Hi all,

here come some improvements of the page walking API code.

First: make_pages_present() would do an infinite recursion, if
   used in find_extend_vma(). I fixed this. Might as well have
   caused the ntp crash, that has been observed. 
   So these make_pages_present parts are really important.

I also did the promised rewrite of make_pages_present() and its
users.

MM-Gurus: Please double check, that I always provide the right vma.

I also did two sample implementations (Kai and Doug, this is why
you are CC'ed) of the scatter list walking and removed ~100
lines of code while doing it.

Gerd: Your video-buf.[ch] is next on my list and I must coalesce 
   videobuf_pages_to_sg() and videobuf_init_user() to do it
   efficiently. May be you can come up with a better solution for
   this or are already working on sth. here. If not, I'll do it
   my way first and wait for your approval ;-)

That's all for now. I omitted the patches, to make 2.5.49-mm1
compile, as usual.

Patch against 2.5.49-mm1 attached.

diffstat of this patch:

 drivers/scsi/sg.c         |  102 +++++++++----------------------------------
 drivers/scsi/st.c         |  109 ++++++++--------------------------------------
 include/linux/mm.h        |    2 
 include/linux/page_walk.h |   13 +++--
 mm/mlock.c                |    2 
 mm/mmap.c                 |   11 ++--
 mm/mremap.c               |    4 -
 mm/page_walk.c            |   83 ++++++++++++++++++++++++-----------
 8 files changed, 119 insertions, 207 deletions

Regards

Ingo Oeser
-- 
Science is what we can tell a computer. Art is everything else. --- D.E.Knuth