[v2,1/2] ACPI / utils: Introduce acpi_dev_get_first_match_dev() helper

The acpi_dev_get_first_match_name() is missing put_device() call
and thus keeping reference counting unbalanced.

In order to fix the issue introduce a new helper to convert existing users
one-by-one to a better API.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/acpi/utils.c    | 24 ++++++++++++++++++++++--
 include/acpi/acpi_bus.h |  3 +++
 include/linux/acpi.h    |  6 ++++++
 3 files changed, 31 insertions(+), 2 deletions(-)

Hi,

On 18-03-19 21:00, Andy Shevchenko wrote:
> The acpi_dev_get_first_match_name() is missing put_device() call
> and thus keeping reference counting unbalanced.
> 
> In order to fix the issue introduce a new helper to convert existing users
> one-by-one to a better API.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Series looks good to me, for the series:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans


> ---
>   drivers/acpi/utils.c    | 24 ++++++++++++++++++++++--
>   include/acpi/acpi_bus.h |  3 +++
>   include/linux/acpi.h    |  6 ++++++
>   3 files changed, 31 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
> index c4b06cc075f9..5a2bae2b6c3a 100644
> --- a/drivers/acpi/utils.c
> +++ b/drivers/acpi/utils.c
> @@ -739,6 +739,7 @@ EXPORT_SYMBOL(acpi_dev_found);
>   
>   struct acpi_dev_match_info {
>   	const char *dev_name;
> +	struct acpi_device *adev;
>   	struct acpi_device_id hid[2];
>   	const char *uid;
>   	s64 hrv;
> @@ -759,6 +760,7 @@ static int acpi_dev_match_cb(struct device *dev, void *data)
>   		return 0;
>   
>   	match->dev_name = acpi_dev_name(adev);
> +	match->adev = adev;
>   
>   	if (match->hrv == -1)
>   		return 1;
> @@ -806,16 +808,34 @@ bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
>   EXPORT_SYMBOL(acpi_dev_present);
>   
>   /**
> - * acpi_dev_get_first_match_name - Return name of first match of ACPI device
> + * acpi_dev_get_first_match_dev - Return the first match of ACPI device
>    * @hid: Hardware ID of the device.
>    * @uid: Unique ID of the device, pass NULL to not check _UID
>    * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
>    *
> - * Return device name if a matching device was present
> + * Return the first match of ACPI device if a matching device was present
>    * at the moment of invocation, or NULL otherwise.
>    *
> + * The caller is responsible to call put_device() on the returned device.
> + *
>    * See additional information in acpi_dev_present() as well.
>    */
> +struct acpi_device *
> +acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
> +{
> +	struct acpi_dev_match_info match = {};
> +	struct device *dev;
> +
> +	strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
> +	match.uid = uid;
> +	match.hrv = hrv;
> +
> +	dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
> +	return dev ? match.adev : NULL;
> +}
> +EXPORT_SYMBOL(acpi_dev_get_first_match_dev);
> +
> +/* DEPRECATED, use acpi_dev_get_first_match_dev() instead */
>   const char *
>   acpi_dev_get_first_match_name(const char *hid, const char *uid, s64 hrv)
>   {
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index 0300374101cd..2063e9e2f384 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -91,6 +91,9 @@ acpi_evaluate_dsm_typed(acpi_handle handle, const guid_t *guid, u64 rev,
>   bool acpi_dev_found(const char *hid);
>   bool acpi_dev_present(const char *hid, const char *uid, s64 hrv);
>   
> +struct acpi_device *
> +acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv);
> +
>   const char *
>   acpi_dev_get_first_match_name(const char *hid, const char *uid, s64 hrv);
>   
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index d5dcebd7aad3..3e1d16b00513 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -669,6 +669,12 @@ static inline bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
>   	return false;
>   }
>   
> +static inline struct acpi_device *
> +acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
> +{
> +	return NULL;
> +}
> +
>   static inline const char *
>   acpi_dev_get_first_match_name(const char *hid, const char *uid, s64 hrv)
>   {
>

On Mon, Mar 18, 2019 at 11:00:54PM +0300, Andy Shevchenko wrote:
> The acpi_dev_get_first_match_name() is missing put_device() call
> and thus keeping reference counting unbalanced.
> 
> In order to fix the issue introduce a new helper to convert existing users
> one-by-one to a better API.

I think it makes more sense to convert all the existing users to this
new API that does not leak, and remove the faulty function completely
instead of marking it deprecated.