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    Subject[PATCH 5.4 010/453] PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter
    Date
    From: Zhang Qilong <zhangqilong3@huawei.com>

    [ Upstream commit dd8088d5a8969dc2b42f71d7bc01c25c61a78066 ]

    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>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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 fe61e3b9a9ca2..7145795b4b9da 100644
    --- a/include/linux/pm_runtime.h
    +++ b/include/linux/pm_runtime.h
    @@ -224,6 +224,27 @@ 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);
    --
    2.27.0


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