write to mmaped buffer

Hi!
Maybe, stupid question, but...
I have DAC and like to output great amount of data. So, need to use mmap 
(?), cannot use mcopy functions (too slow).
Comedi uses vmalloc and remap_page_range. OK, I can get the mmaped buffer 
in user space. Can get some non-zero data in it, produced by driver's 
functions. When I'm trying to write  to that buffer, everything is OK, 
data appears in the buffer (from the 
user point of view; data is changed by the user: map[i]=b;, for example).
But in the driver (kernel space point of view) I see the same (unchanged) 
data in the buffer (dev->async->prealloc_buf), not user data.
I'm using mmap with PROT_[READ|WRITE] flags.

What is wrong in my work?

Thanx!

Received on 2004-08-23Z12:34:01