Re: Exchange Date Userspace<->Kernel

[Eric BEGOT <eric_begot@xxxxxxxx>]

Danilo Reinhardt wrote:
> Hi,
hello,
> I want to develop a driver that exchanges/modifies data between 2
> devices. Now I try to find out whats the best way to do this. 
Maybe u should only make one driver :)
> I think there are 2 ways to do it, the first by doing all work inside
> the driver, and the secondy by passing the data from the driver to an
> userspace programm which handles and forwards the data to the second
> device. 
>
> Whats the fastest way to exchange data between the kernel and a
> userspace process and how fast is it?
The function get_user() and put_user() are used to get and put data in 
user space and from user space. Have a look at some books. But in ur 
case it's not a good idea.
> And on the other side, whats the best way to exchange data inside the
> kernel between 2 devices (which are handled by the same driver!).
Well, all the threads of the kernel runs in the same adress space. So 
from ur driver u can access all the data of the kernel (so of your 
running drivers). But don't forget to export your symbols on your drivers !
> Thanks for all replies!
>
> Bye Dan
Bye :) and i hope i've brought u some help :p
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