struct acpi_device_id *
> +i2c_acpi_match_device(const struct acpi_device_id *matches,
> +		      struct i2c_client *client);
>  void i2c_acpi_register_devices(struct i2c_adapter *adap);
>  #else /* CONFIG_ACPI */
>  static inline void i2c_acpi_register_devices(struct i2c_adapter
> *adap) { }
> +static inline const struct acpi_device_id *
> +i2c_acpi_match_device(const struct acpi_device_id *matches,
> +		      struct i2c_client *client)
> +{
> +	return NULL;
> +}
>  #endif /* CONFIG_ACPI */
>  extern struct notifier_block i2c_acpi_notifier;
>  

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy