[PATCH 0/6] phy: core: Fix bugs for several APIs and simplify an API

[PATCH 0/6] phy: core: Fix bugs for several APIs and simplify an API

[Zijun Hu]

This patch series is to fix bugs for below APIs:

devm_phy_put()
devm_of_phy_provider_unregister()
devm_phy_destroy()
phy_get()
of_phy_get()
devm_of_phy_get_by_index()

And simplify API of_phy_simple_xlate().

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
---
Zijun Hu (6):
      phy: core: Fix API devm_phy_put() can not release the phy
      phy: core: Fix API devm_of_phy_provider_unregister() can not unregister the phy provider
      phy: core: Fix API devm_phy_destroy() can not destroy the phy
      phy: core: Add missing of_node_put() for an error handling path of _of_phy_get()
      phy: core: Add missing of_node_put() in of_phy_provider_lookup()
      phy: core: Simplify API of_phy_simple_xlate() implementation

 drivers/phy/phy-core.c | 39 ++++++++++++++++++---------------------
 1 file changed, 18 insertions(+), 21 deletions(-)
---
base-commit: d8f9d6d826fc15780451802796bb88ec52978f17
change-id: 20241020-phy_core_fix-e3ad65db98f7

Best regards,
-- 
Zijun Hu <quic_zijuhu@quicinc.com>

[PATCH 1/6] phy: core: Fix API devm_phy_put() can not release the phy

[Zijun Hu]

From: Zijun Hu <quic_zijuhu@quicinc.com>

For devm_phy_put(), its comment says it needs to invoke phy_put() to
release the phy, but it does not do that actually, so it can not fully
undo what the API devm_phy_get() does, that is wrong, fixed by using
devres_release() instead of devres_destroy() within the API.

BTW, the API is directly used by below source files in error handling
path, so also fix relevant issue within these source files:
drivers/pci/controller/cadence/pcie-cadence.c
drivers/net/ethernet/ti/am65-cpsw-nuss.c

Fixes: ff764963479a ("drivers: phy: add generic PHY framework")
Cc: stable@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
---
 drivers/phy/phy-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index f053b525ccff..f190d7126613 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -737,7 +737,7 @@ void devm_phy_put(struct device *dev, struct phy *phy)
 	if (!phy)
 		return;
 
-	r = devres_destroy(dev, devm_phy_release, devm_phy_match, phy);
+	r = devres_release(dev, devm_phy_release, devm_phy_match, phy);
 	dev_WARN_ONCE(dev, r, "couldn't find PHY resource\n");
 }
 EXPORT_SYMBOL_GPL(devm_phy_put);

-- 
2.34.1

[PATCH 2/6] phy: core: Fix API devm_of_phy_provider_unregister() can not unregister the phy provider

[Zijun Hu]

From: Zijun Hu <quic_zijuhu@quicinc.com>

For devm_of_phy_provider_unregister(), its comment says it needs to
invoke of_phy_provider_unregister() to unregister the phy provider
but it does not do that actually, so it can not fully undo what the
API devm_of_phy_provider_register() does, that is wrong, fixed by
using devres_release() instead of devres_destroy() within the API.

Fixes: ff764963479a ("drivers: phy: add generic PHY framework")
Cc: stable@vger.kernel.org
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
---
 drivers/phy/phy-core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index f190d7126613..de07e1616b34 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -1259,12 +1259,12 @@ EXPORT_SYMBOL_GPL(of_phy_provider_unregister);
  * of_phy_provider_unregister to unregister the phy provider.
  */
 void devm_of_phy_provider_unregister(struct device *dev,
-	struct phy_provider *phy_provider)
+				     struct phy_provider *phy_provider)
 {
 	int r;
 
-	r = devres_destroy(dev, devm_phy_provider_release, devm_phy_match,
-		phy_provider);
+	r = devres_release(dev, devm_phy_provider_release, devm_phy_match,
+			   phy_provider);
 	dev_WARN_ONCE(dev, r, "couldn't find PHY provider device resource\n");
 }
 EXPORT_SYMBOL_GPL(devm_of_phy_provider_unregister);

-- 
2.34.1

[PATCH 3/6] phy: core: Fix API devm_phy_destroy() can not destroy the phy

[Zijun Hu]

From: Zijun Hu <quic_zijuhu@quicinc.com>

For devm_phy_destroy(), its comment says it needs to invoke phy_destroy()
to destroy the phy, but it does not do that actually, so it can not fully
undo what the API devm_phy_create() does, that is wrong, fixed by using
devres_release() instead of devres_destroy() within the API.

Fixes: ff764963479a ("drivers: phy: add generic PHY framework")
Cc: stable@vger.kernel.org
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
---
 drivers/phy/phy-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index de07e1616b34..52ca590a58b9 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -1121,7 +1121,7 @@ void devm_phy_destroy(struct device *dev, struct phy *phy)
 {
 	int r;
 
-	r = devres_destroy(dev, devm_phy_consume, devm_phy_match, phy);
+	r = devres_release(dev, devm_phy_consume, devm_phy_match, phy);
 	dev_WARN_ONCE(dev, r, "couldn't find PHY resource\n");
 }
 EXPORT_SYMBOL_GPL(devm_phy_destroy);

-- 
2.34.1

[PATCH 4/6] phy: core: Add missing of_node_put() for an error handling path of _of_phy_get()

[Zijun Hu]

From: Zijun Hu <quic_zijuhu@quicinc.com>

It is wrong for _of_phy_get()  not to decrease the OF node refcount which
was increased by previous of_parse_phandle_with_args() when returns due to
of_device_is_compatible() error.

Fixed by adding of_node_put() before the error return.

Fixes: b7563e2796f8 ("phy: work around 'phys' references to usb-nop-xceiv devices")
Cc: stable@vger.kernel.org
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
---
 drivers/phy/phy-core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index 52ca590a58b9..967878b78797 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -629,8 +629,11 @@ static struct phy *_of_phy_get(struct device_node *np, int index)
 		return ERR_PTR(-ENODEV);
 
 	/* This phy type handled by the usb-phy subsystem for now */
-	if (of_device_is_compatible(args.np, "usb-nop-xceiv"))
+	if (of_device_is_compatible(args.np, "usb-nop-xceiv")) {
+		/* Put refcount above of_parse_phandle_with_args() got */
+		of_node_put(args.np);
 		return ERR_PTR(-ENODEV);
+	}
 
 	mutex_lock(&phy_provider_mutex);
 	phy_provider = of_phy_provider_lookup(args.np);

-- 
2.34.1

[PATCH 5/6] phy: core: Add missing of_node_put() in of_phy_provider_lookup()

[Zijun Hu]

From: Zijun Hu <quic_zijuhu@quicinc.com>

The for_each_child_of_node() macro automatically decrements the child
refcount at the end of every iteration. On early exits, of_node_put()
must be used to manually decrement the refcount and avoid memory leaks.

The macro called by of_phy_provider_lookup() has such early exit, but
it does not call of_node_put() before early exit.

Fixed by adding missing of_node_put() in of_phy_provider_lookup().

Fixes: 2a4c37016ca9 ("phy: core: Fix of_phy_provider_lookup to return PHY provider for sub node")
Cc: stable@vger.kernel.org
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>

---
The impact of this change is wide since of_phy_provider_lookup()
is indirectly called by APIs phy_get(), of_phy_get(), and
devm_of_phy_get_by_index().

The following kernel mainline commit has similar fix:
Commit: b337cc3ce475 ("backlight: lm3509_bl: Fix early returns in for_each_child_of_node()")
---
 drivers/phy/phy-core.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index 967878b78797..24bd619a33dd 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -143,10 +143,11 @@ static struct phy_provider *of_phy_provider_lookup(struct device_node *node)
 	list_for_each_entry(phy_provider, &phy_provider_list, list) {
 		if (phy_provider->dev->of_node == node)
 			return phy_provider;
-
 		for_each_child_of_node(phy_provider->children, child)
-			if (child == node)
+			if (child == node) {
+				of_node_put(child);
 				return phy_provider;
+			}
 	}
 
 	return ERR_PTR(-EPROBE_DEFER);

-- 
2.34.1

Re: [PATCH 5/6] phy: core: Add missing of_node_put() in of_phy_provider_lookup()

[Christophe JAILLET]

Le 20/10/2024 à 07:27, Zijun Hu a écrit :
> From: Zijun Hu <quic_zijuhu@quicinc.com>
> 
> The for_each_child_of_node() macro automatically decrements the child
> refcount at the end of every iteration. On early exits, of_node_put()
> must be used to manually decrement the refcount and avoid memory leaks.
> 
> The macro called by of_phy_provider_lookup() has such early exit, but
> it does not call of_node_put() before early exit.
> 
> Fixed by adding missing of_node_put() in of_phy_provider_lookup().
> 
> Fixes: 2a4c37016ca9 ("phy: core: Fix of_phy_provider_lookup to return PHY provider for sub node")
> Cc: stable@vger.kernel.org
> Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
> 
> ---
> The impact of this change is wide since of_phy_provider_lookup()
> is indirectly called by APIs phy_get(), of_phy_get(), and
> devm_of_phy_get_by_index().
> 
> The following kernel mainline commit has similar fix:
> Commit: b337cc3ce475 ("backlight: lm3509_bl: Fix early returns in for_each_child_of_node()")
> ---
>   drivers/phy/phy-core.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index 967878b78797..24bd619a33dd 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -143,10 +143,11 @@ static struct phy_provider *of_phy_provider_lookup(struct device_node *node)
>   	list_for_each_entry(phy_provider, &phy_provider_list, list) {
>   		if (phy_provider->dev->of_node == node)
>   			return phy_provider;
> -
>   		for_each_child_of_node(phy_provider->children, child)
> -			if (child == node)
> +			if (child == node) {
> +				of_node_put(child);
>   				return phy_provider;
> +			}

Hi,

Maybe for_each_child_of_node_scoped() to slightly simplify things at the 
same time?

>   	}
>   
>   	return ERR_PTR(-EPROBE_DEFER);
> 

Re: [PATCH 5/6] phy: core: Add missing of_node_put() in of_phy_provider_lookup()

[Zijun Hu]

On 2024/10/20 15:23, Christophe JAILLET wrote:
> Le 20/10/2024 à 07:27, Zijun Hu a écrit :
>> From: Zijun Hu <quic_zijuhu@quicinc.com>

[snip]

>> ---
>>   drivers/phy/phy-core.c | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
>> index 967878b78797..24bd619a33dd 100644
>> --- a/drivers/phy/phy-core.c
>> +++ b/drivers/phy/phy-core.c
>> @@ -143,10 +143,11 @@ static struct phy_provider
>> *of_phy_provider_lookup(struct device_node *node)
>>       list_for_each_entry(phy_provider, &phy_provider_list, list) {
>>           if (phy_provider->dev->of_node == node)
>>               return phy_provider;
>> -
>>           for_each_child_of_node(phy_provider->children, child)
>> -            if (child == node)
>> +            if (child == node) {
>> +                of_node_put(child);
>>                   return phy_provider;
>> +            }
> 
> Hi,
> 
> Maybe for_each_child_of_node_scoped() to slightly simplify things at the
> same time?
> 

thank you for code review.

it does not use _scoped() since for_each_child_of_node() usage here is
very simple and only has one early exit, _scoped() normally is for
complex case.

i maybe use _scoped() in next revision if one more reviewer also prefers
it.

thank you.

>>       }
>>         return ERR_PTR(-EPROBE_DEFER);
>>
> 

[PATCH 6/6] phy: core: Simplify API of_phy_simple_xlate() implementation

[Zijun Hu]

From: Zijun Hu <quic_zijuhu@quicinc.com>

Simplify of_phy_simple_xlate() implementation by API
class_find_device_by_of_node() which is also safer since it
subsys_get() @phy_class subsystem firstly then iterates devices.

Also comment its parameter @dev with unused in passing since the parameter
provides no available input info but acts as an auto variable.

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
---
 drivers/phy/phy-core.c | 19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index 24bd619a33dd..102fc6b6ff71 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -748,7 +748,7 @@ EXPORT_SYMBOL_GPL(devm_phy_put);
 
 /**
  * of_phy_simple_xlate() - returns the phy instance from phy provider
- * @dev: the PHY provider device
+ * @dev: the PHY provider device unused
  * @args: of_phandle_args (not used here)
  *
  * Intended to be used by phy provider for the common case where #phy-cells is
@@ -759,20 +759,13 @@ EXPORT_SYMBOL_GPL(devm_phy_put);
 struct phy *of_phy_simple_xlate(struct device *dev,
 				const struct of_phandle_args *args)
 {
-	struct phy *phy;
-	struct class_dev_iter iter;
-
-	class_dev_iter_init(&iter, &phy_class, NULL, NULL);
-	while ((dev = class_dev_iter_next(&iter))) {
-		phy = to_phy(dev);
-		if (args->np != phy->dev.of_node)
-			continue;
+	struct device *target_dev;
 
-		class_dev_iter_exit(&iter);
-		return phy;
+	target_dev = class_find_device_by_of_node(&phy_class, args->np);
+	if (target_dev) {
+		put_device(target_dev);
+		return to_phy(target_dev);
 	}
-
-	class_dev_iter_exit(&iter);
 	return ERR_PTR(-ENODEV);
 }
 EXPORT_SYMBOL_GPL(of_phy_simple_xlate);

-- 
2.34.1

Re: [PATCH 6/6] phy: core: Simplify API of_phy_simple_xlate() implementation

[Zijun Hu]

On 2024/10/20 13:27, Zijun Hu wrote:
> From: Zijun Hu <quic_zijuhu@quicinc.com>
> 
> Simplify of_phy_simple_xlate() implementation by API
> class_find_device_by_of_node() which is also safer since it
> subsys_get() @phy_class subsystem firstly then iterates devices.
> 
> Also comment its parameter @dev with unused in passing since the parameter
> provides no available input info but acts as an auto variable.
> 
i am not sure which parameter is unused. @dev or @args

comment says @args is not used here
but code actually uses @args but does not use @dev

> Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
> ---
>  drivers/phy/phy-core.c | 19 ++++++-------------
>  1 file changed, 6 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index 24bd619a33dd..102fc6b6ff71 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -748,7 +748,7 @@ EXPORT_SYMBOL_GPL(devm_phy_put);
>  
>  /**
>   * of_phy_simple_xlate() - returns the phy instance from phy provider
> - * @dev: the PHY provider device
> + * @dev: the PHY provider device unused
>   * @args: of_phandle_args (not used here)
>   *
>   * Intended to be used by phy provider for the common case where #phy-cells is
> @@ -759,20 +759,13 @@ EXPORT_SYMBOL_GPL(devm_phy_put);
>  struct phy *of_phy_simple_xlate(struct device *dev,
>  				const struct of_phandle_args *args)
>  {
> -	struct phy *phy;
> -	struct class_dev_iter iter;
> -
> -	class_dev_iter_init(&iter, &phy_class, NULL, NULL);
> -	while ((dev = class_dev_iter_next(&iter))) {
> -		phy = to_phy(dev);
> -		if (args->np != phy->dev.of_node)
> -			continue;
> +	struct device *target_dev;
>  
> -		class_dev_iter_exit(&iter);
> -		return phy;
> +	target_dev = class_find_device_by_of_node(&phy_class, args->np);
> +	if (target_dev) {
> +		put_device(target_dev);
> +		return to_phy(target_dev);
>  	}
> -
> -	class_dev_iter_exit(&iter);
>  	return ERR_PTR(-ENODEV);
>  }
>  EXPORT_SYMBOL_GPL(of_phy_simple_xlate);
>