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| author | Andy Shevchenko <andy.shevchenko@gmail.com> | 2021-04-13 01:20:51 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2021-04-13 15:48:02 +0200 |
| commit | 81eeb2f57782d0dff15db97665599121e289b614 (patch) | |
| tree | 14f2f2308b8d96135c315062968978e4b9bb2c7c /include/acpi | |
| parent | Linux 5.12-rc7 (diff) | |
| download | linux-81eeb2f57782d0dff15db97665599121e289b614.tar.xz linux-81eeb2f57782d0dff15db97665599121e289b614.zip | |
ACPI: utils: Document for_each_acpi_dev_match() macro
The macro requires to call acpi_dev_put() on each iteration.
Due to this it doesn't tolerate sudden disappearence of the devices.
Document all these nuances to prevent users blindly call it without
understanding the possible issues.
While at it, add the note to the acpi_dev_get_next_match_dev() and
advertise acpi_dev_put() instead of put_device() in the whole family
of the helper functions.
Fixes: bf263f64e804 ("media: ACPI / bus: Add acpi_dev_get_next_match_dev() and helper macro")
Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include/acpi')
| -rw-r--r-- | include/acpi/acpi_bus.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h index f28b097c658f..61937d243374 100644 --- a/include/acpi/acpi_bus.h +++ b/include/acpi/acpi_bus.h @@ -689,6 +689,20 @@ acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const cha struct acpi_device * acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv); +/** + * for_each_acpi_dev_match - iterate over ACPI devices that matching the criteria + * @adev: pointer to the matching ACPI device, NULL at the end of the loop + * @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 + * + * The caller is responsible for invoking acpi_dev_put() on the returned device. + * + * FIXME: Due to above requirement there is a window that may invalidate @adev + * and next iteration will use a dangling pointer, e.g. in the case of a + * hotplug event. That said, the caller should ensure that this will never + * happen. + */ #define for_each_acpi_dev_match(adev, hid, uid, hrv) \ for (adev = acpi_dev_get_first_match_dev(hid, uid, hrv); \ adev; \ |