On Wednesday, May 20, 2020 5:02:30 PM CEST Dan Carpenter wrote: > On Wed, May 20, 2020 at 01:15:44PM +0300, Dmitry Osipenko wrote: > > 20.05.2020 12:51, Dinghao Liu пишет: > > > pm_runtime_get_sync() increments the runtime PM usage counter even > > > it returns an error code. Thus a pairing decrement is needed on > > > the error handling path to keep the counter balanced. > > > > > > Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx> > > > --- > > > drivers/staging/media/tegra-vde/vde.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/staging/media/tegra-vde/vde.c b/drivers/staging/media/tegra-vde/vde.c > > > index d3e63512a765..dd134a3a15c7 100644 > > > --- a/drivers/staging/media/tegra-vde/vde.c > > > +++ b/drivers/staging/media/tegra-vde/vde.c > > > @@ -777,7 +777,7 @@ static int tegra_vde_ioctl_decode_h264(struct tegra_vde *vde, > > > > > > ret = pm_runtime_get_sync(dev); > > > if (ret < 0) > > > - goto unlock; > > > + goto put_runtime_pm; > > > > > > /* > > > * We rely on the VDE registers reset value, otherwise VDE > > > > > > > Hello Dinghao, > > > > Thank you for the patch. I sent out a similar patch a week ago [1]. > > > > [1] > > https://patchwork.ozlabs.org/project/linux-tegra/patch/20200514210847.9269-2-digetx@xxxxxxxxx/ > > > > The pm_runtime_put_noidle() should have the same effect as yours > > variant, although my variant won't change the last_busy RPM time, which > > I think is a bit more appropriate behavior. > > I don't think either patch is correct. The right thing to do is to fix > __pm_runtime_resume() so it doesn't leak a reference count on error. > > The problem is that a lot of functions don't check the return so > possibly we are relying on that behavior. Actually, the function was written with this case in mind. In retrospect, that has been a mistake and there should be a void variant to cover this case, but it's been like that for several years and the documentation doesn't really say that the reference counter will be decremented on errors. > We may need to introduce a > new function which cleans up properly instead of leaking reference > counts? Well, even with that, all of the broken callers of pm_runtime_get_sync() would need to be changed to use the new function instead? Is that what you mean?
