[PATCH] i2c: omap: Fix rumtime PM imbalance on error

[PATCH] i2c: omap: Fix rumtime PM imbalance on error

[Dinghao Liu]

pm_runtime_get_sync() will increase the rumtime 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/i2c/busses/i2c-omap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 12ac4212aded..c9ee0875a79d 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -1404,7 +1404,7 @@ omap_i2c_probe(struct platform_device *pdev)
 	pm_runtime_set_autosuspend_delay(omap->dev, OMAP_I2C_PM_TIMEOUT);
 	pm_runtime_use_autosuspend(omap->dev);
 
-	r = pm_runtime_get_sync(omap->dev);
+	r = pm_runtime_resume_and_get(omap->dev);
 	if (r < 0)
 		goto err_free_mem;
 
-- 
2.17.1

Re: [PATCH] i2c: omap: Fix rumtime PM imbalance on error

[Tony Lindgren]

* Dinghao Liu <dinghao.liu@zju.edu.cn> [210407 03:31]:
> pm_runtime_get_sync() will increase the rumtime 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>

Reviewed-by: Tony Lindgren <tony@atomide.com>

> ---
>  drivers/i2c/busses/i2c-omap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 12ac4212aded..c9ee0875a79d 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -1404,7 +1404,7 @@ omap_i2c_probe(struct platform_device *pdev)
>  	pm_runtime_set_autosuspend_delay(omap->dev, OMAP_I2C_PM_TIMEOUT);
>  	pm_runtime_use_autosuspend(omap->dev);
>  
> -	r = pm_runtime_get_sync(omap->dev);
> +	r = pm_runtime_resume_and_get(omap->dev);
>  	if (r < 0)
>  		goto err_free_mem;
>  
> -- 
> 2.17.1
> 

Re: [PATCH] i2c: omap: Fix rumtime PM imbalance on error

[Vignesh Raghavendra]

On 4/7/21 9:00 AM, Dinghao Liu wrote:
> pm_runtime_get_sync() will increase the rumtime 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>
> ---

Do we need a Fixes: tag to enable stable backports?

Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>

>  drivers/i2c/busses/i2c-omap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 12ac4212aded..c9ee0875a79d 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -1404,7 +1404,7 @@ omap_i2c_probe(struct platform_device *pdev)
>  	pm_runtime_set_autosuspend_delay(omap->dev, OMAP_I2C_PM_TIMEOUT);
>  	pm_runtime_use_autosuspend(omap->dev);
>  
> -	r = pm_runtime_get_sync(omap->dev);
> +	r = pm_runtime_resume_and_get(omap->dev);
>  	if (r < 0)
>  		goto err_free_mem;
>  
> 

Re: [PATCH] i2c: omap: Fix rumtime PM imbalance on error

[Tony Lindgren]

* Vignesh Raghavendra <vigneshr@ti.com> [210407 06:20]:
> Do we need a Fixes: tag to enable stable backports?

Well pm_runtime_resume_and_get() was introduced quite recently, and
we already handle the error and bail out. And likely after an error
not much works anyways :) So it might be better to add just a stable
tag v5.10 and later as further backports are not likely needed.

Naturally nothing stopping doing separate backports if really needed
though.

Regards,

Tony

Re: [PATCH] i2c: omap: Fix rumtime PM imbalance on error

[Vignesh Raghavendra]

Hi,

On 4/7/21 11:57 AM, Tony Lindgren wrote:
> * Vignesh Raghavendra <vigneshr@ti.com> [210407 06:20]:
>> Do we need a Fixes: tag to enable stable backports?
> 
> Well pm_runtime_resume_and_get() was introduced quite recently, and
> we already handle the error and bail out. And likely after an error
> not much works anyways :) So it might be better to add just a stable
> tag v5.10 and later as further backports are not likely needed.
> 

Agree this is not a critical patch for backport. But I do know that
pm_runtime_resume_and_get() is backported to v5.4 stable kernel at least
[1]. So stable tag with v5.4 perhaps would probably help tools looking
for patches to backport.

[1] https://lkml.org/lkml/2020/12/28/588

> Naturally nothing stopping doing separate backports if really needed
> though.
> 
> Regards,
> 
> Tony
> 

Regards
Vignesh

Re: [PATCH] i2c: omap: Fix rumtime PM imbalance on error

[Tony Lindgren]

* Vignesh Raghavendra <vigneshr@ti.com> [210407 07:46]:
> Hi,
> 
> On 4/7/21 11:57 AM, Tony Lindgren wrote:
> > * Vignesh Raghavendra <vigneshr@ti.com> [210407 06:20]:
> >> Do we need a Fixes: tag to enable stable backports?
> > 
> > Well pm_runtime_resume_and_get() was introduced quite recently, and
> > we already handle the error and bail out. And likely after an error
> > not much works anyways :) So it might be better to add just a stable
> > tag v5.10 and later as further backports are not likely needed.
> > 
> 
> Agree this is not a critical patch for backport. But I do know that
> pm_runtime_resume_and_get() is backported to v5.4 stable kernel at least
> [1]. So stable tag with v5.4 perhaps would probably help tools looking
> for patches to backport.

OK no objections to adding a fixes tag.

Regards,

Tony

> [1] https://lkml.org/lkml/2020/12/28/588

Re: [PATCH] i2c: omap: Fix rumtime PM imbalance on error

[Wolfram Sang]

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On Wed, Apr 07, 2021 at 11:30:30AM +0800, Dinghao Liu wrote:
> pm_runtime_get_sync() will increase the rumtime 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>

Thanks, yet I applied this series now:

http://patchwork.ozlabs.org/project/linux-i2c/list/?series=217733&state=*


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