In many case, we need to check return value of pm_runtime_get_sync, but it brings a trouble to the usage counter processing. Many callers forget to decrease the usage counter when it failed. It has been discussed a lot[0][1]. So we add a function to deal with the usage counter for better coding.
[0]https://lkml.org/lkml/2020/6/14/88 [1]https://patchwork.ozlabs.org/project/linux-tegra/patch/20200520095148.10995-1-dinghao....@zju.edu.cn/ Signed-off-by: Zhang Qilong <zhangqilo...@huawei.com> --- include/linux/pm_runtime.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 4b708f4e8eed..6549ce764400 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -386,6 +386,36 @@ static inline int pm_runtime_get_sync(struct device *dev) return __pm_runtime_resume(dev, RPM_GET_PUT); } +/** + * pm_runtime_general_get - Bump up usage counter of a device and resume it. + * @dev: Target device. + * + * Increase runtime PM usage counter of @dev first, and carry out runtime-resume + * of it synchronously. If __pm_runtime_resume return negative value(device is in + * error state), we to need decrease the usage counter before it return. If + * __pm_runtime_resume return positive value, it means the runtime of device has + * already been in active state, and we let the new wrapper return zero instead. + * + * The possible return values of this function is zero or negative value. + * zero: + * - it means resume succeeed or runtime of device has already been active, the + * runtime PM usage counter of @dev remains incremented. + * negative: + * - it means failure and the runtime PM usage counter of @dev has been balanced. + */ +static inline int pm_runtime_general_get(struct device *dev) +{ + int ret = 0; + + ret = __pm_runtime_resume(dev, RPM_GET_PUT); + if (ret < 0) { + pm_runtime_put_noidle(dev); + return ret; + } + + return 0; +} + /** * pm_runtime_put - Drop device usage counter and queue up "idle check" if 0. * @dev: Target device. -- 2.25.4
