[PATCH] PCI: tegra: Fix runtime PM imbalance in pex_ep_event_pex_rst_deassert

[PATCH] PCI: tegra: Fix runtime PM imbalance in pex_ep_event_pex_rst_deassert

[Dinghao Liu]

pm_runtime_get_sync() will increase the runtime PM counter
even it returns an error. Thus a pairing decrement is needed
to prevent refcount leak. Fix this by replacing this API with
pm_runtime_resume_and_get(), which will not change the runtime
PM counter on error.

Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
---
 drivers/pci/controller/dwc/pcie-tegra194.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 6fa216e52d14..0e94190ca4e8 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -1645,7 +1645,7 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
 	if (pcie->ep_state == EP_STATE_ENABLED)
 		return;
 
-	ret = pm_runtime_get_sync(dev);
+	ret = pm_runtime_resume_and_get(dev);
 	if (ret < 0) {
 		dev_err(dev, "Failed to get runtime sync for PCIe dev: %d\n",
 			ret);
-- 
2.17.1

Re: [PATCH] PCI: tegra: Fix runtime PM imbalance in pex_ep_event_pex_rst_deassert

[Jon Hunter]

On 08/04/2021 08:26, Dinghao Liu wrote:
> pm_runtime_get_sync() will increase the runtime PM counter
> even it returns an error. Thus a pairing decrement is needed
> to prevent refcount leak. Fix this by replacing this API with
> pm_runtime_resume_and_get(), which will not change the runtime
> PM counter on error.
> 
> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> ---
>  drivers/pci/controller/dwc/pcie-tegra194.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> index 6fa216e52d14..0e94190ca4e8 100644
> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -1645,7 +1645,7 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
>  	if (pcie->ep_state == EP_STATE_ENABLED)
>  		return;
>  
> -	ret = pm_runtime_get_sync(dev);
> +	ret = pm_runtime_resume_and_get(dev);
>  	if (ret < 0) {
>  		dev_err(dev, "Failed to get runtime sync for PCIe dev: %d\n",
>  			ret);
> 

There are two places in the driver where pm_runtime_get_sync() is called.

Thanks
Jon

-- 
nvpublic

Re: [PATCH] PCI: tegra: Fix runtime PM imbalance in pex_ep_event_pex_rst_deassert

[Thierry Reding]

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On Thu, Apr 08, 2021 at 01:34:37PM +0100, Jon Hunter wrote:
> 
> On 08/04/2021 08:26, Dinghao Liu wrote:
> > pm_runtime_get_sync() will increase the runtime PM counter
> > even it returns an error. Thus a pairing decrement is needed
> > to prevent refcount leak. Fix this by replacing this API with
> > pm_runtime_resume_and_get(), which will not change the runtime
> > PM counter on error.
> > 
> > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> > ---
> >  drivers/pci/controller/dwc/pcie-tegra194.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> > index 6fa216e52d14..0e94190ca4e8 100644
> > --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> > +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> > @@ -1645,7 +1645,7 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
> >  	if (pcie->ep_state == EP_STATE_ENABLED)
> >  		return;
> >  
> > -	ret = pm_runtime_get_sync(dev);
> > +	ret = pm_runtime_resume_and_get(dev);
> >  	if (ret < 0) {
> >  		dev_err(dev, "Failed to get runtime sync for PCIe dev: %d\n",
> >  			ret);
> > 
> 
> There are two places in the driver where pm_runtime_get_sync() is called.

It looks like the second callsite has the proper cleanup code. Although
it might be nice to use pm_runtime_resume_and_get() there as well, and
adjust the cleanup path, to make this consistent.

In any case, this looks good to me:

Acked-by: Thierry Reding <treding@nvidia.com>

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Re: [PATCH] PCI: tegra: Fix runtime PM imbalance in pex_ep_event_pex_rst_deassert

[Lorenzo Pieralisi]

On Thu, 8 Apr 2021 15:26:58 +0800, Dinghao Liu wrote:
> pm_runtime_get_sync() will increase the runtime PM counter
> even it returns an error. Thus a pairing decrement is needed
> to prevent refcount leak. Fix this by replacing this API with
> pm_runtime_resume_and_get(), which will not change the runtime
> PM counter on error.

Applied to pci/tegra, thanks!

[1/1] PCI: tegra: Fix runtime PM imbalance in pex_ep_event_pex_rst_deassert
      https://git.kernel.org/lpieralisi/pci/c/571cdd5294

Thanks,
Lorenzo