Hi,
On 12-07-18 19:23, Andy Shevchenko wrote:
acpi_dev_present() and acpi_dev_get_first_match_name() are 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@xxxxxxxxxxxxxxx>
---
drivers/acpi/utils.c | 50 ++++++++++++++++++++++++-----------------
include/acpi/acpi_bus.h | 2 ++
include/linux/acpi.h | 6 +++++
3 files changed, 38 insertions(+), 20 deletions(-)
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 78db97687f26..b54651b3d4bd 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -738,7 +738,6 @@ bool acpi_dev_found(const char *hid)
EXPORT_SYMBOL(acpi_dev_found);
struct acpi_dev_match_info {
- const char *dev_name;
struct acpi_device_id hid[2];
const char *uid;
s64 hrv;
@@ -758,8 +757,6 @@ static int acpi_dev_match_cb(struct device *dev, void *data)
strcmp(adev->pnp.unique_id, match->uid)))
return 0;
- match->dev_name = acpi_dev_name(adev);
-
if (match->hrv == -1)
return 1;
@@ -771,18 +768,18 @@ static int acpi_dev_match_cb(struct device *dev, void *data)
}
/**
- * acpi_dev_present - Detect that a given ACPI device is present
+ * acpi_dev_get_first_match - Return a first match of ACPI device if present
* @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 %true if a matching device was present at the moment of invocation.
- * Note that if the device is pluggable, it may since have disappeared.
+ * Return a pointer to the first matching ACPI device.
+ * Caller must put device back to balance reference counting.
*
* Note that unlike acpi_dev_found() this function checks the status
- * of the device. So for devices which are present in the dsdt, but
+ * of the device. So for devices which are present in the DSDT, but
* which are disabled (their _STA callback returns 0) this function
- * will return false.
+ * will return NULL.
*
* For this function to work, acpi_bus_scan() must have been executed
* which happens in the subsys_initcall() subsection. Hence, do not
@@ -790,7 +787,8 @@ static int acpi_dev_match_cb(struct device *dev, void *data)
* instead). Calling from module_init() is fine (which is synonymous
* with device_initcall()).
*/
-bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
+struct acpi_device *
+acpi_dev_get_first_match(const char *hid, const char *uid, s64 hrv)
{
struct acpi_dev_match_info match = {};
struct device *dev;
@@ -800,7 +798,25 @@ bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
match.hrv = hrv;
dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
- return !!dev;
+ return dev ? to_acpi_device(dev) : NULL;
+}
+EXPORT_SYMBOL(acpi_dev_get_first_match);
+
+/**
+ * acpi_dev_present - Detect that a given ACPI device is present
+ * @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
+ *
+ * DEPRECATED, use acpi_dev_get_first_match() directly!
+ *
+ * Return %true if a matching device is present.
+ */
+bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
+{
+ struct acpi_device *adev = acpi_dev_get_first_match(hid, uid, hrv);
+
+ return !!adev;
}
EXPORT_SYMBOL(acpi_dev_present);
Why not just do:
bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
{
struct acpi_device *adev = acpi_dev_get_first_match(hid, uid, hrv);
if (!adev)
return false;
put_device(&adev->dev);
return true;
}
And not deprecate this. This fixes the leak while keeping the
API usage simple for users of this API. Having to do a put_device
in all callers seems cumbersome if we can just do it here.
Regards,
Hans
@@ -810,23 +826,17 @@ EXPORT_SYMBOL(acpi_dev_present);
* @uid: Unique ID of the device, pass NULL to not check _UID
* @hrv: Hardware Revision of the device, pass -1 to not check _HRV
*
+ * DEPRECATED, use acpi_dev_get_first_match() directly!
+ *
* Return device name if a matching device was present
* at the moment of invocation, or NULL otherwise.
- *
- * See additional information in acpi_dev_present() as well.
*/
const char *
acpi_dev_get_first_match_name(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;
+ struct acpi_device *adev = acpi_dev_get_first_match(hid, uid, hrv);
- dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
- return dev ? match.dev_name : NULL;
+ return adev ? acpi_dev_name(adev) : NULL;
}
EXPORT_SYMBOL(acpi_dev_get_first_match_name);
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index ba4dd54f2c82..53ca4403f772 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -91,6 +91,8 @@ 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(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 e54f40974eb0..098e0af003b4 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -657,6 +657,12 @@ static inline bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
return false;
}
+struct acpi_device *
+acpi_dev_get_first_match(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)
{
--
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