Re: New IOCTLs

[Enrico Weigelt <weigelt@metux.de>]

* Singaravelan Nallasellan <singaravelann@gmail.com> wrote:

Hi,

> The driver needs to assign an id for each open and create a sysfs
> entry based on that id and expose some properties.
> 
> For example, if the driver assigns an id 2, the sysfs entry will be as below:
> /sys/class/xxx/<drivername>/2/version
> 
> When the driver close is invoked, it will have to remove the entry.
> 
> The issue here is that the application needs:
> 1. To know the id it should use to access properties after the open.
> 2. To have exclusive access to the sysfs entries. No other application
> should and open the entry and use it. There is a chance the the other
> application could open the entries before this application opens it.

Simply add an clone file, reading from it creates new context and 
sends back its ID.

box:/ # cat /sys/class/xxx/foodriver/clone
3

box:/ # cat /sys/class/xxx/foodriver/3/version
1.0

...

To destroy the context:
box:/ # echo "release" > /sys/class/xxx/foodriver/3/ctl


cu
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