RE: vmalloc and kiobuf questions ?

[Nitin Dhingra]

1) Yeah, vmalloc can allocate memory till the
last available ram present in your machine.

2 & 3) You can use kiobuf for locking user memory
area. They are a part of kernel 2.4.x and also if 
you have previous 2.2.x find a patch. If you have
kernel 2.4.4 +, there is a file in source 
arch/cris/drivers/examples/kiobuftest.c that is doing 
exactly what you want. You can check it out. If you 
don't have it, I also made a module for locking user 
buffers using kiobuf, if you want I can mail you the src.

Regards,
Nitin

-----Original Message-----
From: Rajeev Bector [mailto:[e-mail]]
Sent: Wednesday, July 18, 2001 11:16 PM
To: [e-mail]
Subject: vmalloc and kiobuf questions ?

MM Gurus, 
  In trying to understand how to map driver
memory into user space memory, I have the following
questions:

1) Is there a limit to how much memory
   I can allocate using vmalloc() ?
   (This is regular RAM)
2) I want to map the vmalloc'ed memory
   to user space via mmap(). I've read
   that remap_page_range() will not do it
   and I have to do it using nopage
   handlers ? Is that true ? Is there
   a simple answer to why is that the case ?

3) I've also read the kiobufs will simplify
   all this. Is there a documentation on 
   kiobufs - what they can and cannot do ?
   Are kiobufs part of the standard kernel
   now ?
Thanks in advance for your answers !

Rajeev

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