Re: passing array from kernel space to user space

[taha hafeez <tawushafeez@xxxxxxxxx>]

On Mon, 2006-04-03 at 00:26 +0200, Vincenzo Mallozzi wrote:
> --- taha siddiqi <tawushafeez@xxxxxxxxx> wrote:
> 
> > Hi
> > 
> > Same answer, "please explain the situation !!"
> > 
> > taha
> > 
> > Thanks.
> 
> The array I want to pass from kernel space to user
> space contains pid_t elements.
> First, I pass the length of the array from user space
> to kernel space.
> Then, I build the array with the given length filling
> it with the pid of processes I need to monitor.
> Finally, I've to pass this array of pids to the user
> space.
> I hope I've well explained the situation.
> Thanks all.
> Vincenzo Mallozzi.
> 

Well, I think I get you now....

Correct me if I am wrong... 


            data buffer
USER_SPACE ------------>  KERNEL SPACE [fill data with pid_t]
      ^                       |
      |                       | 
      *------<----------------*
            data buffer

Why do we need to pass the data buffer to kernel ? 
Does it contain any information that kernel needs ?
if not, then that step can be avoided ?

Then you just need a read call implementation of 
struct file_operations {}.

taha




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