From: Zhang Qilong zhangqilong3@huawei.com

mainline inclusion from mainline-v5.10-rc5 commit dd8088d5a8969dc2b42f71d7bc01c25c61a78066 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I94JCT CVE: CVE-2020-36782

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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, which could resulted in reference leak. 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/list/?series=178139 Signed-off-by: Zhang Qilong zhangqilong3@huawei.com Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Jakub Kicinski kuba@kernel.org

Conflicts: include/linux/pm_runtime.h

Signed-off-by: Zhang Xiaoxu zhangxiaoxu5@huawei.com --- include/linux/pm_runtime.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)

diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index f0fc4700b6ff..98e922e6ff30 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -225,6 +225,27 @@ static inline int pm_runtime_get_sync(struct device *dev) return __pm_runtime_resume(dev, RPM_GET_PUT); }

+/** + * pm_runtime_resume_and_get - Bump up usage counter of a device and resume it. + * @dev: Target device. + * + * Resume @dev synchronously and if that is successful, increment its runtime + * PM usage counter. Return 0 if the runtime PM usage counter of @dev has been + * incremented or a negative error code otherwise. + */ +static inline int pm_runtime_resume_and_get(struct device *dev) +{ + int ret; + + ret = __pm_runtime_resume(dev, RPM_GET_PUT); + if (ret < 0) { + pm_runtime_put_noidle(dev); + return ret; + } + + return 0; +} + static inline int pm_runtime_put(struct device *dev) { return __pm_runtime_idle(dev, RPM_GET_PUT | RPM_ASYNC);