device driver: cdesw questions?

[Andriy Gapon]

on 21/01/2009 16:15 Kostik Belousov said the following:
> On Wed, Jan 21, 2009 at 04:12:23PM +0200, Andriy Gapon wrote:
>> on 21/01/2009 16:05 Robert Watson said the following:
>>> On Wed, 21 Jan 2009, Andriy Gapon wrote:
>>>
>>>> Question 1: I am writing a driver that would use per-open private data
>>>> (among other features). Do I have to use D_TRACKCLOSE flag in this
>>>> case? In general I am a little bit confused about when d_close is
>>>> invoked. Supposing D_TRACKCLOSE is not set and multiple programs
>>>> concurrently open, use and close a device - when d_close is called -
>>>> when one program closes its last descriptor tied to the device or when
>>>> the system-wide last such descriptor is closed?
>>> Kostik has already pointed at the cdevpriv API, but just to reiterate
>>> his point: most people will find the semantics of D_TRACKCLOSE confusing
>>> and consider them incorrect, so I would advise against using them.
>> Robert, Kostik,
>>
>> in simplistic layman's terms I need the following - when a particular
>> program "closes my cdev" (explicitly or via exit) I need to catch that
>> and de-allocate certain resources. There can be multiple concurrent
>> programs opening, using and closing my cdev.
>>
>> I guess what you both say is that I shouldn't use D_TRACKCLOSE, instead
>> I should perform the resource management in cdevpriv destructor.
>> Am I guessing correctly this time?
> 
> Yes. This is the purpose of the cdevpriv KPI.

Thank you! Sorry for being so thick :-)

-- 
Andriy Gapon