diff mbox

[RFC,6/8] PM / Domains: Remove a provider by referencing the data pointer

Message ID 1457090634-14785-7-git-send-email-jonathanh@nvidia.com (mailing list archive)
State RFC, archived
Headers show

Commit Message

Jon Hunter March 4, 2016, 11:23 a.m. UTC
To remove a PM domain from the system, it is necessary to ensure
that any PM domain providers associated with the PM domain have
been removed. Otherwise it could be possible to obtain a pointer
to a PM domain structure that has been removed.

PM domains now have a reference to the pointer for the PM domain
provider's data variable. Add a function so that a PM domain can
remove a PM domain provider by referencing the data pointer.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
---
 drivers/base/power/domain.c | 24 ++++++++++++++++++++++++
 include/linux/pm_domain.h   |  2 ++
 2 files changed, 26 insertions(+)

Comments

Ulf Hansson June 15, 2016, 2:38 p.m. UTC | #1
On 4 March 2016 at 12:23, Jon Hunter <jonathanh@nvidia.com> wrote:
> To remove a PM domain from the system, it is necessary to ensure
> that any PM domain providers associated with the PM domain have
> been removed. Otherwise it could be possible to obtain a pointer
> to a PM domain structure that has been removed.
>
> PM domains now have a reference to the pointer for the PM domain
> provider's data variable. Add a function so that a PM domain can
> remove a PM domain provider by referencing the data pointer.
>
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> ---
>  drivers/base/power/domain.c | 24 ++++++++++++++++++++++++
>  include/linux/pm_domain.h   |  2 ++
>  2 files changed, 26 insertions(+)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 72055fef6256..438885f2455f 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1738,6 +1738,30 @@ void of_genpd_del_provider(struct device_node *np)
>  EXPORT_SYMBOL_GPL(of_genpd_del_provider);
>
>  /**
> + * of_genpd_del_provider_by_data() - Remove a registered PM domain provider
> + * @data: Pointer to the data associated with the PM domain provider
> + *
> + * Look up a PM domain provider based upon a pointer to it's data and
> + * remove the PM domain provider from the list of providers.
> + */
> +void of_genpd_del_provider_by_data(void *data)
> +{
> +       struct of_genpd_provider *c, *cp;
> +
> +       mutex_lock(&of_genpd_mutex);
> +       list_for_each_entry_safe(cp, c, &of_genpd_providers, link) {
> +               if (cp->data == data) {
> +                       list_del(&cp->link);
> +                       of_node_put(cp->node);
> +                       kfree(cp);
> +                       break;
> +               }
> +       }
> +       mutex_unlock(&of_genpd_mutex);
> +}
> +EXPORT_SYMBOL_GPL(of_genpd_del_provider_by_data);
> +
> +/**
>   * of_genpd_get_from_provider() - Look-up PM domain
>   * @genpdspec: OF phandle args to use for look-up
>   *
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index bed84413546f..7b7921a65cb0 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -199,6 +199,7 @@ int of_genpd_add_provider_simple(struct device_node *np,
>  int of_genpd_add_provider_onecell(struct device_node *np,
>                                   struct genpd_onecell_data *data);
>  void of_genpd_del_provider(struct device_node *np);

There's currently only one user of of_genpd_del_provider().

Could this patch just convert that user to the new API, so we don't
need to keep both the legacy and new one?

I guess we could then just stick to the name "of_genpd_del_provider()".

> +void of_genpd_del_provider_by_data(void *data);
>  struct generic_pm_domain *__of_genpd_xlate_simple(
>                                         struct of_phandle_args *genpdspec,
>                                         void *data);
> @@ -218,6 +219,7 @@ static inline int __of_genpd_add_provider(struct device_node *np,
>         return 0;
>  }
>  static inline void of_genpd_del_provider(struct device_node *np) {}
> +static inline void of_genpd_del_provider_by_data(void *data) {}
>
>  #define __of_genpd_xlate_simple                NULL
>  #define __of_genpd_xlate_onecell       NULL
> --
> 2.1.4
>

Kind regards
Uffe
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Jon Hunter June 21, 2016, 1:47 p.m. UTC | #2
On 15/06/16 15:38, Ulf Hansson wrote:
> On 4 March 2016 at 12:23, Jon Hunter <jonathanh@nvidia.com> wrote:
>> To remove a PM domain from the system, it is necessary to ensure
>> that any PM domain providers associated with the PM domain have
>> been removed. Otherwise it could be possible to obtain a pointer
>> to a PM domain structure that has been removed.
>>
>> PM domains now have a reference to the pointer for the PM domain
>> provider's data variable. Add a function so that a PM domain can
>> remove a PM domain provider by referencing the data pointer.
>>
>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>> ---
>>  drivers/base/power/domain.c | 24 ++++++++++++++++++++++++
>>  include/linux/pm_domain.h   |  2 ++
>>  2 files changed, 26 insertions(+)
>>
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index 72055fef6256..438885f2455f 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -1738,6 +1738,30 @@ void of_genpd_del_provider(struct device_node *np)
>>  EXPORT_SYMBOL_GPL(of_genpd_del_provider);
>>
>>  /**
>> + * of_genpd_del_provider_by_data() - Remove a registered PM domain provider
>> + * @data: Pointer to the data associated with the PM domain provider
>> + *
>> + * Look up a PM domain provider based upon a pointer to it's data and
>> + * remove the PM domain provider from the list of providers.
>> + */
>> +void of_genpd_del_provider_by_data(void *data)
>> +{
>> +       struct of_genpd_provider *c, *cp;
>> +
>> +       mutex_lock(&of_genpd_mutex);
>> +       list_for_each_entry_safe(cp, c, &of_genpd_providers, link) {
>> +               if (cp->data == data) {
>> +                       list_del(&cp->link);
>> +                       of_node_put(cp->node);
>> +                       kfree(cp);
>> +                       break;
>> +               }
>> +       }
>> +       mutex_unlock(&of_genpd_mutex);
>> +}
>> +EXPORT_SYMBOL_GPL(of_genpd_del_provider_by_data);
>> +
>> +/**
>>   * of_genpd_get_from_provider() - Look-up PM domain
>>   * @genpdspec: OF phandle args to use for look-up
>>   *
>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>> index bed84413546f..7b7921a65cb0 100644
>> --- a/include/linux/pm_domain.h
>> +++ b/include/linux/pm_domain.h
>> @@ -199,6 +199,7 @@ int of_genpd_add_provider_simple(struct device_node *np,
>>  int of_genpd_add_provider_onecell(struct device_node *np,
>>                                   struct genpd_onecell_data *data);
>>  void of_genpd_del_provider(struct device_node *np);
> 
> There's currently only one user of of_genpd_del_provider().
> 
> Could this patch just convert that user to the new API, so we don't
> need to keep both the legacy and new one?
> 
> I guess we could then just stick to the name "of_genpd_del_provider()".

I had a look at this and to do that we would end up with
of_genpd_del_provider(struct device_node *np, void *data) where the user
should only pass one of the arguments. It seems a bit odd. However,
unless I have forgotten something, I wonder if we should just make
of_genpd_del_provider_by_name() a local function and not export this at
all? It seems more natural for users to delete a provider by the
device_node than by name rather than the data argument.

The only problem I see with making of_genpd_del_provider_by_name() local
is that I need to add a prototype for the function at the top of the
domain.c source file so that it builds because __pm_genpd_remove() is
defined above it. Yes I could move __pm_genpd_remove() to the bottom of
the file but then it is not located next to pm_genpd_init() which seems odd.

Let me know what you think.

Cheers
Jon
Jon Hunter June 21, 2016, 2:45 p.m. UTC | #3
On 04/03/16 11:23, Jon Hunter wrote:
> To remove a PM domain from the system, it is necessary to ensure
> that any PM domain providers associated with the PM domain have
> been removed. Otherwise it could be possible to obtain a pointer
> to a PM domain structure that has been removed.
> 
> PM domains now have a reference to the pointer for the PM domain
> provider's data variable. Add a function so that a PM domain can
> remove a PM domain provider by referencing the data pointer.
> 
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> ---
>  drivers/base/power/domain.c | 24 ++++++++++++++++++++++++
>  include/linux/pm_domain.h   |  2 ++
>  2 files changed, 26 insertions(+)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 72055fef6256..438885f2455f 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1738,6 +1738,30 @@ void of_genpd_del_provider(struct device_node *np)
>  EXPORT_SYMBOL_GPL(of_genpd_del_provider);
>  
>  /**
> + * of_genpd_del_provider_by_data() - Remove a registered PM domain provider
> + * @data: Pointer to the data associated with the PM domain provider
> + *
> + * Look up a PM domain provider based upon a pointer to it's data and
> + * remove the PM domain provider from the list of providers.
> + */
> +void of_genpd_del_provider_by_data(void *data)
> +{
> +	struct of_genpd_provider *c, *cp;
> +
> +	mutex_lock(&of_genpd_mutex);
> +	list_for_each_entry_safe(cp, c, &of_genpd_providers, link) {
> +		if (cp->data == data) {
> +			list_del(&cp->link);
> +			of_node_put(cp->node);
> +			kfree(cp);
> +			break;
> +		}
> +	}
> +	mutex_unlock(&of_genpd_mutex);

On further the thought I believe that the above does not need to be safe
variant of list_for_each_entry because we are breaking out of the loop
when we find the one we are looking for. of_genpd_del_provider() does
the same.

Cheers
Jon
Jon Hunter July 11, 2016, 1:14 p.m. UTC | #4
Hi Ulf,

On 21/06/16 14:47, Jon Hunter wrote:
> 
> On 15/06/16 15:38, Ulf Hansson wrote:
>> On 4 March 2016 at 12:23, Jon Hunter <jonathanh@nvidia.com> wrote:
>>> To remove a PM domain from the system, it is necessary to ensure
>>> that any PM domain providers associated with the PM domain have
>>> been removed. Otherwise it could be possible to obtain a pointer
>>> to a PM domain structure that has been removed.
>>>
>>> PM domains now have a reference to the pointer for the PM domain
>>> provider's data variable. Add a function so that a PM domain can
>>> remove a PM domain provider by referencing the data pointer.
>>>
>>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>>> ---
>>>  drivers/base/power/domain.c | 24 ++++++++++++++++++++++++
>>>  include/linux/pm_domain.h   |  2 ++
>>>  2 files changed, 26 insertions(+)
>>>
>>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>>> index 72055fef6256..438885f2455f 100644
>>> --- a/drivers/base/power/domain.c
>>> +++ b/drivers/base/power/domain.c
>>> @@ -1738,6 +1738,30 @@ void of_genpd_del_provider(struct device_node *np)
>>>  EXPORT_SYMBOL_GPL(of_genpd_del_provider);
>>>
>>>  /**
>>> + * of_genpd_del_provider_by_data() - Remove a registered PM domain provider
>>> + * @data: Pointer to the data associated with the PM domain provider
>>> + *
>>> + * Look up a PM domain provider based upon a pointer to it's data and
>>> + * remove the PM domain provider from the list of providers.
>>> + */
>>> +void of_genpd_del_provider_by_data(void *data)
>>> +{
>>> +       struct of_genpd_provider *c, *cp;
>>> +
>>> +       mutex_lock(&of_genpd_mutex);
>>> +       list_for_each_entry_safe(cp, c, &of_genpd_providers, link) {
>>> +               if (cp->data == data) {
>>> +                       list_del(&cp->link);
>>> +                       of_node_put(cp->node);
>>> +                       kfree(cp);
>>> +                       break;
>>> +               }
>>> +       }
>>> +       mutex_unlock(&of_genpd_mutex);
>>> +}
>>> +EXPORT_SYMBOL_GPL(of_genpd_del_provider_by_data);
>>> +
>>> +/**
>>>   * of_genpd_get_from_provider() - Look-up PM domain
>>>   * @genpdspec: OF phandle args to use for look-up
>>>   *
>>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>>> index bed84413546f..7b7921a65cb0 100644
>>> --- a/include/linux/pm_domain.h
>>> +++ b/include/linux/pm_domain.h
>>> @@ -199,6 +199,7 @@ int of_genpd_add_provider_simple(struct device_node *np,
>>>  int of_genpd_add_provider_onecell(struct device_node *np,
>>>                                   struct genpd_onecell_data *data);
>>>  void of_genpd_del_provider(struct device_node *np);
>>
>> There's currently only one user of of_genpd_del_provider().
>>
>> Could this patch just convert that user to the new API, so we don't
>> need to keep both the legacy and new one?
>>
>> I guess we could then just stick to the name "of_genpd_del_provider()".
> 
> I had a look at this and to do that we would end up with
> of_genpd_del_provider(struct device_node *np, void *data) where the user
> should only pass one of the arguments. It seems a bit odd. However,
> unless I have forgotten something, I wonder if we should just make
> of_genpd_del_provider_by_name() a local function and not export this at
> all? It seems more natural for users to delete a provider by the
> device_node than by name rather than the data argument.
> 
> The only problem I see with making of_genpd_del_provider_by_name() local
> is that I need to add a prototype for the function at the top of the
> domain.c source file so that it builds because __pm_genpd_remove() is
> defined above it. Yes I could move __pm_genpd_remove() to the bottom of
> the file but then it is not located next to pm_genpd_init() which seems odd.
> 
> Let me know what you think.

Any response on this? This is the last item that we need to sort out?

Cheers
Jon
Ulf Hansson Aug. 5, 2016, 11:55 a.m. UTC | #5
On 21 June 2016 at 15:47, Jon Hunter <jonathanh@nvidia.com> wrote:
>
> On 15/06/16 15:38, Ulf Hansson wrote:
>> On 4 March 2016 at 12:23, Jon Hunter <jonathanh@nvidia.com> wrote:
>>> To remove a PM domain from the system, it is necessary to ensure
>>> that any PM domain providers associated with the PM domain have
>>> been removed. Otherwise it could be possible to obtain a pointer
>>> to a PM domain structure that has been removed.
>>>
>>> PM domains now have a reference to the pointer for the PM domain
>>> provider's data variable. Add a function so that a PM domain can
>>> remove a PM domain provider by referencing the data pointer.


>>>
>>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>>> ---
>>>  drivers/base/power/domain.c | 24 ++++++++++++++++++++++++
>>>  include/linux/pm_domain.h   |  2 ++
>>>  2 files changed, 26 insertions(+)
>>>
>>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>>> index 72055fef6256..438885f2455f 100644
>>> --- a/drivers/base/power/domain.c
>>> +++ b/drivers/base/power/domain.c
>>> @@ -1738,6 +1738,30 @@ void of_genpd_del_provider(struct device_node *np)
>>>  EXPORT_SYMBOL_GPL(of_genpd_del_provider);
>>>
>>>  /**
>>> + * of_genpd_del_provider_by_data() - Remove a registered PM domain provider
>>> + * @data: Pointer to the data associated with the PM domain provider
>>> + *
>>> + * Look up a PM domain provider based upon a pointer to it's data and
>>> + * remove the PM domain provider from the list of providers.
>>> + */
>>> +void of_genpd_del_provider_by_data(void *data)
>>> +{
>>> +       struct of_genpd_provider *c, *cp;
>>> +
>>> +       mutex_lock(&of_genpd_mutex);
>>> +       list_for_each_entry_safe(cp, c, &of_genpd_providers, link) {
>>> +               if (cp->data == data) {
>>> +                       list_del(&cp->link);
>>> +                       of_node_put(cp->node);
>>> +                       kfree(cp);
>>> +                       break;
>>> +               }
>>> +       }
>>> +       mutex_unlock(&of_genpd_mutex);
>>> +}
>>> +EXPORT_SYMBOL_GPL(of_genpd_del_provider_by_data);
>>> +
>>> +/**
>>>   * of_genpd_get_from_provider() - Look-up PM domain
>>>   * @genpdspec: OF phandle args to use for look-up
>>>   *
>>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>>> index bed84413546f..7b7921a65cb0 100644
>>> --- a/include/linux/pm_domain.h
>>> +++ b/include/linux/pm_domain.h
>>> @@ -199,6 +199,7 @@ int of_genpd_add_provider_simple(struct device_node *np,
>>>  int of_genpd_add_provider_onecell(struct device_node *np,
>>>                                   struct genpd_onecell_data *data);
>>>  void of_genpd_del_provider(struct device_node *np);
>>
>> There's currently only one user of of_genpd_del_provider().
>>
>> Could this patch just convert that user to the new API, so we don't
>> need to keep both the legacy and new one?
>>
>> I guess we could then just stick to the name "of_genpd_del_provider()".
>
> I had a look at this and to do that we would end up with
> of_genpd_del_provider(struct device_node *np, void *data) where the user
> should only pass one of the arguments. It seems a bit odd. However,
> unless I have forgotten something, I wonder if we should just make
> of_genpd_del_provider_by_name() a local function and not export this at
> all? It seems more natural for users to delete a provider by the
> device_node than by name rather than the data argument.
>
> The only problem I see with making of_genpd_del_provider_by_name() local
> is that I need to add a prototype for the function at the top of the
> domain.c source file so that it builds because __pm_genpd_remove() is
> defined above it. Yes I could move __pm_genpd_remove() to the bottom of
> the file but then it is not located next to pm_genpd_init() which seems odd.
>
> Let me know what you think.

Sorry for delay! I have now looked into this in more detail.

When an genpd provider is added today, it's supposed to get a
corresponding *unique* OF device node associated with it, right!?

If we store this OF device node from the provider in the struct
generic_pm_domain, instead of the "provider_data pointer", we wouldn't
need to the add of_genpd_del_provider_by_data() at all. Because we can
use the currently available of_genpd_del_provider(), right!?

Or what am I missing? :-)

Kind regards
Uffe
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Jon Hunter Aug. 11, 2016, 4:39 p.m. UTC | #6
On 05/08/16 12:55, Ulf Hansson wrote:
> On 21 June 2016 at 15:47, Jon Hunter <jonathanh@nvidia.com> wrote:
>>
>> On 15/06/16 15:38, Ulf Hansson wrote:
>>> On 4 March 2016 at 12:23, Jon Hunter <jonathanh@nvidia.com> wrote:
>>>> To remove a PM domain from the system, it is necessary to ensure
>>>> that any PM domain providers associated with the PM domain have
>>>> been removed. Otherwise it could be possible to obtain a pointer
>>>> to a PM domain structure that has been removed.
>>>>
>>>> PM domains now have a reference to the pointer for the PM domain
>>>> provider's data variable. Add a function so that a PM domain can
>>>> remove a PM domain provider by referencing the data pointer.
> 
> 
>>>>
>>>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>>>> ---
>>>>  drivers/base/power/domain.c | 24 ++++++++++++++++++++++++
>>>>  include/linux/pm_domain.h   |  2 ++
>>>>  2 files changed, 26 insertions(+)
>>>>
>>>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>>>> index 72055fef6256..438885f2455f 100644
>>>> --- a/drivers/base/power/domain.c
>>>> +++ b/drivers/base/power/domain.c
>>>> @@ -1738,6 +1738,30 @@ void of_genpd_del_provider(struct device_node *np)
>>>>  EXPORT_SYMBOL_GPL(of_genpd_del_provider);
>>>>
>>>>  /**
>>>> + * of_genpd_del_provider_by_data() - Remove a registered PM domain provider
>>>> + * @data: Pointer to the data associated with the PM domain provider
>>>> + *
>>>> + * Look up a PM domain provider based upon a pointer to it's data and
>>>> + * remove the PM domain provider from the list of providers.
>>>> + */
>>>> +void of_genpd_del_provider_by_data(void *data)
>>>> +{
>>>> +       struct of_genpd_provider *c, *cp;
>>>> +
>>>> +       mutex_lock(&of_genpd_mutex);
>>>> +       list_for_each_entry_safe(cp, c, &of_genpd_providers, link) {
>>>> +               if (cp->data == data) {
>>>> +                       list_del(&cp->link);
>>>> +                       of_node_put(cp->node);
>>>> +                       kfree(cp);
>>>> +                       break;
>>>> +               }
>>>> +       }
>>>> +       mutex_unlock(&of_genpd_mutex);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(of_genpd_del_provider_by_data);
>>>> +
>>>> +/**
>>>>   * of_genpd_get_from_provider() - Look-up PM domain
>>>>   * @genpdspec: OF phandle args to use for look-up
>>>>   *
>>>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>>>> index bed84413546f..7b7921a65cb0 100644
>>>> --- a/include/linux/pm_domain.h
>>>> +++ b/include/linux/pm_domain.h
>>>> @@ -199,6 +199,7 @@ int of_genpd_add_provider_simple(struct device_node *np,
>>>>  int of_genpd_add_provider_onecell(struct device_node *np,
>>>>                                   struct genpd_onecell_data *data);
>>>>  void of_genpd_del_provider(struct device_node *np);
>>>
>>> There's currently only one user of of_genpd_del_provider().
>>>
>>> Could this patch just convert that user to the new API, so we don't
>>> need to keep both the legacy and new one?
>>>
>>> I guess we could then just stick to the name "of_genpd_del_provider()".
>>
>> I had a look at this and to do that we would end up with
>> of_genpd_del_provider(struct device_node *np, void *data) where the user
>> should only pass one of the arguments. It seems a bit odd. However,
>> unless I have forgotten something, I wonder if we should just make
>> of_genpd_del_provider_by_name() a local function and not export this at
>> all? It seems more natural for users to delete a provider by the
>> device_node than by name rather than the data argument.
>>
>> The only problem I see with making of_genpd_del_provider_by_name() local
>> is that I need to add a prototype for the function at the top of the
>> domain.c source file so that it builds because __pm_genpd_remove() is
>> defined above it. Yes I could move __pm_genpd_remove() to the bottom of
>> the file but then it is not located next to pm_genpd_init() which seems odd.
>>
>> Let me know what you think.
> 
> Sorry for delay! I have now looked into this in more detail.

No problem. Thanks!

> When an genpd provider is added today, it's supposed to get a
> corresponding *unique* OF device node associated with it, right!?
> 
> If we store this OF device node from the provider in the struct
> generic_pm_domain, instead of the "provider_data pointer", we wouldn't
> need to the add of_genpd_del_provider_by_data() at all. Because we can
> use the currently available of_genpd_del_provider(), right!?
> 
> Or what am I missing? :-)

No that would work as well. I guess I was trying to make it non-DT
specific. However, for now it can be to simplify matters and it could
always be extended later if necessary.

I am also thinking about making pm_genpd_remove_tail()
of_genpd_remove_tail() as it seems silly to have both a struct device
pointer and a struct device_node pointer stored for the provider.

Cheers
Jon
Rafael J. Wysocki Aug. 12, 2016, 12:24 a.m. UTC | #7
On Thu, Aug 11, 2016 at 6:39 PM, Jon Hunter <jonathanh@nvidia.com> wrote:
>
> On 05/08/16 12:55, Ulf Hansson wrote:
>> On 21 June 2016 at 15:47, Jon Hunter <jonathanh@nvidia.com> wrote:
>>>
>>> On 15/06/16 15:38, Ulf Hansson wrote:
>>>> On 4 March 2016 at 12:23, Jon Hunter <jonathanh@nvidia.com> wrote:
>>>>> To remove a PM domain from the system, it is necessary to ensure
>>>>> that any PM domain providers associated with the PM domain have
>>>>> been removed. Otherwise it could be possible to obtain a pointer
>>>>> to a PM domain structure that has been removed.
>>>>>
>>>>> PM domains now have a reference to the pointer for the PM domain
>>>>> provider's data variable. Add a function so that a PM domain can
>>>>> remove a PM domain provider by referencing the data pointer.
>>
>>
>>>>>
>>>>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>>>>> ---
>>>>>  drivers/base/power/domain.c | 24 ++++++++++++++++++++++++
>>>>>  include/linux/pm_domain.h   |  2 ++
>>>>>  2 files changed, 26 insertions(+)
>>>>>
>>>>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>>>>> index 72055fef6256..438885f2455f 100644
>>>>> --- a/drivers/base/power/domain.c
>>>>> +++ b/drivers/base/power/domain.c
>>>>> @@ -1738,6 +1738,30 @@ void of_genpd_del_provider(struct device_node *np)
>>>>>  EXPORT_SYMBOL_GPL(of_genpd_del_provider);
>>>>>
>>>>>  /**
>>>>> + * of_genpd_del_provider_by_data() - Remove a registered PM domain provider
>>>>> + * @data: Pointer to the data associated with the PM domain provider
>>>>> + *
>>>>> + * Look up a PM domain provider based upon a pointer to it's data and
>>>>> + * remove the PM domain provider from the list of providers.
>>>>> + */
>>>>> +void of_genpd_del_provider_by_data(void *data)
>>>>> +{
>>>>> +       struct of_genpd_provider *c, *cp;
>>>>> +
>>>>> +       mutex_lock(&of_genpd_mutex);
>>>>> +       list_for_each_entry_safe(cp, c, &of_genpd_providers, link) {
>>>>> +               if (cp->data == data) {
>>>>> +                       list_del(&cp->link);
>>>>> +                       of_node_put(cp->node);
>>>>> +                       kfree(cp);
>>>>> +                       break;
>>>>> +               }
>>>>> +       }
>>>>> +       mutex_unlock(&of_genpd_mutex);
>>>>> +}
>>>>> +EXPORT_SYMBOL_GPL(of_genpd_del_provider_by_data);
>>>>> +
>>>>> +/**
>>>>>   * of_genpd_get_from_provider() - Look-up PM domain
>>>>>   * @genpdspec: OF phandle args to use for look-up
>>>>>   *
>>>>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>>>>> index bed84413546f..7b7921a65cb0 100644
>>>>> --- a/include/linux/pm_domain.h
>>>>> +++ b/include/linux/pm_domain.h
>>>>> @@ -199,6 +199,7 @@ int of_genpd_add_provider_simple(struct device_node *np,
>>>>>  int of_genpd_add_provider_onecell(struct device_node *np,
>>>>>                                   struct genpd_onecell_data *data);
>>>>>  void of_genpd_del_provider(struct device_node *np);
>>>>
>>>> There's currently only one user of of_genpd_del_provider().
>>>>
>>>> Could this patch just convert that user to the new API, so we don't
>>>> need to keep both the legacy and new one?
>>>>
>>>> I guess we could then just stick to the name "of_genpd_del_provider()".
>>>
>>> I had a look at this and to do that we would end up with
>>> of_genpd_del_provider(struct device_node *np, void *data) where the user
>>> should only pass one of the arguments. It seems a bit odd. However,
>>> unless I have forgotten something, I wonder if we should just make
>>> of_genpd_del_provider_by_name() a local function and not export this at
>>> all? It seems more natural for users to delete a provider by the
>>> device_node than by name rather than the data argument.
>>>
>>> The only problem I see with making of_genpd_del_provider_by_name() local
>>> is that I need to add a prototype for the function at the top of the
>>> domain.c source file so that it builds because __pm_genpd_remove() is
>>> defined above it. Yes I could move __pm_genpd_remove() to the bottom of
>>> the file but then it is not located next to pm_genpd_init() which seems odd.
>>>
>>> Let me know what you think.
>>
>> Sorry for delay! I have now looked into this in more detail.
>
> No problem. Thanks!
>
>> When an genpd provider is added today, it's supposed to get a
>> corresponding *unique* OF device node associated with it, right!?
>>
>> If we store this OF device node from the provider in the struct
>> generic_pm_domain, instead of the "provider_data pointer", we wouldn't
>> need to the add of_genpd_del_provider_by_data() at all. Because we can
>> use the currently available of_genpd_del_provider(), right!?
>>
>> Or what am I missing? :-)

Please don't store device_node pointers in generic data structures at
least in the code that I maintain (some other people may not care).

Store struct fwnode_handle pointers instead if you have to.

Thanks,
Rafael
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diff mbox

Patch

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 72055fef6256..438885f2455f 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1738,6 +1738,30 @@  void of_genpd_del_provider(struct device_node *np)
 EXPORT_SYMBOL_GPL(of_genpd_del_provider);
 
 /**
+ * of_genpd_del_provider_by_data() - Remove a registered PM domain provider
+ * @data: Pointer to the data associated with the PM domain provider
+ *
+ * Look up a PM domain provider based upon a pointer to it's data and
+ * remove the PM domain provider from the list of providers.
+ */
+void of_genpd_del_provider_by_data(void *data)
+{
+	struct of_genpd_provider *c, *cp;
+
+	mutex_lock(&of_genpd_mutex);
+	list_for_each_entry_safe(cp, c, &of_genpd_providers, link) {
+		if (cp->data == data) {
+			list_del(&cp->link);
+			of_node_put(cp->node);
+			kfree(cp);
+			break;
+		}
+	}
+	mutex_unlock(&of_genpd_mutex);
+}
+EXPORT_SYMBOL_GPL(of_genpd_del_provider_by_data);
+
+/**
  * of_genpd_get_from_provider() - Look-up PM domain
  * @genpdspec: OF phandle args to use for look-up
  *
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index bed84413546f..7b7921a65cb0 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -199,6 +199,7 @@  int of_genpd_add_provider_simple(struct device_node *np,
 int of_genpd_add_provider_onecell(struct device_node *np,
 				  struct genpd_onecell_data *data);
 void of_genpd_del_provider(struct device_node *np);
+void of_genpd_del_provider_by_data(void *data);
 struct generic_pm_domain *__of_genpd_xlate_simple(
 					struct of_phandle_args *genpdspec,
 					void *data);
@@ -218,6 +219,7 @@  static inline int __of_genpd_add_provider(struct device_node *np,
 	return 0;
 }
 static inline void of_genpd_del_provider(struct device_node *np) {}
+static inline void of_genpd_del_provider_by_data(void *data) {}
 
 #define __of_genpd_xlate_simple		NULL
 #define __of_genpd_xlate_onecell	NULL