device driver: cdesw questions?

[Andriy Gapon]

on 21/01/2009 15:35 Kostik Belousov said the following:
> On Wed, Jan 21, 2009 at 01:20:51PM +0200, 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?
> No, the dtr registered with devfs_set_cdevpriv(), is called exactly once
> when the last close is performed, or the device is destroyed.

Kostik,

thanks a lot for the explanation!
I am still a little bit confused about the term "last close" - what is
it? I.e. I'd like to get an answer to the below question.

>> 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?



-- 
Andriy Gapon