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@xxxxxx> 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@xxxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>> ---
>>  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
>>
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