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@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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