On Fri, Nov 27, 2020 at 11:16 AM Geert Uytterhoeven <ge...@linux-m68k.org> wrote: > > Hi Zhang, > > On Tue, Nov 10, 2020 at 10:29 AM Zhang Qilong <zhangqilo...@huawei.com> wrote: > > 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 <zhangqilo...@huawei.com> > > Thanks for your patch, which is now commit dd8088d5a8969dc2 ("PM: > runtime: Add pm_runtime_resume_and_get to deal with usage counter") in > v5.10-rc5. > > > --- a/include/linux/pm_runtime.h > > +++ b/include/linux/pm_runtime.h > > @@ -386,6 +386,27 @@ 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) > > Perhaps this function should be called pm_runtime_resume_and_get_sync(),
No, really. I might consider calling it pm_runtime_acquire(), and adding a matching _release() as a pm_runtime_get() synonym for that matter, but not the above. > to make it clear it does a synchronous get? > > I had to look into the implementation to verify that a change like I'm not sure why, because the kerneldoc is unambiguous AFAICS. > > - ret = pm_runtime_get_sync(&pdev->dev); > + ret = pm_runtime_resume_and_get(&pdev->dev); > > in the follow-up patches is actually a valid change, maintaining > synchronous operation. Oh, pm_runtime_resume() is synchronous, too... Yes, it is.
