[PATCH 0/2] extcon: fixes for v4.2-rc1

[PATCH 0/2] extcon: fixes for v4.2-rc1

[Roger Quadros]

Hi,

First patch fixes kernel hang and incorrect states when
extcon_get/set_cable_state() is used.

Second patch fixes extcon_cable_get_state() users from getting old
state after notifier callback.

cheers,
-roger

Roger Quadros (2):
  extcon: fix hang and extcon_get/set_cable_state().
  extcon: Fix extcon_cable_get_state() from getting old state after
    notification

 drivers/extcon/extcon.c | 50 ++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 37 insertions(+), 13 deletions(-)

-- 
2.1.4

[PATCH 1/2] extcon: fix hang and extcon_get/set_cable_state().

[Roger Quadros]

Users of find_cable_index_by_name() will cause a kernel hang
as the while loop counter is never incremented and end condition
is never reached.

extcon_get_cable_state() and extcon_set_cable_state() are broken
because they use cable index instead of cable id. This causes
the first cable state (cable.0) to be always invalid in sysfs
or extcon_get_cable_state() users.

Introduce a new function find_cable_id_by_name() that fixes
both of the above issues.

Fixes: commit 73b6ecdb93e8 ("extcon: Redefine the unique id of supported external connectors without 'enum extcon' type")
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Roger Quadros <rogerq@ti.com>
---
 drivers/extcon/extcon.c | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 76157ab..868c6e2 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -124,15 +124,12 @@ static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id
 	return -EINVAL;
 }
 
-static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
+static int find_cable_id_by_name(struct extcon_dev *edev, const char *name)
 {
-	unsigned int id = EXTCON_NONE;
+	unsigned int id = -EINVAL;
 	int i = 0;
 
-	if (edev->max_supported == 0)
-		return -EINVAL;
-
-	/* Find the the number of extcon cable */
+	/* Find the id of extcon cable */
 	while (extcon_name[i]) {
 		if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
 			id = i;
@@ -140,6 +137,19 @@ static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
 		}
 	}
 
+	return id;
+};
+
+static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
+{
+	unsigned int id = EXTCON_NONE;
+
+	if (edev->max_supported == 0)
+		return -EINVAL;
+
+	/* Find the the number of extcon cable */
+	id = find_cable_id_by_name(edev, name);
+
 	if (id == EXTCON_NONE)
 		return -EINVAL;
 
@@ -228,9 +238,11 @@ static ssize_t cable_state_show(struct device *dev,
 	struct extcon_cable *cable = container_of(attr, struct extcon_cable,
 						  attr_state);
 
+	int i = cable->cable_index;
+
 	return sprintf(buf, "%d\n",
 		       extcon_get_cable_state_(cable->edev,
-					       cable->cable_index));
+					       cable->edev->supported_cable[i]));
 }
 
 /**
@@ -341,6 +353,9 @@ int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
 {
 	int index;
 
+	if (id == EXTCON_NONE)
+		return -EINVAL;
+
 	index = find_cable_index_by_id(edev, id);
 	if (index < 0)
 		return index;
@@ -361,7 +376,7 @@ EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
  */
 int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
 {
-	return extcon_get_cable_state_(edev, find_cable_index_by_name
+	return extcon_get_cable_state_(edev, find_cable_id_by_name
 						(edev, cable_name));
 }
 EXPORT_SYMBOL_GPL(extcon_get_cable_state);
@@ -380,6 +395,9 @@ int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
 	u32 state;
 	int index;
 
+	if (id == EXTCON_NONE)
+		return -EINVAL;
+
 	index = find_cable_index_by_id(edev, id);
 	if (index < 0)
 		return index;
@@ -404,7 +422,7 @@ EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
 int extcon_set_cable_state(struct extcon_dev *edev,
 			const char *cable_name, bool cable_state)
 {
-	return extcon_set_cable_state_(edev, find_cable_index_by_name
+	return extcon_set_cable_state_(edev, find_cable_id_by_name
 					(edev, cable_name), cable_state);
 }
 EXPORT_SYMBOL_GPL(extcon_set_cable_state);
-- 
2.1.4

Re: [PATCH 1/2] extcon: fix hang and extcon_get/set_cable_state().

[Ivan T. Ivanov]

On Mon, 2015-07-06 at 17:46 +0300, Roger Quadros wrote:

> 
> -static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
> +static int find_cable_id_by_name(struct extcon_dev *edev, const char *name)
>  {
> -       unsigned int id = EXTCON_NONE;
> +       unsigned int id = -EINVAL;
>         int i = 0;
> 
> -       if (edev->max_supported == 0)
> -               return -EINVAL;
> -
> -       /* Find the the number of extcon cable */
> +       /* Find the id of extcon cable */
>         while (extcon_name[i]) {
>                 if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
>                         id = i;
> @@ -140,6 +137,19 @@ static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
>                 }
>         }
> 

Thank you Roger, but this still hang. 'i' is not incremented.

Ivan

> +       return id;
> +};
> 

Re: [PATCH 1/2] extcon: fix hang and extcon_get/set_cable_state().

[Roger Quadros]

Hi,

On 07/07/15 15:40, Ivan T. Ivanov wrote:
>
> On Mon, 2015-07-06 at 17:46 +0300, Roger Quadros wrote:
>
>>
>> -static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
>> +static int find_cable_id_by_name(struct extcon_dev *edev, const char *name)
>>   {
>> -       unsigned int id = EXTCON_NONE;
>> +       unsigned int id = -EINVAL;
>>          int i = 0;
>>
>> -       if (edev->max_supported == 0)
>> -               return -EINVAL;
>> -
>> -       /* Find the the number of extcon cable */
>> +       /* Find the id of extcon cable */
>>          while (extcon_name[i]) {
>>                  if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
>>                          id = i;
>> @@ -140,6 +137,19 @@ static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
>>                  }
>>          }
>>
>
> Thank you Roger, but this still hang. 'i' is not incremented.

You are right. Thanks for pointing out.
I will send out a v2.

>
> Ivan
>
>> +       return id;
>> +};
>>

cheers,
-roger

[PATCH v2 1/2] extcon: fix hang and extcon_get/set_cable_state().

[Roger Quadros]

Users of find_cable_index_by_name() will cause a kernel hang
as the while loop counter is never incremented and end condition
is never reached.

extcon_get_cable_state() and extcon_set_cable_state() are broken
because they use cable index instead of cable id. This causes
the first cable state (cable.0) to be always invalid in sysfs
or extcon_get_cable_state() users.

Introduce a new function find_cable_id_by_name() that fixes
both of the above issues.

Fixes: commit 73b6ecdb93e8 ("extcon: Redefine the unique id of supported external connectors without 'enum extcon' type")
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Roger Quadros <rogerq@ti.com>
---
 drivers/extcon/extcon.c | 38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 76157ab..987dd3c 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -124,22 +124,34 @@ static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id
 	return -EINVAL;
 }
 
-static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
+static int find_cable_id_by_name(struct extcon_dev *edev, const char *name)
 {
-	unsigned int id = EXTCON_NONE;
+	unsigned int id = -EINVAL;
 	int i = 0;
 
-	if (edev->max_supported == 0)
-		return -EINVAL;
-
-	/* Find the the number of extcon cable */
+	/* Find the id of extcon cable */
 	while (extcon_name[i]) {
 		if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
 			id = i;
 			break;
 		}
+
+		i++;
 	}
 
+	return id;
+};
+
+static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
+{
+	unsigned int id = EXTCON_NONE;
+
+	if (edev->max_supported == 0)
+		return -EINVAL;
+
+	/* Find the the number of extcon cable */
+	id = find_cable_id_by_name(edev, name);
+
 	if (id == EXTCON_NONE)
 		return -EINVAL;
 
@@ -228,9 +240,11 @@ static ssize_t cable_state_show(struct device *dev,
 	struct extcon_cable *cable = container_of(attr, struct extcon_cable,
 						  attr_state);
 
+	int i = cable->cable_index;
+
 	return sprintf(buf, "%d\n",
 		       extcon_get_cable_state_(cable->edev,
-					       cable->cable_index));
+					       cable->edev->supported_cable[i]));
 }
 
 /**
@@ -341,6 +355,9 @@ int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
 {
 	int index;
 
+	if (id == EXTCON_NONE)
+		return -EINVAL;
+
 	index = find_cable_index_by_id(edev, id);
 	if (index < 0)
 		return index;
@@ -361,7 +378,7 @@ EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
  */
 int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
 {
-	return extcon_get_cable_state_(edev, find_cable_index_by_name
+	return extcon_get_cable_state_(edev, find_cable_id_by_name
 						(edev, cable_name));
 }
 EXPORT_SYMBOL_GPL(extcon_get_cable_state);
@@ -380,6 +397,9 @@ int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
 	u32 state;
 	int index;
 
+	if (id == EXTCON_NONE)
+		return -EINVAL;
+
 	index = find_cable_index_by_id(edev, id);
 	if (index < 0)
 		return index;
@@ -404,7 +424,7 @@ EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
 int extcon_set_cable_state(struct extcon_dev *edev,
 			const char *cable_name, bool cable_state)
 {
-	return extcon_set_cable_state_(edev, find_cable_index_by_name
+	return extcon_set_cable_state_(edev, find_cable_id_by_name
 					(edev, cable_name), cable_state);
 }
 EXPORT_SYMBOL_GPL(extcon_set_cable_state);
-- 
2.1.4

Re: [PATCH v2 1/2] extcon: fix hang and extcon_get/set_cable_state().

[Ivan T. Ivanov]

On Tue, 2015-07-07 at 16:06 +0300, Roger Quadros wrote:
> Users of find_cable_index_by_name() will cause a kernel hang
> as the while loop counter is never incremented and end condition
> is never reached.
> 
> extcon_get_cable_state() and extcon_set_cable_state() are broken
> because they use cable index instead of cable id. This causes
> the first cable state (cable.0) to be always invalid in sysfs
> or extcon_get_cable_state() users.
> 
> Introduce a new function find_cable_id_by_name() that fixes
> both of the above issues.
> 
> Fixes: commit 73b6ecdb93e8 ("extcon: Redefine the unique id of supported external connectors without 'enum extcon' type")
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---

Thank you. It is fine now. For both patches.

Tested-by: Ivan T. Ivanov <ivan.ivanov@linaro.org>

Re: [PATCH v2 1/2] extcon: fix hang and extcon_get/set_cable_state().

[Chanwoo Choi]

Hi Roger,

Thanks for your working.

I'll review, test and apply it on next week because I'm on vacation now.

Thanks,
Chanwoo Choi

On Tue, Jul 7, 2015 at 3:06 PM, Roger Quadros <rogerq@ti.com> wrote:
> Users of find_cable_index_by_name() will cause a kernel hang
> as the while loop counter is never incremented and end condition
> is never reached.
>
> extcon_get_cable_state() and extcon_set_cable_state() are broken
> because they use cable index instead of cable id. This causes
> the first cable state (cable.0) to be always invalid in sysfs
> or extcon_get_cable_state() users.
>
> Introduce a new function find_cable_id_by_name() that fixes
> both of the above issues.
>
> Fixes: commit 73b6ecdb93e8 ("extcon: Redefine the unique id of supported external connectors without 'enum extcon' type")
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
>  drivers/extcon/extcon.c | 38 +++++++++++++++++++++++++++++---------
>  1 file changed, 29 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
> index 76157ab..987dd3c 100644
> --- a/drivers/extcon/extcon.c
> +++ b/drivers/extcon/extcon.c
> @@ -124,22 +124,34 @@ static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id
>         return -EINVAL;
>  }
>
> -static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
> +static int find_cable_id_by_name(struct extcon_dev *edev, const char *name)
>  {
> -       unsigned int id = EXTCON_NONE;
> +       unsigned int id = -EINVAL;
>         int i = 0;
>
> -       if (edev->max_supported == 0)
> -               return -EINVAL;
> -
> -       /* Find the the number of extcon cable */
> +       /* Find the id of extcon cable */
>         while (extcon_name[i]) {
>                 if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
>                         id = i;
>                         break;
>                 }
> +
> +               i++;
>         }
>
> +       return id;
> +};
> +
> +static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
> +{
> +       unsigned int id = EXTCON_NONE;
> +
> +       if (edev->max_supported == 0)
> +               return -EINVAL;
> +
> +       /* Find the the number of extcon cable */
> +       id = find_cable_id_by_name(edev, name);
> +
>         if (id == EXTCON_NONE)
>                 return -EINVAL;
>
> @@ -228,9 +240,11 @@ static ssize_t cable_state_show(struct device *dev,
>         struct extcon_cable *cable = container_of(attr, struct extcon_cable,
>                                                   attr_state);
>
> +       int i = cable->cable_index;
> +
>         return sprintf(buf, "%d\n",
>                        extcon_get_cable_state_(cable->edev,
> -                                              cable->cable_index));
> +                                              cable->edev->supported_cable[i]));
>  }
>
>  /**
> @@ -341,6 +355,9 @@ int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
>  {
>         int index;
>
> +       if (id == EXTCON_NONE)
> +               return -EINVAL;
> +
>         index = find_cable_index_by_id(edev, id);
>         if (index < 0)
>                 return index;
> @@ -361,7 +378,7 @@ EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
>   */
>  int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
>  {
> -       return extcon_get_cable_state_(edev, find_cable_index_by_name
> +       return extcon_get_cable_state_(edev, find_cable_id_by_name
>                                                 (edev, cable_name));
>  }
>  EXPORT_SYMBOL_GPL(extcon_get_cable_state);
> @@ -380,6 +397,9 @@ int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
>         u32 state;
>         int index;
>
> +       if (id == EXTCON_NONE)
> +               return -EINVAL;
> +
>         index = find_cable_index_by_id(edev, id);
>         if (index < 0)
>                 return index;
> @@ -404,7 +424,7 @@ EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
>  int extcon_set_cable_state(struct extcon_dev *edev,
>                         const char *cable_name, bool cable_state)
>  {
> -       return extcon_set_cable_state_(edev, find_cable_index_by_name
> +       return extcon_set_cable_state_(edev, find_cable_id_by_name
>                                         (edev, cable_name), cable_state);
>  }
>  EXPORT_SYMBOL_GPL(extcon_set_cable_state);
> --
> 2.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v2 1/2] extcon: fix hang and extcon_get/set_cable_state().

[Roger Quadros]

Chanwoo,

On 10/07/15 18:54, Chanwoo Choi wrote:
> Hi Roger,
> 
> Thanks for your working.
> 
> I'll review, test and apply it on next week because I'm on vacation now.

Can you please take this for -rc cycle? Thanks.

cheers,
-roger

> 
> Thanks,
> Chanwoo Choi
> 
> On Tue, Jul 7, 2015 at 3:06 PM, Roger Quadros <rogerq@ti.com> wrote:
>> Users of find_cable_index_by_name() will cause a kernel hang
>> as the while loop counter is never incremented and end condition
>> is never reached.
>>
>> extcon_get_cable_state() and extcon_set_cable_state() are broken
>> because they use cable index instead of cable id. This causes
>> the first cable state (cable.0) to be always invalid in sysfs
>> or extcon_get_cable_state() users.
>>
>> Introduce a new function find_cable_id_by_name() that fixes
>> both of the above issues.
>>
>> Fixes: commit 73b6ecdb93e8 ("extcon: Redefine the unique id of supported external connectors without 'enum extcon' type")
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>> ---
>>  drivers/extcon/extcon.c | 38 +++++++++++++++++++++++++++++---------
>>  1 file changed, 29 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
>> index 76157ab..987dd3c 100644
>> --- a/drivers/extcon/extcon.c
>> +++ b/drivers/extcon/extcon.c
>> @@ -124,22 +124,34 @@ static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id
>>         return -EINVAL;
>>  }
>>
>> -static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
>> +static int find_cable_id_by_name(struct extcon_dev *edev, const char *name)
>>  {
>> -       unsigned int id = EXTCON_NONE;
>> +       unsigned int id = -EINVAL;
>>         int i = 0;
>>
>> -       if (edev->max_supported == 0)
>> -               return -EINVAL;
>> -
>> -       /* Find the the number of extcon cable */
>> +       /* Find the id of extcon cable */
>>         while (extcon_name[i]) {
>>                 if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
>>                         id = i;
>>                         break;
>>                 }
>> +
>> +               i++;
>>         }
>>
>> +       return id;
>> +};
>> +
>> +static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
>> +{
>> +       unsigned int id = EXTCON_NONE;
>> +
>> +       if (edev->max_supported == 0)
>> +               return -EINVAL;
>> +
>> +       /* Find the the number of extcon cable */
>> +       id = find_cable_id_by_name(edev, name);
>> +
>>         if (id == EXTCON_NONE)
>>                 return -EINVAL;
>>
>> @@ -228,9 +240,11 @@ static ssize_t cable_state_show(struct device *dev,
>>         struct extcon_cable *cable = container_of(attr, struct extcon_cable,
>>                                                   attr_state);
>>
>> +       int i = cable->cable_index;
>> +
>>         return sprintf(buf, "%d\n",
>>                        extcon_get_cable_state_(cable->edev,
>> -                                              cable->cable_index));
>> +                                              cable->edev->supported_cable[i]));
>>  }
>>
>>  /**
>> @@ -341,6 +355,9 @@ int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
>>  {
>>         int index;
>>
>> +       if (id == EXTCON_NONE)
>> +               return -EINVAL;
>> +
>>         index = find_cable_index_by_id(edev, id);
>>         if (index < 0)
>>                 return index;
>> @@ -361,7 +378,7 @@ EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
>>   */
>>  int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
>>  {
>> -       return extcon_get_cable_state_(edev, find_cable_index_by_name
>> +       return extcon_get_cable_state_(edev, find_cable_id_by_name
>>                                                 (edev, cable_name));
>>  }
>>  EXPORT_SYMBOL_GPL(extcon_get_cable_state);
>> @@ -380,6 +397,9 @@ int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
>>         u32 state;
>>         int index;
>>
>> +       if (id == EXTCON_NONE)
>> +               return -EINVAL;
>> +
>>         index = find_cable_index_by_id(edev, id);
>>         if (index < 0)
>>                 return index;
>> @@ -404,7 +424,7 @@ EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
>>  int extcon_set_cable_state(struct extcon_dev *edev,
>>                         const char *cable_name, bool cable_state)
>>  {
>> -       return extcon_set_cable_state_(edev, find_cable_index_by_name
>> +       return extcon_set_cable_state_(edev, find_cable_id_by_name
>>                                         (edev, cable_name), cable_state);
>>  }
>>  EXPORT_SYMBOL_GPL(extcon_set_cable_state);
>> --
>> 2.1.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v2 1/2] extcon: fix hang and extcon_get/set_cable_state().

[Chanwoo Choi]

Hi Roger,

On 07/27/2015 07:39 PM, Roger Quadros wrote:
> Chanwoo,
> 
> On 10/07/15 18:54, Chanwoo Choi wrote:
>> Hi Roger,
>>
>> Thanks for your working.
>>
>> I'll review, test and apply it on next week because I'm on vacation now.
> 
> Can you please take this for -rc cycle? Thanks.

I'm sorry for delay review. I'll do it within this week.

Thanks,
Chanwoo Choi

> 
> cheers,
> -roger
> 
>>
>> Thanks,
>> Chanwoo Choi
>>
>> On Tue, Jul 7, 2015 at 3:06 PM, Roger Quadros <rogerq@ti.com> wrote:
>>> Users of find_cable_index_by_name() will cause a kernel hang
>>> as the while loop counter is never incremented and end condition
>>> is never reached.
>>>
>>> extcon_get_cable_state() and extcon_set_cable_state() are broken
>>> because they use cable index instead of cable id. This causes
>>> the first cable state (cable.0) to be always invalid in sysfs
>>> or extcon_get_cable_state() users.
>>>
>>> Introduce a new function find_cable_id_by_name() that fixes
>>> both of the above issues.
>>>
>>> Fixes: commit 73b6ecdb93e8 ("extcon: Redefine the unique id of supported external connectors without 'enum extcon' type")
>>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>>> ---
>>>  drivers/extcon/extcon.c | 38 +++++++++++++++++++++++++++++---------
>>>  1 file changed, 29 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
>>> index 76157ab..987dd3c 100644
>>> --- a/drivers/extcon/extcon.c
>>> +++ b/drivers/extcon/extcon.c
>>> @@ -124,22 +124,34 @@ static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id
>>>         return -EINVAL;
>>>  }
>>>
>>> -static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
>>> +static int find_cable_id_by_name(struct extcon_dev *edev, const char *name)
>>>  {
>>> -       unsigned int id = EXTCON_NONE;
>>> +       unsigned int id = -EINVAL;
>>>         int i = 0;
>>>
>>> -       if (edev->max_supported == 0)
>>> -               return -EINVAL;
>>> -
>>> -       /* Find the the number of extcon cable */
>>> +       /* Find the id of extcon cable */
>>>         while (extcon_name[i]) {
>>>                 if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
>>>                         id = i;
>>>                         break;
>>>                 }
>>> +
>>> +               i++;
>>>         }
>>>
>>> +       return id;
>>> +};
>>> +
>>> +static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
>>> +{
>>> +       unsigned int id = EXTCON_NONE;
>>> +
>>> +       if (edev->max_supported == 0)
>>> +               return -EINVAL;
>>> +
>>> +       /* Find the the number of extcon cable */
>>> +       id = find_cable_id_by_name(edev, name);
>>> +
>>>         if (id == EXTCON_NONE)
>>>                 return -EINVAL;
>>>
>>> @@ -228,9 +240,11 @@ static ssize_t cable_state_show(struct device *dev,
>>>         struct extcon_cable *cable = container_of(attr, struct extcon_cable,
>>>                                                   attr_state);
>>>
>>> +       int i = cable->cable_index;
>>> +
>>>         return sprintf(buf, "%d\n",
>>>                        extcon_get_cable_state_(cable->edev,
>>> -                                              cable->cable_index));
>>> +                                              cable->edev->supported_cable[i]));
>>>  }
>>>
>>>  /**
>>> @@ -341,6 +355,9 @@ int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
>>>  {
>>>         int index;
>>>
>>> +       if (id == EXTCON_NONE)
>>> +               return -EINVAL;
>>> +
>>>         index = find_cable_index_by_id(edev, id);
>>>         if (index < 0)
>>>                 return index;
>>> @@ -361,7 +378,7 @@ EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
>>>   */
>>>  int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
>>>  {
>>> -       return extcon_get_cable_state_(edev, find_cable_index_by_name
>>> +       return extcon_get_cable_state_(edev, find_cable_id_by_name
>>>                                                 (edev, cable_name));
>>>  }
>>>  EXPORT_SYMBOL_GPL(extcon_get_cable_state);
>>> @@ -380,6 +397,9 @@ int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
>>>         u32 state;
>>>         int index;
>>>
>>> +       if (id == EXTCON_NONE)
>>> +               return -EINVAL;
>>> +
>>>         index = find_cable_index_by_id(edev, id);
>>>         if (index < 0)
>>>                 return index;
>>> @@ -404,7 +424,7 @@ EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
>>>  int extcon_set_cable_state(struct extcon_dev *edev,
>>>                         const char *cable_name, bool cable_state)
>>>  {
>>> -       return extcon_set_cable_state_(edev, find_cable_index_by_name
>>> +       return extcon_set_cable_state_(edev, find_cable_id_by_name
>>>                                         (edev, cable_name), cable_state);
>>>  }
>>>  EXPORT_SYMBOL_GPL(extcon_set_cable_state);
>>> --
>>> 2.1.4
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>> Please read the FAQ at  http://www.tux.org/lkml/
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 

Re: [PATCH v2 1/2] extcon: fix hang and extcon_get/set_cable_state().

[Chanwoo Choi]

Hi Roger,

I add minor comment about code clean.
After I modified it by myself, I applied it on extcon-fixes.

Best Regards,
Chanwoo Choi

On 07/07/2015 10:06 PM, Roger Quadros wrote:
> Users of find_cable_index_by_name() will cause a kernel hang
> as the while loop counter is never incremented and end condition
> is never reached.
> 
> extcon_get_cable_state() and extcon_set_cable_state() are broken
> because they use cable index instead of cable id. This causes
> the first cable state (cable.0) to be always invalid in sysfs
> or extcon_get_cable_state() users.
> 
> Introduce a new function find_cable_id_by_name() that fixes
> both of the above issues.
> 
> Fixes: commit 73b6ecdb93e8 ("extcon: Redefine the unique id of supported external connectors without 'enum extcon' type")
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
>  drivers/extcon/extcon.c | 38 +++++++++++++++++++++++++++++---------
>  1 file changed, 29 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
> index 76157ab..987dd3c 100644
> --- a/drivers/extcon/extcon.c
> +++ b/drivers/extcon/extcon.c
> @@ -124,22 +124,34 @@ static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id
>  	return -EINVAL;
>  }
>  
> -static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
> +static int find_cable_id_by_name(struct extcon_dev *edev, const char *name)
>  {
> -	unsigned int id = EXTCON_NONE;
> +	unsigned int id = -EINVAL;
>  	int i = 0;
>  
> -	if (edev->max_supported == 0)
> -		return -EINVAL;
> -
> -	/* Find the the number of extcon cable */
> +	/* Find the id of extcon cable */
>  	while (extcon_name[i]) {
>  		if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
>  			id = i;
>  			break;
>  		}
> +

Remove blank line.

> +		i++;
>  	}
>  
> +	return id;
> +};
> +
> +static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
> +{
> +	unsigned int id = EXTCON_NONE;
> +
> +	if (edev->max_supported == 0)
> +		return -EINVAL;
> +
> +	/* Find the the number of extcon cable */
> +	id = find_cable_id_by_name(edev, name);
> +
>  	if (id == EXTCON_NONE)
>  		return -EINVAL;
>  
> @@ -228,9 +240,11 @@ static ssize_t cable_state_show(struct device *dev,
>  	struct extcon_cable *cable = container_of(attr, struct extcon_cable,
>  						  attr_state);
>  
> +	int i = cable->cable_index;
> +
>  	return sprintf(buf, "%d\n",
>  		       extcon_get_cable_state_(cable->edev,
> -					       cable->cable_index));
> +					       cable->edev->supported_cable[i]));
>  }
>  
>  /**
> @@ -341,6 +355,9 @@ int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
>  {
>  	int index;
>  
> +	if (id == EXTCON_NONE)
> +		return -EINVAL;
> +

This if statement don't be necessary.
Instead, I check the error value on extcon_get_cable_state() by checking the
return value of find_cable_id_by_name().


>  	index = find_cable_index_by_id(edev, id);
>  	if (index < 0)
>  		return index;
> @@ -361,7 +378,7 @@ EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
>   */
>  int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
>  {
> -	return extcon_get_cable_state_(edev, find_cable_index_by_name
> +	return extcon_get_cable_state_(edev, find_cable_id_by_name
>  						(edev, cable_name));

I modified it as following:
       unsigned int id;

       id = find_cable_id_by_name(edev, cable_name);
       if (id < 0)
               return id;

       return extcon_get_cable_state_(edev, id);

>  }
>  EXPORT_SYMBOL_GPL(extcon_get_cable_state);
> @@ -380,6 +397,9 @@ int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
>  	u32 state;
>  	int index;
>  
> +	if (id == EXTCON_NONE)
> +		return -EINVAL;
> +

ditto.

>  	index = find_cable_index_by_id(edev, id);
>  	if (index < 0)
>  		return index;
> @@ -404,7 +424,7 @@ EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
>  int extcon_set_cable_state(struct extcon_dev *edev,
>  			const char *cable_name, bool cable_state)
>  {
> -	return extcon_set_cable_state_(edev, find_cable_index_by_name
> +	return extcon_set_cable_state_(edev, find_cable_id_by_name
>  					(edev, cable_name), cable_state);

ditto.

Thanks,
Chanwoo Choi

[PATCH 2/2] extcon: Fix extcon_cable_get_state() from getting old state after notification

[Roger Quadros]

Currently the extcon code notifiers the interested listeners
before it updates the extcon state with the new state.
This will cause the listeners that use extcon_cable_get_state()
to get the stale state and loose the new state.

Fix this by first changing the extcon state variable and then
notifying listeners.

Signed-off-by: Roger Quadros <rogerq@ti.com>
---
 drivers/extcon/extcon.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 868c6e2..26d1e1e 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -275,19 +275,25 @@ int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
 	spin_lock_irqsave(&edev->lock, flags);
 
 	if (edev->state != ((edev->state & ~mask) | (state & mask))) {
+		u32 old_state;
+
 		if (check_mutually_exclusive(edev, (edev->state & ~mask) |
 						   (state & mask))) {
 			spin_unlock_irqrestore(&edev->lock, flags);
 			return -EPERM;
 		}
 
+		old_state = edev->state;
+		edev->state &= ~mask;
+		edev->state |= state & mask;
+
 		for (index = 0; index < edev->max_supported; index++) {
-			if (is_extcon_changed(edev->state, state, index, &attached))
-				raw_notifier_call_chain(&edev->nh[index], attached, edev);
+			if (is_extcon_changed(old_state, edev->state, index,
+					      &attached))
+				raw_notifier_call_chain(&edev->nh[index],
+							attached, edev);
 		}
 
-		edev->state &= ~mask;
-		edev->state |= state & mask;
 
 		/* This could be in interrupt handler */
 		prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
-- 
2.1.4

Re: [PATCH 2/2] extcon: Fix extcon_cable_get_state() from getting old state after notification

[Chanwoo Choi]

Hi Roger,

On 07/06/2015 11:46 PM, Roger Quadros wrote:
> Currently the extcon code notifiers the interested listeners
> before it updates the extcon state with the new state.
> This will cause the listeners that use extcon_cable_get_state()
> to get the stale state and loose the new state.
> 
> Fix this by first changing the extcon state variable and then
> notifying listeners.
> 
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
>  drivers/extcon/extcon.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)

Applied it.

Thanks,
Chanwoo Choi

> 
> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
> index 868c6e2..26d1e1e 100644
> --- a/drivers/extcon/extcon.c
> +++ b/drivers/extcon/extcon.c
> @@ -275,19 +275,25 @@ int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
>  	spin_lock_irqsave(&edev->lock, flags);
>  
>  	if (edev->state != ((edev->state & ~mask) | (state & mask))) {
> +		u32 old_state;
> +
>  		if (check_mutually_exclusive(edev, (edev->state & ~mask) |
>  						   (state & mask))) {
>  			spin_unlock_irqrestore(&edev->lock, flags);
>  			return -EPERM;
>  		}
>  
> +		old_state = edev->state;
> +		edev->state &= ~mask;
> +		edev->state |= state & mask;
> +
>  		for (index = 0; index < edev->max_supported; index++) {
> -			if (is_extcon_changed(edev->state, state, index, &attached))
> -				raw_notifier_call_chain(&edev->nh[index], attached, edev);
> +			if (is_extcon_changed(old_state, edev->state, index,
> +					      &attached))
> +				raw_notifier_call_chain(&edev->nh[index],
> +							attached, edev);
>  		}
>  
> -		edev->state &= ~mask;
> -		edev->state |= state & mask;
>  
>  		/* This could be in interrupt handler */
>  		prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
>